Yerba mate consumption by ovariectomized rats alters white adipose tissue.

INTRODUCTION: Menopause and post-menopause are characterized by low levels of estrogen that can be associated with the emergence of metabolic diseases. While hormone replacement therapy can alleviate many symptoms, it can also exacerbate other diseases such as breast cancer. In the search for natural alternatives, Ilex paraguariensis (Yerba Mate) has been identified as a potential therapy for the onset of obesity. Here, the effect of MATE consumption on white adipose tissue (WAT) was studied in ovariectomized rats, an animal model for post-menopause hormone loss. METHODS: Four groups of animals were used: ovariectomy with MATE (OVX MATE) and without MATE (OVX), as well as sham surgery with MATE (Sham MATE) and without MATE (Sham). MATE was provided by gavage at 1 g/kg of body weight for eight weeks before measuring biochemical parameters in plasma and characterizing WAT morphology. RESULTS: The consumption of Yerba MATE significantly decreased weight gain in ovariectomized rats and presented near control levels of triglycerides, total cholesterol, and LDL. A morphometric analysis of WAT showed a significant decrease in the area occupied by adipocytes in the group that consumed MATE. Finally, MATE consumption increased the UCP1 content in the WAT of the ovariectomized group. Yerba MATE treatment was also associated with higher levels of SIRT1 protein. CONCLUSION: MATE consumption has a preventive effect on the weight gain observed in ovariectomized rats and potential benefits in naturally avoiding the onset of obesity post menopause.

Human chagasic IgGs bind to cardiac muscarinic receptors and impair L-type Ca2+ currents.

OBJECTIVES: Antibodies against cardiac G protein-coupled receptors have been reported in sera from chronic chagasic patients (CChP) and other non-parasitic cardiomyopathies, but the effects and underlying mechanism of interaction between these antibodies and heart cells are not fully established. To address this point, binding of antibodies purified from sera of CChP patients and normal blood donors (NBD) to cardiac muscarinic acetylcholine receptors (mAChR) and their effect on L-type Ca(2+) currents were examined. METHODS AND RESULTS: Saturation [3H]NMS binding experiments with porcine atrial membranes showed that B(max) in the presence of CChP-immunoglobulin G (IgG) decreased from 280.2+/-16.08 fmol/mg (control) to 91.00+/-5.98 fmol/mg, with no apparent change in K(D), while NBD-IgG did not significantly alter these parameters. At the single channel level, CChP-IgG decreased both the fast and slow mean open times and P(o) (from 0.074+/-0.023 to 0.025+/-0.007) without changes in single channel conductance. I/V plots of isoproterenol-stimulated whole-cell L-type Ca(2+) currents (I(Ca)) from rabbit ventricular cardiomyocytes showed a significant reduction in peak I(Ca) during perfusion with CChP-IgG (at 0 mV: from 10.61+/-2.97 to 8.45+/-2.54 pA/pF). NBD-IgGs had no effect on I(Ca). A CChP-IgG purified against a peptide corresponding to the second extracellular loop of the M(2) receptor also impaired L-type Ca(2+) currents. All effects of CChP-IgG were blocked by atropine. CONCLUSIONS: Our results show that antibodies from CChP bind to mAChR in a non-competitive manner and are able to activate the receptor in an agonist-like form resulting in L-type Ca(2+) current inhibition.