Distal extremity pain as a presenting feature of Fabry's disease

Objective

Fabry's disease (FD) is an X‐linked lysosomal storage disease. Distal extremity pain can be an early finding and renal, cardiac, and cerebrovascular complications may lead to complications and mortality. Treatment is now available for these patients, who may not be diagnosed correctly for years if the neuropathic nature of the pain is not recognized. The aim of our study was to describe early clinical features in a cohort of patients with FD and to emphasize the importance of distal extremity pain for early diagnosis.

Methods

The medical charts of 35 patients with FD followed in a single center were reviewed. When data were incomplete, a detailed pain questionnaire was sent to patients. Nonresponders were contacted by telephone.

Results

Distal extremity pain was present in the majority of cases (25 of 35). The mean age at diagnosis of FD was 43.5 years (range 5–77 years). Distal extremity pain was more prevalent in males than females and occurred mostly in childhood or adolescence. When present at onset, the disease progressed with subsequent organ system involvement. Misdiagnoses were frequent and included growing pains, juvenile idiopathic arthritis, connective tissue disease, and gout.

Conclusion

Clinical manifestations of FD, including episodes of severe pain in the feet and hands, often start in childhood. Distal extremity pain may be the only symptom for a considerable period of time. Patients may be wrongly labeled as having rheumatologic conditions, resulting in long diagnostic and therapeutic delays. Rheumatologists should be aware of the clinical aspects of FD and include it in the differential diagnosis of distal extremity pain in childhood and adolescence.     

Altered intracellular distribution of PrPC and impairment of proteasome activity in tau overexpressing cortical neurons

The microtubule associated protein tau plays a crucial role in Alzheimer's disease and in many neurodegenerative disorders collectively known as tauopathies. Recently, tau pathology has been also documented in prion diseases although the possible molecular events linking these two proteins are still unknown. We have investigated the fate of normal cellular prion protein (PrP(C)) in primary cortical neurons overexpressing tau protein. We found that overexpression of tau reduces PrP(C) expression at the cell surface and causes its accumulation and aggregation in the cell body but does not affect its maturation and glycosylation. Trapped PrP(C) forms detergent-insoluble aggregates, mainly composed of un-glycosylated and mono-glycosylated forms of prion protein. Interestingly, co-transfection of tau gene in cortical neurons with a proteasome activity reporter, consisting of a short peptide degron fused to the carboxyl-terminus of green fluorescent protein (GFP-CL1), results in down-regulation of the proteasome system, suggesting a possible mechanism that contributes to intracellular PrP(C) accumulation. These findings open a new perspective for the possible crosstalk between tau and prion proteins in the pathogenesis of tau induced-neurodegeneration.     

The amyloid-β₄₂ proxy, amyloid-β(25-35), induces normal human cerebral astrocytes to produce amyloid-β₄₂

Amyloid-β (Aβ) peptides in the brain of patients with Alzheimer's disease (AD) assemble into various aggregation forms that differ in size, structure, and functional properties. Previous studies have shown that Aβ binds to nicotinic acetylcholine receptors (nAChRs) and activates signaling cascades that result in the disruption of synaptic functions. These findings suggest a possible link between impaired cholinergic neurotransmitter function in AD and Aβ pathogenesis. However, it is not yet known how the different Aβ assemblies interact with specific nAChR subtypes. In the present study, we demonstrate that neurotoxicity in neuronal cells in culture induced by fibrillar Aβ(1-40) is prevented through an α7 nAChR-dependent mechanism. The α7 nAChR agonists varenicline and JN403 increased binding of the amyloid ligand [3H]PIB to fibrillar Aβ in AD frontal cortex autopsy tissue. This suggests that the presence of nAChR agonists may inhibit interaction of Aβ with α7 nAChRs and prevent the formation of Aβ/α7 nAChR complexes. This interaction was confirmed in binding assays with [12?I]Aβ(1-40) and α7 nAChRs in autopsy brain tissue homogenates from the frontal cortex. The functional effects of Aβ fibrils and oligomers on nAChRs were examined by measuring intracellular calcium ([Ca(2+)](i) levels. Oligomeric, but not fibrillar Aβ(1-40), increased [Ca(2+)](i) in neuronal cells, and this effect was attenuated by varenicline. Our findings demonstrate that fibrillar Aβ exerts neurotoxic effects mediated partly through a blockade of α7 nAChRs, whilst oligomeric Aβ may act as a ligand activating α7 nAChRs, thereby stimulating downstream signaling pathways.     

Long-term Retinal Function and Structure Rescue Using Capsid Mutant AAV8 Vector in the rd10 Mouse,a Model of Recessive Retinitis Pigmentosa

The retinal degeneration 10 (rd10) mouse is a well-characterized model of autosomal recessive retinitis pigmentosa (RP), which carries a spontaneous mutation in the β subunit of rod cGMP-phosphodiesterase (PDEβ). Rd10 mouse exhibits photoreceptor dysfunction and rapid rod photoreceptor degeneration followed by cone degeneration and remodeling of the inner retina. Here, we evaluate whether gene replacement using the fast-acting tyrosine-capsid mutant AAV8 (Y733F) can provide long-term therapy in this model. AAV8 (Y733F)-smCBA-PDEβ was subretinally delivered to postnatal day 14 (P14) rd10 mice in one eye only. Six months after injection, spectral domain optical coherence tomography (SD-OCT), electroretinogram (ERG), optomotor behavior tests, and immunohistochemistry showed that AAV8 (Y733F)-mediated PDEβ expression restored retinal function and visual behavior and preserved retinal structure in treated rd10 eyes for at least 6 months. This is the first demonstration of long-term phenotypic rescue by gene therapy in an animal model of PDEβ-RP. It is also the first example of tyrosine-capsid mutant AAV8 (Y733F)-mediated correction of a retinal phenotype. These results lay the groundwork for the development of PDEβ-RP gene therapy trial and suggest that tyrosine-capsid mutant AAV vectors may be effective for treating other rapidly degenerating models of retinal degeneration.     

Effects of Multimodal Analgesia on the Success of Mouse Embryo Transfer Surgery

Multimodal analgesia is promoted as the best practice pain management for invasive animal research procedures. Universal acceptance and incorporation of multimodal analgesia requires assessing potential effects on study outcome. The focus of this study was to assess effects on embryo survival after multimodal analgesia comprising an opioid and nonsteroidal antiinflammatory drug (NSAID) compared with opioid-only analgesia during embryo transfer procedures in transgenic mouse production. Mice were assigned to receive either carprofen (5 mg/kg) with buprenorphine (0.1 mg/kg; CB) or vehicle with buprenorphine (0.1 mg/kg; VB) in a prospective, double-blinded placebo controlled clinical trial. Data were analyzed in surgical sets of 1 to 3 female mice receiving embryos chimeric for a shared targeted embryonic stem-cell clone and host blastocyst cells. A total of 99 surgical sets were analyzed, comprising 199 Crl:CD1 female mice and their 996 offspring. Neither yield (pups weaned per embryo implanted in the surgical set) nor birth rate (average number of pups weaned per dam in the set) differed significantly between the CB and VB conditions. Multimodal opioid–NSAID analgesia appears to have no significant positive or negative effect on the success of producing novel lines of transgenic mice by blastocyst transfer.Abbreviation: CB, carprofen–buprenorphine; ES cell, embryonic stem cell; ET, embryo transfer; NSAID, nonsteroidal antiinflammatory drug; VB, vehicle–buprenorphineSurgical transfer of mouse embryos (embryonic transfer, ET) to surrogate dams is currently standard procedure in producing transgenic mouse models for research; the technique also is used to reestablish pathogen-free stocks of mice.²⁵ The procedure is invasive, in that it penetrates the peritoneal cavity and reproductive tract, often requires bilateral flank incisions through skin and muscle (each equivalent in length to approximately 10% of the snout–anus length), entails externalization and traction of internal organs, and requires wound closure. The ideal analgesia regimen for rodent ET would safely manage pain in the recipient female mouse without adversely affecting the quality or number of offspring from implanted embryos. Studies to date have found no effect of either the opioid buprenorphine or the nonsteroidal antiinflammatory drug (NSAID) flunixin on the number of embryos surviving after ET when compared with those after untreated or saline-placebo mice.^17,20 Furthermore, no study to date has looked at whether a multimodal combination of opioid and NSAID might either improve or decrease embryo survival.In the present study, we sought to compare reproductive outcomes of NSAID–opioid analgesia compared with opioid alone in embryo-transfer recipient mice by comparing outcomes from surrogate dams treated with carprofen and buprenorphine (CB) with those from dams treated with vehicle and buprenorphine (VB). We performed our analgesic comparison in the context of ongoing work in the University of California–San Francisco Transgenics Core. The Core receives targeted embryonic stem (ES) cell clones from laboratories and microinjects them into 8-cell embryos obtained from superovulated B6D2F1/Crl and Swiss Webster mice. The Core then surgically places these embryos into 1 to 3 recipient female mice, resulting in the generation of mice chimeric for the targeted ES cells and host blastocyst cells. To minimize any effects of learning curves, disruption of routine, and variability to ongoing research, the surgeon was instructed not to deviate from Core protocol in regard to animal anesthesia, handling, or housing. Therefore, the only change was to substitute buprenorphine with either carprofen–buprenorphine or vehicle–buprenorphine.Measured outcomes were the average number of weaned offspring produced per embryo implanted in the surgical set (that is, yield) and the average number of weaned offspring produced per dam in the surgical set (that is, birth rate).     

Assessment of myocardial fibrosis by endoventricular electromechanical mapping in experimental nonischemic cardiomyopathy

Cardiac fibrosis plays an important prognostic role in nonischemic cardiomyopathy (NICM), making it a potential therapeutic target. Although electromechanical mapping has been used to identify myocardial scar and facilitate intramyocardial intervention in the setting of ischemic heart disease, its application has not been described in NICM. We assessed the detection of myocardial fibrosis by endoventricular electromechanical mapping in an experimental model of NICM. The NOGA^® XP system was used to perform left ventricular mapping in twelve sheep that had undergone intracoronary doxorubicin dosing to induce NICM and in six healthy control animals. Results for endocardial voltage and mechanical shortening were evaluated against myocardial fibrosis burden, as determined by delayed-enhancement cardiac magnetic resonance and quantitative histomorphometry. Doxorubicin treatment resulted in dilated cardiomyopathy with moderate-severe impairment of left ventricular ejection fraction. Late gadolinium uptake was present in 9/12 doxorubicin animals, while histological fibrosis was approximately doubled compared to controls and was distributed multisegmentally throughout the left ventricle. Cardiomyopathy was associated with widespread reductions in unipolar and bipolar voltage amplitude and endocardial shortening. Each parameter showed an inverse relationship with the burden of fibrosis. Moreover, unipolar voltage and linear local shortening ratio displayed moderate accuracy for identifying myocardial segments with delayed contrast enhancement or increased fibrosis content, with optimal discriminatory thresholds of 7.5 mV and 11.5%, respectively. In this model of NICM, electromechanical mapping shows potential for delineating segmental differences in fibrosis. Pending clinical evaluation, it may therefore have applicability for directing targeted intramyocardial interventions in nonischemic heart disease.     

Prevalence of RET/PTC rearrangement in benign and malignant thyroid nodules and its clinical application

Fine-needle aspiration cytology (FNAC) is the primary means to distinguish benign thyroid nodules from malignant ones. About 20% of FNAC yields indeterminate results leading to unnecessary or delayed surgery. Many studies of tissue samples, the majority of which are retrospective advocate testing for RET rearrangements as a diagnostic adjunctive tool in thyroid nodules with indeterminate cytological findings. Because of the uncertain prevalence of RET rearrangements, its utility as a tumor marker is still controversial. The goal of this study was to establish the prevalence and the utility of testing for RET rearrangements in FNAC suspicious of cancer in a clinical setting. In this prospective study, we analysed a large series of thyroid aspirates by RT-PCR only and Southern blot on RT-PCR products for type 1 and 3 RET rearrangements. Results were compared with clinical findings, cytological diagnosis and final histopathology. By the higher sensitive Southern-blot on RT-PCR method, RET rearrangements were present in 36% of papillary thyroid carcinomas (RET/PTC-1, 12%; RET/PTC-3, 20%; both, 4%) and of 13.3% of benign nodules. By means of RT-PCR only, RET rearrangements were disclosed only in 14.3% of PTC and in 3.6% of benign nodules. No significant correlation was found between RET rearrangements and clinicopathological features of patients. These results indicate that molecular testing of thyroid nodules for RET/PTC must take into account of its high prevalence in benign nodules, inducing false positive diagnoses when the highly sensitive assay Southern-blot on RT-PCR is used. Its searching by means of RT-PCR only, has a specificity superior of conventional cytology and can be used to refine inconclusive FNAC.     

Effects of combination of sibutramine and l-carnitine compared with sibutramine monotherapy on inflammatory parameters in diabetic patients

The aim of the study was to evaluate the effects of 12-month treatment with sibutramine plus l-carnitine compared with sibutramine alone on body weight, glycemic control, insulin resistance, and inflammatory state in type 2 diabetes mellitus patients. Two hundred fifty-four patients with uncontrolled type 2 diabetes mellitus (glycated hemoglobin [HbA_1c] >8.0%) in therapy with different oral hypoglycemic agents or insulin were enrolled in this study and randomized to take sibutramine 10 mg plus l-carnitine 2 g or sibutramine 10 mg in monotherapy. We evaluated at baseline and after 3, 6, 9, and 12 months these parameters: body weight, body mass index, HbA_1c, fasting plasma glucose, postprandial plasma glucose, fasting plasma insulin, homeostasis model assessment of insulin resistance index, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, leptin, tumor necrosis factor-α, adiponectin, vaspin, and high-sensitivity C-reactive protein. Sibutramine plus l-carnitine gave a faster improvement of fasting plasma glucose, postprandial plasma glucose, lipid profile, leptin, tumor necrosis factor-α, and high-sensitivity C-reactive protein compared with sibutramine alone. Furthermore, there was a better improvement of body weight, HbA_1c, fasting plasma insulin, homeostasis model assessment of insulin resistance index, vaspin, and adiponectin with sibutramine plus l-carnitine compared with sibutramine alone. Sibutramine plus l-carnitine gave a better and faster improvement of all the analyzed parameters compared with sibutramine alone without giving any severe adverse effect.