Klinische Wochenschrift
Klin Wochenschr (1991) 69: 233-238 0023217391000520
9 Springer-Verlag 1991
Reviews
Sympathetic Neuronal Activity in Diabetic and Non-Diabetic Subjects with Peripheral Arterial Occlusive Disease K.H. Huber 1, W. Rexroth 1, E. Werle 2, T. Koeth 1, H. Weicker 2, and R. Hild ~ 1 Abteilung fiir Innere Medizin, St. Josefskrankenhaus und 2 Abteilung ffir Sport- und Leistungsmedizin, Universitfit Heidelberg
Summary. Despite the vasoconstrictory influence
Key words: Peripheral arterial occlusive disease -
of the ~-adrenergic system on the peripheral blood circulation the results of the sympathectomy were not satisfying in the therapy of peripheral arterial occlusive disease (PAOD). The aim of the present investigation was to clarify the pathophysiologic mechanisms of this clinical observation. Free and sulfoconjugated catecholamines were determined in the femoral artery, vein, and cubital vein of 19 healthy controls, 21 non-diabetic patients with PAOD stage II, 8 non-diabetic (PAOD IV) and 20 diabetic patients (D IV) with PAOD stage IV. In comparison with controls and group PAOD II an increased sympathoneuronal tone in group PAOD IV was evident at rest. Sympathetic activation was not restricted to the affected limb, since femoral and cubital venous norepinephrine levels were not different and plasma epinephrine fractional extraction (PEFE) was not altered by angiopathy. The lower sympathoneuronal activation in the group D IV may be attributed to an impaired pain perception or a reduced dopamine fl-hydroxylase activity indicated by a lower ratio of norepinephrine to dopamine. The failing long-term efficacy of lumbar sympathectomy in critical arterial limb disease may be explained by marked spontaneous sympathicolysis in diabetics, whereas in nondiabetics with sympathetic activation other mechanisms like development of unilateral MSnckeberg sclerosis, progression of proximal arterial occlusion or induction of steal effects have to be discussed.
Catecholamines, diabetes mellitus
Abbreviations: DA = dopamine; DBH = dopamine beta-hyd-
roxylase; EGTA = ethylene glycol-bis(fl-aminoethylether)N,N,N',N'-tetraacetic acid; EPI=epinephrine; HPLCA=high performance liquid chromatography with amperometric detection; NE=norepinephrine; PAOD=peripheral arterial occlusive disease; PEFE=plasma epinephrine fractional extraction
The sympathoadrenal system has an important effect on the peripheral blood circulation, especially on the regulation of the total vascular resistance. Subsequent to the introduction of sensitive and specific methods for measuring plasma concentrations of catecholamines, several studies have been able to verify a close relation between the intensity of sympathetic stimulation and the increment of circulating plasma catecholamines [2, 7, 23]. Norepinephrine (NE) is synthesized from its precursor dopamine (DA) by dopamine-beta-hydroxylase (DBH). After being released from sympathetic nerve endings, NE is inactivated primarily by neuronal re-uptake from the synaptic cleft. The small overflow of NE which enters blood circulation serves as an index of the actual sympathoneuronal tone. Adrenal stimulation is reflected by the plasma concentration of epinephrine (EPI). In nonneuronal cells, catecholamines are metabolized mainly by O-methylation, whereas in neurons monoamine oxidase is the main metabolizing enzyme [7]. Additionally, free catecholamines are inactivated by sulfoconjugation [25]. The resulting NE-O-sulfate and EPI-O-sulfate exceed the concentrations of NE and EPI by more than double and are considered as a potential pool of free catecholamines released by deconjugation [12, 13, 15]. It was the aim of the present study to investigate the sympathoneuronal activity in patients with different stages of PAOD and to clarify the biochemical basis of the poor clinical efficacy of lumbar sympathectomy. The sympathetic outflow and adrenoceptor density in the various vascular beds are not uni-
234
K.H. Huber et al. : Catecholamines in Arterial Occlusive Disease
form. As a result, local differences exist in the regulation of the peripheral blood flow. Venous plasma NE, which reflects an average of the overall sympathetic tone, is not suitable to evaluate local sympathoneuronal changes resulting from an insufficient blood supply caused by a peripheral arterial occlusive disease (PAOD). Therefore, in addition to systemic venous plasma NE we investigated femoral arteriovenous differences of plasma catecholamines in the affected limbs of patients with different stages of PAOD. To provoke a local ischemia, the patients with stage II PAOD were asked to exercise on a calf-ergometer. In order to assess the effect of a potential autonomic diabetic neuropathy on the sympathetic tone differentiation was made between non-diabetic and diabetic patients in PAOD stage IV. Patients and Methods Patients: 49 hospitalized patients with PAOD participated in this study. According to Fontaine's classification, they were divided into three groups consisting of 21 non-diabetics in the clinical stage II (PAOD II), 8 non-diabetics in stage IV (PAOD IV), and 20 patients with diabetic angiopathy in stage IV (D IV). The latter group generally had combined macro- and microangiopathy (Tables 1 and 2). Both group PAOD IV and D IV suffered from non-healing ulcers with diameters of at least 10 mm in the examined leg. The complete angiological status including Doppler sonography and arteriography is shown in Table 1. From the group studied we excluded subjects with hepatic or renal failure, sepsis, neuromuscular diseases, myocardial infarction within the past 3 months, incomplete angiological status or inability to cooperate.
19 healthy male volunteers with mean age of 23.5 (20-26) years served as controls. Methods: Blood samples were drawn in supine position 20 minutes after puncturing the femoral artery and vein as well as a cubital vein with a 18 g needle to estimate plasma free and conjugated catecholamine levels at rest. Additionally, concentrations of serum lactate, ammonia and other metabolites were determined in order to evaluate the metabolic changes caused by an impaired blood supply. These results are discussed elsewhere [17, 18]. As the PAOD IV and D IV patients already showed insufficient peripheral circulation in the resting state, it was not justifiable to stimulate the sympathetic activity by physical work. In these subjects, only basal plasma catecholamine levels were determined. Group PAOD H and the controls performed ergometric calf exercise in supine position according to the method described by Hild et al. [9]. The patients were exercised to their individual claudication pain limit. They achieved a maximum load between 290 and 1500 N m with a mean of 590.8 _+54.9 N m in 170+ 13.8 s. The work load of the healthy volunteers was standardized at 1500 N m (mean duration 274_+15.9 s) which has been known to produce a certain lactate formation in muscle tissue [17]. In both groups, blood samples were collected immediately after and 20 min after the end of exercise. Immediately after sampling, the blood was filled into a 5-ml vacutainer containing 9 mg E G T A and 5 mg glutathione, chilled on ice and centrifuged within 30 rain at 4 ~ C. NE, DA, EPI and their sulfoconjugates were analyzed by high performance liquid chromatography with amperometric detection (HPLCA) [24]. In group D IV an
Table 1. Anthropometric data and angiological state of the investigated patients ( P A O D = p e r i p h e r a l arterial occlusive disease according to Fontaine's classification, means _+SEM) G r o u p of patients
P A O D stage II
PAOD stage IV
Diabetic angiopathy stage IV
n
Age
Sex
21
63.8 (2.5)
8
74.9 (3.3)
6m 2f
20
70.2 (2.3)
9m 11 f
all m
Walking distance
Anklebrachial pressure index
Main site of occlusion
217.4 m (33.0)
0.49 (0.02)
--
variable
Number of patients with 0, 1, 2 or 3 patent crural arteries 0
1
2
3
iliacal 2 femoral 16 popliteal 3
0
5
10
6
0.27 (0.07)
iliacal femoral popliteal
5
2
1
0
0.48 (0.09)
femoral 6 popliteal 2 crural 12
7
10
3
0
2 5 1
K.H. Huber et al. : Catecholamines in Arterial Occlusive Disease
235
Table 2. Diabetic Angiopathy Stage IV - clinical data including assessment of autonomic diabetic neuropathy in 20 type II diabetics (means-+ SEM) Duration of diabetes (years) Normal beat-to-beat variation Beat-to-beat variation < 1.10
4 16
5.0_+1.5 16.44-_2.5
Therapy (number of subjects)
Serum creatinine [~tmol/1]
Proteinurea (number of subjects)
Retinopathy and/or polyneuropathy
insulin (2) sulfonylurea (2)
84.0_ 7.5
2
2
sulfonyturea (3) insulin (1 l) diet (2)
134.4+ 19.4
9
15
electrocardiogram was recorded during a period of deep breathing in order to evaluate the existence of autonomic diabetic neuropathy. The ratio of the longest R-R intervals during expiration and the shortest R-R intervals during inspiration was calculated. A quotient of
Klin Wochenschr (1991) 69: 233-238 0023217391000520
9 Springer-Verlag 1991
Reviews
Sympathetic Neuronal Activity in Diabetic and Non-Diabetic Subjects with Peripheral Arterial Occlusive Disease K.H. Huber 1, W. Rexroth 1, E. Werle 2, T. Koeth 1, H. Weicker 2, and R. Hild ~ 1 Abteilung fiir Innere Medizin, St. Josefskrankenhaus und 2 Abteilung ffir Sport- und Leistungsmedizin, Universitfit Heidelberg
Summary. Despite the vasoconstrictory influence
Key words: Peripheral arterial occlusive disease -
of the ~-adrenergic system on the peripheral blood circulation the results of the sympathectomy were not satisfying in the therapy of peripheral arterial occlusive disease (PAOD). The aim of the present investigation was to clarify the pathophysiologic mechanisms of this clinical observation. Free and sulfoconjugated catecholamines were determined in the femoral artery, vein, and cubital vein of 19 healthy controls, 21 non-diabetic patients with PAOD stage II, 8 non-diabetic (PAOD IV) and 20 diabetic patients (D IV) with PAOD stage IV. In comparison with controls and group PAOD II an increased sympathoneuronal tone in group PAOD IV was evident at rest. Sympathetic activation was not restricted to the affected limb, since femoral and cubital venous norepinephrine levels were not different and plasma epinephrine fractional extraction (PEFE) was not altered by angiopathy. The lower sympathoneuronal activation in the group D IV may be attributed to an impaired pain perception or a reduced dopamine fl-hydroxylase activity indicated by a lower ratio of norepinephrine to dopamine. The failing long-term efficacy of lumbar sympathectomy in critical arterial limb disease may be explained by marked spontaneous sympathicolysis in diabetics, whereas in nondiabetics with sympathetic activation other mechanisms like development of unilateral MSnckeberg sclerosis, progression of proximal arterial occlusion or induction of steal effects have to be discussed.
Catecholamines, diabetes mellitus
Abbreviations: DA = dopamine; DBH = dopamine beta-hyd-
roxylase; EGTA = ethylene glycol-bis(fl-aminoethylether)N,N,N',N'-tetraacetic acid; EPI=epinephrine; HPLCA=high performance liquid chromatography with amperometric detection; NE=norepinephrine; PAOD=peripheral arterial occlusive disease; PEFE=plasma epinephrine fractional extraction
The sympathoadrenal system has an important effect on the peripheral blood circulation, especially on the regulation of the total vascular resistance. Subsequent to the introduction of sensitive and specific methods for measuring plasma concentrations of catecholamines, several studies have been able to verify a close relation between the intensity of sympathetic stimulation and the increment of circulating plasma catecholamines [2, 7, 23]. Norepinephrine (NE) is synthesized from its precursor dopamine (DA) by dopamine-beta-hydroxylase (DBH). After being released from sympathetic nerve endings, NE is inactivated primarily by neuronal re-uptake from the synaptic cleft. The small overflow of NE which enters blood circulation serves as an index of the actual sympathoneuronal tone. Adrenal stimulation is reflected by the plasma concentration of epinephrine (EPI). In nonneuronal cells, catecholamines are metabolized mainly by O-methylation, whereas in neurons monoamine oxidase is the main metabolizing enzyme [7]. Additionally, free catecholamines are inactivated by sulfoconjugation [25]. The resulting NE-O-sulfate and EPI-O-sulfate exceed the concentrations of NE and EPI by more than double and are considered as a potential pool of free catecholamines released by deconjugation [12, 13, 15]. It was the aim of the present study to investigate the sympathoneuronal activity in patients with different stages of PAOD and to clarify the biochemical basis of the poor clinical efficacy of lumbar sympathectomy. The sympathetic outflow and adrenoceptor density in the various vascular beds are not uni-
234
K.H. Huber et al. : Catecholamines in Arterial Occlusive Disease
form. As a result, local differences exist in the regulation of the peripheral blood flow. Venous plasma NE, which reflects an average of the overall sympathetic tone, is not suitable to evaluate local sympathoneuronal changes resulting from an insufficient blood supply caused by a peripheral arterial occlusive disease (PAOD). Therefore, in addition to systemic venous plasma NE we investigated femoral arteriovenous differences of plasma catecholamines in the affected limbs of patients with different stages of PAOD. To provoke a local ischemia, the patients with stage II PAOD were asked to exercise on a calf-ergometer. In order to assess the effect of a potential autonomic diabetic neuropathy on the sympathetic tone differentiation was made between non-diabetic and diabetic patients in PAOD stage IV. Patients and Methods Patients: 49 hospitalized patients with PAOD participated in this study. According to Fontaine's classification, they were divided into three groups consisting of 21 non-diabetics in the clinical stage II (PAOD II), 8 non-diabetics in stage IV (PAOD IV), and 20 patients with diabetic angiopathy in stage IV (D IV). The latter group generally had combined macro- and microangiopathy (Tables 1 and 2). Both group PAOD IV and D IV suffered from non-healing ulcers with diameters of at least 10 mm in the examined leg. The complete angiological status including Doppler sonography and arteriography is shown in Table 1. From the group studied we excluded subjects with hepatic or renal failure, sepsis, neuromuscular diseases, myocardial infarction within the past 3 months, incomplete angiological status or inability to cooperate.
19 healthy male volunteers with mean age of 23.5 (20-26) years served as controls. Methods: Blood samples were drawn in supine position 20 minutes after puncturing the femoral artery and vein as well as a cubital vein with a 18 g needle to estimate plasma free and conjugated catecholamine levels at rest. Additionally, concentrations of serum lactate, ammonia and other metabolites were determined in order to evaluate the metabolic changes caused by an impaired blood supply. These results are discussed elsewhere [17, 18]. As the PAOD IV and D IV patients already showed insufficient peripheral circulation in the resting state, it was not justifiable to stimulate the sympathetic activity by physical work. In these subjects, only basal plasma catecholamine levels were determined. Group PAOD H and the controls performed ergometric calf exercise in supine position according to the method described by Hild et al. [9]. The patients were exercised to their individual claudication pain limit. They achieved a maximum load between 290 and 1500 N m with a mean of 590.8 _+54.9 N m in 170+ 13.8 s. The work load of the healthy volunteers was standardized at 1500 N m (mean duration 274_+15.9 s) which has been known to produce a certain lactate formation in muscle tissue [17]. In both groups, blood samples were collected immediately after and 20 min after the end of exercise. Immediately after sampling, the blood was filled into a 5-ml vacutainer containing 9 mg E G T A and 5 mg glutathione, chilled on ice and centrifuged within 30 rain at 4 ~ C. NE, DA, EPI and their sulfoconjugates were analyzed by high performance liquid chromatography with amperometric detection (HPLCA) [24]. In group D IV an
Table 1. Anthropometric data and angiological state of the investigated patients ( P A O D = p e r i p h e r a l arterial occlusive disease according to Fontaine's classification, means _+SEM) G r o u p of patients
P A O D stage II
PAOD stage IV
Diabetic angiopathy stage IV
n
Age
Sex
21
63.8 (2.5)
8
74.9 (3.3)
6m 2f
20
70.2 (2.3)
9m 11 f
all m
Walking distance
Anklebrachial pressure index
Main site of occlusion
217.4 m (33.0)
0.49 (0.02)
--
variable
Number of patients with 0, 1, 2 or 3 patent crural arteries 0
1
2
3
iliacal 2 femoral 16 popliteal 3
0
5
10
6
0.27 (0.07)
iliacal femoral popliteal
5
2
1
0
0.48 (0.09)
femoral 6 popliteal 2 crural 12
7
10
3
0
2 5 1
K.H. Huber et al. : Catecholamines in Arterial Occlusive Disease
235
Table 2. Diabetic Angiopathy Stage IV - clinical data including assessment of autonomic diabetic neuropathy in 20 type II diabetics (means-+ SEM) Duration of diabetes (years) Normal beat-to-beat variation Beat-to-beat variation < 1.10
4 16
5.0_+1.5 16.44-_2.5
Therapy (number of subjects)
Serum creatinine [~tmol/1]
Proteinurea (number of subjects)
Retinopathy and/or polyneuropathy
insulin (2) sulfonylurea (2)
84.0_ 7.5
2
2
sulfonyturea (3) insulin (1 l) diet (2)
134.4+ 19.4
9
15
electrocardiogram was recorded during a period of deep breathing in order to evaluate the existence of autonomic diabetic neuropathy. The ratio of the longest R-R intervals during expiration and the shortest R-R intervals during inspiration was calculated. A quotient of
