Susceptibility of female rats to cardiac arrhythmias following refeeding after severe food restriction

Abstract

Background Many studies have shown malnutrition and inadequate caloric consumption have adverse acute effects on cardiovascular structure and function. Methods To determine the adverse long term cardiovascular effects, we studied cardiac morphology and function in female (F) and male (M) severe food restricted rats 3 months after refeeding (sFR-Refed). Results Two weeks of a normal chow diet in which calories were reduced by 60% decreased body weight (BW) by approximately 15% in both sexes. Within 2 weeks of refeeding, no differences in BW were detected between CT and sFR-Refed groups. However, male rats gained almost 3 times more BW than the females over the 3-month refeeding period. Sex differences were also observed in cardiac pathology. Hearts from F-sFR-Refed rats exhibited more atrophy and less hypertrophy, while M-sFR-Refed rats predominantly exhibited hypertrophic remodeling. While there were no differences in the frequency of ventricular arrhythmias induced by ischemia/reperfusion (I/R) in the isolated heart between M-CT and M-sFR-Refed rats, I/R induced twice as many arrhythmias in the F-sFR-Refed rats compared to F-CT. Conclusions These findings indicate the female heart is more susceptible to the long term adverse cardiovascular effects of sFR months after refeeding. Thus, this study provides a rationale for studying sex differences in cardiovascular risk in individuals who experience sFR for voluntary (e.g., very low-calorie dieting) or involuntary (e.g., poverty) reasons earlier in life.

Long-Term Impact of the Great Chinese Famine on the Risks of Specific Arrhythmias and Severe Hypertension in the Offspring at an Early Stage of Aging

“…Although previous laboratory studies showed that malnutrition could induce arrhythmia in animal models [ 33 , 34 ], the present study first demonstrated that famine is a significant risk for developing bradycardia, atrial fibrillation, and atrioventricular block, not tachycardia, in humans. In the GCF exposure offspring, the chi-square test demonstrated that if subjects had an increased BMI, total cholesterol, blood pressure, or metabolic syndrome, they were more vulnerable in developing bradycardia.…”