CD4+ T-cell activation of bone marrow causes bone fragility and insulin resistance in type 2 diabetes.

Type 2 diabetes mellitus (T2DM) causes an increased risk of bone fractures. However, the pathophysiology of diabetic bone fragility is not completely understood. It has been proposed that an inflammatory microenvironment in bone could be a major mechanism by inducing uncontrolled bone resorption, inadequate bone formation and consequently more porous bones. We propose that activated T-cells in the bone marrow cause a pro-inflammatory microenvironment in bone, and cause bone fragility in T2DM. We induced T2DM in C57BL/6 male mice through a hypercaloric diet rich in carbohydrates and low doses of streptozocin. In T2DM mice we inhibited systemic activation of T-cells with a fusion protein between the extracellular domain of Cytotoxic T-Lymphocyte Antigen 4 and the Fc domain of human immunoglobulin G (CTLA4-Ig). We analysed the effects of T2DM or CTLA4-Ig in lymphocyte cell subsets and antigen-presenting cells in peripheral blood and femoral bone marrow; and their effect on the metabolic phenotype, blood and bone cytokine concentration, femoral bone microarchitecture and biomechanical properties, and the number of osteoblast-like cells in the femoral endosteum. We performed a Pearson multiple correlation analysis between all variables in order to understand the global mechanism. Results demonstrated that CTLA4-Ig decreased the number of activated CD4+ T-cells in the femoral bone marrow and consequently decreased TNF-α and RANK-L concentration in bone, notably improved femoral bone microarchitecture and biomechanical properties, increased the number of osteoblast-like cells, and reduces osteoclastic activity compared to T2DM mice that did not receive the inhibitor. Interestingly, we observed that blood glucose levels and insulin resistance may be related to the increase in activated CD4+ T-cells in the bone marrow. We conclude that bone marrow activated CD4+ T-cells cause poor bone quality and insulin resistance in T2DM.

[IGF-1 levels in anterior cruciate ligament reconstruction using allograft vs autograft in patients at Central Military Hospital]. / Niveles de IGF-1 en la plastía de ligamento cruzado anterior de rodilla empleando aloinjerto vs autoinjerto en pacientes del Hospital Central Militar.

BACKGROUND: Treatment of ACL injury is surgical reconstruction. It is not known whether the result is better depending on the type of graft used. Insulin-like growth factor type 1(IGF-1) is a powerful stimulant of extracellular matrix and chondrocyte growth. MATERIAL AND METHODS: Experimental, analytical, prospective, longitudinal study in patients with ACL reconstruction in a period from 2016 to 2017. The concentration of IGF-1 in synovial fluid of these patients operated with allograft and autograft was determined, its association with postoperative evolution was determined. For statistical analysis, two-way ANOVA with Mann-Whitney post-hoc U was used. RESULTS: A significant increase in IGF-1 was identified in the allograft group at 90 days of postopertory. In the autograft group, a significant increase in IGF-1 was observed from 30 days of postoperative. The autograft group was found to have significantly higher levels of IGF-1 (3.27 ± 0.09 ng/ml) compared to the allograft group (2.80 ± 0.11 ng/ml; p 0.001) at 90 days after graft placement. DISCUSSION: IGF-1 levels were higher in patients with autologous graft, knee functionality was clinically similar in both groups at 30 and 90 days.

ANTECEDENTES: El tratamiento para la lesión del ligamento cruzado anterior (LCA) es la reconstrucción quirúrgica. Se desconoce si el resultado mejora, pues depende del tipo de injerto empleado. El factor de crecimiento semejante a la insulina tipo 1(IGF-1) es un potente estimulante de matriz extracelular y del crecimiento de condrocitos. MATERIAL Y MÉTODOS: Estudio experimental, analítico, prospectivo, longitudinal en pacientes con reconstrucción del LCA en un período comprendido entre los años 2016 y 2017. Se determinó la concentración de IGF-1 en el líquido sinovial de estos pacientes operados con aloinjerto y autoinjerto además de determinar su asociación con la evolución postoperatoria. Para el análisis estadístico, se utilizó ANOVA de dos vías post hoc con la prueba U de Mann-Whitney. RESULTADOS: Dentro del grupo de aloinjerto, se identificó un aumento significativo de IGF-1 a los 90 días del postoperatorio. En el grupo de autoinjerto, se observó un aumento significativo de IGF-1 desde los 30 días de postoperatorio. Se encontró además que el grupo de autoinjerto presentó niveles significativamente más altos de IGF-1 (3.27 ± 0.09 ng/ml) en comparación con el grupo de aloinjerto (2.80 ± 0.11 ng/ml; p 0.001) a los 90 días después de la colocación del injerto. DISCUSIÓN: Los niveles de IGF-1 fueron más altos en pacientes con injerto autólogo; la funcionalidad de la rodilla fue clínicamente similar en ambos grupos a los 30 y 90 días.

Protective Effect of Moderate Exercise for BALB/c Mice with Salmonella Typhimurium Infection.

Moderate exercise enhances resistance to pathogen-associated infections. However, its influence on intestinal IgA levels and resistance to Salmonella typhimurium in mice has not been reported. The aim of this study was to assess the impact of moderate exercise on bacterial resistance and the intestinal-IgA response in a murine typhoid model. Sedentary and exercised (under a protocol of moderate swimming) BALB/c mice were orally infected with Salmonella typhimurium and sacrificed on days 7 or 14 post-infection (n=5 per group). Compared with infected sedentary mice, infected exercised animals had i) lower intestinal and systemic bacterial loads; ii) higher total and specific intestinal-IgA levels, iii) a higher percentage of IgA plasma cells in lamina propria; iv) a higher level on day 7 and lower level on day 14 of intestinal α- and J-chain mRNA and plasma corticosterone, v) unchanged mRNA expression of intestinal pIgR, and vi) a higher mRNA expression of liver pIgR, α-chain and J-chain on day 7. Hence, it is likely that an increase in corticosterone levels (stress response) induced by moderate exercise increased intestinal IgA levels by enabling greater liver expression of pIgR mRNA, leading to a rise in IgA transcytosis from the liver to intestine. The overall effect of these changes is an enhanced resistance to infection.

Intermittent fasting promotes bacterial clearance and intestinal IgA production in Salmonella typhimurium-infected mice.

The impact of intermittent fasting versus ad libitum feeding during Salmonella typhimurium infection was evaluated in terms of duodenum IgA levels, bacterial clearance and intestinal and extra-intestinal infection susceptibility. Mice that were intermittently fasted for 12 weeks or fed ad libitum were infected with S. typhimurium and assessed at 7 and 14 days post-infection. Next, we evaluated bacterial load in the faeces, Peyer's patches, spleen and liver by plate counting, as well as total and specific intestinal IgA and plasmatic corticosterone levels (by immunoenzymatic assay) and lamina propria IgA levels in plasma cells (by cytofluorometry). Polymeric immunoglobulin receptor, α- and J-chains, Pax-5 factor, pro-inflammatory cytokine (tumour necrosis factor-α and interferon-γ) and anti-inflammatory cytokine (transforming growth factor-ß) mRNA levels were assessed in mucosal and liver samples (by real-time PCR). Compared with the infected ad libitum mice, the intermittently fasted infected animals had (1) lower intestinal and systemic bacterial loads; (2) higher SIgA and IgA plasma cell levels; (3) higher mRNA expression of most intestinal parameters; and (4) increased or decreased corticosterone levels on day 7 and 14 post-infection, respectively. No contribution of liver IgA was observed at the intestinal level. Apparently, the changes following metabolic stress induced by intermittent fasting during food deprivation days increased the resistance to S. typhimurium infection by triggering intestinal IgA production and presumably, pathogen elimination by phagocytic inflammatory cells.

Moderate exercise enhances expression of SIgA in mouse ileum.

The immune-suppression caused by acute stress can be reduced by a regular practice of moderate exercise which is known to modulate the expression of secretory-IgA. This antibody is essential for protection against infections and maintenance of homeostasis at the mucosal level. In order to explore the effects of moderate exercise on secretory-IgA production in ileum of the small intestine, 2 groups of mice were submitted to this protocol for 6 months, an exercise group and a sedentary group. After sacrifice, levels of secretory-IgA in intestinal fluid and levels of adrenal hormones in serum were determined by enzyme immunoenzymatic assay. IgA-plasma cells in lamina propria were evaluated by flow cytometry. Transcriptional mRNA expression in mucosa of alpha-chain, J-chain, pIgR and cytokines (Interleukin-2, -4, -6, -10, transforming growth factor-beta, interferon-gamma and tumor necrosis factor) were determined by RT-PCR. In comparison with sedentary mice, moderate exercised mice displayed an up-regulating effect on the production of secretory-IgA and IgA-plasma cells, on the expression of all mRNA transcripts from secretory-IgA associated proteins, and on all cytokines tested. However, serum levels of adrenal hormones were not altered. Future studies on secretory-IgA production are necessary to support the substantive effect of moderate exercise on protection and homeostasis at the intestinal level.

Perezone and its isomer isoperezone induce caspase-dependent and caspase-independent cell death.

In this study, we investigated the cytotoxic effect of perezone, a constituent isolated from the roots of Perezia spp. and of its synthetic isomer isoperezone on the K562 human leukemia cell line. Perezone showed greater cytotoxic effect than isoperezone but both compounds were found to induce cytotoxicity trough a caspase-dependent and a caspase-independent mechanisms; important changes in their light scattering properties, phosphatidylserine translocation and mitochondrial membrane potential disruption were detected by cytometry. The mechanism of death induction of each compound showed interesting concentration-dependent differences. Neither compound induced the apoptosis inducing factor.