Toxicology, 70 (1991) 151-162 Elsevier Scientific Publishers Ireland Ltd.
151
Renal accumulation and urinary excretion of cisplatin in diabetic rats Monica A. Valentovic a, Laurie A. Scott a*, Elio Madan b and Robert A. Yokel c Depts. of "Pharmacology and hPathology, Marshall University School of Medicine, Huntington, WV and CDivision of Pharmacology and Toxicology, University of Kentucky College of Pharmacy, Lexington, K Y (U.S.A.) (Received December 27th, 1990; accepted August 5th, 1991)
Summary Previous work has demonstrated that cisplatin nephrotoxicity was attenuated in streptozotocin (STZ)induced diabetic rats. The following studies investigated the hypothesis that renal cisplatin accumulation was reduced in diabetic rats. Male Fischer 344 (F344) rats were injected with 32 mg/kg STZ (i.p.) or citrate buffer. Renal platinum (Pt) accumulation was quantitated 0 - 9 6 h after the administration of 5 mg/kg cisplatin (i.p.) to normoglycemic and diabetic rats (_>4/group). Total renal Pt accumulation was decreased (P < 0.05) in the diabetic rats, when compared to the normoglycemic group, 6-48 h after cisplatin injection. Further studies were also conducted to examine if urinary cisplatin excretion was enhanced in diabetic relative to normoglycemic groups. Urinary Pt excretion was quantitated 0 - 9 6 h following cisplatin (5 mg/kg, i.p.) administration. Pt excretion was increased in the diabetic group relative to the normoglycemics when comparisons were made on the basis of Pt excreted per hour or cumulative Pt excretion. Differences were also detected in urinary Pt concentration. The diabetic group had a lower urinary concentration of the metal 12-96 h after cisplatin injection. These findings suggest that the reduction in nephrotoxicity in diabetic rats may be at least partially due to decreased renal accumulation as well as altered renal excretion.
Key words. Cisplatin; Nephrotoxicity; Streptozotocin
Introduction Renal toxicity has been demonstrated in mice, dogs and rats [1,2] following acute administration of the cancer chemotherapeutic agent, cis-diamminedichloroplatinum (cisplatin). Nephrotoxicity has been characterized by alterations in glomerular filtration rate, decreased inulin clearance, decreased urine osmolality and increased sodium excretion [3-5]. Morphological examination in rats has indicated that the primary site of damage is the $3 segment of the proximal convoluted tubule [6]. Correspondence to." M. Valentovic, Dept. Pharmacology, Marshall University School of Medicine, 1542 Spring Valley Dr., Huntington, WV 25755-9310, U.S.A. *Present address." lvorydale Technical Center, Procter and Gamble Co., Cincinnati, OH, U.S.A. 0300-483 X/91/$03.50 © 1991 Elsevier Scientific Publishers Ireland Ltd. Printed and Published in Ireland
152
Structural changes include extensive tubular degeneration, loss of the brush border, tubular dilation and the presence of casts [2,7-8]. Previous work has shown that cisplatin nephrotoxicity was reduced in STZinduced diabetic rats [9]. Acute administration of cisplatin to normoglycemic rats produced a marked increase in blood urea nitrogen (BUN) levels, increased kidney weight, proteinuria, glucosuria and decreased renal cortical slice accumulation of organic ions. This was in contrast to cisplatin administration in the diabetic rats which failed to alter morphology and renal cortical slice accumulation of organic ions. Further studies by our laboratory have demonstrated that the resistance to cisplatin toxicity cannot be attributed to the polyuria associated with the diabetic state [10]. The purpose of the following studies was to examine the mechanism for reduced cisplatin toxicity in the diabetic rat. Experiments were first conducted to investigate if the mechanism for reduced toxicity would be attributed to decreased renal accumulation of the toxicant. The rationale for these studies was based on previous knowledge that the toxicity of some proximal tubular toxicants required accumulation of the toxic species [11-13]. Experiments were also conducted to examine if the mechanism for reduced toxicity could be attributed to enhanced cisplatin excretion in diabetic rats. These studies are very important in providing an initial foundation to elucidate the mechanism for reduced cisplatin toxicity in diabetic rats. Materials and methods
Chemicals The STZ, BUN reagents and glucose oxidase kits were obtained from Sigma Chemical (St. Louis, MO). Cis-diamminedichloroplatinum was a generous gift from Bristol-Myers Pharmaceutical Co. (Evansville, IN). All other chemicals were obtained from Fisher Scientific (Pittsburgh, PA) and were of analytical or spectrometric quality. Animals and induction of diabetes Male F344 rats (190-220 g) were obtained from Hilltop Laboratory Animals (Scottsdale, PA). Animals were housed at a constant ambient temperature (21-23°C) and were exposed to light from 06:00-18:00 h. All animals were given a minimum 5-day quarantine period prior to initiation of any experimental procedures. During the quarantine period, the animals had free access to food (Purina Rat Chow) and water. Diabetes was induced with a single injection of 32 mg/kg STZ (1 ml/kg; i.p.) freshly prepared in citrate-phosphate buffer (pH 4.6; 0.053 M). Normoglycemic rats received a single injection of citrate-phosphate buffer (1 ml/kg). Diabetes was confirmed by glucosuria in excess of 100 mg/dl using Diastix. All experiments described below were conducted in animals 14 days after STZ or citrate buffer vehicle injection. Renal accumulation studies Experiments were conducted to compare renal platinum (Pt) accumulation following a single injection of cisplatin. Measurement of renal Pt concentration has been
153 employed as an indication of cisplatin exposure and toxicity by many investigators [14,15]. Normoglycemic and diabetic rats (4-6/group) received 5 mg/kg cisplatin or water (4 ml/kg, i.p.). Animals were anesthetized with diethyl ether and laparotomized 6, 24, 48 and 96 h after cisplatin or vehicle administration. The kidney was decapsulated and placed in Teflon PFA screw cap containers (Savillex, Minnetonka, MN). Pt determinations were performed utilizing the entire kidney in order to obviate potential differences in dissecting the corticomedullary region between normoglycemic and diabetic kidneys. Pt levels were quantitated as outlined below. Serum was separated and stored at -20°C until assayed for BUN and glucose levels.
Urinary Pt excretion A series of experiments were conducted to compare urinary cisplatin excretion between normoglycemic and diabetic rats following acute administration. Animals were individually housed in stainless steel metabolism cages for a 48 h acclimation period. The rats were injected (4-8/group) with 5 mg/kg cisplatin (i.p.) (4 ml/kg). Urine samples were collected 3, 6, 12, 24, 48, 72 and 96 h after cisplatin or vehicle injection. Urinary Pt levels were quantitated as outlined below. BUN and serum glucose determination BUN levels were quantitated using a urease (Sigma, #640) assay. Serum glucose was measured using a glucose oxidase spectrophotometric assay (Sigma, #510). Histological Preparations The right kidney was cut into quarters and fixed in 10"/,, neutral buffered formalin solution. Fixed tissues were paraffin embedded, sectioned at a maximal thickness of 6~m and stained with hematoxylin and eosin (H&E). Determination of Pt Tissue and urine samples were treated according to the following methods in order to optimize measurement of Pt. The kidneys were dried overnight at 70°C to a constant weight and then digested in 0.5 ml of an acid mixture. The composition of the acid mixture (in ml) was: 392 nitric: 98 perchloric: 10 sulfuric acid. The digested tissues were dried for 24 h at 100°C followed by 96 h at 160°C. The residue was finally diluted in 0.2% nitric acid. Preparation of the urine samples required a simple dilution in 0.2% nitric acid. Pt levels were quantitated using a Perkin-EImer 460 atomic absorption (AA) spectrophotometer equipped with a H G A 500 graphite furnace and programmer. Pt determinations were performed using a charring procedure described by Oster [16] with a modification to maximize sample linearity. The specific instrument conditions are listed in Table I. The absorption wavelength was 306.5 nm. Daily Pt standards were obtained by diluting a Pt standard (Aldrich Chemical 20,736-5). Statistical Analysis All data were expressed as mean ± S.E. and all groups contained a minimum of 4 different animals. Differences between groups were assessed using an unpaired student's t-test or an analysis of variance (ANOVA) followed by a Newman-Keuls test
154
TABLE 1 AA INSTRUMENTCONDITIONSFOR Pt DETERMINATION~' Step
Temperature (°C)
Ramp time (s)
Hold time (sl
Dry Dry Char Atomize
100 140 1500 2700
10 10 40 I
10 10 5 7
aSettings are for a Perkin-Elmer 460 AA with a HGA 500 graphite furnace.
at a 95% confidence interval. Differences within groups were quantitated using an ANOVA followed by a Dunnett's test. Results
Cisplatin toxicity Nephrotoxicity was reduced in the diabetic group 96 h after cisplatin injection. Comparisons of treated, relative to pair-fed controls indicated BUN concentration was more markedly increased in the normoglycemic group than in the diabetic rats 96 h after cisplatin injection (Table I1). Tubular necrosis, casts and nuclear lysis were evident in the cisplatin-treated normoglycemic group compared to pair-fed controls (Fig. 1A,B). Morphological changes were not observed between diabetic animals treated with vehicle (Fig. 1C) or cisplatin (Fig. 1D). The diabetic group was not totally resistant to cisplatin since kidney weight was increased in normoglycemic as well as in diabetic rats (Table II).
Renal Pt accumulation Pt levels in the vehicle-treated groups were below 0.6/~g/g wet tissue at all time points. Renal Pt accumulation (/~g/g kidney per kg body wt) was diminished in the diabetic group relative to the normoglycemic animals for the first 48 h after cisplatin administration (Fig. 2). Comparable tissue levels were detected within 96 h after cisplatin injection between the normoglycemic and diabetic groups.
Urinary Pt excretion Urinary excretion was expressed as the rate of Pt excreted per kg body wt per h during designated time periods. Values were expressed in this manner in order to reduce variability in data due to differences in urine output and body weight between normoglycemic and diabetic rats. Cisplatin administration produced a rapid increase in Pt excretion in normoglycemic and diabetic animals. Urinary Pt excretion rate was greater (P < 0.05) in the diabetic group for 48 h after cisplatin injection (Table lll). Comparisons were also made of the total amount of Pt excreted as a function of time between the normoglycemic and diabetic groups. Total Pt excretion was also increased in the diabetics (Table III) following a single injection of cisplatin relative to the normoglycemic animals. Comparisons were also made of urinary Pt concen-
155 TABLE 1! EFFECT OF CISPLATIN ON BUN LEVELS AND KIDNEY WEIGHT Time (h) post injection
Cisplatin
Vehicle
Normoglycemic
Diabetic
Normoglycemic
Diabetic
263 241 232 226
208 205 193 188
261 250 238 238
229 214 210 202
Body weight (g) 0 24 48 96
4± 44-
3a 3 3* 2*
± + ± 4-
8 9 11 14
± a: ± ±
2 2 2 5
4± ± 4-
2 5 2 4
BUN (mg/dl) 24 48 96
33 4- 6 51 4- 11' 144 ± 11"
29 4- 8 34 4- 13 46 ± 9*
25 ± 2 18 ± I 15 4- 1
32 ± 3 28 ± 1 16 ± 1
Kidney weight (g/lO0 g body wt) 6 24 48 96
0.36 0.37 0.39 0.46
± 4± ±
O.Ol 0.01 0.02* 0.01"*
0.47 0.49 0.49 0,55
+ ± ± +
0.01 0.01 O.OI 0.02*
0.34 4- 0.01 b
0.50 4- 0.01 b
aValues represent mean 4- S.E. for 4 - 6 different rats per group at the designated time periods. Animals were treated with a single 5 mg/kg dose of cisplatin or vehicle. bpooled values for all vehicle-treated rats. *Statistically different at a level of P < 0.05 from respective vehicle-treated group. **Statistically different at a level of P < 0.01 from respective vehicle-treated group.
t r a t i o n b e t w e e n n o r m o g l y c e m i c a n d d i a b e t i c rats. T h e P t c o n c e n t r a t i o n w a s c o m p a r e d s i n c e t h e d i a b e t i c s t a t e w a s a s s o c i a t e d w i t h a m a r k e d i n c r e a s e in u r i n e o u t p u t . T h e u r i n a r y c o n c e n t r a t i o n o f P t w a s l o w e r in t h e d i a b e t i c g r o u p c o m p a r e d t o t h e n o r m o g l y c e m i c g r o u p (Fig. 3).
Discussion S t u d i e s e x a m i n i n g r e n a l c i s p l a t i n d i s t r i b u t i o n h a v e d e t e c t e d m a x i m a l P t levels in t h e c o r t i c o m e d u l l a r y r e g i o n w i t h l o w e r c o n c e n t r a t i o n s in t h e o u t e r c o r t e x a n d m e d u l l a [7]. M o r p h o l o g i c e x a m i n a t i o n h a s c o n f i r m e d t h a t t h e p r i m a r y site o f c i s p l a t i n t o x i c i t y w a s t h e c o r t i c o m e d u l l a r y r e g i o n [2,7]. T h e f i n d i n g s in t h i s p a p e r s u g g e s t t h a t t h e r e d u c e d c i s p l a t i n n e p h r o t o x i c i t y in d i a b e t i c r a t s c a n b e p a r t i a l l y attributed to decreased renal accumulation of the toxicant. D i m i n i s h e d r e n a l a c c u m u l a t i o n w a s s u g g e s t e d as p a r t o f t h e m e c h a n i s m f o r att e n u a t i o n o f o t h e r p r o x i m a l t u b u l a r t o x i n s in d i a b e t i c rats. T h e d a m a g e i n d u c e d b y g e n t a m i c i n [17] w a s d i m i n i s h e d in d i a b e t i c r e l a t i v e t o n o r m o g l y c e m i c rats. S t u d i e s examining the distribution and handling of gentamicin demonstrated that the diabetic s t a t e w a s a s s o c i a t e d w i t h d i m i n i s h e d r e n a l g e n t a m i c i n a c c u m u l a t i o n [18,19]. Micropuncture
s t u d i e s h a v e a l s o q u a n t i t a t e d a s l o w e r u p t a k e r a t e f o r n e t i l m i c i n in
56
Fig. 1. Morphological changes associated with cisplatin in normoglycemic and diabetic rats. Renal tissue was examined 96 h after administration of 5 mg/kg cisplatin (i.p.). Normoglycemic rats treated with vehicle exhibited normal morphology (1A). Cisplatin administration ( l B) produced proximal tubular necrosis in the normoglycemic rats. Morphological alterations were not observed in diabetic rats treated with vehicle (IC) or cisplatin (ID). Tissues were stained with H&E and magnification was 100 x .
157
158
[-----7 NC
240 ~0
m
200
DC
5_ 160 "0 *r-~ 2-~
120
~0 ~0
80
.~o O~
40
6
24
48
96
T i m e (h) Fig. 2. Renal Pt accumulation. Renal Pt accumulation was quantitated 0 - 9 6 h after cisplatin (5 mg/kg) administration. Accumulation was expressed as/~g Pt/g kidney per kg body wt. Groups were designated as normoglycemic (NC) and diabetic (DC) rats treated with cisplatin. Values represent mean a: S.E. with each group containing a minimum of 4 rats. (*) Values were statistically different (P < 0.05) from the normoglycemic group treated with cisplatin.
diabetic rats [20]. Studies by other investigators [21] have indicated that the mechanism for reduced gentamicin accumulation may be attributed to differences in phospholipid composition in the diabetic group. These findings would suggest that STZ-diabetes was associated with a defect in proximal tubular uptake of some nephrotoxicants. Additional studies are needed to establish the specific cellular mechanism for reduced renal cisplatin accumulation in diabetic rats. One possible theory for reduced accumulation is an impairment in cellular uptake processes. An alternate explanation for reduced renal accumulation would be redistribution of cisplatin to other organs. Decreased renal cisplatin accumulation could be due to higher accumulation in other organs in the diabetic rat. A reduction in renal toxicity may also be attributed to differences in renal excretion between normoglycemic and diabetic animals. The diabetic group had a tendency toward increased renal Pt excretion during the first 48 h after cisplatin injection (Table IlI). Cisplatin primarily undergoes renal excretion and nearly 50% of the drug appears in the urine in the first 24 h [14,22]. The increase in renal excretion would be expected to account for a shorter duration of exposure to the toxicant which would reduce toxicity.
159 TABLE III COMPARISON OF URINARY Pt EXCRETION BETWEEN NORMOGLYCEMIC AND DIABETIC RATS Time (h)
Normoglycemic
Pt excretion (#g/h per kg)a 0-3 3-6 6-12 12-24 24-48 48-72 72-96
188.1 5.6 11.5 12.2 14.3 15.3 6.3
4444444-
2.5 2.1 0.8 0.2 0.4 0.5 0.1
Total Pt excreted (l~g/kg)b 0-3 3-6 6-12 12-24 24-48 48-72 72-96
516.3 529.6 591.4 789.0 1229.2 1629.1 1860.4
± ± ± 44± 4-
4.9 5.5 5.6 10.4 18.4 16.0 9.7
Diabetic 216.2 21.4 20.3 21.0 29.9 6.0 14.0
581.2 637.3 746.2 1036.4 1706.8 1908.0 2249.0
4444444-
9.1' 0.9* 1.9 1.0' 1.9" 4.2 1.0"
-4- 7.4* ± 6.8* -4- 9.5* -4- 20.9* 4- 11.3' 4- 31.1' 4- 42.2*
apt levels were quantitated in urine collected during the designated time periods and were expressed as #g Pt excreted per h per kg body wt. Values were expressed as the mean + S.E. with n >_ 4 different animals. bCumulative urinary Pt excretion was expressed as total Pt excreted per kg body wt at each designated time period. *Statistically different (P < 0.05) from normoglycemic group.
A m a r k e d d i f f e r e n c e in u r i n a r y Pt c o n c e n t r a t i o n s was m e a s u r e d b e t w e e n n o r m o g l y c e m i c a n d d i a b e t i c rats. T h e s i g n i f i c a n c e o f l o w e r l u m i n a l Pt c o n c e n t r a t i o n o n p r o x i m a l t u b u l a r t o x i c i t y has n o t b e e n e s t a b l i s h e d since v e r y little i n f o r m a t i o n is a v a i l a b l e r e g a r d i n g p e r i t u b u l a r u p t a k e o f cisplatin. S t u d i e s c o n d u c t e d by F i e l d et al. [23] w o u l d i n d i c a t e c i s p l a t i n d o e s elicit a n effect o n b r u s h b o r d e r m e m b r a n e s since p r o x i m a l t u b u l a r r e a b s o r p t i o n o f s o d i u m was d e c r e a s e d by cisplatin. O t h e r i n d i r e c t e v i d e n c e w o u l d also suggest t h a t l u m i n a l c i s p l a t i n c o n c e n t r a t i o n m a y be r e l a t e d to c y t o t o x i c i t y . M a n n i t o l diuresis o r p r e h y d r a t i o n are c o m m o n adj u n c t s to the clinical a p p l i c a t i o n o f c i s p l a t i n [24]. M a n n i t o l diuresis has been r e p o r t e d to also p r o d u c e a slight r e d u c t i o n in c i s p l a t i n t o x i c i t y in a n i m a l s since B U N levels are less m a r k e d l y increased. M a n n i t o l p r e t r e a t m e n t , h o w e v e r , was n o t successful in t o t a l l y p r o t e c t i n g a g a i n s t renal d a m a g e since m o r p h o l o g i c a l c h a n g e s w e r e still e v i d e n t [25]. P h a r m a c o k i n e t i c studies [26] h a v e s h o w n m a n n i t o l diuresis in d o g s was ineffective in e n h a n c i n g u r i n a r y Pt e x c r e t i o n o r d e c r e a s i n g s e r u m e l i m i n a t i o n half-life b u t was successful in r e d u c i n g the u r i n a r y c o n c e n t r a t i o n o f Pt. D e c r e a s e d u r i n a r y Pt c o n c e n t r a t i o n w o u l d be e x p e c t e d to a t t e n u a t e t o x i c i t y if u p t a k e c a n o c c u r a l o n g the
160
60 50
f
1 NC
I
DC
40 v
a., .¢
Z
30 20 10
3
6
12
24
48
72
96
TIME (h) Fig. 3. Urinary Pt concentration following cisplatin administration. The urinary Pt concentration was quantitated 0-96 h after injection of 5 mg/kg cisplatin and expressed as ~g/ml. Groups were designated as cisplatin-treated normoglycemic (NC) and diabetic (DC) rats. Values represent mean + S.E. with each group containing a minimum of 4 rats. (*) Values were lower (P < 0.05) than the normoglycemic group treated with cisplatin.
p e r i t u b u l a r side o f the cell. The results o f Safirstein et al. [27] would suggest that p e r i t u b u l a r c o n c e n t r a t i o n was not i m p o r t a n t . The investigators had observed insignificant r e a b s o r p t i o n following i n t r a t u b u l a r microinjection o f an inorganic Pt salt. F u r t h e r studies are needed to examine p e r i t u b u l a r a b s o r p t i o n since the a b o v e study administered an inorganic Pt salt which w o u l d have very different physiochemical characteristics from cisplatin and its metabolites. Previous w o r k has d e m o n s t r a t e d that cisplatin n e p h r o t o x i c i t y was a t t e n u a t e d in diabetic rats. The m e c h a n i s m for reduced cisplatin toxicity in diabetic rats can be at least partially a t t r i b u t e d to decreased renal a c c u m u l a t i o n and increased renal excretion o f the toxicant. The diabetic state was also associated with a decrease in urinary Pt c o n c e n t r a t i o n relative to the n o r m o g l y c e m i c animals. F u r t h e r experiments are needed to establish the c o n t r i b u t i o n o f luminal Pt c o n c e n t r a t i o n to renal cytotoxicity.
Acknowledgment The a u t h o r s a p p r e c i a t e the generous d o n a t i o n o f cisplatin by the Bristol Myers Pharmaceutical C o m p a n y . The expert technical assistance o f Elda Jackson is greatly appreciated. This w o r k was s u p p o r t e d by N I H G r a n t RR05870.
161
References 1 2 3 4
5
6 7 8 9 10
11 12
13 14
15
16 17
18
19
20
21
N.E. Madias and J.T. Harrington, Platinum nephrotoxicity. Am. J. Med. 65 (1978) 307. J.M. Ward and K.A. Fauvie, The nephrotoxicity of cis-diamminedichloroplatinum (ll) (NSC-119875) in male F344 rats. Toxicol. Appl. Pharmacol. 38 (1976) 535. J.A. Winston and R. Safirstein, Reduced blood flow in early cisplatin-induced acute renal failure in the rat. Am. J. Physiol., 249 (1985) F490. R.S. Goldstein, B. Noordwier, J.T. Bond, J.B. Hook and G.H. Mayor, (-Ts-dichlorodiammineplatinum nephrotoxicity: time course and dose response of renal functional impairment. Toxicol. Appl. Pharmacol., 60 (1981) 165. G. Daugaard, U. Abildgaard, S. Larsen, N.-H. Holstein-Rathlou, O. Amtrop, H.P. Olesen and P.P. Leyssac, Functional and histopathological changes in dog kidneys after administration of cisplatin. Renal Physiol., 10 (1987) 54. D.C. Dobyan, J. Levi, C. Jacobs, J. Kosek and M.W. Weiner, Mechanisms of cisplatinum nephrotoxicity: 11. Morphologic observations. J. Pharmacol. Exp. Ther., 213 (1980) 551. D.D. Choie, D.S. Longnecker and A.A. Del Campo, Acute and chronic cisplatin ncphrotoxicity in rats. Lab. Invest., 44 (1981) 397. R. Safirstein, P. Miller, S. Dikman, N. Lyman and C. Shapiro, Cisplatin ncphrotoxicity in rats: defect in papillary hypertonicity. Am. J. Physiol., 241 (1981) F175. L.A. Scott, E. Madan and M.A. Valentovic, Attenuation of cisplatin nephrotoxicity by streptozotocin-induced diabetes. Fundam. Appl. Toxicol., 12 (1989) 530. L.A. Scott, E. Madan and M.A. Valentovic, Influence of streptozotocin (STZ)-induccd diabetes, dextrose diuresis and acetone on cisplatin nephrotoxicity in Fischer 344 (F344) rats. Toxicology, 60 (1990) 109. B. Tune, Relationship between the transport and toxicity of cephalosporins in the kidney. J. Infect. Dis., t32 (1975) 189. G.P. Datson, B.F. Rehnberg, L.L. Hall and R.J. Kavlock, Toxicity of mercuric chloride to the developing rat kidney. 111. Distribution and elimination of mercury during postnatal maturation. Toxicol. Appl. Pharmacol., 85 (1986) 39. G.L. Diamond, J.J. Cohen and S.J. Weinstein, Rcnal handling of cadmium in perfused rat kidney and effects on renal function and tissue composition. Am. J. Physiol., 251 (1986) F784. C.L. Litterest, l.J. Torres and A.M. Guarino, Plasma levels and organ distribution of Pt in the rat, dog and dogfish shark following single intravenous administration of cis-dichlorodiammineplatinum (II). J. Clin. Hematol. Oncol., 7 (1977) 169. J.H. Smith, M.A. Smith, C.L. Litterst, M.P. Copley, J Uozumi and M.R. Boyd, Comparative toxicity and renal distribution of the platinum analogs tetraplatin, CHIP and cisplatin at equimolar doses in the F344 rat. Fundam. Appl. Toxicol., 10 (1988) 45. O. Oster, The aluminum content of h u m a n serum determined by atomic absorption spectroscopy with a graphite furnace. Clin. Chim. Acta, 114 (1981) 53. C.A. Vaamonde, R.T. Bier, W. Gouvea, H. Alpert, J. Kelley and V. Pardo, Effect of duration of diabetes on the protection observed in the diabetic rat against gentamicin-induced acute renal failure, Miner. Electrolyte Metab., 10 (1984) 209. W.C. Elliott, D.C. Houghton, D.N. Gilbert, J. Baines-Hunter and W.M. Bennett, Experimental gentamicin nephrotoxicity: effect of Streptozotocin-induced diabetes. J. Pharmacol. Exp. Ther., 233 (1985) 264. V.M. Pattyn, G.A. Verpooten, R.A. Giuliano, F. Zheng and M.E. De Broe, Effect ofhyperfiltration, proteinuria and diabetes mellitus on the uptake of kinetics of gentamicin in the kidney cortex of rats. J. Pharmacol. Exp. Then, 244 (1985) 694. E. Pastoriza-Munoz, C. Josepovitz, L. R a m s a m m y and G.J. Kaloyanides, Renal handling of netilmicin in the rat with Streptozotocin-induced diabctes mcllitus. J. Pharmacol. Exp. Ther., 241 (1987) 166. G.J. Kaloyanides, M. Wang, W. Govea, J. Kelly, H. Alpert and C.A. Vaamonde, Altered phosphatidylinositol metabolism in diabetic rats confers resistance to genatmicin induced acute renal failure. Kidney Int., 21 (1982) 219A.
162 22
23 24 25
26
27
C.L. Litterest, T.E. Gram, R.L. Dedrick, A.F. Leroy and A.M. Guarino, Distribution and disposition of platinum following intravenous administration of cis-diamminedichloroplatinum (ll) (NSC-119875) to dogs. Cancer Res., 36 (1976) 2340. M.J. Field, T.E. Bostrom, A.Z. Gyory and D.J. Cockayne, Acute cisplatin nephrotoxicity in the rat. Evidence for impaired entry of sodium into proximal tubular cells. Pfluegers Arch., 414 (1989) 647. D,M. Hayes, E. Cvitkovic, R.B. Golby, E. Scheiner, L. Helson and 1.H. Krakoff, High dose cisplatinum diamminedichloride. Cancer, 39 (1977) 1372. M.F. Pera, B.C. Zook and H.C. Harder, Effects of mannitol or furosemide diuresis on the nephrotoxicity and physiological disposition of cis-dichlorodiammineplatinum (ll) in rats. Cancer Res., 39 (1979) 1269. E. Cvitkovic, J. Spaulding, V. Bethune, J. Martin and W.F. Whitmore, Improvement of cisdichlorodiammineplatinum (NSC-119875): therapeutic index in an animal model. Cancer, 39 (1977) 1357. R, Safirstein, J. Winston, D. Moel, S. Dikman and J. Guttenplan, Cisplatin nephrotoxicity: insights into mechanism. Int. J. Androl., 10 (1987) 325.
151
Renal accumulation and urinary excretion of cisplatin in diabetic rats Monica A. Valentovic a, Laurie A. Scott a*, Elio Madan b and Robert A. Yokel c Depts. of "Pharmacology and hPathology, Marshall University School of Medicine, Huntington, WV and CDivision of Pharmacology and Toxicology, University of Kentucky College of Pharmacy, Lexington, K Y (U.S.A.) (Received December 27th, 1990; accepted August 5th, 1991)
Summary Previous work has demonstrated that cisplatin nephrotoxicity was attenuated in streptozotocin (STZ)induced diabetic rats. The following studies investigated the hypothesis that renal cisplatin accumulation was reduced in diabetic rats. Male Fischer 344 (F344) rats were injected with 32 mg/kg STZ (i.p.) or citrate buffer. Renal platinum (Pt) accumulation was quantitated 0 - 9 6 h after the administration of 5 mg/kg cisplatin (i.p.) to normoglycemic and diabetic rats (_>4/group). Total renal Pt accumulation was decreased (P < 0.05) in the diabetic rats, when compared to the normoglycemic group, 6-48 h after cisplatin injection. Further studies were also conducted to examine if urinary cisplatin excretion was enhanced in diabetic relative to normoglycemic groups. Urinary Pt excretion was quantitated 0 - 9 6 h following cisplatin (5 mg/kg, i.p.) administration. Pt excretion was increased in the diabetic group relative to the normoglycemics when comparisons were made on the basis of Pt excreted per hour or cumulative Pt excretion. Differences were also detected in urinary Pt concentration. The diabetic group had a lower urinary concentration of the metal 12-96 h after cisplatin injection. These findings suggest that the reduction in nephrotoxicity in diabetic rats may be at least partially due to decreased renal accumulation as well as altered renal excretion.
Key words. Cisplatin; Nephrotoxicity; Streptozotocin
Introduction Renal toxicity has been demonstrated in mice, dogs and rats [1,2] following acute administration of the cancer chemotherapeutic agent, cis-diamminedichloroplatinum (cisplatin). Nephrotoxicity has been characterized by alterations in glomerular filtration rate, decreased inulin clearance, decreased urine osmolality and increased sodium excretion [3-5]. Morphological examination in rats has indicated that the primary site of damage is the $3 segment of the proximal convoluted tubule [6]. Correspondence to." M. Valentovic, Dept. Pharmacology, Marshall University School of Medicine, 1542 Spring Valley Dr., Huntington, WV 25755-9310, U.S.A. *Present address." lvorydale Technical Center, Procter and Gamble Co., Cincinnati, OH, U.S.A. 0300-483 X/91/$03.50 © 1991 Elsevier Scientific Publishers Ireland Ltd. Printed and Published in Ireland
152
Structural changes include extensive tubular degeneration, loss of the brush border, tubular dilation and the presence of casts [2,7-8]. Previous work has shown that cisplatin nephrotoxicity was reduced in STZinduced diabetic rats [9]. Acute administration of cisplatin to normoglycemic rats produced a marked increase in blood urea nitrogen (BUN) levels, increased kidney weight, proteinuria, glucosuria and decreased renal cortical slice accumulation of organic ions. This was in contrast to cisplatin administration in the diabetic rats which failed to alter morphology and renal cortical slice accumulation of organic ions. Further studies by our laboratory have demonstrated that the resistance to cisplatin toxicity cannot be attributed to the polyuria associated with the diabetic state [10]. The purpose of the following studies was to examine the mechanism for reduced cisplatin toxicity in the diabetic rat. Experiments were first conducted to investigate if the mechanism for reduced toxicity would be attributed to decreased renal accumulation of the toxicant. The rationale for these studies was based on previous knowledge that the toxicity of some proximal tubular toxicants required accumulation of the toxic species [11-13]. Experiments were also conducted to examine if the mechanism for reduced toxicity could be attributed to enhanced cisplatin excretion in diabetic rats. These studies are very important in providing an initial foundation to elucidate the mechanism for reduced cisplatin toxicity in diabetic rats. Materials and methods
Chemicals The STZ, BUN reagents and glucose oxidase kits were obtained from Sigma Chemical (St. Louis, MO). Cis-diamminedichloroplatinum was a generous gift from Bristol-Myers Pharmaceutical Co. (Evansville, IN). All other chemicals were obtained from Fisher Scientific (Pittsburgh, PA) and were of analytical or spectrometric quality. Animals and induction of diabetes Male F344 rats (190-220 g) were obtained from Hilltop Laboratory Animals (Scottsdale, PA). Animals were housed at a constant ambient temperature (21-23°C) and were exposed to light from 06:00-18:00 h. All animals were given a minimum 5-day quarantine period prior to initiation of any experimental procedures. During the quarantine period, the animals had free access to food (Purina Rat Chow) and water. Diabetes was induced with a single injection of 32 mg/kg STZ (1 ml/kg; i.p.) freshly prepared in citrate-phosphate buffer (pH 4.6; 0.053 M). Normoglycemic rats received a single injection of citrate-phosphate buffer (1 ml/kg). Diabetes was confirmed by glucosuria in excess of 100 mg/dl using Diastix. All experiments described below were conducted in animals 14 days after STZ or citrate buffer vehicle injection. Renal accumulation studies Experiments were conducted to compare renal platinum (Pt) accumulation following a single injection of cisplatin. Measurement of renal Pt concentration has been
153 employed as an indication of cisplatin exposure and toxicity by many investigators [14,15]. Normoglycemic and diabetic rats (4-6/group) received 5 mg/kg cisplatin or water (4 ml/kg, i.p.). Animals were anesthetized with diethyl ether and laparotomized 6, 24, 48 and 96 h after cisplatin or vehicle administration. The kidney was decapsulated and placed in Teflon PFA screw cap containers (Savillex, Minnetonka, MN). Pt determinations were performed utilizing the entire kidney in order to obviate potential differences in dissecting the corticomedullary region between normoglycemic and diabetic kidneys. Pt levels were quantitated as outlined below. Serum was separated and stored at -20°C until assayed for BUN and glucose levels.
Urinary Pt excretion A series of experiments were conducted to compare urinary cisplatin excretion between normoglycemic and diabetic rats following acute administration. Animals were individually housed in stainless steel metabolism cages for a 48 h acclimation period. The rats were injected (4-8/group) with 5 mg/kg cisplatin (i.p.) (4 ml/kg). Urine samples were collected 3, 6, 12, 24, 48, 72 and 96 h after cisplatin or vehicle injection. Urinary Pt levels were quantitated as outlined below. BUN and serum glucose determination BUN levels were quantitated using a urease (Sigma, #640) assay. Serum glucose was measured using a glucose oxidase spectrophotometric assay (Sigma, #510). Histological Preparations The right kidney was cut into quarters and fixed in 10"/,, neutral buffered formalin solution. Fixed tissues were paraffin embedded, sectioned at a maximal thickness of 6~m and stained with hematoxylin and eosin (H&E). Determination of Pt Tissue and urine samples were treated according to the following methods in order to optimize measurement of Pt. The kidneys were dried overnight at 70°C to a constant weight and then digested in 0.5 ml of an acid mixture. The composition of the acid mixture (in ml) was: 392 nitric: 98 perchloric: 10 sulfuric acid. The digested tissues were dried for 24 h at 100°C followed by 96 h at 160°C. The residue was finally diluted in 0.2% nitric acid. Preparation of the urine samples required a simple dilution in 0.2% nitric acid. Pt levels were quantitated using a Perkin-EImer 460 atomic absorption (AA) spectrophotometer equipped with a H G A 500 graphite furnace and programmer. Pt determinations were performed using a charring procedure described by Oster [16] with a modification to maximize sample linearity. The specific instrument conditions are listed in Table I. The absorption wavelength was 306.5 nm. Daily Pt standards were obtained by diluting a Pt standard (Aldrich Chemical 20,736-5). Statistical Analysis All data were expressed as mean ± S.E. and all groups contained a minimum of 4 different animals. Differences between groups were assessed using an unpaired student's t-test or an analysis of variance (ANOVA) followed by a Newman-Keuls test
154
TABLE 1 AA INSTRUMENTCONDITIONSFOR Pt DETERMINATION~' Step
Temperature (°C)
Ramp time (s)
Hold time (sl
Dry Dry Char Atomize
100 140 1500 2700
10 10 40 I
10 10 5 7
aSettings are for a Perkin-Elmer 460 AA with a HGA 500 graphite furnace.
at a 95% confidence interval. Differences within groups were quantitated using an ANOVA followed by a Dunnett's test. Results
Cisplatin toxicity Nephrotoxicity was reduced in the diabetic group 96 h after cisplatin injection. Comparisons of treated, relative to pair-fed controls indicated BUN concentration was more markedly increased in the normoglycemic group than in the diabetic rats 96 h after cisplatin injection (Table I1). Tubular necrosis, casts and nuclear lysis were evident in the cisplatin-treated normoglycemic group compared to pair-fed controls (Fig. 1A,B). Morphological changes were not observed between diabetic animals treated with vehicle (Fig. 1C) or cisplatin (Fig. 1D). The diabetic group was not totally resistant to cisplatin since kidney weight was increased in normoglycemic as well as in diabetic rats (Table II).
Renal Pt accumulation Pt levels in the vehicle-treated groups were below 0.6/~g/g wet tissue at all time points. Renal Pt accumulation (/~g/g kidney per kg body wt) was diminished in the diabetic group relative to the normoglycemic animals for the first 48 h after cisplatin administration (Fig. 2). Comparable tissue levels were detected within 96 h after cisplatin injection between the normoglycemic and diabetic groups.
Urinary Pt excretion Urinary excretion was expressed as the rate of Pt excreted per kg body wt per h during designated time periods. Values were expressed in this manner in order to reduce variability in data due to differences in urine output and body weight between normoglycemic and diabetic rats. Cisplatin administration produced a rapid increase in Pt excretion in normoglycemic and diabetic animals. Urinary Pt excretion rate was greater (P < 0.05) in the diabetic group for 48 h after cisplatin injection (Table lll). Comparisons were also made of the total amount of Pt excreted as a function of time between the normoglycemic and diabetic groups. Total Pt excretion was also increased in the diabetics (Table III) following a single injection of cisplatin relative to the normoglycemic animals. Comparisons were also made of urinary Pt concen-
155 TABLE 1! EFFECT OF CISPLATIN ON BUN LEVELS AND KIDNEY WEIGHT Time (h) post injection
Cisplatin
Vehicle
Normoglycemic
Diabetic
Normoglycemic
Diabetic
263 241 232 226
208 205 193 188
261 250 238 238
229 214 210 202
Body weight (g) 0 24 48 96
4± 44-
3a 3 3* 2*
± + ± 4-
8 9 11 14
± a: ± ±
2 2 2 5
4± ± 4-
2 5 2 4
BUN (mg/dl) 24 48 96
33 4- 6 51 4- 11' 144 ± 11"
29 4- 8 34 4- 13 46 ± 9*
25 ± 2 18 ± I 15 4- 1
32 ± 3 28 ± 1 16 ± 1
Kidney weight (g/lO0 g body wt) 6 24 48 96
0.36 0.37 0.39 0.46
± 4± ±
O.Ol 0.01 0.02* 0.01"*
0.47 0.49 0.49 0,55
+ ± ± +
0.01 0.01 O.OI 0.02*
0.34 4- 0.01 b
0.50 4- 0.01 b
aValues represent mean 4- S.E. for 4 - 6 different rats per group at the designated time periods. Animals were treated with a single 5 mg/kg dose of cisplatin or vehicle. bpooled values for all vehicle-treated rats. *Statistically different at a level of P < 0.05 from respective vehicle-treated group. **Statistically different at a level of P < 0.01 from respective vehicle-treated group.
t r a t i o n b e t w e e n n o r m o g l y c e m i c a n d d i a b e t i c rats. T h e P t c o n c e n t r a t i o n w a s c o m p a r e d s i n c e t h e d i a b e t i c s t a t e w a s a s s o c i a t e d w i t h a m a r k e d i n c r e a s e in u r i n e o u t p u t . T h e u r i n a r y c o n c e n t r a t i o n o f P t w a s l o w e r in t h e d i a b e t i c g r o u p c o m p a r e d t o t h e n o r m o g l y c e m i c g r o u p (Fig. 3).
Discussion S t u d i e s e x a m i n i n g r e n a l c i s p l a t i n d i s t r i b u t i o n h a v e d e t e c t e d m a x i m a l P t levels in t h e c o r t i c o m e d u l l a r y r e g i o n w i t h l o w e r c o n c e n t r a t i o n s in t h e o u t e r c o r t e x a n d m e d u l l a [7]. M o r p h o l o g i c e x a m i n a t i o n h a s c o n f i r m e d t h a t t h e p r i m a r y site o f c i s p l a t i n t o x i c i t y w a s t h e c o r t i c o m e d u l l a r y r e g i o n [2,7]. T h e f i n d i n g s in t h i s p a p e r s u g g e s t t h a t t h e r e d u c e d c i s p l a t i n n e p h r o t o x i c i t y in d i a b e t i c r a t s c a n b e p a r t i a l l y attributed to decreased renal accumulation of the toxicant. D i m i n i s h e d r e n a l a c c u m u l a t i o n w a s s u g g e s t e d as p a r t o f t h e m e c h a n i s m f o r att e n u a t i o n o f o t h e r p r o x i m a l t u b u l a r t o x i n s in d i a b e t i c rats. T h e d a m a g e i n d u c e d b y g e n t a m i c i n [17] w a s d i m i n i s h e d in d i a b e t i c r e l a t i v e t o n o r m o g l y c e m i c rats. S t u d i e s examining the distribution and handling of gentamicin demonstrated that the diabetic s t a t e w a s a s s o c i a t e d w i t h d i m i n i s h e d r e n a l g e n t a m i c i n a c c u m u l a t i o n [18,19]. Micropuncture
s t u d i e s h a v e a l s o q u a n t i t a t e d a s l o w e r u p t a k e r a t e f o r n e t i l m i c i n in
56
Fig. 1. Morphological changes associated with cisplatin in normoglycemic and diabetic rats. Renal tissue was examined 96 h after administration of 5 mg/kg cisplatin (i.p.). Normoglycemic rats treated with vehicle exhibited normal morphology (1A). Cisplatin administration ( l B) produced proximal tubular necrosis in the normoglycemic rats. Morphological alterations were not observed in diabetic rats treated with vehicle (IC) or cisplatin (ID). Tissues were stained with H&E and magnification was 100 x .
157
158
[-----7 NC
240 ~0
m
200
DC
5_ 160 "0 *r-~ 2-~
120
~0 ~0
80
.~o O~
40
6
24
48
96
T i m e (h) Fig. 2. Renal Pt accumulation. Renal Pt accumulation was quantitated 0 - 9 6 h after cisplatin (5 mg/kg) administration. Accumulation was expressed as/~g Pt/g kidney per kg body wt. Groups were designated as normoglycemic (NC) and diabetic (DC) rats treated with cisplatin. Values represent mean a: S.E. with each group containing a minimum of 4 rats. (*) Values were statistically different (P < 0.05) from the normoglycemic group treated with cisplatin.
diabetic rats [20]. Studies by other investigators [21] have indicated that the mechanism for reduced gentamicin accumulation may be attributed to differences in phospholipid composition in the diabetic group. These findings would suggest that STZ-diabetes was associated with a defect in proximal tubular uptake of some nephrotoxicants. Additional studies are needed to establish the specific cellular mechanism for reduced renal cisplatin accumulation in diabetic rats. One possible theory for reduced accumulation is an impairment in cellular uptake processes. An alternate explanation for reduced renal accumulation would be redistribution of cisplatin to other organs. Decreased renal cisplatin accumulation could be due to higher accumulation in other organs in the diabetic rat. A reduction in renal toxicity may also be attributed to differences in renal excretion between normoglycemic and diabetic animals. The diabetic group had a tendency toward increased renal Pt excretion during the first 48 h after cisplatin injection (Table IlI). Cisplatin primarily undergoes renal excretion and nearly 50% of the drug appears in the urine in the first 24 h [14,22]. The increase in renal excretion would be expected to account for a shorter duration of exposure to the toxicant which would reduce toxicity.
159 TABLE III COMPARISON OF URINARY Pt EXCRETION BETWEEN NORMOGLYCEMIC AND DIABETIC RATS Time (h)
Normoglycemic
Pt excretion (#g/h per kg)a 0-3 3-6 6-12 12-24 24-48 48-72 72-96
188.1 5.6 11.5 12.2 14.3 15.3 6.3
4444444-
2.5 2.1 0.8 0.2 0.4 0.5 0.1
Total Pt excreted (l~g/kg)b 0-3 3-6 6-12 12-24 24-48 48-72 72-96
516.3 529.6 591.4 789.0 1229.2 1629.1 1860.4
± ± ± 44± 4-
4.9 5.5 5.6 10.4 18.4 16.0 9.7
Diabetic 216.2 21.4 20.3 21.0 29.9 6.0 14.0
581.2 637.3 746.2 1036.4 1706.8 1908.0 2249.0
4444444-
9.1' 0.9* 1.9 1.0' 1.9" 4.2 1.0"
-4- 7.4* ± 6.8* -4- 9.5* -4- 20.9* 4- 11.3' 4- 31.1' 4- 42.2*
apt levels were quantitated in urine collected during the designated time periods and were expressed as #g Pt excreted per h per kg body wt. Values were expressed as the mean + S.E. with n >_ 4 different animals. bCumulative urinary Pt excretion was expressed as total Pt excreted per kg body wt at each designated time period. *Statistically different (P < 0.05) from normoglycemic group.
A m a r k e d d i f f e r e n c e in u r i n a r y Pt c o n c e n t r a t i o n s was m e a s u r e d b e t w e e n n o r m o g l y c e m i c a n d d i a b e t i c rats. T h e s i g n i f i c a n c e o f l o w e r l u m i n a l Pt c o n c e n t r a t i o n o n p r o x i m a l t u b u l a r t o x i c i t y has n o t b e e n e s t a b l i s h e d since v e r y little i n f o r m a t i o n is a v a i l a b l e r e g a r d i n g p e r i t u b u l a r u p t a k e o f cisplatin. S t u d i e s c o n d u c t e d by F i e l d et al. [23] w o u l d i n d i c a t e c i s p l a t i n d o e s elicit a n effect o n b r u s h b o r d e r m e m b r a n e s since p r o x i m a l t u b u l a r r e a b s o r p t i o n o f s o d i u m was d e c r e a s e d by cisplatin. O t h e r i n d i r e c t e v i d e n c e w o u l d also suggest t h a t l u m i n a l c i s p l a t i n c o n c e n t r a t i o n m a y be r e l a t e d to c y t o t o x i c i t y . M a n n i t o l diuresis o r p r e h y d r a t i o n are c o m m o n adj u n c t s to the clinical a p p l i c a t i o n o f c i s p l a t i n [24]. M a n n i t o l diuresis has been r e p o r t e d to also p r o d u c e a slight r e d u c t i o n in c i s p l a t i n t o x i c i t y in a n i m a l s since B U N levels are less m a r k e d l y increased. M a n n i t o l p r e t r e a t m e n t , h o w e v e r , was n o t successful in t o t a l l y p r o t e c t i n g a g a i n s t renal d a m a g e since m o r p h o l o g i c a l c h a n g e s w e r e still e v i d e n t [25]. P h a r m a c o k i n e t i c studies [26] h a v e s h o w n m a n n i t o l diuresis in d o g s was ineffective in e n h a n c i n g u r i n a r y Pt e x c r e t i o n o r d e c r e a s i n g s e r u m e l i m i n a t i o n half-life b u t was successful in r e d u c i n g the u r i n a r y c o n c e n t r a t i o n o f Pt. D e c r e a s e d u r i n a r y Pt c o n c e n t r a t i o n w o u l d be e x p e c t e d to a t t e n u a t e t o x i c i t y if u p t a k e c a n o c c u r a l o n g the
160
60 50
f
1 NC
I
DC
40 v
a., .¢
Z
30 20 10
3
6
12
24
48
72
96
TIME (h) Fig. 3. Urinary Pt concentration following cisplatin administration. The urinary Pt concentration was quantitated 0-96 h after injection of 5 mg/kg cisplatin and expressed as ~g/ml. Groups were designated as cisplatin-treated normoglycemic (NC) and diabetic (DC) rats. Values represent mean + S.E. with each group containing a minimum of 4 rats. (*) Values were lower (P < 0.05) than the normoglycemic group treated with cisplatin.
p e r i t u b u l a r side o f the cell. The results o f Safirstein et al. [27] would suggest that p e r i t u b u l a r c o n c e n t r a t i o n was not i m p o r t a n t . The investigators had observed insignificant r e a b s o r p t i o n following i n t r a t u b u l a r microinjection o f an inorganic Pt salt. F u r t h e r studies are needed to examine p e r i t u b u l a r a b s o r p t i o n since the a b o v e study administered an inorganic Pt salt which w o u l d have very different physiochemical characteristics from cisplatin and its metabolites. Previous w o r k has d e m o n s t r a t e d that cisplatin n e p h r o t o x i c i t y was a t t e n u a t e d in diabetic rats. The m e c h a n i s m for reduced cisplatin toxicity in diabetic rats can be at least partially a t t r i b u t e d to decreased renal a c c u m u l a t i o n and increased renal excretion o f the toxicant. The diabetic state was also associated with a decrease in urinary Pt c o n c e n t r a t i o n relative to the n o r m o g l y c e m i c animals. F u r t h e r experiments are needed to establish the c o n t r i b u t i o n o f luminal Pt c o n c e n t r a t i o n to renal cytotoxicity.
Acknowledgment The a u t h o r s a p p r e c i a t e the generous d o n a t i o n o f cisplatin by the Bristol Myers Pharmaceutical C o m p a n y . The expert technical assistance o f Elda Jackson is greatly appreciated. This w o r k was s u p p o r t e d by N I H G r a n t RR05870.
161
References 1 2 3 4
5
6 7 8 9 10
11 12
13 14
15
16 17
18
19
20
21
N.E. Madias and J.T. Harrington, Platinum nephrotoxicity. Am. J. Med. 65 (1978) 307. J.M. Ward and K.A. Fauvie, The nephrotoxicity of cis-diamminedichloroplatinum (ll) (NSC-119875) in male F344 rats. Toxicol. Appl. Pharmacol. 38 (1976) 535. J.A. Winston and R. Safirstein, Reduced blood flow in early cisplatin-induced acute renal failure in the rat. Am. J. Physiol., 249 (1985) F490. R.S. Goldstein, B. Noordwier, J.T. Bond, J.B. Hook and G.H. Mayor, (-Ts-dichlorodiammineplatinum nephrotoxicity: time course and dose response of renal functional impairment. Toxicol. Appl. Pharmacol., 60 (1981) 165. G. Daugaard, U. Abildgaard, S. Larsen, N.-H. Holstein-Rathlou, O. Amtrop, H.P. Olesen and P.P. Leyssac, Functional and histopathological changes in dog kidneys after administration of cisplatin. Renal Physiol., 10 (1987) 54. D.C. Dobyan, J. Levi, C. Jacobs, J. Kosek and M.W. Weiner, Mechanisms of cisplatinum nephrotoxicity: 11. Morphologic observations. J. Pharmacol. Exp. Ther., 213 (1980) 551. D.D. Choie, D.S. Longnecker and A.A. Del Campo, Acute and chronic cisplatin ncphrotoxicity in rats. Lab. Invest., 44 (1981) 397. R. Safirstein, P. Miller, S. Dikman, N. Lyman and C. Shapiro, Cisplatin ncphrotoxicity in rats: defect in papillary hypertonicity. Am. J. Physiol., 241 (1981) F175. L.A. Scott, E. Madan and M.A. Valentovic, Attenuation of cisplatin nephrotoxicity by streptozotocin-induced diabetes. Fundam. Appl. Toxicol., 12 (1989) 530. L.A. Scott, E. Madan and M.A. Valentovic, Influence of streptozotocin (STZ)-induccd diabetes, dextrose diuresis and acetone on cisplatin nephrotoxicity in Fischer 344 (F344) rats. Toxicology, 60 (1990) 109. B. Tune, Relationship between the transport and toxicity of cephalosporins in the kidney. J. Infect. Dis., t32 (1975) 189. G.P. Datson, B.F. Rehnberg, L.L. Hall and R.J. Kavlock, Toxicity of mercuric chloride to the developing rat kidney. 111. Distribution and elimination of mercury during postnatal maturation. Toxicol. Appl. Pharmacol., 85 (1986) 39. G.L. Diamond, J.J. Cohen and S.J. Weinstein, Rcnal handling of cadmium in perfused rat kidney and effects on renal function and tissue composition. Am. J. Physiol., 251 (1986) F784. C.L. Litterest, l.J. Torres and A.M. Guarino, Plasma levels and organ distribution of Pt in the rat, dog and dogfish shark following single intravenous administration of cis-dichlorodiammineplatinum (II). J. Clin. Hematol. Oncol., 7 (1977) 169. J.H. Smith, M.A. Smith, C.L. Litterst, M.P. Copley, J Uozumi and M.R. Boyd, Comparative toxicity and renal distribution of the platinum analogs tetraplatin, CHIP and cisplatin at equimolar doses in the F344 rat. Fundam. Appl. Toxicol., 10 (1988) 45. O. Oster, The aluminum content of h u m a n serum determined by atomic absorption spectroscopy with a graphite furnace. Clin. Chim. Acta, 114 (1981) 53. C.A. Vaamonde, R.T. Bier, W. Gouvea, H. Alpert, J. Kelley and V. Pardo, Effect of duration of diabetes on the protection observed in the diabetic rat against gentamicin-induced acute renal failure, Miner. Electrolyte Metab., 10 (1984) 209. W.C. Elliott, D.C. Houghton, D.N. Gilbert, J. Baines-Hunter and W.M. Bennett, Experimental gentamicin nephrotoxicity: effect of Streptozotocin-induced diabetes. J. Pharmacol. Exp. Ther., 233 (1985) 264. V.M. Pattyn, G.A. Verpooten, R.A. Giuliano, F. Zheng and M.E. De Broe, Effect ofhyperfiltration, proteinuria and diabetes mellitus on the uptake of kinetics of gentamicin in the kidney cortex of rats. J. Pharmacol. Exp. Then, 244 (1985) 694. E. Pastoriza-Munoz, C. Josepovitz, L. R a m s a m m y and G.J. Kaloyanides, Renal handling of netilmicin in the rat with Streptozotocin-induced diabctes mcllitus. J. Pharmacol. Exp. Ther., 241 (1987) 166. G.J. Kaloyanides, M. Wang, W. Govea, J. Kelly, H. Alpert and C.A. Vaamonde, Altered phosphatidylinositol metabolism in diabetic rats confers resistance to genatmicin induced acute renal failure. Kidney Int., 21 (1982) 219A.
162 22
23 24 25
26
27
C.L. Litterest, T.E. Gram, R.L. Dedrick, A.F. Leroy and A.M. Guarino, Distribution and disposition of platinum following intravenous administration of cis-diamminedichloroplatinum (ll) (NSC-119875) to dogs. Cancer Res., 36 (1976) 2340. M.J. Field, T.E. Bostrom, A.Z. Gyory and D.J. Cockayne, Acute cisplatin nephrotoxicity in the rat. Evidence for impaired entry of sodium into proximal tubular cells. Pfluegers Arch., 414 (1989) 647. D,M. Hayes, E. Cvitkovic, R.B. Golby, E. Scheiner, L. Helson and 1.H. Krakoff, High dose cisplatinum diamminedichloride. Cancer, 39 (1977) 1372. M.F. Pera, B.C. Zook and H.C. Harder, Effects of mannitol or furosemide diuresis on the nephrotoxicity and physiological disposition of cis-dichlorodiammineplatinum (ll) in rats. Cancer Res., 39 (1979) 1269. E. Cvitkovic, J. Spaulding, V. Bethune, J. Martin and W.F. Whitmore, Improvement of cisdichlorodiammineplatinum (NSC-119875): therapeutic index in an animal model. Cancer, 39 (1977) 1357. R, Safirstein, J. Winston, D. Moel, S. Dikman and J. Guttenplan, Cisplatin nephrotoxicity: insights into mechanism. Int. J. Androl., 10 (1987) 325.
