Muscle stem cell behavior is modified by microRNA-27 regulation of Pax3 expression

Skeletal muscle stem cells are regulated by Pax3/7. During development, Pax3 is required for the maintenance of these cells in the somite and their migration to sites of myogenesis; high levels of Pax3 interfere with muscle cell differentiation, both in the embryo and in the adult. Quantitative fine-tuning of Pax3 is critical, and microRNAs provide a potential mechanism. We identify microRNA-27b (miR-27b), which directly targets the 3′-UTR of Pax3 mRNA, as such a regulator. miR-27b is expressed in the differentiating skeletal muscle of the embryonic myotome and in activated satellite cells of adult muscle. In vivo overexpression of a miR-27b transgene in Pax3-positive cells in the embryo leads to down-regulation of Pax3, resulting in interference with progenitor cell migration and in premature differentiation. In a complementary experiment, miR-27b inhibitors were transfected into cultures of adult muscle satellite cells that normally express miR-27b at the onset of differentiation, when Pax3 protein levels undergo rapid down-regulation. Interference with miR-27b function results in continuing Pax3 expression leading to more proliferation and a delay in the onset of differentiation. Pax7 levels are not affected. Introduction of miR-27b antagomirs at a site of muscle injury in vivo also affects Pax3 expression and regeneration in vivo. We therefore conclude that miR-27b regulates Pax3 protein levels and this down-regulation ensures rapid and robust entry into the myogenic differentiation program.     

Correlation between leukocytosis and thrombosis in Philadelphia-negative chronic myeloproliferative neoplasms

The evidence that leukocytes may contribute to the pathogenesis of thrombosis in Chronic Myeloproliferative Neoplasms is increasing but not definitive. To further enforces whether an increased leukocyte count is associated with thrombosis and whether this effect can be modulated by cytoreductive therapy, we analyzed the clinical course of 187 patients with Polycythemia Vera (PV) and Essential Thrombocythemia (ET) followed at two Italian Institutions over a period of 7 years. The association was measured at diagnosis or before thrombotic events: a multivariable analysis was carried out using data at baseline and time-dependent covariates. We found that white blood cells (WBC) count above 9.5 × 10⁹/L at diagnosis (baseline analysis) was associated with thrombosis during the follow-up (Hazard Ratio [HR] of 1.8, p 0.03). At the time-dependent analysis, therapy with hydroxyurea (HU), lowering by 35% the baseline WBC level, reduced such strength of association giving a HR of 1.3 (p value non significant). We found a trend between WBC level and thrombosis in untreated low-risk patients (RR of 1.9, 95% CI 0.9 to 3.1); in high-risk patients treated with HU this correlation was clearly lost (RR 1.1, 95% CI 0.2 to 2.7). Finally, we could not identify the presence of JAK2 ^V617F as a risk factor for thrombosis. Properly designed prospective studies should corroborate such results.     

The relationship between body weight and drug costs: An Italian population-based study

OBJECTIVES: This study determined the prevalence of 3 categories of body mass index (BMI)--normal weight, overweight, and obesity--in a sample of subjects from general clinical practice in Ravenna, Italy, and evaluated the impact of comorbidities associated with overweight and obesity on the costs of drug treatment from the perspective of the Italian national health system. METHODS: This was a cross-sectional study conducted in a sample of subjects aged > or =18 years from 10 general practices in the Ravenna local health unit (LHU) in 2001-2002. Subjects were invited to attend a screening visit at which weight and height were measured for determination of BMI, blood pressure was measured, and a fasting blood sample was obtained for laboratory tests. The screening examinations were conducted by 2 physicians at a dedicated practice. Normal weight, overweight, and obesity were defined as a BMI < or =24.9, between 25 and 29.9, and > or =30 kg/m2, respectively. The costs of classes of drug treatment that were reimbursable to the LHU in the 12 months before the screening examination were evaluated using the Ravenna LHU administrative databases. Drug treatments were classified as antihypertensive agents, statins, NSAIDs, gastroprotective drugs, antidiabetic agents, respiratory drugs, antiplatelet agents, antidepressants, and all other drugs. The data were analyzed by age group. RESULTS: Of the 2622 subjects in the sample, 1256 (47.9%) had a normal BMI, 918 (35.0%) were overweight, and 448 (17.1%) were obese. The prevalence of overweight and obesity increased in relation to age up to 50-59 years (P < 0.001), after which it remained stable. Overweight and obese subjects had significantly more exposure to individual and multiple drug treatments compared with subjects with normal weight (P < 0.001). By type of drug treatment, 16.7% of normal-weight subjects, 35.6% of overweight subjects, and 51.8% of obese subjects were exposed to antihypertensives; 4.1%, 8.7%, and 12.1%, respectively, to statins; 14.2%, 22.0%, and 29.0% to NSAIDs; and 1.0%, 4.7%, and 9.4% to antidiabetics. The mean annual cost of drugs was Euro 132.71 in normal-weight subjects, Euro 246.19 in overweight subjects, and Euro 335.64 in obese subjects (P < 0.001). After adjustment for differences in age distribution between the study sample and the overall population of Ravenna, the estimated excess drug costs associated with overweight and obesity in Ravenna were Euro 5,661,126.20 and Euro 6,688,099.85, respectively. CONCLUSIONS: In this study sample, the prevalence of overweight increased by approximately 10% and the prevalence of obesity increased by approximately 5% with each decade of age up to 60 years, after which it remained stable at approximately 40% and approximately 20%, respectively. Overweight and obesity were associated with increased drug exposure and costs in all age groups considered.     

Voluntary Exercise and Sucrose Consumption Enhance Cannabinoid CB1 Receptor Sensitivity in the Striatum

The endogenous cannabinoid system is involved in the regulation of the central reward pathway. Running wheel and sucrose consumption have rewarding and reinforcing properties in rodents, and share many neurochemical and behavioral characteristics with drug addiction. In this study, we investigated whether running wheel or sucrose consumption altered the sensitivity of striatal synapses to the activation of cannabinoid CB1 receptors. We found that cannabinoid CB1 receptor-mediated presynaptic control of striatal inhibitory postsynaptic currents was remarkably potentiated after these environmental manipulations. In contrast, the sensitivity of glutamate synapses to CB1 receptor stimulation was unaltered, as well as that of GABA synapses to the stimulation of presynaptic GABAB receptors. The sensitization of cannabinoid CB1 receptor-mediated responses was slowly reversible after the discontinuation of running wheel or sucrose consumption, and was also detectable following the mobilization of endocannabinoids by metabotropic glutamate receptor 5 stimulation. Finally, we found that the upregulation of cannabinoid transmission induced by wheel running or sucrose had a crucial role in the protective effects of these environmental manipulations against the motor and synaptic consequences of stress.     

Testing the GlaaS algorithm for dose measurements on low- and high-energy photon beams using an amorphous silicon portal imager

The GLAaS algorithm for pretreatment intensity modulation radiation therapy absolute dose verification based on the use of amorphous silicon detectors, as described in Nicolini et al. [G. Nicolini, A. Fogliata, E. Vanetti, A. Clivio, and L. Cozzi, Med. Phys. 33, 2839-2851 (2006)], was tested under a variety of experimental conditions to investigate its robustness, the possibility of using it in different clinics and its performance. GLAaS was therefore tested on a low-energy Varian Clinac (6 MV) equipped with an amorphous silicon Portal Vision PV-aS500 with electronic readout IAS2 and on a high-energy Clinac (6 and 15 MV) equipped with a PV-aS1000 and IAS3 electronics. Tests were performed for three calibration conditions: A: adding buildup on the top of the cassette such that SDD-SSD = d(max) and comparing measurements with corresponding doses computed at d(max), B: without adding any buildup on the top of the cassette and considering only the intrinsic water-equivalent thickness of the electronic portal imaging devices device (0.8 cm), and C: without adding any buildup on the top of the cassette but comparing measurements against doses computed at d(max). This procedure is similar to that usually applied when in vivo dosimetry is performed with solid state diodes without sufficient buildup material. Quantitatively, the gamma index (gamma), as described by Low et al. [D. A. Low, W. B. Harms, S. Mutic, and J. A. Purdy, Med. Phys. 25, 656-660 (1998)], was assessed. The gamma index was computed for a distance to agreement (DTA) of 3 mm. The dose difference deltaD was considered as 2%, 3%, and 4%. As a measure of the quality of results, the fraction of field area with gamma larger than 1 (%FA) was scored. Results over a set of 50 test samples (including fields from head and neck, breast, prostate, anal canal, and brain cases) and from the long-term routine usage, demonstrated the robustness and stability of GLAaS. In general, the mean values of %FA remain below 3% for deltaD equal or larger than 3%, while they are slightly larger for deltaD = 2% with %FA in the range from 3% to 8%. Since its introduction in routine practice, 1453 fields have been verified with GLAaS at the authors' institute (6 MV beam). Using a DTA of 3 mm and a deltaD of 4% the authors obtained %FA = 0.9 +/- 1.1 for the entire data set while, stratifying according to the dose calculation algorithm, they observed: %FA = 0.7 +/- 0.9 for fields computed with the analytical anisotropic algorithm and %FA = 2.4 +/- 1.3 for pencil-beam based fields with a statistically significant difference between the two groups. If data are stratified according to field splitting, they observed %FA = 0.8 +/- 1.0 for split fields and 1.0 +/- 1.2 for nonsplit fields without any significant difference.     

Morphological and functional analyses of skeletal muscles from an immunodeficient animal model of limb‐girdle muscular dystrophy type 2E

Introduction: Limb‐girdle muscular dystrophy type 2E (LGMD2E) is caused by mutations in the β‐sarcoglycan gene, which is expressed in skeletal, cardiac, and smooth muscles. β‐Sarcoglycan‐deficient (Sgcb‐null) mice develop severe muscular dystrophy and cardiomyopathy with focal areas of necrosis. Methods: In this study we performed morphological (histological and cellular characterization) and functional (isometric tetanic force and fatigue) analyses in dystrophic mice. Comparison studies were carried out in 1‐month‐old (clinical onset of the disease) and 7‐month‐old control mice (C57Bl/6J, Rag2/γc‐null) and immunocompetent and immunodeficient dystrophic mice (Sgcb‐null and Sgcb/Rag2/γc‐null, respectively). Results: We found that the lack of an immunological system resulted in an increase of calcification in striated muscles without impairing extensor digitorum longus muscle performance. Sgcb/Rag2/γc‐null muscles showed a significant reduction of alkaline phosphate‐positive mesoangioblasts. Discussion: The immunological system counteracts skeletal muscle degeneration in the murine model of LGMD2E. Muscle Nerve 58 : 133–144, 2018