A Chronic High-Intensity Interval Training and Diet-Induced Obesity Model to Maximize Exercise Effort and Induce Physiologic Changes in Rats

Compared to continuous-moderate or low-intensity training, high-intensity interval training (HIIT) is a more time-efficient alternative method that ...

West Virginia School of Osteopathic Medicine

Similarities in offspring phenotype due to maternal under- or over-nutrition during gestation have been observed in studies conducted at University of Wyoming. In these studies, ewes were either nutrient-restricted (NR) from early to mid-gestation, or fed an obesogenic diet (MO) from preconception through term. Offspring necropsies occurred at mid-gestation, late-gestation, and after parturition. At mid gestation, body weights of NR fetuses were ~30% lighter than controls, whereas MO fetuses were ~30% heavier than those of controls. At birth, lambs born to NR, MO, and control ewes exhibited similar weights. This was a consequence of accelerated fetal growth rates in NR ewes, and reduced fetal growth rates in MO ewes in late gestation, when compared to their respective controls. These fetal growth patterns resulted in remarkably similar effects of increased susceptibility to obesity, cardiovascular disease, and glucose intolerance in offspring programmed mostly during fetal stages of development. These data provide evidence that maternal under- and over-nutrition similarly induce the development of the same cadre of physical and metabolic problems in postnatal life.

A Review of Maternal Nutrition during Pregnancy and Impact on the Offspring through Development: Evidence from Animal Models of Over- and Undernutrition.

Accumulating evidence suggests that indications of metabolic syndrome can be inherited through the germline as a result of maternal obesity. We hypothesized that diet-induced maternal obesity during gestation would program metabolic consequences for multiple generations of offspring, even when first, second, and third generation offspring (F1, F2, F3, respectively) were fed only to requirements. Control (CON) and obese (OB) ewes (generation 0; F0) were bred to a single ram to produce the first generation of offspring (F1). From 60 d prior to conception through term, CONF0 ate 100% National Research Council recommendations (NRC), while OBF0 ewes ate 150% NRC. All F1, F2, and F3 ate 100% NRC after weaning. All mature F1 ewes were bred to a single ram to generate CONF2 (n = 6) and OBF2 (n = 10). All mature F2 ewes were bred to a single ram to produce CONF3 (n = 6) and OBF3 (n = 10). OBF2 ewes exhibited greater (P < 0.0001) plasma cortisol than CONF2 throughout gestation. A glucose tolerance test at 90% gestation revealed OBF2 ewes had higher (P < 0.05) insulin response with similar glucose, resulting in greater (P < 0.05) insulin resistance. OBF3 neonates had similar weight, lean mass, and body fat mass to CONF3 neonates. These data suggest that multigenerational programming of adverse metabolic phenotypes occur in association with F0 maternal obesity, yet adiposity may return to CON levels in F3 neonates.

Effects of maternal obesity in an ovine model on metabolic outcomes in F2 adults and F3 neonates.

Evidence links parent-offspring weight status, but few studies have evaluated whether markers of socioeconomic status moderate this relation. The 2014 Family Life, Activity, Sun, Health, and Eating study was used to assess intergenerational weight status in a national sample of parent-teen dyads. Multivariable logistic regression models assessed the relation between parent-teen weight status, controlling for teen and parent dietary factors, physical activity, demographic factors, and socioeconomic factors. Models with interaction assessed moderation by household food security status and participation in federal assistance programs. In fully adjusted models, sons were 2.66 (95% CI: 1.56, 4.55) times more likely to have overweight/obesity if their mother had overweight/obesity, and daughters were 3.35 (95% CI: 1.91, 5.86) times more likely. This relation was stronger in mother-son pairs in households with lower food security. These findings provide important new information that can be used to inform nutritional counseling efforts and educational programs that support families with socioeconomic disadvantage.

Evaluating Moderation of Parent-Teen Overweight/Obesity Relation by Household Socioeconomic Status.

Obesity continues to be a significant global health issue and contributes to a variety of comorbidities and disease states. Importantly, obesity contributes to adverse cardiovascular health outcomes, which is the leading cause of death worldwide. Further, maternal obesity during gestation has been shown to predispose offspring to adverse phenotypic outcomes, specifically cardiovascular outcomes. Therefore, we hypothesized that diet-induced obesity during gestation would result in adverse cardiovascular phenotypes in first-generation offspring that would have functional consequences in juvenile and advanced ages. Multiparous Rambouillet/Columbia cross ewes (F0) were fed a highly palatable, pelleted diet at either 100% (CON), or 150% (OB) of National Research Council recommendations from 60 days prior to conception, until necropsy at d 135 (90%) of gestation (CON: n = 5, OB: n = 6), or through term for lambs (F1: 2.5 mo. old; CON: n = 9, OB: n = 6) and ewes (F1:9 years old; CON: n = 5, OB: n = 8). Paraffin-embedded fetal aorta section staining revealed increased collagen:elastin ratio and greater aortic wall thickness in OBF1 fetuses. Invasive auricular blood pressure recordings revealed elevated systolic blood pressure in OBF1 lambs, but no differences in diastolic pressure. In aged F1 ewes, systolic and diastolic blood pressures were reduced in OBF1 relative to CONF1. Echocardiography revealed no treatment differences in F1 lambs, but F1 ewes show tendencies for increased end systolic volume and decreased stroke volume, and markedly reduced ejection fraction. Therefore, we conclude that maternal obesity programs altered cardiovascular development that results in a hypertensive state in OBF1 lambs. Increased cardiac workload resulting from early life hypertension precedes the failure of the heart to maintain function later in life.

Christopher L. Pankey

West Virginia School of Osteopathic Medicine

A Chronic High-Intensity Interval Training and Diet-Induced Obesity Model to Maximize Exercise Effort and Induce Physiologic Changes in Rats