Background:Matrix metalloproteinase-2 (MMP-2) is an enzyme with proteolytic activity on matrix proteins, particularly basement membrane constituents. A single nucleotide polymorphism C>T transition at –1306 displayed a strong association with several cancers. Our study investigated whether or not the MMP-2 –1306C>T polymorphism contributed to the development of breast cancer (BC) in a Mexican population. Methods: 90 patients with BC and 96 control subjects were analyzed to detect MMP-2 –1306C>T polymorphism. Results: The frequency of MMP-2 CC genotype was significantly higher in BC patients when compared with the control group (OR 2.15; 95% CI 1.1–4.1). MMP-2 CC genotype frequency was more pronounced in younger subjects (≤50 years) at diagnosis (OR 2.66; 95% CI 1.04–6.96). Conclusion: The data suggest that MMP-2 –1306C>T polymorphism strongly contributes to the development of BC in the population studied, especially among women 50 years old and younger.
BackgroundPhysical exercise improves glucose metabolism and insulin sensitivity. Brain-derived neurotrophic factor (BDNF) enhances insulin activity in diabetic rodents. Because physical exercise modifies BDNF production, this study aimed to investigate the effects of chronic exercise on plasma BDNF levels and the possible effects on insulin tolerance modification in healthy rats.MethodsWistar rats were divided into five groups: control (sedentary, C); moderate- intensity training (MIT); MIT plus K252A TrkB blocker (MITK); high-intensity training (HIT); and HIT plus K252a (HITK). Training comprised 8 weeks of treadmill running. Plasma BDNF levels (ELISA assay), glucose tolerance, insulin tolerance, and immunohistochemistry for insulin and the pancreatic islet area were evaluated in all groups. In addition, Bdnf mRNA expression in the skeletal muscle was measured.Principal FindingsChronic treadmill exercise significantly increased plasma BDNF levels and insulin tolerance, and both effects were attenuated by TrkB blocking. In the MIT and HIT groups, a significant TrkB-dependent pancreatic islet enlargement was observed. MIT rats exhibited increased liver glycogen levels following insulin administration in a TrkB-independent manner.Conclusions/SignificanceChronic physical exercise exerted remarkable effects on insulin regulation by inducing significant increases in the pancreatic islet size and insulin sensitivity in a TrkB-dependent manner. A threshold for the induction of BNDF in response to physical exercise exists in certain muscle groups. To the best of our knowledge, these are the first results to reveal a role for TrkB in the chronic exercise-mediated insulin regulation in healthy rats.
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