Exposure to high-fat diet since post-weaning induces cardiometabolic damage in adult rats

The Effects of Calorie Restriction and Time-Restricted Feeding on IGF1 Serum Level and Lipid Profile in Male Wister Rats with Previous Obesity

BACKGROUND

Calorie restriction (CR) is known as a nutritional gold standard for life extension and different studies have shown that insulin-like growth factor (IGF1) reduction through CR may be involved in CR's anti-aging effects. Besides, time-restricted-feeding (TRF) is also highlighted due to more feasibility and positive health effects. We designed this study to compare the effects of CR and TRF on IGF1 and other metabolic parameters.

METHODS

Fifty-two male Wistar rats (3 weeks old) were subjected to either a control (CON, n = 11) diet or high-fat diet (HFD, n = 42) for 17 weeks. In the second phase of the study, the HFD group were divided into four groups (n = 9) 1) 30% CR, 2) Night Intermittent Fasting (NIF, active phase), 3) day intermittent fasting (DIF, rest phase), and 4) Ad-Libitum (AL) with a standard diet for 10 weeks. Blood samples were collected at the end of both phases.

RESULTS

HFD increased IGF1 and deteriorated lipid profiles, except for triglycerides (P: 0.018, 0.008.0.012, 0.032) but CR in these obese subjects could not lower the IGF1 level. HDL significantly decreased in DIF compared to CON and CR (P; 0.001). Meanwhile, HOMA-IR increased in DIF and was significant compared to CR (P: 0.002). Serum glucose levels decreased in CR compared to all groups except for CON (P: 0.001).

CONCLUSION

Data indicates the role of previous obesity on the effect of CR on the IGF1 level and highlights the effect of inappropriate time of food intake on HDL and APOA1.

High fat high sucrose diet-induced dyslipidemia in guinea pigs

Easy access to high-calorie and fat-dense fast food has resulted in unhealthy dietary and lifestyle changes worldwide, which affects both developed and developing economies. This predisposes populations to a considerable number of metabolic and inflammatory conditions, such as diabetes, nonalcoholic fatty liver disease (NAFLD), and cardiovascular disease (CVD). Guinea pigs have been proposed as a model to study high-fat diet-induced metabolic disease due to their similar antioxidant metabolism and lipid profile to humans, and their susceptibility to atherosclerosis and endothelial disease. This study aims to evaluate cardiovascular and metabolic disorders induced by high-fat high-sucrose diet (HFHSD) in guinea pigs. Two to three-week-old male guinea pigs were fed a normal diet (ND) or HFHSD for 12 wk. Guinea pigs fed a HFHSD developed glucose intolerance, dyslipidemia, and liver, cardiac, and kidney damage. However, hypertension, dysautonomia, endothelial disease, and obesity were absent in these HFHSD guinea pigs. Taken together, these results show that guinea pigs fed a HFHSD are a nonobese model of metabolic disorders, resulting in important cardiac damage. Moreover, our findings suggest that NAFLD may be an important risk factor for diet-induced CVD.NEW & NOTEWORTHY In this study, we show a new animal model for diet-induced disease metabolic disorders without obesity in guinea pigs. Moreover, results suggest a strong relation between liver disease and increased cardiovascular risks.

High-fat diet effect on periapical lesions and hepatic enzymatic antioxidant in rats

AIMS

To evaluate the effects of a high-fat diet (HFD) on the progression of apical periodontitis (AP), local inflammation, systemic antioxidant status, and blood lipid profile in rats.

MAIN METHODS

Sixteen male Wistar rats were fed a standard diet (SD) or a HFD. At the sixth experimental week, the pulp chambers of the mandibular first molars were exposed to develop AP. A glucose tolerance test was performed the week before euthanasia. At the tenth experimental week, the animals were euthanized and the livers were collected to estimate catalase (CAT) and reduced glutathione (GSH) levels. Blood was acquired for biochemical analysis. The size of AP was estimated from radiographs and described as AP size-to-body weight ratio; inflammatory grade of AP was determined by histological analysis.

KEY FINDINGS

At the end of the experimental period, the rats fed the HFD had 30% less weight (P < 0.0001) and higher blood glucose levels after 30 min of sucrose intake (P < 0.05) than those fed the SD. Animals from the HFD group had lower levels of CAT (P < 0.01), but the same was not observed in the GSH levels. Plasma insulin and total cholesterol were not affected by the diet. The rats fed the HFD presented greater AP than those fed the SD (P < 0.05). However, the local inflammatory infiltrate was similar in both groups.

SIGNIFICANCE

The alterations promoted by the consumption of a HFD were not only observed systemically, but also locally, producing greater AP in rats than a SD.

Maternal blood pressure mediates the association between maternal obesity and infant weight gain in early postpartum

BACKGROUND

It is unknown to what extent higher maternal blood pressure (BP) in early postpartum impacts the relationship between higher maternal weight status and greater infant weight gain in early postpartum.

OBJECTIVE

To evaluate the mediating role of higher maternal BP at 1 month postpartum on the association between higher maternal weight status at 1 month postpartum and greater infant weight gain over 6 months postpartum.

METHODS

Participants were 169 Hispanic mother-infant pairs. Maternal body mass index (BMI) and BP were assessed at 1 month postpartum. Infant weight was measured at 1 and 6 months postpartum to calculate weight-for-age z scores (WAZ). Multiple linear regression models were used for prediction, and Sobel test was used to determine mediation.

RESULTS

Controlling for maternal pre-pregnancy BMI, age, delivery mode, infant sex, and infant birth weight revealed that both maternal BMI (β = .29) and BP (β = .32) predicted infant WAZ gain (both P ≤ .03). However, the relationship between infant WAZ gain and maternal BMI was no longer significant after further adjustment for maternal BP, which remained significant (P < .05). Maternal BP explained 23.6% (Sobel T = 2.01) of the association between maternal BMI at 1 month and infant WAZ gain over 6 months.

CONCLUSION

Our data suggest that higher maternal weight status at 1 month postpartum is related to greater infant weight gain over 6 months postpartum, and this relationship is mediated by higher maternal BP at 1 month postpartum.

Post-weaning Exposure to High-Fat Diet Induces Kidney Lipid Accumulation and Function Impairment in Adult Rats

Aim: We investigated the kidney morphofunctional consequences of high-fat diet intake since post-weaning in adult rats.

Main Methods: Male Wistar rats were divided into two groups: ND (normal diet; n = 10) and HD (high-fat diet; n = 10). The high-fat diet was introduced post-weaned and animals were followed for 8 weeks.

Key Findings: HD group did not change body weight gain even though food consumption has decreased with no changes in caloric consumption. The HD group showed glucose intolerance and insulin resistance. The glomerular filtration rate (GFR) was decreased in vivo (ND: 2.8 ± 1.01; HD: 1.1 ± 0.14 ml/min) and in the isolated perfusion method (34% of decrease). Renal histological analysis showed a retraction in glomeruli and an increase in kidney lipid deposition (ND: 1.5 ± 0.17 HD: 5.9 ± 0.06%). Furthermore, the high-fat diet consumption increased the pro-inflammatory cytokines IL-6 (ND: 1,276 ± 203; HD: 1,982 ± 47 pg/mL/mg) and IL-1b (ND: 97 ± 12 HD: 133 ± 5 pg/mL/mg) without changing anti-inflammatory cytokine IL-10.

Significance: Our study provides evidence that high-fat diet consumption leads to renal lipid accumulation, increases inflammatory cytokines, induces glomeruli retraction, and renal dysfunction. These damages observed in the kidney could be associated with an increased risk to advanced CKD in adulthood suggesting that reduction of high-fat ingestion during an early period of life can prevent metabolic disturbances and renal lipotoxicity.

At the heart of programming: the role of micro-RNAs

Epidemiological and experimental observations tend to prove that environment, lifestyle or nutritional challenges influence heart functions together with genetic factors. Furthermore, when occurring during sensitive windows of heart development, these environmental challenges can induce an 'altered programming' of heart development and shape the future heart disease risk. In the etiology of heart diseases driven by environmental challenges, epigenetics has been highlighted as an underlying mechanism, constituting a bridge between environment and heart health. In particular, micro-RNAs which are involved in each step of heart development and functions seem to play a crucial role in the unfavorable programming of heart diseases. This review describes the latest advances in micro-RNA research in heart diseases driven by early exposure to challenges and discusses the use of micro-RNAs as potential targets in the reversal of the pathophysiology.

A high-fat diet can affect bone healing in growing rats

A high-fat diet (HFD) can have a negative effect on bone quality in young and old people. Although bone healing in children is normally efficient, there is no evidence that children who have a diet rich in fat have compromised bone fracture regeneration compared with children with recommended dietary fat levels. The purpose of the present study was to evaluate the effects of an HFD on bone healing in growing female rats. Twenty-six postweaning female Wistar rats were divided into two groups (13 animals per group): a standard diet (SD) group and an HFD (with 60% of energy from fat) group. The rats received the assigned diets for 5 weeks, and in the third week they were submitted to an osteotomy procedure of the left tibia. Body mass and feed intake were recorded during the experiment. One day before euthanasia, an insulin tolerance test was performed. After euthanasia, the tibiae were removed and analyzed by densitometry, mechanical testing, histomorphometry, stereology and immunohistochemistry. An HFD caused an adaptive response to maintain energetic balance by decreasing feed intake and causing insulin insensitivity. There was no change in bone mineral density, collagen amount and immunostaining for bone formation, but maximal load and stiffness were decreased in the HFD group. In addition, bone volume had a tendency to be higher in the SD group than in the HFD group. Compared with rats receiving an SD, growing rats receiving an HFD for 5 weeks had similar bone mineral density but altered mechanical properties at the osteotomy defect site.

High-Fat and Fat-Enriched Diets Impair the Benefits of Moderate Physical Training in the Aorta and the Heart in Rats

AIM

Millions of people die each year due to cardiovascular disease (CVD). A Western lifestyle not only fuses a significant intake of fat with physical inactivity and obesity but also promotes CVD. Recent evidence suggests that dietary fat intake impairs the benefits of physical training. We investigated whether aerobic training could reverse the adverse effects of a high-fat diet (HFD) on the aorta. Then, we explored whether this type of exercise could reverse the damage to the heart that is imposed by fat-enriched diet (FED).

METHODS

Rats were randomly assigned to two experiments, which lasted 8 weeks each. First, rats swam for 60 min and were fed either a regular diet [standard diet (STD)] or an HFD. After aortic samples had been collected, the rats underwent a histopathological analysis for different biomarkers. Another experiment subjected rats that were fed either an STD or an FED to swimming for 20 or 90 min.

RESULTS

The first experiment revealed that rats that were subjected to an HFD-endured increased oxidative damage in the aorta that exercises could not counteract. Together with increased cyclooxygenase 2 expression, an HFD in combination with physical training increased the number of macrophages. A reduction in collagen fibers with an increased number of positive α-actin cells and expression of matrix metalloproteinase-2 occurred concomitantly. Upon analyzing the second experiment, we found that physically training rats that were given an FED for 90 min/day decreased the cardiac adipose tissue density, although it did not protect the heart from fat-induced oxidative damage. Even though the physical training lowered cholesterol levels that were promoted by the FED, the levels were still higher than those in the animals that were given an STD. Feeding rats an FED impaired the swimming protocol's effects on lowering triglyceride concentration. Additionally, exercise was unable to reverse the fat-induced deregulation in hepatic antioxidant and lipid peroxidation activities.

CONCLUSION

Our findings reveal that an increased intake of fat undermines the potential benefits of physical exercise on the heart and the aorta.