A. Gallanti

Ubidecarenone in the treatment of mitochondrial myopathies: a multi-center double-blind trial

Forty-four patients with mitochondrial myopathies were treated with Ubidecarenone (CoQ10) for 6 months in an open multi-center trial. No side effects of the drug were observed. Sixteen patients showing at least 25% decrease of post-exercise lactate levels were selected as responders. Responsiveness was apparently not related to CoQ10 level in serum and platelets or to the presence or absence of mtDNA deletions. The responders were treated for a further 3 months with CoQ10 or placebo in the second blind part of the trial; no significant differences were observed between the 2 groups. It is not clear why CoQ10 had therapeutic effects in some patients and not in others with the same clinical presentation and biochemical defect, and we failed to identify candidate responders before treatment. At the dose of CoQ10 used in this study (2 mg/kg/day) the therapy requires a long administration time before a response is seen.

Desmin and Vimentin as markers of regeneration in muscle diseases

SummaryLocalization and distribution of desmin and vimentin have been studied in different neuromuscular disorders using monoclonal antibodies. We have demonstrated that vimentin, although virtually absent in normal human muscle fibers, is expressed in regenerating fibers in different neuromuscular disorders. Moreover, these fibers showed a strong positivity with desmin antibodies. In normal muscle fibers desmin is only localized at Z-line level. These results suggest that desmin and vimentin may be over-expressed during muscle regeneration processes, probably because of their importance in the structural organization of the sarcomere.

Congenital myopathy associated with abnormal accumulation of desmin and dystrophin

We studied a 5-yr-old boy clinically presenting congenital myopathy. Muscle biopsy showed sarcoplasmic accumulation of desmin filaments leading to diagnosis of desmin storage myopathy. An immunohistochemical study of other cytoskeletal proteins (actin, alpha-actinin, vimentin and dystrophin) was performed. Desmin positive areas reacted strongly with anti-mid-rod and C-terminus dystrophin antibodies. Probed with the same antibodies by Western blot, desmin and dystrophin showed normal molecular size but densitometric analysis demonstrated a parallel increase of both proteins. Our results indicate that intrasarcoplasmic desmin storage is associated with an abnormal accumulation of dystrophin. Since no other cytoskeletal proteins are accumulated this finding seems to be specific and suggests a possible structural and functional association between these two proteins in striated muscle.

A CAV3 microdeletion differentially affects skeletal muscle and myocardium.

To the Editor: In their article, Cagliani et al. observed a 40% reduction of caveolin-3 in the myocardium of a single patient and concluded that this mutation affects skeletal muscle and myocardium differentially. The findings raise concerns. Was cardiac involvement absent in the patients because there were no comprehensive cardiac investigations? At least history, clinical cardiologic examination, ECG, echocardiography, and 24hour ECG are necessary to assess cardiac involvement. Only rudimentary data of these investigations were provided for Patients III-1, III-4, and IV-1. Since cardiac involvement may also develop during the disease course, it is important to regularly follow up. Reduced myocardial caveolin-3 in Patient III-1 may be independent of the underlying mutation and could be also influenced by coronary heart disease or extracorporal circulation during surgery. In rabbits, chronic myocardial hypoxia increased nitric oxide synthase and simultaneously reduced caveolin-3. Was myocardial biopsy taken from a region supplied by a stenosed or normal coronary artery? Was the microdeletion also detected in the myocardium? Possibly hyper-CK-emia in Patient III-2 erroneously led to the diagnosis of myocardial infarction, although the patient died from cardiac involvement in caveolinopathy. Did Patient III-1 have myocardial thickening from arterial hypertension? Since caveolin-3 reduction manifests in the skeletal muscle with various different phenotypes, CI may be also heterogeneous, even within a single family. How do the authors explain that caveolin-3 knockout mice develop severe cardiomyopathy with hypertrophic cardiomyocytes, while humans with caveolin-3 mutations seem to show few cardiac abnormalities? How is it explained that increased nitric oxide synthase results in decrease of caveolin-3 and the development of hypertrophic cardiomyopathy in mice but not in humans? That reduction of caveolin-3 leads to cardiomyopathy is supported by inhibition of hypertrophy of rat cardiomyocytes by adenovirus-mediated overexpression of caveolin-3. On the contrary, overexpression of caveolin-3 induces severe cardiomyopathy in mice. Which are the modifying factors that led to muscle but not to cardiac disease? Figure 4 shows the muscle of a control subject. Did all control subjects undergo muscle biopsy? Atypical absences in Patient IV-1 may be associated with the expression of caveolin-3 also in endothelial cells and astrocytes of the brain. Besides skeletal muscle, myocardium, and brain, caveolin-3 also occurs in the smooth muscle. Did the authors find involvement also of smooth musclecontaining organs? To demonstrate cardiac involvement in caveolinopathies, thorough cardiologic examination, regular follow-ups, and investigations not only of a single patient but all mutation carriers are required.

A novel de novo nonsense mutation in ATP1A2 associated with sporadic hemiplegic migraine and epileptic seizures

Familial hemiplegic migraine (FHM) is a severe dominant form of migraine with aura associated with transient hemiparesis. Several other neurological signs and symptoms can be associated with FHM such as cerebellar abnormalities, cerebral edema and coma after minor head trauma, epileptic seizures and mental retardation. The sporadic form of hemiplegic migraine named SHM, presents with identical clinical symptoms. Here we report a case of a young hemiplegic migraine patient, 11 years old, who had the first hemiplegic attack at the age of 10 years. This patient has a clinical history of epileptic seizures in the childhood successfully controlled with drug therapy. No familiarity for any type of migraine or seizures can be observed within the paternal or maternal line. The patient who can therefore be considered a sporadic case, carries a novel de novo nonsense mutation p.Tyr1009X in the ATP1A2 gene (FHM2), leading to a truncated alpha-2 subunit of the Na+/K+-ATPase pump thus lacking the last 11 amino acids. The novel mutation identified confirms the role of FHM2 gene in forms of hemiplegic migraine associated with epilepsy with both familial and sporadic occurrence, and expands the spectrum of mutations related to these forms of the disease.

Clinical, morphological and immunological evaluation of six patients with dysferlin deficiency

Limb girdle muscular dystrophy (LGMD) type 2B and distal Miyoshi myopathy (MM) are caused by mutations in a recently discovered mammalian gene coding for a skeletal muscle protein called dysferlin. The protein is normally expressed at the skeletal muscle level and absent or reduced in affected patients. We selected a clinically heterogeneous population of Italian myopathic patients with clinical evidence of myopathy and/or hyperCKemia, EMG myopathic pattern, and no alterations of the dystrophin-sarcoglycan complex. Calpain, merosin, emerin and caveolin were also tested and found normal in all patients. Dysferlin immunohistochemical and Western blot analyses allowed us to identify six patients with dysferlin deficiency: one with distal myopathy, four with limb girdle myopathy and one with hyperCKemia. No apoptosis was found in any of the six muscle specimens, although expression of the pro-apoptotic Fas antigen was mildly increased in two cases. Inflammatory reactions were present in two of the six cases, but we found no evidence of immune-mediated processes.

Appearance and localization of dystrophin in normal human fetal muscle

We studied the localization of dystrophin in normal human fetal muscle by immunohistochemistry. Our results show the appearance of dystrophin at week 11 and a progressive organization of the protein along membrane in the following weeks of gestation. At week 22 almost all fibers show a clear membrane immunostaining. Concomitant analysis of muscle fiber‐type composition reveals no correlation between progressive appearance of dystrophin and muscle fiber‐type differentiation. Our findings suggest that synthesis and localization of dystrophin in developing human skeletal muscle is time‐related and probably independent of neuronal influences.

Dystrophin deficiency in a case of congenital myopathy

SummaryWe studied a 5-year-old boy who had the “floppy infant syndrome” and a dystrophic pattern on muscle biopsy. According to the clinical presentation and the histopathological findings the diagnosis of congenital muscular dystrophy with associated intellectual retardation was made. Immunohistochemical and immunoblot studies using anti-dystrophin antibodies showed complete absence of the protein in the patients muscle. DNA analysis using cDNA probes showed a deletion at the 5′ end of the dystrophin gene. Our observations on this patient suggest a new phenotypical variant of Duchenne muscular dystrophy.

Cytochrome c oxidase during human fetal development

Histochemical, biochemical and immunologic analysis of cytochrome c oxidase (COX) in skeletal muscle, heart and kidney during human fetal development was performed. COX histochemical activity was present only in few muscle fibres from the 11th to the 20th week of gestation. At the same developmental stage intrafusal muscle fibres, heart and kidney already showed strong activity. At the 28th week of gestation muscular COX activity was present in about 90% of the fibres. Tissue biochemical analysis confirmed these histochemical findings. Histochemical and biochemical findings compared to the immunocytochemical results and ELISA indicate that COX activity parallels the progressive synthesis of the enzyme in each tissue.

Migraine, stroke and patent foramen ovale: a dangerous trio?

The relationship between migraine, stroke and patent foramen ovale (PFO) has been the subject of considerable research efforts. Indeed, a lot of interest has focused on the potential benefits of percutaneous PFO closure. The aim of this article is to review data from the currently available literature. A total of 10 relevant studies were found in the literature, for a total of 1038 patients undergoing percutaneous PFO closure after events of cryptogenic stroke. Thirty-eight percent of these patients suffered from migraine. Combining the results of the available studies, 72% of patients were cured or improved significantly. Analysing the results according to migraine type, 81% of patients with migraine with aura had complete resolution or significantly improved as compared to 72% of patients with migraine without aura. Several limitations and drawbacks exist, however, and they are extensively discussed in this paper.