Induced degeneration and regeneration in aged muscle reduce tubular aggregates but not muscle function.

Introduction: Tubular aggregates (TA) are skeletal muscle structures that arise from the progressive accumulation of sarcoplasmic reticulum proteins. Cytoplasmic aggregates in muscle fibers have already been observed in mice and humans, mainly during aging and muscle disease processes. However, the effects of muscle regeneration on TA formation have not yet been reported. This study aimed to investigate the relationship between degeneration/regeneration and TA in aged murine models. We investigated the presence and quantity of TA in old males from two murine models with intense muscle degeneration and regeneration. Methods: One murine lineage was a Dmdmdx model of Duchenne muscular dystrophy (n = 6). In the other model, muscle damage was induced by electroporation in C57BL/6J wild-type mice, and analyzed after 5, 15, and 30 days post-electroporation (dpe; n = 15). Regeneration was evaluated based on the quantity of developmental myosin heavy chain (dMyHC)-positive fibers. Results: The frequency of fibers containing TA was higher in aged C57BL/6J (26 ± 8.3%) than in old dystrophic Dmdmdx mice (2.4 ± 2%). Comparing the data from induced degeneration/regeneration in normal mice revealed a reduced proportion of TA-containing fibers after 5 and 30 dpe. Normal aged muscle was able to regenerate and form dMyHC+ fibers, mainly at 5 dpe (0.1 ± 0.1 vs. 16.5 ± 2.6%). However, there was no difference in force or resistance between normal and 30 dpe animals, except for the measurements by the Actimeter device, which showed the worst parameters in the second group. Discussion: Our results suggest that TA also forms in the Dmdmdx muscle but in smaller amounts. The intense degeneration and regeneration of the old dystrophic model resulted in the generation of new muscle fibers with a lower quantity of TA. Data from electroporated wild-type mice support the idea that muscle regeneration leads to a reduction in the amount of TA. We suggest that TA accumulates in muscle fibers throughout physiological aging and that regeneration leads to the formation of new fibers without these structures. In addition, these new fibers do not confer functional benefits to the muscle.

A Comprehensive Review of Syndromic Forms of Obesity: Genetic Etiology, Clinical Features and Molecular Diagnosis.

Syndromic obesity refers to obesity occurring with additional clinical findings, such as intellectual disability/developmental delay, dysmorphic features, and congenital malformations. PURPOSE OF REVIEW: To present a narrative review regarding the genetic etiology, clinical description, and molecular diagnosis of syndromic obesity, which is a rare condition with high phenotypic variability and genetic heterogeneity. The following syndromes are presented in this review: Prader-Willi, Bardet-Biedl, Pseudohypoparathyroidism, Alström, Smith-Magenis, Cohen, Temple, 1p36 deletion, 16p11.2 microdeletion, Kleefstra, SIM1-related, Börjeson-Forssman-Lehmann, WAGRO, Carpenter, MORM, and MYT1L-related syndromes. RECENT FINDINGS: There are three main groups of mechanisms for syndromic obesity: imprinting, transcriptional activity regulation, and cellular cilia function. For molecular diagnostic, methods of genome-wide investigation should be prioritized over sequencing of panels of syndromic obesity genes. In addition, we present novel syndromic conditions that need further delineation, but evidences suggest they have a higher frequency of obesity. The etiology of syndromic obesity tends to be linked to disrupted neurodevelopment (central) and is associated with a diversity of genes and biological pathways. In the genetic investigation of individuals with syndromic obesity, the possibility that the etiology of the syndromic condition is independent of obesity should be considered. The accurate genetic diagnosis impacts medical management, treatment, and prognosis, and allows proper genetic counseling.

Haptoglobin levels are influenced by Hp1-Hp2 polymorphism, obesity, inflammation, and hypertension in type 2 diabetes mellitus / Los niveles de haptoglobina están influenciados por el polimorfismo Hp1-Hp2, la obesidad, la inflamación y la hipertensión en la diabetes mellitus tipo 2

Background: Type 2 diabetes mellitus (T2DM) is an inflammatory condition associated to obesity and increased oxidative stress. Haptoglobin (Hp) is an acute phase reactant that scavenges extracorpuscular hemoglobin from circulation and prevents heme-iron oxidative damage. Objective: To assess the association between Hp levels and Hp1-Hp2 gene polymorphism and clinical and laboratory parameters in patients with T2DM. Methods: The study sample consisted of 102 T2DM patients and 62 controls. Hp plasma levels were measured using an ELISA assay, and Hp genotyping was performed using a specific two-step allelic polymerase chain reaction. Results: Hp levels were higher in T2DM patients as compared to controls (p=0.005). T2DM patients with high blood pressure had higher Hp levels than patients without this comorbidity (p=0.021). Obese T2DM patients had higher Hp levels as compared to obese controls (p=0.009) and to non-obese T2DM patients (p=0.003). The Hp1-Hp1 genotype was showed to be associated to T2DM according to additive (OR=3.038, 95% CI 1.127-8.192; p=0.036) and dominant model (OR=0.320, 95% CI 0.118-0.839; p=0.010), but Hp2 allele carriers contributed with higher Hp levels in T2DM as compared to controls. Waist circumference (p=0.002), BMI (p=0.001), and IL-6 (p=0.012), and hs-CRP (p=0.001) levels positively correlated with Hp levels in the T2DM group. Conclusion: These results suggest that Hp levels are influenced by Hp1-Hp2 polymorphism, obesity, inflammatory status, and high blood pressure in T2DM

Antecedentes: La diabetes mellitus tipo 2 (DM2) es una afección inflamatoria asociada con la obesidad y el aumento del estrés oxidativo. La haptoglobina (Hp) es un reactante de fase aguda que elimina la hemoglobina extracorpuscular de la circulación y previene el daño oxidativo del hierro hemo. Objetivo: Evaluar la asociación entre los niveles de Hp y el polimorfismo del gen Hp1-Hp2, y los parámetros clínicos y de laboratorio en individuos con DM2. Métodos: Ciento dos pacientes con DM2 y 62 controles se incluyeron en este estudio. Los niveles plasmáticos de Hp se cuantificaron por ELISA y el genotipado de Hp se llevó a cabo mediante una PCR alelo-específica en dos pasos. Resultados: Los niveles de Hp fueron más altos en pacientes con DM2 en comparación con los controles (p=0,005). Los pacientes con DM2 con hipertensión arterial mostraron niveles más altos de Hp en comparación con los pacientes sin hipertensión (p=0,021). Los pacientes obesos con DM2 mostraron niveles más altos de Hp en comparación con los controles obesos (p=0,009) y con los pacientes con DM2 no obesos (p=0,003). El genotipo Hp1-Hp1 mostró asociación con DM2 según el modelo aditivo (OR=3,038; IC 95%: 1,127-8,192; p=0,036) y el modelo dominante (OR=0,320; IC 95%: 0,118-0,839; p=0,010), pero entre los portadores del alelo Hp2, las concentraciones de Hp eran más altas en T2DM que en controles. La circunferencia de la cintura (p=0,002), el IMC (p=0,001), IL-6 (p=0,012) y la hs-CRP (p=0,001) se correlacionaron positivamente con los niveles de Hp en el grupo DM2. Conclusión: Estos resultados sugieren que los niveles de Hp están influenciados por el polimorfismo Hp1-Hp2, la obesidad, el estado inflamatorio y la hipertensión en DM2