Role of nitric oxide as mediator of nerve injury in inflammatory neuropathies.

Different lines of evidence suggest that nitric oxide (NO) plays a key role in the pathogenesis of inflammatory neuropathies; however, it is still unclear which structures in the peripheral nerve are the primary targets of NO-mediated nerve injury. To address this issue, we determined the expression of NO metabolites in sural nerve biopsies and in cerebrospinal fluid from patients with inflammatory neuropathies and studied the pathologic effects of NO in an in vitro model of myelinated Schwann cell-neuron cocultures. In cerebrospinal fluid samples, nitrite levels remained unaltered; however, nitrotyrosine, a marker for peroxynitrite formation, could be identified in nerve biopsies from patients with inflammatory neuropathies. In an in vitro model of Schwann cell neuron cocultures, high concentrations of NO induced robust demyelination, which was the result of NO-mediated axonal injury, whereas Schwann cell viability remained unaffected. These findings suggest that in contrast to Schwann cells, sensory neurons are the primary target of NO-mediated cytotoxicity and the loss of myelin is the result of selective damage to axons rather than a direct harmful effect to Schwann cells. Our findings imply that NO contributes to the pathologic changes seen in the inflamed peripheral nervous system, which is characterized by the features of axonal injury and subsequent myelin degradation, previously described as Wallerian-like degeneration.

[Polyradiculoneuropathy in an adult with primitive hyperoxaluria]. / Polyradiculoneuropathie au cours d'une hyperoxalurie primitive de l'adulte.

From the age of 31 a patient began to suffer from recurrent calcium oxalate urolithiasis. Liver biopsy showed a decrease in catalytic activity of the hepatic peroxisomal enzyme alanine: glyoxilate aminotransferase (AGT), which was mistargeted from peroxisomes to mitochondria. The genetic analysis revealed a mutation of the AGT gene. At age 47 he developed end-stage renal failure and underwent hemodialysis. After 12 months of hemodialysis he presented a rapidly declining clinical condition, a decrease of the residual renal function, a livedo reticularis with painful of extremities, and shortly thereafter a general weakness, which predominated on lower limbs. Apart from renal failure, routine biological examination and CSF were normal. Nerve conduction studies and electromyography supported the diagnosis of polyradiculoneuropathy. Pathological studies revealed mixed demyelinating-axonal lesions and deposits of calcium oxalate crystals within the media and the intima of epineural arterioles. A combined liver-kidney transplant was rapidly performed. The patient's condition improved in a few months and motor signs completely disappeared.

Matrix metalloproteinase upregulation in chronic inflammatory demyelinating polyneuropathy and nonsystemic vasculitic neuropathy.

OBJECTIVE: To determine the expression pattern and cellular source of matrix metalloproteinases (MMPs) in chronic inflammatory demyelinating polyneuropathy (CIDP) and nonsystemic vasculitic neuropathy (NSVN). BACKGROUND: MMPs are endopeptidases involved in tissue destruction and infiltration by immune cells in multiple sclerosis and Guillain-Barré syndrome. Enzyme inhibitors of MMPs attenuate clinical symptoms in corresponding animal models of these diseases. MMP inhibition may therefore be a novel approach for the treatment of CIDP and NSVN. However, the spectrum of MMPs expressed in chronic inflammatory neuropathies has not been established. METHODS: The expression of MMP-2, MMP-3, MMP-7, and MMP-9 in T cells, macrophages, and stromal cells in CIDP, NSVN, and noninflammatory neuropathies (NIN) was quantitated by immunohistochemistry. Results were correlated with clinical and electrophysiologic findings. RESULTS: The production of MMP-2 and MMP-9 is increased in nerve tissue in CIDP and NSVN compared with NIN. T cells are the predominant source of MMP-2 and MMP-9 in CIDP and NSVN, whereas macrophages contribute only to a minor extent. Stromal cells of the perineurium/epineurium are an additional source of MMP-2 in NSVN, but not in CIDP. Expression of MMP-3 and MMP-7 was not detectable in CIDP or NSVN. Expression of MMP-2 and MMP-9 did not correlate with clinical disease activity and electrophysiologic measurements. CONCLUSIONS: The upregulation of MMP-2 and MMP-9 is a specific feature of CIDP and NSVN, and selective inhibitors of these enzymes could be used to prevent inflammatory tissue damage. The similar increase of MMP-2 and MMP-9 in both demyelinating (CIDP) and nondemyelinating (NSVN) neuropathies raises doubts about whether MMPs play a primary role in demyelination.

Matrix metalloproteinases MMP-9 and MMP-7 are expressed in experimental autoimmune neuritis and the Guillain-Barré syndrome.

Matrix metalloproteinases (MMPs) are a family of enzymes that may be implicated in the pathogenesis of inflammatory demyelinating disorders such as multiple sclerosis. The present study investigated the expression of 92-kd gelatinase (MMP-9) and five other MMPs in sciatic nerve from Lewis rats with autoimmune experimental neuritis (EAN), an experimental model of the Guillain-Barré syndrome (GBS). Quantitative polymerase chain reaction analysis revealed an up-regulation of MMP-9 mRNA with peak levels concurrent with maximal disease severity. Increased mRNA expression was associated with enhanced enzyme activity, as detected by gelatin zymography. Immunohistochemically, MMP-9 could be localized primarily around blood vessels within the epineurium and endoneurium in diseased but not normal sciatic nerve. Among all other MMPs investigated, mRNA levels of matrilysin (MMP-7) were found to be up-regulated at the peak of the disorder, remaining at high levels throughout the clinical recovery phase of the disease. To apply these findings to human disease, sural nerve biopsies from GBS patients were examined. By using immunohistochemistry, positive immunoreactivity against MMP-9 and MMP-7 was noted and corroborated by demonstrating augmented mRNA expression in comparison with noninflammatory neuropathies. Furthermore, increased MMP-9 activity was detected by zymography. These findings indicate that 92-kd gelatinase and matrilysin are selectively up-regulated during EAN and expressed in nerves of GBS patients and thus may contribute to the pathogenesis of inflammatory demyelination of the peripheral nervous system.

Increased frequencies of HPRT mutant T lymphocytes in patients with Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy: further evidence for a role of T cells in the etiopathogenesis of peripheral demyelinating diseases.

We have used the HPRT mutant clonal assay to determine the frequency of mutant T lymphocytes (FMC), as a measure of recent T cell stimulation, in the blood of patients with Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP). We found that, compared to healthy controls, the FMC in patients with GBS (16) and CIDP (10) was significantly increased in the progressive phase of the neuropathy. FMC returned to normal values during recovery, suggesting a relationship between FMC and disease activity. No correlation was found between FMC values and motor deficit or severity of the neuropathy. The FMC of the GBS patients with a history of infection before onset of neurological symptoms or with insufficient respiration was not significantly different from the other GBS patients. Immunophenotypic analysis showed that the fraction of CD8+ HPRT mutant T cell clones was significantly increased in GBS patients (48%) compared to healthy controls (3%) or CIDP patients (4.5%). Our results are compatible with the notion that T cells are involved in the pathogenesis of demyelinating inflammatory neuropathies.

Prognostic value of cerebrospinal fluid neuron-specific enolase and S-100b protein in Guillain-Barré syndrome.

We measured the cerebrospinal fluid (CSF) concentrations of neuron-specific enolase (NSE) and S-100b protein (S-100b) using enzyme immunoassay methods, in 24 patients with Guillain-Barré syndrome and 46 controls, and examined their prognostic values. Sixteen of 24 patients showed elevated levels (> the mean + 2SD levels of controls) of NSE, S-100b, or both, and in those with higher NSE or S-100b levels there was a rather longer duration of disease, whereas 8 patients with the normal levels showed an early recovery. Further, NSE or S-100b levels were significantly correlated with months to recovery. Thus, NSE and S-100b in CSF may be useful markers for predicting the outcome of Guillain-Barré syndrome.

Acute rhabdomyolysis associated with atypical Guillain-Barré syndrome.

We report a patient with atypical Guillain-Barré syndrome associated with acute rhabdomyolysis. Rhabdomyolysis may be the cause of elevation of creatine kinase sometimes seen in patients with Guillain-Barré syndrome.

[Electrophoresis of cholinesterases of the cerebrospinal fluid in the Guillain-Barré syndrome]. / Electrophorèse des cholinestérases du liquide céphalorachidien dans le syndrome de Guillain-Barré.

Polyacrylamide gel electrophoresis of cholinesterase from cerebrospinal fluid was performed in 22 patients with Guillain-Barré syndrome. Fifteen of these patients had an abnormal cerebrospinal fluid with emergence of a second electrophoretic migration band corresponding to non-specific cholinesterase. Among 182 patients with a variety of diseases who served as controls, only one presented with this abnormality. From these data the sensitivity and specificity of cerebrospinal fluid cholinesterase electrophoresis were calculated at 68 and 99 percent respectively. The second migration band seems to appear early in the course of the disease and disappears when the patient is cured. Moreover, the occurrence of this band is correlated with the severity of the condition, as shown by a greater number of patients under artificial ventilation and by a longer stay in intensive care unit. Cerebrospinal fluid electrophoresis could be used as a prognosis factor.

Guillain-Barré syndrome and serum activities of gamma-glutamyltransferase and glutamic-pyruvic transaminase.

Objective laboratory indicators of alcohol consumption (mean corpuscular volume and serum glutamic-pyruvic transaminase (GPT), glutamyltransferase (gamma-GT), and glutamic-oxaloacetic transaminase (GOT] were measured in 18 patients with Guillain-Barré syndrome (GBS) and 710 control patients. All of the indicators examined were more frequently found to be pathological in GBS patients, reaching significance for gamma-GT and GPT. Some explanations for this result are discussed. It is concluded that alcohol consumption may be a risk factor for GBS.

Angiotensin I converting enzyme in cerebrospinal fluid of patients with neurological diseases.

The angiotensin I converting enzyme activity (kininase II, EC 3.4.15.1) was measured fluorimetrically in cerebrospinal fluid (CACE) of 154 patients with neurological disorders and 27 controls. The concentrations of total protein, albumin, and immunoglobulins G and A were also determined. There was no correlation between CACE and sex or age, but a slight positive relation between CACE and total protein and an inverse correlation between CACE and albumin were observed. Compared to controls, significantly elevated CACE was found in acute untreated CNS sarcoidosis (P less than 0.0001), followed by viral encephalitis, CNS syphilis, Huntington's disease, and multiple sclerosis (P less than 0.001). In treated CNS sarcoidosis, only a minor increase of CACE was observed (P less than 0.05). The determination of CACE can be used for the diagnosis of neurological disorders.

Pain in Guillain-Barré syndrome.

The clinical features of pain were prospectively analyzed in 29 consecutive patients with Guillain-Barré syndrome (GBS). Sixteen (55%) had characteristic pain early in the illness described as similar to the muscular discomfort following exercise ("charley horse"). Pain preceded weakness by one to five days in four patients. The anterior and posterior aspects of the thighs, the buttocks, and the low part of the back were most frequently affected. Pain was frequently worse at night. Specific clinical signs or electrophysiologic abnormalities were not associated with pain, but serum creatine kinase level was elevated in ten of 13 patients with pain and only one of eight without pain. A review of previously reported pathologic material in five patients with GBS failed to disclose a relation between inflammation of dorsal root ganglia and pain. These results suggest that alterations in muscle related to neurogenic changes may cause the typical pain of GBS.