A descriptive and prognostic study of systemic sclerosis-associated myopathies

Objectives:

To describe the clinical characteristics and muscle pathological features of patients with systemic sclerosis (SSc) and myopathy and analyse their impact on muscle outcome.

Methods:

Thirty-five patients with myopathy and available muscle biopsy were restrospectively investigated from the charts of four hospital centres.

Results:

Twenty-six (74%) cases had diffuse SSc. The median time from SSc diagnosis was 5 years (range 0–23) at myopathy onset. The main myopathological features were mononuclear inflammation (63%), muscle atrophy (60%), necrosis (59%), regeneration (44%), fibrosis (24%) or microangiopathy (27%). After a median follow-up of 4.4 years, 24 patients (69%) showed complete or partial muscle remission. Only histological muscle inflammation was associated with good muscle prognosis in multivariate analysis (odds ratio 44.7, 95% CI 2.8 to 704.7). Patients without muscle inflammation had a poor response to corticosteroids (38% favourable response vs 90% in patients with inflammation).

Conclusion:

Muscle histopathology is critical in the therapeutic management of SSc-associated myopathy.

Long term course of the H reflex after selective tibial neurotomy

OBJECTIVES

This study was conducted to evaluate the long term clinical and electrophysiological outcome by recording the H reflex in a consecutive series of six patients treated by selective tibial neurotomy for spastic equinus foot.

METHOD

The amplitudes of Hmax reflexes, Mmax responses, and Hmax:Mmax ratio were recorded in six patients with chronic lower limb spasticity, before and after surgery, at day 1 and 8 months and 24 months after selective tibial neurotomy. The passive range of movement, the stretch reflex score according to the Tardieu scale, the osteoarticular and tendon repercussions, and the quality of motor control of dorsiflexion were evaluated preoperatively and postoperatively.

RESULTS

At the end of the study, all patients presented a reduction of equines. Gait and Tardieu's score of spasticity had improved in all patients. Active dorsiflexion of the ankle was unchanged in four patients, but two improved by 5 degrees to 12 degrees. In five cases, fascicular resection of the superior nerve to soleus was, alone, sufficient to reduce spastic equinus foot, without recurrence, for a mean follow up of 28 months. Two patients were reoperated on, one for remaining spasticity related to an underestimated spasticity of the gastrocnemius muscles, and the other for painful claw toes. Hmax, Mmax, and Hmax:Mmax ratios were significantly lower the day after surgery. The reduction of Hmax and Hmax/Mmax ratio remained stable over time and was still statistically significant two years after the operation. However, the value of Mmax eight months postoperatively was no longer significantly different from the preoperative value.

CONCLUSION

This study shows the long term efficacy of the selective tibial neurotomy as treatment of spastic equinus foot. Neurotomy confined to fibres supplying the soleus muscle is sufficient in most cases and acts by decreasing sensory afferents without significant long term motor denervation.

[Camptocornia presenting with a proximal myotonic myopathy]

We report the case of a 74-year-old patient who presented with an anterior inflexion of the trunk which increased during the day. His past medical history included treatment for hypothyroidism, a cure of cataracts and an increase of gammaGT. This camptocormic attitude revealed a proximal myotonic myopathy (PROMM). Clinical and paraclinical arguments (hypothyroidism, cataracts, weakness, EMG, muscle biopsy, biology) led to diagnosis.

[Cellular aspect of neuroinflammation in Guillain-Barré syndrome: a key to a new therapeutic option?]

Guillain-Barré syndrome (GBS) is an acute inflammatory demyelinating neuropathy associated with long-lasting morbidity and substantial risk of mortality. The two reference treatments (plasma exchange-PE and intravenous immunoglobulins-IVIGs) do not change the functional prognosis in patients with very severe disease. Pathogenesis of GBS associates recently characterized humoral and cellular immune dysfunctions. Antibodies against nerve antigens may participate in complement activation, antibody-dependent macrophage cytotoxicity, and reversible conduction failure. Cellular immune reaction is associated with an increase of proinflammatory cytokines (for exemple TNF-alpha), a decrease of anti-inflammatory cytokines (such as TGF-B1), an increase of matrix metalloproteinases (MMP-9-gelatinase B), all abnomalities favoring adhesion to and transmigration across endothelium of immune cells, a key phenomenon in GBS. Recovery of GBS is characterized by the normalization of these abnormalities. Experimental allergic neuritis (EAN), the experimental model of GBS has strikingly similar immunological abnormalities. The treatments of GBS, PE and IVIGs, mainly target the humoral component of the immune response. IFN-B is a cellular immunomodulator that inhibits antigen presentation, TNF-alpha production and binding, modulates macrophages properties. IFN-B increases anti-inflammatory T cell functions and cytokines, such as TGF-B1. IFN-B has important properties on leukodiapedesis by modulating expression of cell adhesion molecules and the MMP-9 proteinase. IFN-B has been used with success in EAN, in some patients with acute exacerbation of chronic inflammatory demyelinating polyneuropathy, and in one patient with GBS. Pathophysiology of GBS, IFN-B properties, and experimental studies support the initiation of a trial of IFN-B in GBS.

Impaired redox status and cytochrome c oxidase deficiency in patients with polymyalgia rheumatica

OBJECTIVE

To evaluate redox status and muscular mitochondrial abnormalities in patients with polymyalgia rheumatica (PMR).

METHODS

Prospective evaluation of deltoid muscle biopsy in 15 patients with PMR. Fifteen subjects matched for age and sex, with histologically normal muscle and without clinical evidence of myopathy, were used as controls. Cryostat sections of muscle were processed for conventional dyes, cytochrome c oxidase (COX), usual histochemical reactions, and Sudan black. A total of 300-800 fibres was examined in each case. Blood lactate, pyruvate, and lactate/pyruvate ratio were determined in all patients.

RESULTS

Ragged red fibres were found in eight patients with PMR and accounted for 0-0.5% of fibres. Focal COX deficiency was found in 14 (93%) of 15 patients and in nine (60%) of 15 controls. COX deficient fibres were more common in patients with PMR (range 0-2.5%; mean 0.9%) than in controls (range 0-1.2%; mean 0.3%) (paired t test, p=0.001). Seven (47%) of 15 patients had high blood lactate levels (1.50-2.60 mmol/l) or high blood lactate/pyruvate ratios (22-25).

CONCLUSIONS

PMR is associated with mitochondrial abnormalities not solely related to the aging process.

Cytochrome c oxidase deficiency in the muscle of patients with zidovudine myopathy is segmental and affects both mitochondrial DNA- and nuclear DNA-encoded subunits

Zidovudine (AZT) can induce a mitochondrial disorder associated with mitochondrial (mt) DNA depletion affecting skeletal muscle, heart, and liver. Zidovudine myopathy is characterized by ragged-red fibers and partial cytochrome c oxidase (COX) deficiency. We evaluated at a single fiber level the expression of COX II (mtDNA-encoded) and COX IV (nuclear DNA-encoded) subunits in 12 HIV-infected patients with zidovudine myopathy. We also evaluated COX activity on longitudinal muscle sections in one patient. In all patients, evaluation of the expression of COX II and COX IV subunits showed focal deficiency. All fibers negative for COX II or COX IV were negative by COX histochemistry; 32-92% (median 61%) of COX-negative fibers were negative for COX II antigens, and 7-58% (median 28%) were negative for COX IV antigens. One hundred and thirty-nine of 317 COX-negative fibers 139 (43.8%) were selectively negative for COX II; 28 of 317 (8.8%) COX-negative fibers were selectively negative for COX IV. A study of longitudinal distribution of COX activity demonstrated that COX deficiency was segmental with blurred borders, as previously observed in patients with myoclonus epilepsy with ragged-red fibers. We conclude that proteins encoded by mtDNA are predominantly, but not exclusively, involved in zidovudine myopathy. Our results confirm the value of single muscle fiber evaluation in the assessment of mitochondrial abnormalities related to zidovudine.

DNA breaks detected by in situ end-labelling in dorsal root ganglia of patients with AIDS

Distal sensory axonal polyneuropathy (DSP) is the most frequent HIV-associated peripheral neuropathy. DSPs tend to occur in full-blown AIDS and worsen as CD4 cell counts decrease in blood. To assess a possible role for apoptosis in the pathogenesis of the neuropathy, we used in situ end-labelling (ISEL) detecting DNA strand breaks in DRG neurons of 19 HIV-infected patients, of whom nine had axonal polyneuropathy, and 11 controls. Sensory neurons with ISEL-assessed DNA breaks were observed in 9/19 patients with AIDS, 0/3 patients with pre-AIDS, and 1/11 controls. The prevalence of DNA breaks in neurons was higher in AIDS patients than in controls (P < 0.05). Among AIDS patients, DNA breaks in neurons were more abundant in patients with peripheral neuropathy (P < 0.04). It is possible that DNA breaks of DRG neurons induce the axonopathy and consequently play a role in the pathogenesis of DSP. It cannot be excluded, however, that DNA breaks could represent the result rather than the cause of axonopathy. We suggest that ISEL may detect neurons that were primed to apoptosis before death in relation with the HIV infection, and undergo DNA fragmentation at time of death, rather than neurons that underwent premortem both priming and triggering steps of the apoptotic process. This hypothesis could explain why most ISEL-positive neurons lack typical apoptotic morphology and why normal controls do not show ISEL positive cells.

Acute, relapsing brain oedema with diffuse blood-brain barrier alteration and axonal damage in the acquired immunodeficiency syndrome

A 38-year-old homosexual male with AIDS suffered four neurological episodes including headaches, confusion, visual impairment, memory disturbances, and dysarthria which resolved spontaneously in a few days. He was admitted to hospital during a fifth episode. Neurological examination revealed a cerebellar syndrome. General examination was normal. CD4 count was 90. CSF contained two WBCs/mm(3) and 12.30 mg/dL protein. MRI revealed diffuse ill defined increased signal on T2-weighted images in the white matter. His condition worsened rapidly with vomiting and he died 1 month after admission. Neuropathological examination revealed diffuse brain oedema with ventricular compression, central diencephalic herniation and bilateral tonsilar herniation in the absence of a focal lesion. Microscopical examination revealed predominant involvement of the white matter with diffuse myelin pallor and massive perivascular dilatation containing an exudate expressing serum proteins and occasional macrophages. The same exudate was also diffuse in the leptomeninges. Parenchymal damage predominated around the perivascular spaces and included loosening of tissue, axonal damage with spheroids and reactive astrocytosis. There was no evidence of productive HIV encephalitis, no multinucleated giant cells; p24 immunostaining and RT-PCR for HIV genome were negative. There was neither significant inflammation nor microglial activation. In this illustrative case, the relapsing course of the neurological signs, the diffuse topography of the blood-brain barrier breakdown and the absence of local cause make it likely that the diffuse leak and axonal damage could be related to circulating factors.

[Chronic pseudo-hypertrophic myopathy in sarcoidosis. Apropos of 3 cases]

We report three cases of pseudohypertrophic chronic myopathy in patients with sarcoidosis. The patients were aged 41-50 years and were of African or mixed ethnic origin. All three patients had multiorgan sarcoidosis recently diagnosed by the presence of hiliary and/or mediastinal node enlargement with or without reticulomicronodulation in the lung fields. Hypertrophy of the proximal portion of the limbs dominated the clinical presentation. In 2 cases, the myopathy was preceded by myalgia and in 2 cases associated with muscle nodules. The muscle enzymes were elevated in 2 cases. The importance of tuberculoid granulomas and the discretion of the myopathy characterised the histological findings in all 3 cases. Cortisone therapy was given early and long-term treatment led to favorable course in 2 cases, probably due to the importance of the granulomatous muscle mass. In the third case, peripheral neuropathy developed.

Pulmonary hypertension in POEMS syndrome: a new feature mediated by cytokines

POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome is a rare variant of plasma cell dyscrasia with multiple systemic manifestations. We followed the progress of 20 patients with POEMS syndrome in our institution over a 10-yr period. Pulmonary hypertension (PH) was observed in five patients. All patients suffered dyspnea on exertion, which always appeared during an exacerbation of POEMS syndrome. The typical echocardiographic signs of PH were observed in all of these patients, and the median pulmonary-artery systolic pressure was 57 mm Hg (range, 50 to 65 mm Hg). Mean pulmonary-artery pressure during right side heart catheterization in two patients was 32 mm Hg. No other explanation for the PH could be found. Overproduction of cytokines was found in all cases, with high serum concentrations of interleukin-1beta, interleukin-6, tumor necrosis factor-alpha, and vascular endothelial growth factor. We suggest that PH should be added to the list of symptoms of POEMS syndrome. Cytokines may mediate POEMS syndrome-associated PH, as proposed for the other systemic manifestations of this disorder.

Polyarteritis nodosa, microscopic polyangiitis, and Churg-Strauss syndrome: clinical aspects, neurologic manifestations, and treatment

Polyarteritis nodosa (PAN), microscopic polyangiitis (MPA), and Churg-Strauss syndrome (CSS) all have neurologic symptoms and share characteristics and outcomes. Clinical aspects, neurologic manifestations, and treatment of these three diseases are examined in this article.

[Muscular complications in HIV infection]

Skeletal muscle involvement may occur at all stages of HIV-infection and represents the first manifestation of the disease into some patients. We usually classify muscle involvement in HIV-infected patients in one of the following categories: HIV-associated myopathy, a myopathy that meets the criteria for polymyositis in a majority of patients, and those for acquired nemaline myopathy in some cases (1); zidovudine myopathy, a reversible mitochondrial myopathy (2); HIV-wasting syndrome and other AIDS-associated cachexias (3); opportunistic infections and tumor infiltrations of the skeletal muscle (4); vasculitic processes and iron pigment deposits (5); HIV-associated myasthenia gravis (6) and rhabdomyolysis (7). Immunohistology for major histocompatibility complex class I antigen and histochemical reaction for cytochrome coxidase are helpful in the correct classification of a myopathy as HIV polymyositis or zidovudine myopathy.

[Neuronal apoptosis in the central and peripheral nervous system in HIV infection]

Apart from the unique changes characteristic of "HIV encephalitis", the productive infection of central nervous system by HIV, which predominantly involves the white matter and basal ganglia, evidence is accumulating that the cerebral cortex may also be affected in AIDS patients. Neuronal loss, suspected at microscopic examination, has been demonstrated by a number of morphometric studies. However, the cause and mechanism of neuronal damage in HIV infection, are still unclear. In an attempt to look for an apoptotic process at the origin of neuronal loss in AIDS, we examined samples of frontal cortex, temporal cortex and basal ganglia from 12 patients who died from AIDS and 4 asymptomatic HIV-positive cases using in situ end labelling to demonstrate characteristic DNA fragmentation. These were compared with 5 asymptomatic seronegative controls, and 2 seronegative patients with Alzheimer's disease. We demonstrated neuronal apoptosis in all AIDS cases and in the Alzheimer's cases. Positive in situ end labelling was usually associated with morphological changes suggestive of neuronal apoptosis. Semiquantitative assessment of the density of apoptotic neurons showed that neuronal apoptosis was more severe in atrophic brains. In contrast, no correlation was found between the density of apoptotic neurons and the presence of HIV-encephalitis or a history of cognitive disorder. Only occasional apoptotic neurons were found in one asymptomatic, HIV-positive case. Apoptosis was never observed in asymptomatic seronegative cases. We also looked for apoptotic neurons in spinal ganglia of 20 AIDS cases, 5 of whom had a terminal sensory distal neuropathy, and 10 seronegative controls devoid of neuropathy. Apoptotic neurons were found in 6 of the AIDS patients and in none of the seronegative controls. However, no correlation was found between the severity of neuronal apoptosis in the spinal root ganglia and the presence of absence of a terminal distal sensory neuropathy. Experimental studies tend to support our in vivo findings. HIV-infection of primary cultures of human embryonic central nervous system induced frequent apoptosis of neurons. No apoptotic cell was identified in non infected control cultures.

Cellular and mitochondrial toxicity of zidovudine (AZT), didanosine (ddI) and zalcitabine (ddC) on cultured human muscle cells

Zidovudine (AZT), didanosine (ddI) and zalcitabine (ddC) are the reference antiretroviral therapy in patients with AIDS. A toxic mitochondrial myopathy can be observed in patients treated with AZT, but not with ddI and ddC. All 3 compounds can inhibit mitochondrial (mt)DNA polymerase and cause termination of synthesis of growing mtDNA strands and mtDNA depletion. The propensity to injure particular target tissues is unexplained. In our work, cultured muscle cells prepared from human muscle biopsies, were exposed to various concentrations of AZT (4-5000 micromol/l), ddI (5-1000 micromol/l) and ddC (1-1000 micromol/l) for 10 days. We evaluated cell proliferation and differentiation and measured lipid droplet accumulation, lactate production and respiratory chain enzyme activities. All 3 compounds induced a dose-related decrease of cell proliferation and differentiation. AZT seemed to be the most potent inhibitor of cell proliferation. AZT, ddI and ddC induced cytoplasmic lipid droplet accumulations, increased lactate production and decreased activities of COX (complex IV) and SDH (part of complex II). NADHR (complex I) and citrate sinthase activities were unchanged. Zalcitabine (ddC) and, to a lesser extent, ddI, were the most potent inhibitors of mitochondrial function. In conclusion, AZT, ddI and ddC all exert cytotoxic effects on human muscle cells and induce functional alterations of mitochondria possibly due to mechanisms other than the sole mtDNA depletion. Our results provide only a partial explanation of the fact that AZT, but not ddI and ddC, can induce a myopathy in HIV-infected patients. AZT myopathy might not simply result from a direct mitochondrial toxic effect of crude AZT.

Evidence of a non-conventional role for the urokinase tripartite complex (uPAR/uPA/PAI-1) in myogenic cell fusion

Urokinase can form a tripartite complex binding urokinase receptor (uPAR) and plasminogen activator inhibitor type-1 (PAI-1), a component of the extracellular matrix (ECM). The components of the tripartite complex are modulated throughout the in vitro myogenic differentiation process. A series of experiments aimed at elucidating the role of the urokinase tripartite complex in the fusion of human myogenic cells were performed in vitro. Myogenic cell fusion was associated with increased cell-associated urokinase-type plasminogen activator (uPA) activity, cell-associated uPAR, and uPAR occupancy. Incubation of cultures with either uPA anticatalytic antibodies, or the amino-terminal fragment of uPA (ATF), which inhibits competitively uPA binding to its receptor, or anti-PAI-1 antibodies, which inhibit uPA binding to PAI-1, resulted in a 30 to 47% decrease in fusion. Incubation of cultures with the plasmin inhibitor aprotinin did not affect fusion. Decreased fusion rates induced by interfering with uPAR/uPA/PAI-1 interactions were not associated with significant changes in mRNA levels of both the myogenic regulatory factor myogenin and its inhibitor of DNA binding, Id. Incubation of cultures with purified uPA resulted in a decrease in fusion, likely due to a competitive inhibition of PAI-1 binding of endogenous uPA. We conclude that muscle cell fusion largely depends on interactions between the members of the urokinase complex (uPAR/uPA/PAI-1), but does not require proteolytic activation of plasmin. Since the intrinsic muscle cell differentiation program appears poorly affected by the state of integrity of the urokinase complex, and since cell migration is a prerequisite for muscle cell fusion in vitro, it is likely that the urokinase system is instrumental in fusion through its connection with the cell migration process. Our results suggest that the urokinase tripartite complex may be involved in cell migration in a non conventional way, playing the role of an adhesion system bridging cell membrane to ECM.

Antineutrophil cytoplasmic antibodies, abnormal angiograms and pathological findings in polyarteritis nodosa and Churg-Strauss syndrome: indications for the classification of vasculitides of the polyarteritis Nodosa Group

The present study attempted to define the clinical, radiological, immunological and pathological characteristics of microscopic polyangiitis (MPA), and to separate them from classic PAN (c-PAN) and Churg-Strauss syndrome (CSS). In most cases, patients presenting microaneurysms and/or multiple vessel stenoses, which reflect medium-sized vessel involvement, did not have antineutrophil cytoplasmic antibodies (ANCA) (6.6%). Conversely, patients with glomerulonephritis almost never had abnormal angiograms. Furthermore, the clinical characteristics of ANCA-positive patients also indicate small-sized vessel involvement. Skin involvement (73.1 vs 26.7%, P < or = 0.05), glomerulonephritis (38.5 vs 0%, P < or = 0.001) and the presence of ANCA (34.6 vs 6.7%, P < or = 0.05) were significantly more frequent in patients with normal than abnormal angiograms, respectively. Conversely, hypertension (66.7 vs 23.1%, P < or = 0.02), renal vasculitis (46.7 vs 0%, P < or = 0.001) and hepatitis B antigenaemia (60 vs 11.5%, P < or = 0.01) were significantly more common in patients with abnormal angiograms. Stratification of patients according to vessel size showed that, except for skin involvement (P < or = 0.05) and glomerulonephritis (P < or = 0.01), which are direct manifestations of small-sized vessel diseases, clinical symptoms of PAN or CSS, angiographic findings and ANCA were not correlated to arteriole size. Although at present it is not possible to separate definitively MPA from c-PAN, our results show that ANCA should be considered diagnostic for MPA and, in most cases, should be an exclusion criterion for c-PAN. Conversely, small-sized vessel involvement can be observed in patients presenting characteristics of c-PAN, MPA or CSS and, therefore, is not a sufficient criterion for assigning diagnosis.

Lipid-lowering drugs and mitochondrial function: effects of HMG-CoA reductase inhibitors on serum ubiquinone and blood lactate/pyruvate ratio

1. Statins inhibit synthesis of mevalonate, a precursor of ubiquinone that is a central compound of the mitochondrial respiratory chain. The main adverse effect of statins is a toxic myopathy possibly related to mitochondrial dysfunction. 2. This study was designed to evaluate the effect of lipid-lowering drugs on ubiquinone (coenzyme Q10) serum level and on mitochondrial function assessed by blood lactate/pyruvate ratio. 3. Eighty hypercholesterolaemic patients (40 treated by statins, 20 treated by fibrates, and 20 untreated patients, all 80 having total cholesterol levels > 6.0 mmol l-1) and 20 healthy controls were included. Ubiquinone serum level and blood lactate/pyruvate ratio used as a test for mitochondrial dysfunction were evaluated in all subjects. 4. Lactate/pyruvate ratios were significantly higher in patients treated by statins than in untreated hypercholesterolaemic patients or in healthy controls (P < 0.05 and P < 0.001). The difference was not significant between fibratetreated patients and untreated patients. 5. Ubiquinone serum levels were lower in statin-treated patients (0.75 mg l-1 +/- 0.04) than in untreated hypercholesterolaemic patients (0.95 mg l-1 +/- 0.09; P < 0.05). 6. We conclude that statin therapy can be associated with high blood lactate/ pyruvate ratio suggestive of mitochondrial dysfunction. It is uncertain to what extent low serum levels of ubiquinone could explain the mitochondrial dysfunction.

Acute arterial obliteration: a new feature of the POEMS syndrome?

The POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammapathy, and skin changes) syndrome is a rare variant of plasma cell dyscrasia with multisystemic manifestations. We present 4 cases with arterial symptoms typical of acute arterial obliteration (AAO) and review 9 similar cases in the literature. The clinical course of AAO was unusual and particularly severe when affecting the lower limbs; recurrent events required amputations. As demonstrated by angiographic and histologic studies, thrombotic and atheromatous lesions were the main pathologic features of AAO. Atherosclerotic risk factors were absent or moderate in 3 of our cases, and no cause of thrombosis other than the POEMS syndrome was found. A high production of cytokines was found in all cases, with elevated serum levels of interleukin-1 beta (9/9 samples), interleukin-6 (7/9 samples), and tumor necrosis factor-alpha (6/9 samples). We suggest that arterial manifestations should be added to the spectrum of manifestations of the POEMS syndrome. Cytokines may mediate the POEMS syndrome-associated AAO, as previously proposed for the other systemic manifestations of this disorder.

Cytochrome c oxidase deficiencies in the muscle of patients with inflammatory myopathies

We studied mitochondrial function in inflammatory myopathies, using cytochrome c oxidase (COX) reaction on muscle biopsy samples from 30 patients (15 with dermatomyositis, 12 with polymyositis, and 3 with inclusion body myositis) and 30 age-matched controls. We also performed immunocytochemistry for COX II and COX IV subunits in 7 of these patients who had COX deficiency. COX-deficient fibers were a constant finding in patients or controls older than 65 years and the percentage of COX-deficient fibers correlated with age in both patients and controls. Focal COX deficiency was found in 24 patients (13 of 15 with dermatomyositis, 8 of 12 with polymyositis, and 3 of 3 with inclusion body myositis) and 18 controls. The percentages of COX-deficient fibers were higher in patients with inflammatory myopathies (range: 0-4.7%; mean: 1.2%) than in age-matched controls (range: 0-1.9%; mean: 0.4%) (P < 0.01). In the subgroup of patients under age 65, COX-deficient fibers were more frequent in dermatomyositis than in polymyositis (mean: 0.8% vs 0.2%, P = 0.02). In patients with dermatomyositis, capillary loss correlated positively with COX deficiency (P < 0.02). Immunocytochemistry for COX II and IV showed that 82% of COX-negative fibers were COX II-negative and 26% were COX IV-negative, suggesting that proteins encoded by mitochondrial DNA are predominantly, but not exclusively, involved in COX deficiency. We conclude that mitochondrial dysfunction and COX deficiency can occur in inflammatory myopathies. Such a mitochondrial dysfunction is not solely related to the aging process. We suggest that muscle ischemia contributes to mitochondrial dysfunction in dermatomyositis.

Dermatomyositis without muscle weakness. Long-term follow-up of 12 patients without systemic corticosteroids

BACKGROUND AND DESIGN

We retrospectively studied 12 patients with dermatomyositis (DM) with at least one laboratory criterion of muscle involvement but without muscle weakness. We reported their outcome without systemic corticosteroid treatment and searched for distinctive baseline data and associated neoplasia among a group of 29 patients with classic DM.

RESULTS

After a mean follow-up of 5.3 years, complete or partial skin improvement occurred in nine patients with DM without muscle weakness, and muscle enzyme levels were normalized in all. When compared with the classic DM group, no statistical differences were found for associated neoplasia or for any baseline data studied except, as expected, for muscle parameters.

CONCLUSIONS

The lack of distinctive baseline data between DM without muscle weakness and classic DM suggests that there is a continuum from amyopathic to classic DM. However, DM without muscle weakness is a clinical entity with respect to favorable long-term prognosis. Unless frank muscle weakness develops, treatment with systemic corticosteroids can be avoided.

Cytochrome c oxidase deficiency in zidovudine myopathy affects perifascicular muscle fibres and arterial smooth muscle cells

In order to assess the pathogenesis of myopathological alterations induced by zidovudine, we studied muscle samples from 21 patients infected by human immunodeficiency virus with zidovudine myopathy. Cytochrome c oxidase histoenzymatic reaction was evaluated in skeletal muscle fibres and arterial smooth muscle cells. Other investigations included immunocytochemistry for membrane attack complex and endomysial capillary counts. All patients had partial cytochrome c oxidase deficiency. A perifascicular distribution of cytochrome c oxidase-deficient fibres was found in 14 of 21 patients. Cytochrome c oxidase-deficient fibres were significantly more frequent in perifascicular areas than in the complete muscle sections (28% vs 12%, P < 0.001). Cytochrome c oxidase-deficient arteries were found in 11 patients, of whom 10 also had a perifascicular deficiency. Mononuclear microvascular inflammation was observed in four patients and membrane attack complex deposition in capillary walls in two patients. The capillary counts were not significantly different in the patients and in the controls. These results suggest that, in addition to a direct action of zidovudine on mitochondrial DNA, chronic muscle ischaemia related to zidovudine-induced vascular dysfunction might be implicated at the inception of muscle damage in zidovudine myopathy.

[Muscular involvement in HIV infection]

Skeletal muscle involvement may occur at all stages of HIV-infection and represents the first manifestation of the disease in some patients. We usually classify muscle involvement in HIV-infected patients in one of the following categories: (1) HIV-associated myopathy, a myopathy that meets the criteria for polymyositis in a majority of patients, and those for acquired nemaline myopathy in some; (2) zidovudine myopathy, a reversible mitochondrial myopathy; (3) the HIV-wasting syndrome and other AIDS-associated cachexias; (4) opportunistic infections and tumoral infiltrations of the skeletal muscle; (5) vasculitic processes and iron pigment deposits; (6) HIV-associated myasthenia gravis and (7) rhabdomyolysis. Immunohistology for major histocompatibility complex class I antigen and histochemical reaction for cytochrome c oxidase are helpful in correct classification of a myopathy as HIV polymyositis or zidovudine myopathy.

Myopathy and HIV infection

Skeletal muscle involvement may occur at all stages of HIV infection. The most simple classification of muscular disorders in HIV-infected patients is 1) HIV-associated myopathies, 2) zidovudine myopathy, 3) HIV wasting syndrome, and 4) opportunistic infections and tumoral infiltrations of muscle. Immunohistology for major histocompatibility complex class I antigen and histochemical reaction for cytochrome c oxidase are helpful in correctly classifying a myopathy as HIV polymyositis or zidovudine myopathy. Studies of cytokine expression in HIV-infected patients and of supplementation with compounds such as carnitine or micronutrients such as selenium might yield new insights into the pathogenesis and treatment of the various AIDS-associated muscular disorders.

Proinflammatory cytokine expression in cervicovaginal secretions of normal and HIV-infected women

Proinflammatory cytokines may stimulate replication and spread of HIV. To evaluate to what extent the female genital tract represents a source of these cytokines, we determined TNF-alpha, IL-1 beta and IL-6 concentrations in paired serum and cervicovaginal washings from 45 HIV-negative and 50 HIV-positive women, and then we looked for the relevant mRNAs in cervicovaginal secretions by RT-PCR. Cytokines were detected by ELISA in cervicovaginal fluid from most healthy women. Cervicovaginal washing levels of TNF-alpha were increased above the control value +2 SD in 11/50 HIV-positive women, those of IL-1 beta in 13/50, and those of IL-6 in 14/50. The prevalences of TNF-alpha, IL-1 beta and IL-6 increase and their levels in cervicovaginal washings were significantly higher in the 20 patients at stage IV than in the 30 patients at earlier stages of the disease. In HIV-infected patients, serum and cervicovaginal washing levels correlated positively for TNF-alpha and IL-6, but not for IL-1 beta. Nine of 15 cytokine mRNAs determinations were positive in HIV-infected women versus 1 of 15 in controls (P < 0.01). These findings could be relevant to bidirectional heterosexual transmission of HIV.

Fenoverine-induced rhabdomyolysis

Fenoverine is a spasmolytic drug that inhibits calcium channel currents. We describe the clinicopathologic findings in two patients with fenoverine-induced rhabdomyolysis, of whom one died. A transient left-bundle-branch block was observed in both patients. In one case, pre-existing hepatic dysfunction may have induced accumulation of the drug. Concurrent treatment by fibrates, as observed in the second patient, may have been a predisposing factor for fenoverine-induced rhabdomyolysis. The incidence of muscular complications of fenoverine therapy could be reduced by avoidance of prescription of the drug in patients with hepatopathy or those being treated with cholesterol-lowering agents. Physicians should be aware of life-threatening adverse effects of apparently innocuous drugs.

Hyperplastic pacinian corpuscles: an uncommonly encountered lesion of the hand

The occurrence of hyperplastic pacinian corpuscles in the hand is rare, with only 13 cases reported in the literature. We describe such a case in a 70-year-old male who had worked as a locksmith for many years. A grape-like cluster of firm, rice-sized nodules was discovered in the subcutaneous tissue of the finger following a glass-induced injury. Histopathological findings revealed pacinian corpuscles to be increased in size and number. Individual corpuscles consisted of a central nerve fiber surrounded by 35 to 60 concentric lamellae (normal controls from other specimens: 13-15 lamellae). The external corpuscular diameter ranged from 1.8 to 3.2 mm (normal controls from other specimens: 1.6 mm). Immunohistochemistry showed positive staining with Leu 7 antibody and antiglial fibrillary acidic protein in the small nerves situated in the vicinity of the pacinian corpuscles, but not in the corpuscles themselves. The lesion reported here clearly differed from both neurofibroma with occasional pacinian differentiation and the so-called pacinian neurofibroma. There was no evidence of neurofibromatosis.

Acute rhabdomyolysis in patients infected by human immunodeficiency virus

To delineate the spectrum of rhabdomyolysis associated with human immunodeficiency virus (HIV) infection, we reviewed the clinical and pathologic data from nine HIV-infected individuals with acute rhabdomyolysis, and pooled data with those of 11 previously reported cases. Patients with rhabdomyolysis were at all stages of HIV infection and could be classified into three groups: (1) HIV-associated rhabdomyolysis (7 of 20), including rhabdomyolysis in primary HIV infection, recurrent rhabdomyolysis, and isolated rhabdomyolysis; (2) rhabdomyolysis induced by drugs (6 of 20), including didanosine; and (3) rhabdomyolysis at the end stage of acquired immunodeficiency syndrome (7 of 20), including opportunistic infections of muscle and rhabdomyolysis without a definite cause. Because prognosis, in part, depends on the cause of rhabdomyolysis, recognition of drug-induced or opportunistic infectious muscle disorders is required.

Expression of cytochrome c oxidase subunits encoded by mitochondrial or nuclear DNA in the muscle of patients with zidovudine myopathy

The present study was carried out to determine whether a selective decrease of mitochondrial (mt) DNA-encoded cytochrome c oxidase (CCO) subunits occurs in zidovudine myopathy, as expected with a compound known to induce selective mtDNA depletion. Fourteen HIV-infected patients with zidovudine myopathy were studied. Thirteen had partial CCO deficiency assessed by histochemistry. Western blot analysis of CCO subunits (II/III, IV, Va, Vb, VIa, VIb, VIc, VIIa, VIIb, and VIIc) was performed on muscle biopsy samples. We evaluated the mtDNA-encoded subunits to nuclear DNA-encoded subunits ratio with the II/III to IV ratio. Patients had either a selective decrease of mtDNA-encoded CCO subunits (3 patients), or an overall decrease affecting both mtDNA-and nuclear DNA-encoded subunits (5 patients), or a normal expression of CCO subunits (6 patients). Positive correlations could not be established between the pattern of expression of CCO subunits and total zidovudine intake, degree of inflammation, and percentages of ragged-red fibers or CCO-deficient fibers. The finding of a decrease of both mtDNA- and nuclear DNA-encoded CCO subunits suggests that a factor additional to zidovudine could be implicated in the pathogenesis of the myopathy, at least in some patients. New insights into the pathogenesis of zidovudine myopathy might come from the use of more sensitive methods, including evaluation of CCO subunits in single fibers.

Optimal handling of blood samples for routine measurement of lactate and pyruvate

Blood lactate and pyruvate are of critical importance for the diagnosis of mitochondrial diseases. To determine guidelines for adequate blood pyruvate and lactate determinations, intraindividual studies were carried out on 10 subjects, and the influences of venostasis, delay before deproteinization, and pH in the pyruvate assay were analyzed. Delays of 1 hour or more before deproteinization of samples induced major elevations of lactate-pyruvate ratios. The lactate-pyruvate ratio correlated positively with pH in the pyruvate assay, and inadequate pH appeared as a largely underestimated cause of misleading results, while venostasis was a minor source of errors.

Zidovudine therapy and HIV encephalitis: a 10-year neuropathological survey

OBJECTIVE

To assess the effect of zidovudine on productive HIV infection of the brain.

DESIGN

To correlate the incidence of HIV-specific neuropathology with zidovudine therapy.

PATIENTS

We examined 192 AIDS cases neuropathologically; 97 had never been treated with zidovudine, 72 had received zidovudine for over 3 months and until death, 23 had their treatment terminated more than 1 month before death.

RESULTS

The incidence of HIV encephalitis/HIV leukoencephalopathy (HIVE/HIVL) and of multinucleated giant cells (MGC) was significantly lower in patients who had received zidovudine than in those who had never received zidovudine. The yearly incidence of HIVE/HIVL increased between 1982 and 1987 probably because of improved survival, and decreased between 1987 and 1990 although the percentage of patients treated with zidovudine increased. Since 1991 the incidence of HIVE/HIVL and of MGC increased slightly. The percentage of patients treated with zidovudine until death decreased and that of patients whose treatment was terminated increased concomitantly. In 1989 and 1990, most patients whose treatment was terminated had MGC and HIVE/HIVL. In 1991 and 1992 this incidence decreased markedly, coinciding with the introduction of dideoxyinosine therapy.

CONCLUSION

Zidovudine treatment significantly reduces the occurrence of productive HIV infection of the brain in AIDS. Discontinuing zidovudine therapy may favour the occurrence of HIV encephalitis. Substitution therapy with dideoxyinosine also appears to protect against HIV-specific brain pathology.

Determination of the blood lactate:pyruvate ratio as a noninvasive test for the diagnosis of zidovudine myopathy

OBJECTIVE

To evaluate the use of the lactate: pyruvate ratio as a test for the detection of zidovudine myopathy.

METHODS

Twenty consecutive human immunodeficiency virus-infected patients with muscle involvement and 20 without muscle involvement were studied prospectively. Blood lactate and pyruvate levels and serum creatine kinase levels were tested, muscle involvement was assessed both clinically and electrophysiologically, and muscle biopsy was performed in patients with myopathy.

RESULTS

Nine patients had biopsy-proven zidovudine myopathy. All 9 had a high lactate:pyruvate ratio, with elevations on 2 of 2 determinations in 6 patients and on 1 of 2 in 3 patients. Two of 11 patients with other myopathies and 2 of 20 patients without myopathy had a high lactate:pyruvate ratio on 1 of 2 determinations.

CONCLUSION

The lactate:pyruvate ratio, when determined repeatedly, is a sensitive test for detecting mitochondrial muscular toxicity of zidovudine.

Uncompacted myelin lamellae in polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes syndrome. Ultrastructural study of peripheral nerve biopsy from 22 patients

Mechanisms of peripheral neuropathies in polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome are poorly understood. A peripheral nerve biopsy was performed in 22 patients. Of these 9 had histological features of Castleman's disease on lymph node biopsies, and 19 had a monoclonal lambda light chain in their serum. Certain nerve fragments were paraffin embedded, others were frozen and studied by direct immunofluorescence, and others were fixed for ultrastructural examination. Paraffin-embedded fragments did not show any amyloid deposits, and at direct immunofluorescence there was no immunoglobulin fixation. At ultrastructural examination, features of uncompacted myelin lamellae (UML) were present in 19 patients, and their frequency varied from 1% to 16% of myelinated fibres. Up to now UML have been reported only in 7 patients with POEMS syndrome in the literature. UML have also been noticed in a few cases of inflammatory demyelinating polyradiculoneuritis and inherited tendency to pressure palsy.