Metaboreflex Dysregulation In Type 2 Diabetes Mellitus

Abstract

In healthy subjects, when the muscle metaboreflex (MM) is activated, mean blood pressure (MBP) increases because of a sympathetic-induced increase in both systemic vascular resistance (SVR) and cardiac output (CO)1. It has been reported that this reflex is dys-regulated in patients suffering some metabolic diseases. In detail, patients with type 1 diabetes mellitus (DM) have a blunted MBP response during the MM due to sympathetic deficit2; moreover, patients suffering from metabolic syndrome show an exaggerated SVR during the MM because of their sympathetic hyperactivation. PURPOSE: to discover whether the MM is dys-regulated is patients with type 2 DM. METHODS: 14 MS patients with type 2 DM obesity (4 females, 62.7±8.3 yrs) together with 13 control subjects (CTL, 5 females 61.2±10.5 yrs) participated in this study. They underwent randomly assigned the following protocol: 1) post-exercise muscle ischemia (PEMI) session, to study the MM, and 2) control exercise recovery (CER) session. Response to the metaboreflex for each cardiovascular parameter was assessed as PEMI minus CER level. Hemodynamic parameters were evaluated by impedance cardiography. RESULTS: patients with type 2 DM showed an exaggerated SVR response as compared to the CTL group (392.5±549.6, vs -68±248.5 dynes•s-1•cm-5 respectively, p<0.05), whereas MBP response was not different between groups (8.9±5.7 vs. 6.8±8.7 mmHg respectively, p>0.05). CONCLUSIONS: This investigation indicates that patients with type 2 DM have an exaggerated vasoconstriction in response to the MM activation. This phenomenon is different to what observed in type 1 DM2 and similar to what reported for metabolic syndrome3. 1 Crisafulli A et al. Muscle metaboreflex-induced increases in stroke volume. Med Sci Sports Exerc 2003; 35: 221-228. 2 Roberto S et al. Altered hemodynamics during muscle metaboreflex in young, type 1 diabetes patients. J Appl Physiol 2012; 113: 1323-1331. 3 Milia R et al. Differences in hemodynamic response to metaboreflex activation between obese patients with metabolic syndrome and healthy subjects with obese phenotype. Am J Physiol (Heart Circ Physiol) 2015; 309: H779-789.