Evaluation of polyneuropathy markers in type 1 diabetic kidney transplant patients and effects of islet transplantation: neurophysiological and skin biopsy longitudinal analysis

OBJECTIVE

The purpose of this study was to evaluate whether islet transplantation may stabilize polyneuropathy in uremic type 1 diabetic patients (end-stage renal disease [ESRD] and type 1 diabetes), who received a successful islet-after-kidney transplantation (KI-s).

RESEARCH DESIGN AND METHODS

Eighteen KI-s patients underwent electroneurographic tests of sural, peroneal, ulnar, and median nerves: the nerve conduction velocity (NCV) index and amplitudes of both sensory action potentials (SAPs) and compound motor action potentials (CMAPs) were analyzed longitudinally at 2, 4, and 6 years after islet transplantation. Skin content of advanced glycation end products (AGEs) and expression of their specific receptors (RAGE) were also studied at the 4-year follow-up. Nine patients with ESRD and type 1 diabetes who received kidney transplantation alone (KD) served as control subjects.

RESULTS

The NCV score improved in the KI-s group up to the 4-year time point (P = 0.01 versus baseline) and stabilized 2 years later, whereas the same parameter did not change significantly in the KD group throughout the follow-up period or when a cross-sectional analysis between groups was performed. Either SAP or CMAP amplitudes recovered in the KI-s group, whereas they continued worsening in KD control subjects. AGE and RAGE levels in perineurium and vasa nervorum of skin biopsies were lower in the KI-s than in the KD group (P < 0.01 for RAGE).

CONCLUSIONS

Islet transplantation seems to prevent long-term worsening of polyneuropathy in patients with ESRD and type 1 diabetes who receive islets after kidney transplantation. No statistical differences between the two groups were evident on cross-sectional analysis. A reduction in AGE/RAGE expression in the peripheral nervous system was shown in patients receiving islet transplantation.

Multimodal evoked potentials to assess the evolution of multiple sclerosis: a longitudinal study

BACKGROUND

Evoked potentials are used in the functional assessment of sensory and motor pathways. Their usefulness in monitoring the evolution of multiple sclerosis has not been fully clarified.

OBJECTIVE

The aim of this longitudinal study was to examine the usefulness of multimodal evoked potential in predicting paraclinical outcomes of disease severity and as a prognostic marker in multiple sclerosis.

METHODS

Eighty four patients with clinically definite multiple sclerosis underwent Expanded Disability Status Scale (EDSS) and functional system scoring at study entry and after a mean (standard deviation) follow-up of 30.5 (11.7) months. Sensory and motor evoked potentials were obtained in all patients at study entry and at follow-up in 64 of them, and quantified according to a conventional score.

RESULTS

Cross-sectionally, the severity of each evoked potential score significantly correlated with the corresponding functional system (0.32 < R < 0.60, p < 0.01, for all but follow-up visual evoked potential) and with EDSS (0.34 < R < 0.61; p < 0.001 for all but brain stem evoked potential). EDSS significantly correlated with global evoked potential score severity (baseline R = 0.60, follow-up R = 0.46, p < 0.001). Using longitudinal analysis, only changes in somatosensory evoked potential scores were significantly correlated with changes of sensory functional system (R = 0.34, p = 0.006). However, patients with multiple sclerosis with disability progression at follow-up had more severe baseline evoked potential scores than patients who remained stable. Patients with severe baseline global evoked potential score (higher than the median value) had a risk of 72.5% to progress on disability at follow-up, whereas patients with multiple sclerosis with lower scores had a risk of only 36.3%.

CONCLUSIONS

These results suggest that evoked potential is a good marker of the severity of nervous damage in multiple sclerosis and may have a predictive value regarding the evolution of disability.

Linkage analysis and disease models in benign familial infantile seizures: a study of 16 families

PURPOSE

Benign familial infantile seizures (BFIS) is a genetically heterogeneous condition characterized by partial seizures, onset age from 3 to 9 months, and favorable outcome. BFIS loci were identified on chromosomes 19q12-13.1 and 16p12-q12, allelic to infantile convulsions and choreathetosis. The identification of SCN2A mutations in families with only infantile seizures indicated that BFNIS and BFIS may show overlapping clinical features. Infantile seizures also were in a family with familial hemiplegic migraine and mutations in the ATP1A2 gene. We have examined the heterogeneous genetics of BFIS by means of linkage analysis.

METHODS

Sixteen families were examined. Probands underwent neurologic examination, at least one EEG recording, and, when possible, brain CT and MRI. Clinical information about relatives was collected. Families with SCN2A or ATP1A2 mutations were excluded from the study. Chromosome 16p and 19q loci were examined by linkage analysis using two models that differed in penetrance rate. Genetic heterogeneity was evaluated with both models.

RESULTS

Clinical information was available for 124 members of affected families. BFIS was diagnosed in 69 subjects. One patient without BFIS had a single febrile seizure, and another had rare episodes of paroxysmal dystonia. Evidence of linkage was obtained only for chromosome 16. Moreover, the high penetrance allowed the identification of genetic heterogeneity.

CONCLUSIONS

Our data confirm the relevance of the chromosome 16 locus in BFIS and suggest the presence of an additional locus. This study shows that the genetic model used affects the outcome of linkage analysis.

Pharmacogenetics of autoimmune diseases: research issues in the case of Multiple Sclerosis and the role of IFN-beta

Pharmacogenetics of auto-immune diseases is a complex field of application for this relatively new discipline, since we still have a partial knowledge of the biological mechanisms of the disease and of the drugs currently used to treat it. We address a few key issues that emerge when planning a pharmacogenetic investigation in Multiple Sclerosis and that relate to the complexities existing at the biological-genetic level and at the phenotypic characterization. In fact, we think that a clearer characterization of the clinical phenotype representing the end-point of the investigation together with a critical appraisal of the multi-faceted dimension of the genetic component of either the disease and the pharmacogenetic profile of the drug investigated, will help to design more thorough study and to achieve deeper understanding of the practical results. We will primarily focus our research considerations on the role of Interferon Beta (IFN-beta) as a prototypal therapeutic agent in Multiple Sclerosis.

Motor evoked potentials in a mouse model of chronic multiple sclerosis

We tested cortical motor evoked potentials (cMEPs) as a quantitative marker for in vivo monitoring of corticospinal tract damage in a murine multiple sclerosis model (experimental autoimmune encephalomyelitis, EAE). The cMEPs, previously standardized in naive C57BL/6 developing and adult mice, were studied longitudinally in adult EAE mice. Central conduction times (CCTs) increased significantly shortly before the earliest clinical signs developed (10 days postimmunization, dpi), with peak delay in acute EAE (20-40 dpi). In clinically stable disease (80 dpi), CCTs did not increase further, but cMEP amplitude declined progressively, with complete loss in >80% of mice at 120 dpi. Increase in CCT correlated with presence of inflammatory infiltrates and demyelination in acute EAE, whereas small or absent cMEPs were associated with continuing axonal damage in clinically-stabilized disease and beyond (>80 dpi). These results demonstrate that cMEPs are a useful method for monitoring corticospinal tract function in chronic-progressive EAE, and provide insight into the pathological substrate of the condition.

No evidence of ATP1A2 involvement in 12 multiplex Italian families with benign familial infantile seizures

A missense mutation in the gene encoding the alpha(2) subunit of the Na(+),K(+) ATPase pump (ATP1A2) was found in a family with both familial hemiplegic migraine (FHM) and Benign Familial Infantile Seizures (BFIC). As it is still unclear whether ATP1A2 is responsible for pure BFIC syndromes, we checked mutations of the ATP1A2 gene in probands of 12 Italian multiplex families with pure BFIC, who were negative for mutations in the SCN2A gene. We screened the ATP1A2 gene by denaturing high performance liquid chromatography (D-HPLC) and direct sequencing of DNA fragments showing an aberrant elution pattern. We found one exonic variant and five intronic variants, none leading to significant amino acid changes or causing a modification of the physiological mRNA maturation. The ATP1A2 gene does not appear to be involved in the ethiopathogenesis of pure BFIC syndromes, at least in the explored Italian multiplex families. It could be either responsible of a minority of cases, or of complex syndromes where BFIC and FHM co-occur.

Immunological patterns identifying disease course and evolution in multiple sclerosis patients

Reliable, and easy to measure, immunological markers able to denote disease characteristics in multiple sclerosis (MS) patients are still lacking. We applied a multivariate statistical analysis on results obtained by measuring-by real-time RT-PCR-mRNA levels of 25 immunological relevant molecules in PBMCs from 198 MS patients. The combined measurement of mRNA levels of IL-1beta, TNF-alpha, TGF-beta, CCL20 and CCR3 was able to distinguish MS patients from healthy individuals. CXCR5, CCL5, and CCR3 combined mRNA levels identify primary progressive MS patients while TNF-alpha, IL-10, CXCL10 and CCR3 differentiate relapsing MS patients. Our results indicate that multi-parametric analysis of mRNA levels of immunological relevant molecules in PBMCs may represent a successful strategy for the identification of putative peripheral markers of disease state and disease activity in MS patients.

The use of magnetic resonance imaging in multiple sclerosis: lessons learned from clinical trials

Magnetic resonance imaging (MRI) is an important paraclinical tool for the diagnosis of multiple sclerosis (MS) and for monitoring its disease course. The efficacy of most of the available MS disease-modifying treatments has been tested in clinical trials where MRI-derived quantities served as primary or secondary outcome measures. However, conventional MRI measures (i.e., the number and volume of contrast-enhancing, the volumes of T2-hyperintense and T1-hypointense lesions and the assessment of brain volume changes) are limited in terms of pathological specificity and, as a consequence, are modestly correlated with clinical measures of disease activity and have a modest prognostic value as predictors of MS evolution. In the present review, we discuss the main factors potentially responsible for the so-called 'clinical MRI paradox' and how modern quantitative MR-based techniques might contribute to, at least partially, overcome it. The lessons learned from MS trials suggest that future applications of MRI to assess MS evolution should rely upon the use of composite measures thought to reflect the various components of the disease, as well as on study protocols specifically designed on the individual trial characteristics.

Vascular endothelial growth factor gene variability is associated with increased risk for AD

Converging evidence points to a pivotal role of vascular endothelial growth factor (VEGF) in neuronal protection and a lack of its activity in neurodegenerative disorders. To investigate this possible association, we screened the VEGF gene promoter for various well-known single-nucleotide polymorphisms in a series of 249 consecutively recruited Italian patients with sporadic Alzheimer's disease (AD). Genetic analysis indicated different distributions of two single-nucleotide polymorphisms in the AD population compared with healthy control subjects. In particular, the frequencies of -2578A/A and -1198C/T genotypes were significantly greater in AD patients than in control subjects (23.7 vs 14.7% and 2.8 vs 0%, respectively). The -2578A/A genotype was associated with an increased risk for disease, independently of apolipoprotein E genotype. The risk was significantly increased with respect to various VEGF genotype combinations. In contrast, no difference in serum VEGF levels was detected comparing 96 patients and 49 control subjects. These findings suggest that polymorphisms within the promoter region of the VEGF gene confer greater risk for AD, probably by reducing its neuroprotective effect, and confirm the biological role of VEGF in neurodegenerative processes.

Effects of glatiramer acetate on relapse rate and accumulated disability in multiple sclerosis: meta-analysis of three double-blind, randomized, placebo-controlled clinical trials

Three randomized, double-blind, placebo-controlled trials have shown that glatiramer acetate (GA) is effective in reducing relapse rate in patients with relapsing-remitting (RR) multiple sclerosis (MS). Using raw data pooled from 540 patients, we performed a meta-analysis of these three trials, to investigate whether the extent of GA efficacy varies according to disease-related variables at study entry. Three regression models were developed to assess the efficacy of GA on the annualized relapse rate (primary outcome measure), on the total number of on-trial relapses and on the time to first relapse. We also explored the efficacy of GA on accumulated disability and the potential role of baseline clinical variables as predictors of relapse-rate variables and treatment efficacy. The mean adjusted annualized relapse rate on study was 1.14 in the pooled placebo-treated subjects and 0.82 in the pooled GA group (P = 0.004), indicating an average reduction in annualized relapse rate of 28%. About a one third reduction of the total number of on-trial relapses was also observed in patients receiving GA (P < 0.0001), who had a median time to the first relapse of 322 days versus a median time to the first relapse of 219 days seen in those receiving placebo (P = 0.01). A beneficial effect on accumulated disability was also found (risk ratio of 0.6; 95%; CI = 0.4-0.9; P = 0.02). The drug assignment (P = 0.004), baseline EDSS score (P = 0.02) and number of relapses during the two years prior to study entry (P = 0.002) were significant predictors of on-trial annualized relapse rate. No other demographic or clinical variable at baseline significantly influenced the treatment effect. This meta-analysis reaffirms the effectiveness of GA in reducing relapse rate and disability accumulation in RRMS, at a magnitude comparable to that of other available immunomodulating treatments. It also suggests that GA efficacy is not significantly influenced by the patients' clinical characteristics at the time of treatment initiation.

Evidence and age-related distribution of mtDNA D-loop point mutations in skeletal muscle from healthy subjects and mitochondrial patients

The progressive accumulation of mitochondrial DNA (mtDNA) alterations, ranging from single mutations to large-scale deletions, in both the normal ageing process and pathological conditions is a relevant phenomenon in terms of frequency and heteroplasmic degree. Recently, two point mutations (A189G and T408A) within the Displacement loop (D-loop) region, the control region for mtDNA replication, were shown to occur in skeletal muscles from aged individuals. We evaluated the presence and the heteroplasmy levels of these two mutations in muscle biopsies from 91 unrelated individuals of different ages (21 healthy subjects and 70 patients affected by mitochondrial encephalomyopathies). Overall, both mutations significantly accumulate with age. However, a different relationship was discovered among the different subgroups of patients: a higher number of A189G positive subjects younger than 53 years was detected in the subgroup of multiple-deleted patients; furthermore, a trend towards an increased risk for the mutations was evidenced among patients carrying multiple deletions when compared to healthy controls. These findings support the idea that a common biological mechanism determines the accumulation of somatic point mutations in the D-loop region, both in healthy subjects and in mitochondrial myopathy patients. At the same time, it appears that disorders caused by mutations of nuclear genes controlling mtDNA replication (the "mtDNA multiple deletions" syndromes) present a temporal advantage to mutate in the D-loop region. This observation may be relevant to the definition of the molecular pathogenesis of these latter syndromes.

Mutations in LGI1 cause autosomal-dominant partial epilepsy with auditory features

The epilepsies are a common, clinically heterogeneous group of disorders defined by recurrent unprovoked seizures. Here we describe identification of the causative gene in autosomal-dominant partial epilepsy with auditory features (ADPEAF, MIM 600512), a rare form of idiopathic lateral temporal lobe epilepsy characterized by partial seizures with auditory disturbances. We constructed a complete, 4.2-Mb physical map across the genetically implicated disease-gene region, identified 28 putative genes (Fig. 1) and resequenced all or part of 21 genes before identifying presumptive mutations in one copy of the leucine-rich, glioma-inactivated 1 gene (LGI1) in each of five families with ADPEAF. Previous studies have indicated that loss of both copies of LGI1 promotes glial tumor progression. We show that the expression pattern of mouse Lgi1 is predominantly neuronal and is consistent with the anatomic regions involved in temporal lobe epilepsy. Discovery of LGI1 as a cause of ADPEAF suggests new avenues for research on pathogenic mechanisms of idiopathic epilepsies.

Retrospective study of a large population of patients with asymptomatic or minimally symptomatic raised serum creatine kinase levels

A retrospective evaluation of asymptomatic subjects with persistent elevation of serum creatine kinase (CK) levels (hyperCKemia) was made in order to verify the presence of subclinical myopathy or idiopathic hyperCKemia and to define the most appropriate diagnostic pathway. Persistently increased serum CK levels are occasionally encountered in healthy individuals. In 1980 Rowland coined for them the term idiopathic hyperCKemia. Despite the increase of scientific knowledge, several healthy subjects with hyperCKemia still represent a problem for the clinician. We made a retrospective evaluation of 114 asymptomatic or minimally symptomatic individuals with incidentally detected persistent hyperCKemia. They underwent neurological examination and laboratory/instrumental evaluation. Skeletal muscle biopsy was performed and thoroughly investigated. Biochemical and genetic investigations were added in selected cases. Logistic regression analysis was applied. We diagnosed a neuromuscular disorder in 21 patients (18.4%), and found, by muscle biopsy and/or EMG, pathological but not conclusive findings in 57 subjects (50%). The statistic correlation between elevated serum CK levels and the probability of making a diagnosis changed according to the age of the patient.

CONCLUSIONS

Muscle biopsy is the basic tool for screening asymptomatic subjects with hyperCKemia. It allowed us to make a diagnosis of disease in 18.4% of patients, and to detect skeletal muscle abnormalities in 38.6% of the subjects. Interestingly, 31.6% of individuals had completely normal muscle findings. These best fit the "diagnosis" of idiopathic hyperCKemia.

Four new families with autosomal dominant partial epilepsy with auditory features: clinical description and linkage to chromosome 10q24

PURPOSE

Autosomal dominant partial epilepsy with auditory features (ADPEAF) is a rare form of nonprogressive lateral temporal lobe epilepsy characterized by partial seizures with auditory disturbances. The gene predisposing to this syndrome was localized to a 10-cM region on chromosome 10q24. We assessed clinical features and linkage evidence in four newly ascertained families with ADPEAF, to refine the clinical phenotype and confirm the genetic localization.

METHODS

We genotyped 41 individuals at seven microsatellite markers spanning the previously defined 10-cM minimal genetic region. We conducted two-point linkage analysis with the ANALYZE computer package, and multipoint parametric and nonparametric linkage analyses as implemented in GENEHUNTER2.

RESULTS

In the four families, the number of individuals with idiopathic epilepsy ranged from three to nine. Epilepsy was focal in all of those with idiopathic epilepsy who could be classified. The proportion with auditory symptoms ranged from 67 to 100%. Other ictal symptoms also were reported; of these, sensory symptoms were most common. Linkage analysis showed a maximum 2-point LOD score of 1.86 at (theta=0.0 for marker D10S603, and a maximum multipoint LOD score of 2.93.

CONCLUSIONS

These findings provide strong confirmation of linkage of a gene causing ADPEAF to chromosome 10q24. The results suggest that the susceptibility gene has a differential effect on the lateral temporal lobe, thereby producing the characteristic clinical features described here. Molecular studies aimed at the identification of the causative gene are underway.