Selectively breeding for high voluntary physical activity in female mice does not bestow inherent characteristics that resemble eccentric remodeling of the heart,but the mini-muscle phenotype does

Physical activity engagement results in a variety of positive health outcomes,including a reduction in cardiovascular disease risk partially due to eccentric remodeling of the heart.The purpose of this investigation was to determine if four replicate lines of High Runner mice that have been selectively bred for voluntary exercise on wheels have a cardiac phenotype that resembles the outcome of eccentric remodeling.Adult females(average age 55 days)from the 4 High Runner and 4 non-selected control lines were anaesthetized via vaporized isoflurane,then echocardiographic images were collected and analyzed for structural and functional differences.High Runner mice in general had lower ejection fractions compared to control mice lines(2-tailed p=0.0236)and tended to have thicker walls of the anterior portion of the left ventricle(p=0.065).However,a subset of the High Runner individuals,termed mini-muscle mice,had greater ejection fraction(p=0.0006),fractional shortening percentage(p<0.0001),and ventricular mass at dissection(p<0.0027 with body mass as a covariate)compared to non-mini muscle mice.Mice from replicate lines bred for high voluntary exercise did not all have inherent positive cardiac functional or structural characteristics,although a genetically unique subset of mini-muscle individuals did have greater functional cardiac characteristics,which in conjunction with their previously described peripheral aerobic enhancements(e.g.,increased capillarity)would partially account for their increased VO2max.

C-reactive protein and telomerase reverse transcriptase(TERT)associate with chronic disease markers in a sample from low-income neighborhoods in Detroit,Michigan

Racial and ethnic minorities in economically deprived inner cities experience high rates of chronic diseases compared to neighborhoods with higher socioeconomic status(SES).However,these economically deprived populations are understudied in terms of biomarkers associated with chronic disease risk which include C-reactive protein(CRP),telomerase reverse transcriptase(TERT),and glycosylated hemoglobin(A1C).We examined relationships between CRP and TERT and chronic disease indicators(body mass index[BMI]and A1C)in two lowincome,predominantly African American(AA)neighborhoods in Detroit,Michigan.Sixty-nine adults(43 females,26 males,mean age 46 years[y],standard deviation[SD]=15.9)completed a health survey,anthropometry,and finger stick blood tests.A1C was measured using A1CNow test strips,and CRP and TERT levels were measured using enzyme-linked immunosorbent assay(ELISA)with samples extracted from dried blood spots.We examined CRP(mean=4.9,SD=3.1),TERT(mean=32.5,SD=15.1),and A1C(mean=5.4,SD=1.0)by BMI category.We fitted restricted maximum likelihood regression models to evaluate associations between CRP,TERT,BMI,and A1C,after adjustment for demographics and inclusion of a random effect for the neighborhood.In this predominantly AA sample(91%,63/69),68%had levels of CRP(means=4.8 mg/L,SD=3.0 for AAs;6.4 mg/L,SD=3.9 for all others)indicative of chronic inflammation(CRP greater than 3 mg/L).BMI was significantly associated with CRP(p=0.004)and TERT(p=0.026).TERT levels indicate that being overweight is associated with markers of chromosome remodeling,suggestive of chronic disease.CRP followed a similar trend with overweight individuals having higher inflammation and risk of chronic disease.Our findings warrant further exploration of additional factors that may influence CRP and TERT.Furthermore,examining populations in a more ethnically and/or economically diverse,yet still high proportion minority,sample will fill a knowledge gap in this understudied field.