though our paper illustrated that gamma-trace peptide is frequently associated with A4, especially in the most prominently amyloidotic microvessels. The relative roles of the peptides in the ultimate microvascular degeneration leading to cerebral hemorrhage o r encephalomalacia remain to be determined. Even if gamma-trace peptide deposition is secondary, it may be important in the final evolution of CAArelated stroke syndromes C41. The significance of the presence of A4 peptide itself in the brains of patients with Alzheimer’s disease (AD) o r senile dementia of Alzheimer type is still the subject of some debate. Is it a marker for some other primary cortical degenerative process or the cause of the neurobehavioral deficit we recognize as AD? The etiology and pathogenesis of the leukoencephalopathy frequently seen with sporadic and hereditary CAA remain to be determined. For example, significant leukoencephalopathy may be seen in A D brains in which CAA is a relatively minor or negligible histological component [53. Even studies that have examined neuropathological correlates of the white matter change in A D brains have not conclusively shown that these alterations, sometimes referred to as leukoaraiosis, are strongly associated with the presence of overlying neocortical CAA and thus attributable simplistically to stenosis of long perforating arterioles, the walls of which are heavily infiltrated by A4 (or gamma-trace) amyloid 163.The most conclusive statement at the present time is that “the findings indicate an association between CAA and white matter changes, but do not confirm that the former produces the latter” C6}. Nevertheless, the final point of Drs Haan and Roos is valuable insofar as it points the way to testable hypotheses that can be evaluated using new immunohistochemical and morphometric techniques applied to postmortem brain tissue C7).
Department of Pathology Brain Research InJtitute U C W Medical Center Los Angeles, C A
References 1. Wattendorff AR, Bots GThAM, Went LN, Endtz LJ. Familial cerebral amyloid angioparhy presenting as recurrent cerebral haemorrhage. J Neurol Sci 1982;55:121-135 2. Luyendijk W, Bots GTAM, Vegter-van der Vlis M, et al. Heredi-
3.
4. 5.
6.
7.
tary cerebral haemorrhage caused by cortical arnyloid angiopathy. J Neurol Sci 1988;85:267-280 Haan J, Lanser JBK, Zijderveld I, van der Does IGF, Roos RAC. Dementia in hereditary cerebral hemorrhage with arnyloidosisDutch type. Arch Neurol 1990;47:965-967 Vinters HV. Cerebral amyloid angiopathy. A critical review. Stroke 1987;18:311-3 14 Brun A, Englund E. A white matter disorder in dementia of the Alzheimer type: A pathoanatomical study. Anti Neurol 1986; 1925 3-262 Janota I, Mirsen TR,Hachinski VC, et al. Neuropathologiccorrelates uf leuko-araiosis. Arch Neurol 1989;46:1124-1128 Vinters HV. Amyloid and the central nervous system: the neurobiology, genetics and immunocytochemisuyof a process important in neurodegenerative diseases and stroke. In: Cancilla PA, Vogel FS, Kaufman N, eds. Neuroparhology (US. and Canadian Academy of Pathology Monograph in Pathology #32). Balcimore: Williams & Wilkins, 1990:55-85
342 Annals of Neurology Vol 29 No 3 March 1991
Blood Lactate in Parkinson’s Disease Donato Di Monte, MD, James W. Tetrud, MD, and J. William Langston, MD
A new pathogenetic hypothesis that regards Parkinson’s disease as a “mitochondrial disorder” has recently evolved from experimental and clinical evidence. Studies on the l-methyl4-phenyl-1,2,3,6-tetrahydropyridine(MF‘TP) model of parkinsonism have indicated that the cytotoxic effects of this compound are likely to be due to an impairment of mitochondrial function and a depletion of cellular energy supplies. Indeed, 1-methyl-4-phenylpyridinium ion (MPP+), the toxic metabolite of MPTP, inhibits mitochondrial electron flow coupled to ATP production at the level of Complex I [l, 2). Interestingly, decreased mitochondrial Complex I activity has been found in parkinsonian patients as well. The activity of this enzyme complex was reduced in autopsy specimens of the substantia nigra [ 3 ) and its levels were decreased in the striatum 143 of patients who died with Parkinson’s disease. Finally, a decrease of approximately 50% in the activity of Complex I has been measured in platelet mitochondria isolated from parkinsonian patients { 5 ] . The hypothesis that a defect of mitochondrial function is involved in the pathogenesis of Parkinson’s disease and is not limited to neurons of the nigrostriatal system leads to a number of clinical and biochemical considerations. For example, biochemical studies have identified several specific errors of mitochondrial metabolism (including Complex I activity) as possible causes of clinically heterogeneous disorders, generally referred to as mitochondrial encephalomyopathies [6]. Pathological features of these disorders involve aerobically active organs with a relatively high demand for ATP, such as the brain, retina, and cardiac and skeletal muscle. An important, though nonspecific and variable in severity, laboratory abnormality is represented by an increase in blood concentration of lactic acid at rest [7}. Lactic acidemia in rnitochondrial disorders results from enhanced glycolytic activity, accumulation of pyruvate and reduction of pyruvate to lactate by lactate dehydrogenase (LDH) at the expense of NADH. If a deficiency of Complex I is a major, systemic biochemical defect in Parkinson’s disease, an increase in blood lactic acid level may be expected, at least in some patients. We therefore undertook a study in which Iactic acidemia was measured in 23 parkinsonian patients (average age 64.0 t 9.5 yr) and compared to 14 controls (age 65.8 9.8 yr). Severity of yarkinsonism was assessed using the Hoehn and Yahr scale 181. Blood was drawn from the antecubital vein in subjects at rest and after overnight fasting. Samples were immediately extracted by acid and lactate was measured spectrophotometrically as oxidation of N A D H (at 340 mm) in the presence of pyruvate and LDH. No significant difference in blood concentration of lactic acid was found between the parkinsonian and the control group (p > 0.5) (Table). The three patient groups were not significantly different as calculated by two-way analysis of variance. Finally, no significant correlation was found between the concentrations of lactic
*
Lweh of Lactate in Venous Blood of Fasting Control Subjects and Parkinsonian Patients Subject
No.
Lactate (mmol1L)
Control Parkinson's disease Stage I Stage I1 Stage 111
14 23 4 13
0.88 t 0.5 0.83 2 0.4 1.03 + 0.2 0.80 2 0.4 0.76 f 0.4
6
acid and the milligrams of L-dopa administered daily to the patients ( Y = 0.14). These results, which failed to demonstrate an elevation of blood lactate concentrations at rest in patients with Parkinson's disease, do not support the hypothesis of a systemic defect in aerobic metabolism. These data might, however, reflect the fact that the metabolic consequences of mitochondrial impairment are adequately compensated when patients are at rest, or the defect is more selective for the central nervous system. Future studies designed to assess lactate production with exercise and in the cerebrospinal fluid may help answer these questions. Cahyoornia Parkinson's Foundztion California Institute /br Medical Research San Jme, C A
References 1. Nicklas WJ, Vyas I , Heikkila RE. Inhibition of NADH-linked oxidation in brain mitochondria by l-merhyl-4-phenylpyridine, a
metabolite of the neurotoxin, l-methyl-4-phenyl-l,2~3,6tetrahydropyridine.Life Sci 198J ;3 6 2 503-2 508 2. Di Monte D, Jewel1 SA, Ekstrom G, et al. I-Methyl-4phenyl-1,2,3,6-tetrahydropyridine (MFTP) and l-methyl-4phenylpyridine (MPP') cause rapid ATP depletion in isolated hepatocytes. Hiochem Biophys Res Cornmun 1986;137:310-315 3. Schapira AHV, CooperJM, Dexter D, et al. Mitochondrial Complex I deficiency in Parkinson's disease. Lancer 1989;1:1269 4. Mizuno Y, Ohta S, Tanaka M, et al. Deficiencies in Complex I subunits of the respiratory chain in Parkinson's disease. Biochem Biophys Res Commun 1989;163:1450-1455 5. Parker WD, Boyson SJ, Parks JK. Abnormalities of the electron transport chain in idiopathic Parkinson's disease. Ann Neurol 1989;26:719-723 6. DiMauro S, Bonilla E, Zeviani M, et al. Mitochondrial myopathies. Ann Neurol 1985;17:521-538 7. Scholte HR, Busch HFM, Luyt-Houwen E M , et al. Defects in oxidative phosphorylation. Biochemical investigations in skeletal muscle and expression of the lesion in other cells. J Inher Metab Dis 1987;10:81-97 8. Hoehn MM, Yahr MD. Parkinsonism: onset, progression and mortaliry. Neurology 1967;17:427-442
Multiple Sclerosis, Human T-Lymphotropic Virus Type I, and Human Endogenous Retrovirus Sequences Gary F. Cabirac, Phl1,"t Dana Ries, BS," and Rondd s. Murray, MD" A letter in the June issue of this journal describes a recent workshop on the use of the polymerase chain reaction (PCR) to study thc relationship between multiple sclerosis and human T-lymphotropic virus type I (HTLV-I) { 11. The problem of interpreting recent data on PCR amplification of HTLVI-related sequences from human tissue C2-63 is due to many factors: the extreme sensitivity of PCR, i.e., contamination difficulties; the high mutation rate of retrovirus sequences [7];heterogeneous patient population; the possibility of lowlevel infections; and endogenous retrovirus sequences within the human gcnomc. We have used PCR with HTLV-I-specific primers to amplify sequences in nucleic acid obtained not only from peripheral blood leukocytes (PBL) and cerebrospinal fluid leukocytes (CSL) but also from MS white matter containing demyelinating plaques and control white matter. The primers used in our study were as follows: RTAIB-Qoll) 258426071 2905-2882; RTC/D-(pol2) 2774-279813020-2996; GGli 2-1gag) 1054-1077/1278-1255. Numbers refer to HTLV-I sequence as reported by Seiki and colleagues 181. Leukocyte nucleic acid from adult T-cell leukemia (ATL) and tropical spastic paraparesis (TSP) patients and from the HTLV-I cell line, MT2 191 were used as positive controls. Internal oligo probes were: RTPl-(poll region) 2614-2643; SG232-(pol2 r e g i o n b a s described by Greenberg and associates [3}; G G P l -(gag region) 121 1- 1240. Pol andlor gag related sequences were amplified from PBL D N A in 3 of 20 MS, 6 of 1 7 normal control, and 2 of 3 neurological disease control samples. Amplified products were not detectable in any of the 10 MS brain samples whereas 1 of the 10 control brain samples was positive. Two samples were positive for both the gag and one of the pel regions. None of the CSL samples, 3 MS, 3 normal control, and 1 neurological disease control produced detectable PCR products. The CSL samples were tested only with the pol 2 primers. Gel eleccrophoresisiSouthern blot hybridization analysis revealed that amplified products detected with the HTLV-I specific oligo probes varied in size and that some samples had two different sized amplified products when compared to the control ATL, TSP, and MT2 PCR products. These results show no incidence of HTLV-I infection in MS patients and in particular no association of the prototypical virus in MS brain lesions. The distribution of the detected PCR products behveen the MS and control samples plus thc size variation of these products compared to those from HTLV-I suggest that the amplified products were due to endogenous sequences. O u r results d o not rule out the possibility of a very low level infection of HTLV-I or related viruses in MS.
Annals of Neurology
Vol 29
No 3 March 1991
343
Department of Pathology Brain Research InJtitute U C W Medical Center Los Angeles, C A
References 1. Wattendorff AR, Bots GThAM, Went LN, Endtz LJ. Familial cerebral amyloid angioparhy presenting as recurrent cerebral haemorrhage. J Neurol Sci 1982;55:121-135 2. Luyendijk W, Bots GTAM, Vegter-van der Vlis M, et al. Heredi-
3.
4. 5.
6.
7.
tary cerebral haemorrhage caused by cortical arnyloid angiopathy. J Neurol Sci 1988;85:267-280 Haan J, Lanser JBK, Zijderveld I, van der Does IGF, Roos RAC. Dementia in hereditary cerebral hemorrhage with arnyloidosisDutch type. Arch Neurol 1990;47:965-967 Vinters HV. Cerebral amyloid angiopathy. A critical review. Stroke 1987;18:311-3 14 Brun A, Englund E. A white matter disorder in dementia of the Alzheimer type: A pathoanatomical study. Anti Neurol 1986; 1925 3-262 Janota I, Mirsen TR,Hachinski VC, et al. Neuropathologiccorrelates uf leuko-araiosis. Arch Neurol 1989;46:1124-1128 Vinters HV. Amyloid and the central nervous system: the neurobiology, genetics and immunocytochemisuyof a process important in neurodegenerative diseases and stroke. In: Cancilla PA, Vogel FS, Kaufman N, eds. Neuroparhology (US. and Canadian Academy of Pathology Monograph in Pathology #32). Balcimore: Williams & Wilkins, 1990:55-85
342 Annals of Neurology Vol 29 No 3 March 1991
Blood Lactate in Parkinson’s Disease Donato Di Monte, MD, James W. Tetrud, MD, and J. William Langston, MD
A new pathogenetic hypothesis that regards Parkinson’s disease as a “mitochondrial disorder” has recently evolved from experimental and clinical evidence. Studies on the l-methyl4-phenyl-1,2,3,6-tetrahydropyridine(MF‘TP) model of parkinsonism have indicated that the cytotoxic effects of this compound are likely to be due to an impairment of mitochondrial function and a depletion of cellular energy supplies. Indeed, 1-methyl-4-phenylpyridinium ion (MPP+), the toxic metabolite of MPTP, inhibits mitochondrial electron flow coupled to ATP production at the level of Complex I [l, 2). Interestingly, decreased mitochondrial Complex I activity has been found in parkinsonian patients as well. The activity of this enzyme complex was reduced in autopsy specimens of the substantia nigra [ 3 ) and its levels were decreased in the striatum 143 of patients who died with Parkinson’s disease. Finally, a decrease of approximately 50% in the activity of Complex I has been measured in platelet mitochondria isolated from parkinsonian patients { 5 ] . The hypothesis that a defect of mitochondrial function is involved in the pathogenesis of Parkinson’s disease and is not limited to neurons of the nigrostriatal system leads to a number of clinical and biochemical considerations. For example, biochemical studies have identified several specific errors of mitochondrial metabolism (including Complex I activity) as possible causes of clinically heterogeneous disorders, generally referred to as mitochondrial encephalomyopathies [6]. Pathological features of these disorders involve aerobically active organs with a relatively high demand for ATP, such as the brain, retina, and cardiac and skeletal muscle. An important, though nonspecific and variable in severity, laboratory abnormality is represented by an increase in blood concentration of lactic acid at rest [7}. Lactic acidemia in rnitochondrial disorders results from enhanced glycolytic activity, accumulation of pyruvate and reduction of pyruvate to lactate by lactate dehydrogenase (LDH) at the expense of NADH. If a deficiency of Complex I is a major, systemic biochemical defect in Parkinson’s disease, an increase in blood lactic acid level may be expected, at least in some patients. We therefore undertook a study in which Iactic acidemia was measured in 23 parkinsonian patients (average age 64.0 t 9.5 yr) and compared to 14 controls (age 65.8 9.8 yr). Severity of yarkinsonism was assessed using the Hoehn and Yahr scale 181. Blood was drawn from the antecubital vein in subjects at rest and after overnight fasting. Samples were immediately extracted by acid and lactate was measured spectrophotometrically as oxidation of N A D H (at 340 mm) in the presence of pyruvate and LDH. No significant difference in blood concentration of lactic acid was found between the parkinsonian and the control group (p > 0.5) (Table). The three patient groups were not significantly different as calculated by two-way analysis of variance. Finally, no significant correlation was found between the concentrations of lactic
*
Lweh of Lactate in Venous Blood of Fasting Control Subjects and Parkinsonian Patients Subject
No.
Lactate (mmol1L)
Control Parkinson's disease Stage I Stage I1 Stage 111
14 23 4 13
0.88 t 0.5 0.83 2 0.4 1.03 + 0.2 0.80 2 0.4 0.76 f 0.4
6
acid and the milligrams of L-dopa administered daily to the patients ( Y = 0.14). These results, which failed to demonstrate an elevation of blood lactate concentrations at rest in patients with Parkinson's disease, do not support the hypothesis of a systemic defect in aerobic metabolism. These data might, however, reflect the fact that the metabolic consequences of mitochondrial impairment are adequately compensated when patients are at rest, or the defect is more selective for the central nervous system. Future studies designed to assess lactate production with exercise and in the cerebrospinal fluid may help answer these questions. Cahyoornia Parkinson's Foundztion California Institute /br Medical Research San Jme, C A
References 1. Nicklas WJ, Vyas I , Heikkila RE. Inhibition of NADH-linked oxidation in brain mitochondria by l-merhyl-4-phenylpyridine, a
metabolite of the neurotoxin, l-methyl-4-phenyl-l,2~3,6tetrahydropyridine.Life Sci 198J ;3 6 2 503-2 508 2. Di Monte D, Jewel1 SA, Ekstrom G, et al. I-Methyl-4phenyl-1,2,3,6-tetrahydropyridine (MFTP) and l-methyl-4phenylpyridine (MPP') cause rapid ATP depletion in isolated hepatocytes. Hiochem Biophys Res Cornmun 1986;137:310-315 3. Schapira AHV, CooperJM, Dexter D, et al. Mitochondrial Complex I deficiency in Parkinson's disease. Lancer 1989;1:1269 4. Mizuno Y, Ohta S, Tanaka M, et al. Deficiencies in Complex I subunits of the respiratory chain in Parkinson's disease. Biochem Biophys Res Commun 1989;163:1450-1455 5. Parker WD, Boyson SJ, Parks JK. Abnormalities of the electron transport chain in idiopathic Parkinson's disease. Ann Neurol 1989;26:719-723 6. DiMauro S, Bonilla E, Zeviani M, et al. Mitochondrial myopathies. Ann Neurol 1985;17:521-538 7. Scholte HR, Busch HFM, Luyt-Houwen E M , et al. Defects in oxidative phosphorylation. Biochemical investigations in skeletal muscle and expression of the lesion in other cells. J Inher Metab Dis 1987;10:81-97 8. Hoehn MM, Yahr MD. Parkinsonism: onset, progression and mortaliry. Neurology 1967;17:427-442
Multiple Sclerosis, Human T-Lymphotropic Virus Type I, and Human Endogenous Retrovirus Sequences Gary F. Cabirac, Phl1,"t Dana Ries, BS," and Rondd s. Murray, MD" A letter in the June issue of this journal describes a recent workshop on the use of the polymerase chain reaction (PCR) to study thc relationship between multiple sclerosis and human T-lymphotropic virus type I (HTLV-I) { 11. The problem of interpreting recent data on PCR amplification of HTLVI-related sequences from human tissue C2-63 is due to many factors: the extreme sensitivity of PCR, i.e., contamination difficulties; the high mutation rate of retrovirus sequences [7];heterogeneous patient population; the possibility of lowlevel infections; and endogenous retrovirus sequences within the human gcnomc. We have used PCR with HTLV-I-specific primers to amplify sequences in nucleic acid obtained not only from peripheral blood leukocytes (PBL) and cerebrospinal fluid leukocytes (CSL) but also from MS white matter containing demyelinating plaques and control white matter. The primers used in our study were as follows: RTAIB-Qoll) 258426071 2905-2882; RTC/D-(pol2) 2774-279813020-2996; GGli 2-1gag) 1054-1077/1278-1255. Numbers refer to HTLV-I sequence as reported by Seiki and colleagues 181. Leukocyte nucleic acid from adult T-cell leukemia (ATL) and tropical spastic paraparesis (TSP) patients and from the HTLV-I cell line, MT2 191 were used as positive controls. Internal oligo probes were: RTPl-(poll region) 2614-2643; SG232-(pol2 r e g i o n b a s described by Greenberg and associates [3}; G G P l -(gag region) 121 1- 1240. Pol andlor gag related sequences were amplified from PBL D N A in 3 of 20 MS, 6 of 1 7 normal control, and 2 of 3 neurological disease control samples. Amplified products were not detectable in any of the 10 MS brain samples whereas 1 of the 10 control brain samples was positive. Two samples were positive for both the gag and one of the pel regions. None of the CSL samples, 3 MS, 3 normal control, and 1 neurological disease control produced detectable PCR products. The CSL samples were tested only with the pol 2 primers. Gel eleccrophoresisiSouthern blot hybridization analysis revealed that amplified products detected with the HTLV-I specific oligo probes varied in size and that some samples had two different sized amplified products when compared to the control ATL, TSP, and MT2 PCR products. These results show no incidence of HTLV-I infection in MS patients and in particular no association of the prototypical virus in MS brain lesions. The distribution of the detected PCR products behveen the MS and control samples plus thc size variation of these products compared to those from HTLV-I suggest that the amplified products were due to endogenous sequences. O u r results d o not rule out the possibility of a very low level infection of HTLV-I or related viruses in MS.
Annals of Neurology
Vol 29
No 3 March 1991
343
