Postnatal early overfeeding induces cardiovascular dysfunction by oxidative stress in adult male Wistar rats

Postnatally overfed mice display cardiac function alteration following myocardial infarction

BACKGROUND

Cardiovascular (CV) pathologies remain a leading cause of death worldwide, often associated with common comorbidities such as overweight, obesity, type 2 diabetes or hypertension. An innovative mouse model of metabolic syndrome induced by postnatal overfeeding (PNOF) through litter size reduction after birth was developed experimentally. This study aimed to evaluate the impact of PNOF on cardiac remodelling and the development of heart failure following myocardial infarction.

METHODS

C57BL/6 male mice were raised in litter adjusted to 9 or 3 pups for normally-fed (NF) control and PNOF group respectively. After weaning, all mice had free access to standard diet and water. At 4 months, mice were subjected to myocardial infarction (MI). Echocardiographic follows-up were performed up to 6-months post-surgery and biomolecular analyses were carried-out after heart collection.

FINDINGS

At 4 months, PNOF mice exhibited a significant increase in body weight, along with a basal reduction in left ventricular ejection fraction (LVEF) and an increase in left ventricular end-systolic area (LVESA), compared to NF mice. Following MI, PNOF mice demonstrated a significant decrease in stroke volume and an increased heart rate compared to their respective initial values, as well as a notable reduction in cardiac output 4-months after MI. After 6-months, left ventricle and lung masses, fibrosis staining, and mRNA expression were all similar in the NF-MI and PNOF-MI groups.

INTERPRETATION

After MI, PNOF mice display signs of cardiac function worsening as evidenced by a decrease in cardiac output, which could indicate an early sign of heart failure decompensation.

High-fat diet during lactation, as opposed to during adolescence or gestation, programs cardiometabolic and autonomic dysfunctions in adult offspring

The Developmental Origins of Health and Disease (DOHaD) concept has been established for three decades. Many studies have shown that, besides pregnancy, other plastic phases (mainly preconception, lactation, and infancy-adolescence) are also sensitive to environmental changes, including nutritional conditions, that can program health or disease later in life. This study compared the susceptibility of the gestation, lactation and adolescence to a high-fat diet (HFD) intervention to program rats into autonomic nervous system imbalance and cardiometabolic dysfunction in adulthood. Four groups of rats were studied: offspring from mothers exposed to a HFD (35% fat) or a standard chow diet (4.5% fat) during gestation (GEST and CONT groups, respectively), offspring from mothers exposed to the HFD during lactation (LAC), and adolescent rats exposed to the HFD (ADOL). Mothers treated during pregnancy exhibited a higher body mass, but nursing mothers presented the highest food energy intake and higher adiposity. Compared to the other groups, the LAC rats showed increased body mass gain, food energy intake, body fat, glucose intolerance and blood pressure. LAC group also showed increased parasympathetic activity. In contrast, LAC sympathetic nerve activity decreased compared with the other groups. The ADOL group exhibited mostly similar responses but of a smaller magnitude. This suggests that the lactation phase is the most sensitive to HFD programming for cardiometabolic dysfunction in adulthood and that early overnutrition may affect neural connections by altering the autonomic nervous system balance.

Geroprotective effects of GdVO4:Eu3 + nanoparticles, metformin and calorie restriction in male rats with accelerated aging induced by overnutrition in early postnatal ontogenesis

GdVO4:Eu3+ nanoparticles (OVNPs) have previously been shown to exhibit anti-aging effects in old rats.The accelerated aging model (overnutrition in early postnatal ontogenesis (POF)) was used to confirm the effect of OVNPs as a potential geroprotector. A comparative study of the effect of OVNPs, calorierestriction (CR) and CR-mimetic-metformin was carried out using a number of criteria: survival, prooxidant-antioxidant balance in the liver and blood, physiological parameters of male Wistar rats with accelerated aging. It was found that the survival of rats with POF was lower than that of control animals.It was found that the rate of superoxide radical formation and the content of lipid hydroperoxides in the mitochondria and microsomes of the liver and blood serum of rats with POF were higher, and the activities of glutathione peroxidases and the GSH content were significantly lower than in the control animals.It was also found that POF leads to perturbation of physiological parameters (body weight, liver weight, liver mass coefficient, body temperature and blood thyroxine concentration) characterizing the quality of life. Long-term use of OVNPs, CR or metformin in rats with accelerated aging normalized the imbalance of the prooxidant-antioxidant system, improved the physiological parameters, and increased the survival of these experimental animals. Moreover, the increase in survival was most pronounced with the use of CR and OVNPs. Considering our results andthe inadmissibility of long-term use of CR, it should be concluded that GdVO4:Eu3+ nanoparticles are promising for the development of agents that slow down the accelerated aging of an organism.

Short-Term Postnatal Overfeeding Induces Long-Lasting Cardiometabolic Syndrome in Mature and Old Mice Associated with Increased Sensitivity to Myocardial Infarction

SCOPE

Perinatal nutritional disturbances may "program" an increased cardio-metabolic risk in adulthood; however, few experimental studies have explored their effects on mature and/or old animal. This study aims to investigate the influence of postnatal overfeeding (PNOF) on cardiac function, sensitivity to ischemia-reperfusion (I-R) injury in vivo, glucose metabolism, and metabolic profile of pericardial adipose tissue (PAT) in young (4 months), adult (6 months), old (12 months), and very old (18 months) male mice.

METHODS AND RESULTS

Two days after birth, PNOF is induced by adjusting the litter size of C57BL/6 male mice to three pups/mother, while the normally fed (NF) control group is normalized to nine pups/mother. After weaning, all mice have free access to standard diet. Glucose/insulin tests and in vivo myocardial I-R injury are conducted on mice aged from 2 to 12 months, while echocardiography is performed at all ages up to 18 months. PNOF mice exhibit an early and persistent 10-20% increase in body weight and a 10% decrease in left ventricular ejection fraction throughout their lifespan. In PNOF mice aged 4, 6, and 12 months, glucose intolerance and insulin resistance are observed, as well as a 27-34% increase in infarct size. This is accompanied by a higher PAT mass with increased inflammatory status.

CONCLUSION

Short-term PNOF results in nutritional programming, inducing long-lasting alterations in glucose metabolism and cardiac vulnerability in male mice, lasting up to 12 months.

Postnatal Overfeeding during Lactation Induces Endothelial Dysfunction and Cardiac Insulin Resistance in Adult Rats

Early overnutrition is associated with cardiometabolic alterations in adulthood, likely attributed to reduced insulin sensitivity due to its crucial role in the cardiovascular system. This study aimed to assess the long-term effects of early overnutrition on the development of cardiovascular insulin resistance. An experimental childhood obesity model was established using male Sprague Dawley rats. Rats were organized into litters of 12 pups/mother (L12-Controls) or 3 pups/mother (L3-Overfed) at birth. After weaning, animals from L12 and L3 were housed three per cage and provided ad libitum access to food for 6 months. L3 rats exhibited elevated body weight, along with increased visceral, subcutaneous, and perivascular fat accumulation. However, heart weight at sacrifice was reduced in L3 rats. Furthermore, L3 rats displayed elevated serum levels of glucose, leptin, adiponectin, total lipids, and triglycerides compared to control rats. In the myocardium, overfed rats showed decreased IL-10 mRNA levels and alterations in contractility and heart rate in response to insulin. Similarly, aortic tissue exhibited modified gene expression of TNFα, iNOS, and IL-6. Additionally, L3 aortas exhibited endothelial dysfunction in response to acetylcholine, although insulin-induced relaxation remained unchanged compared to controls. At the molecular level, L3 rats displayed reduced Akt phosphorylation in response to insulin, both in myocardial and aortic tissues, whereas MAPK phosphorylation was elevated solely in the myocardium. Overfeeding during lactation in rats induces endothelial dysfunction and cardiac insulin resistance in adulthood, potentially contributing to the cardiovascular alterations observed in this experimental model.

Postnatal Overfeeding in Rodents Induces a Neurodevelopment Delay and Anxious-like Behaviour Accompanied by Sex- and Brain-Region-Specific Synaptic and Metabolic Changes

Nutritional disturbances during the early postnatal period can have long-lasting effects on neurodevelopment and may be related to behavioural changes at adulthood. While such neuronal connection disruption can contribute to social and behaviour alterations, the dysregulation of the neuroendocrine pathways involved in nutrient-sensing balance may also cause such impairments, although the underlying mechanisms are still unclear. We aimed to evaluate sex-specific neurodevelopmental and behavioural changes upon postnatal overfeeding and determine the potential underpinning mechanisms at the central nervous system level, with a focus on the interconnection between synaptic and neuroendocrine molecular alterations. At postnatal day 3 (PND3) litters were culled to three animals (small litter procedure). Neurodevelopmental tests were conducted at infancy, whereas behavioural tests to assess locomotion, anxiety, and memory were performed at adolescence, together with molecular analysis of the hippocampus, hypothalamus, and prefrontal cortex. At infancy, females presented impaired acquisition of an auditory response, eye opening, olfactory discrimination, and vestibular system development, suggesting that female offspring neurodevelopment/maturation was deeply affected. Male offspring presented a transitory delay in locomotor performance., while both offspring had lower upper limb strength. At adolescence, both sexes presented anxious-like behaviour without alterations in short-term memory retention. Both males and females presented lower NPY1R levels in a region-specific manner. Furthermore, both sexes presented synaptic changes in the hippocampus (lower GABAA in females and higher GABAA levels in males), while, in the prefrontal cortex, similar higher GABAA receptor levels were observed. At the hypothalamus, females presented synaptic changes, namely higher vGLUT1 and PSD95 levels. Thus, we demonstrate that postnatal overfeeding modulates offspring behaviour and dysregulates nutrient-sensing mechanisms such as NPY and GABA in a sex- and brain-region-specific manner.

Can breastfeeding affect the rest of our life?

The breastfeeding period is one of the most important critical windows in our development, since milk, our first food after birth, contains several compounds, such as macronutrients, micronutrients, antibodies, growth factors and hormones that benefit human health. Indeed, nutritional, and environmental alterations during lactation, change the composition of breast milk and induce alterations in the child's development, such as obesity, leading to the metabolic dysfunctions, cardiovascular diseases and neurobehavioral disorders. This review is based on experimental animal models, most of them in rodents, and summarizes the impact of an adequate breast milk supply in view of the developmental origins of health and disease (DOHaD) concept, which has been proposed by researchers in the areas of epidemiology and basic science from around the world. Here, experimental advances in understanding the programming during breastfeeding were compiled with the purpose of generating knowledge about the genesis of chronic noncommunicable diseases and to guide the development of public policies to deal with and prevent the problems arising from this phenomenon. This review article is part of the special issue on "Cross talk between periphery and brain".

Postnatal overfeeding induces hepatic microRNA-221 expression and impairs the PI3K/AKT pathway in adult male rats

BACKGROUND

Increasing evidence suggests that postnatal overfeeding induces childhood obesity, which is strongly associated with metabolic syndrome. Insulin resistance is a risk factor for metabolic syndrome. MicroRNA-221 (miR-221) is involved in the development of obesity and has been reported to negatively regulate insulin sensitivity. However, the underlying mechanism remains unclear.

METHODS

Rats raised in small litters (SLs, three pups/dam, n = 10) and normal litters (NLs, 10 pups/dam, n = 10) were used to model early postnatal overfeeding and act as controls, respectively. miR-221 and proteins related to the phosphoinositide 3-kinases (PI3K)/protein kinase B (AKT) pathway were assessed in the liver.

RESULTS

Early postnatal overfeeding significantly increased body weight, visceral fat index, blood glucose, serum triglycerides, and the homeostasis model assessment of insulin resistance at 9 weeks. Real-time polymerase chain reaction (PCR) and western blot analysis revealed that postnatal overfeeding induced insulin receptor and insulin receptor substrate 2 expression, but decreased PI3K and AKT phosphorylation in the liver. Quantitative real-time PCR showed that hepatic miR-221 was significantly overexpressed in the SL group.

CONCLUSIONS

These results indicate that postnatal overfeeding induces hepatic miR-221 overexpression and impairs the PI3K/AKT signal pathway, which may cause insulin resistance.

IMPACT

We first report postnatal overfeeding induces hepatic miR-221 expression. Postnatal overfeeding impairs PI3K/AKT pathway in the liver of adult rats. Postnatal overfeeding induces obesity and high blood glucose. Avoidance of overfeeding during early postnatal life may prevent obesity and T2DM.

Programming of Cardiovascular Dysfunction by Postnatal Overfeeding in Rodents

Nutritional environment in the perinatal period has a great influence on health and diseases in adulthood. In rodents, litter size reduction reproduces the effects of postnatal overnutrition in infants and reveals that postnatal overfeeding (PNOF) not only permanently increases body weight but also affects the cardiovascular function in the short- and long-term. In addition to increased adiposity, the metabolic status of PNOF rodents is altered, with increased plasma insulin and leptin levels, associated with resistance to these hormones, changed profiles and levels of circulating lipids. PNOF animals present elevated arterial blood pressure with altered vascular responsiveness to vasoactive substances. The hearts of overfed rodents exhibit hypertrophy and elevated collagen content. PNOF also induces a disturbance of cardiac mitochondrial respiration and produces an imbalance between oxidants and antioxidants. A modification of the expression of crucial genes and epigenetic alterations is reported in hearts of PNOF animals. In vivo, a decreased ventricular contractile function is observed during adulthood in PNOF hearts. All these alterations ultimately lead to an increased sensitivity to cardiac pathologic challenges such as ischemia-reperfusion injury. Nevertheless, caloric restriction and physical exercise were shown to improve PNOF-induced cardiac dysfunction and metabolic abnormalities, drawing a path to the potential therapeutic correction of early nutritional programming.

Impact of experimental obesity on diaphragm structure, function, and bioenergetics

Obesity is associated with bioenergetic dysfunction of peripheral muscles; however, little is known regarding the impact of obesity on the diaphragm. We hypothesized that obesity would be associated with diaphragm dysfunction attributable to mitochondrial oxygen consumption and structural and ultrastructural changes. Wistar rat litters were culled to 3 pups to induce early postnatal overfeeding and consequent obesity. Control animals were obtained from unculled litters. From postnatal day 150, diaphragm ultrasound, computed tomography, high-resolution respirometry, immunohistochemical, biomolecular, and ultrastructural histological analyses were performed. The diaphragms of obese animals, compared with those of controls, presented changes in morphology as increased thickening fraction, diaphragm excursion, and diaphragm dome height, as well as increased mitochondrial respiratory capacity coupled to ATP synthesis and maximal respiratory capacity. Fatty acid synthase gene expression was also higher in obese animals, suggesting a source of energy for the respiratory chain. Myosin heavy chain-IIA was increased, indicating shift from glycolytic toward oxidative muscle fiber profile. Diaphragm tissue also exhibited ultrastructural changes, such as compact, round, and swollen mitochondria with fainter cristae and more lysosomal bodies. Dynamin-1 expression in the diaphragm was reduced in obese rats, suggesting decreased mitochondrial fission. Furthermore, gene expressions of peroxisome γ proliferator-activated receptor coactivator-1α and superoxide dismutase-2 were lower in obese animals than in controls, which may indicate a predisposition to oxidative injury. In conclusion, in the obesity model used herein, muscle fiber phenotype was altered in a manner likely associated with increased mitochondrial respiratory capability, suggesting respiratory adaptation to increased metabolic demand.NEW & NOTEWORTHY Obesity has been associated with peripheral muscle dysfunction; however, little is known about its impact on the diaphragm. In the current study, we found high oxygen consumption in diaphragm tissue and changes in muscle fiber phenotypes toward a more oxidative profile in experimental obesity.

Long-term effects of early overfeeding and food restriction during puberty on cardiac remodeling in adult rats

Nutritional disorders during the perinatal period cause cardiometabolic dysfunction, which is observable in the early overfeeding (EO) experimental model. Therefore, severe caloric restriction has the potential of affecting homeostasis through the same epigenetic mechanisms, and its effects need elucidation. This work aims to determine the impact of food restriction (FR) during puberty in early overfed obese and non-obese animals in adult life. Three days after delivery (PN3), Wistar rats were separated into two groups: normal litter (NL; 9 pups) and small litter (SL; 3 pups). At PN30, some offspring were subjected to FR (50%) until PN60, or maintained with free access to standard chow. NL and SL animals submitted to food restriction (NLFR and SLFR groups) were kept in recovery with free access to standard chow from PN60 until PN120. Body weight and food intake were monitored throughout the experimental period. At PN120 cardiovascular parameters were analyzed and the animals were euthanized for sample collection. SLNF and SLFR offspring were overweight and had increased adiposity. Differences in blood pressure were observed only between obese and non-obese animals. Obese and FR animals have cardiac remodeling showing cardiomyocyte hypertrophy and the presence of interstitial and perivascular fibrosis. FR animals also show increased expression of AT1 and AT2 receptors and of total ERK and p-ERK. The present study showed that EO leads to the obese phenotype and cardiovascular disruptions. Interestingly, we demonstrated that severe FR during puberty leads to cardiac remodeling.

High salt intake during puberty leads to cardiac remodelling and baroreflex impairment in lean and obese male Wistar rats

Modern lifestyle increases the prevalence of obesity and its co-morbidities in the young population. High-salt (HS) diets are associated with hypertension and cardiac remodelling. The present study evaluated the potential effects of cardiometabolic programming induced by HS intake during puberty in lean and obese rats. Additionally, we investigated whether HS could exacerbate the impairment of cardiovascular parameters in adult life due to postnatal early overnutrition (PO). At postnatal day 3 (PN3), twenty-four litters of Wistar rats were divided into two groups: normal litter (NL, nine pups/dam) and small litter (SL, three pups/dam) throughout the lactation period; weaning was at PN21. At PN30, the pups were subdivided into two more groups: NL plus HS (NLHS) and SL plus HS (SLHS). HS intake was from PN30 until PN60. Cardiovascular parameters were evaluated at PN120. SL rats became overweight at adulthood due to persistent hyperphagia; however, HS exposure during puberty reduced the weight gain and food intake of NLHS and SLHS. Both HS and obesity raised the blood pressure, impaired baro- and chemoreflex sensitivity and induced cardiac remodelling but no worsening was observed in the association of these factors, except a little reduction in the angiotensin type-2 receptor in the hearts from SLHS animals. Our results suggest that the response of newborn offspring to PO and juveniles to a HS diet leads to significant changes in cardiovascular parameters in adult rats. This damage may be accompanied by impairment of both angiotensin signalling and antioxidant defence in the heart.

Ethanol exposure in prenatal and early postnatal induced cardiac injury in rats: involvement of oxidative stress, Hsp70, ERK 1/2, JNK, and apoptosis in a 3-month follow-up study

Alcohol exposure during pregnancy induces a wide range of structural and functional abnormalities in the fetal heart. However, the underlying mechanism of this phenomenon is not well known. This study was undertaken to elucidate probable mechanisms of myocardial damage induced by prenatal and early postnatal ethanol treatment. Pregnant Wistar rats received ethanol 4.5 g/kg BW once per day from the seventh day of gestation (GD7) throughout lactation. The oxidative stress injury of the myocardium in pups was evaluated by measuring levels of oxidative stress biomarkers. Histopathological examinations and Western blot were performed to evaluate histological features, apoptosis, and molecular alterations in the myocardial tissue of male pups on the postnatal day 21 (PN-21) and postnatal day 90 (PN-90). The results showed that maternal ethanol consumption caused oxidative stress (impaired total antioxidant capacity and malondialdehyde), histological changes, and apoptosis of the myocardium in the pups on PN-21 and PN-90. At the molecular levels, Western blot analysis revealed that ethanol modulated the protein expression of p-ERK1/2, p-JNK, and Hsp70 in the myocardial tissue of the pups after 21 and 90 days of birth compared with the controls. These findings revealed that maternal ethanol intake induced cardiac toxicity in part, mediated by oxidative stress and apoptosis in the pups. A further mechanism study revealed that ethanol enhanced ERK1/2 and JNK phosphorylation and Hsp70 protein expression.