Isocaloric Low-protein Diet Research Articles

NAD+ precursors and bile acid sequestration treat preclinical refractory environmental enteric dysfunction.

Environmental enteric dysfunction (EED) is a diffuse small bowel disorder associated with poor growth, inadequate responses to oral vaccines, and nutrient malabsorption in millions of children worldwide. We identify loss of the small intestinal Paneth and goblet cells that are critical for innate immunity, reduced villous height, increased bile acids, and dysregulated nicotinamide adenine dinucleotide (NAD+) synthesis signaling as potential mechanisms underlying EED and which also correlated with diminished length-for-age z score. Isocaloric low-protein diet (LPD) consumption in mice recapitulated EED histopathology and transcriptomic changes in a microbiota-independent manner, as well as increases in serum and fecal bile acids. Children with refractory EED harbor single-nucleotide polymorphisms in key enzymes involved in NAD+ synthesis. In mice, deletion of Nampt, the gene encoding the rate-limiting enzyme in the NAD+ salvage pathway, from intestinal epithelium also reduced Paneth cell function, a deficiency that was further aggravated by LPD. Separate supplementation with NAD+ precursors or bile acid sequestrant partially restored LPD-associated Paneth cell defects and, when combined, fully restored all histopathology defects in LPD-fed mice. Therapeutic regimens that increase protein and NAD+ contents while reducing excessive bile acids may benefit children with refractory EED.

A maternal low-protein diet results in sex-specific differences in synaptophysin expression and milk fatty acid profiles in neonatal rats.

The developmental origins of health and disease hypothesis have highlighted the link between early life environment and long-term health outcomes in offspring. For example, maternal protein restriction during pregnancy and lactation can result in adverse metabolic and cognitive outcomes in offspring postnatal. Hence, in the present study, we assess whether an isocaloric low-protein diet (ILPD) affects the fatty acid profile in breast milk, the hippocampal synaptophysin (Syn) ratio, and the oxidative stress markers in the neonatal stage of male and female offspring. The aim of this work was to assess the effect of an ILPD on the fatty acid profile in breast milk, quantified the hippocampal synaptophysin (Syn) ratio and oxidative stress markers in neonatal stage of male and female offspring. Female Wistar rats were fed with either a control diet or an ILPD during gestation to day 10 of lactation. Oxidative stress markers were assessed in serum and liver. All quantifications were done at postnatal day 10. The results showed: ILPD led to decreases of 38.5% and 17.4% in breast milk volume and polyunsaturated fatty acids content. Significant decreases of hippocampal Syn ratio in male offspring (decreases of 98% in hippocampal CA1 pyramidal and CA1 oriens, 83%, stratum pyramidal in CA3, 80%, stratum lucidum in CA3, and 81% stratum oriens in CA3). Male offspring showed an increase in pro-oxidant status in serum and liver. Thus, the data suggest that male offspring are more vulnerable than females to an ILPD during gestation and lactation.

Low Protein Programming Causes Increased Mitochondrial Fusion and Decreased Oxygen Consumption in the Hepatocytes of Female Rats.

The liver is one of the major organs involved in the regulation of glucose and lipid homeostasis. The effectiveness of metabolic activity in hepatocytes is determined by the quality and quantity of its mitochondria. Mitochondrial function is complex, and they act via various dynamic networks, which rapidly adapt to changes in the cellular milieu. Our present study aims to investigate the effects of low protein programming on the structure and function of mitochondria in the hepatocytes of adult females. Pregnant rats were fed with a control or isocaloric low-protein diet from gestational day 4 until delivery. A normal laboratory chow was given to all dams after delivery and to pups after weaning. The rats were euthanized at 4 months of age and the livers were collected from female offspring for investigating the mitochondrial structure, mtDNA copy number, mRNA, and proteins expression of genes associated with mitochondrial function. Primary hepatocytes were isolated and used for the analysis of the mitochondrial bioenergetics profiles. The mitochondrial ultrastructure showed that the in utero low-protein diet exposure led to increased mitochondrial fusion. Accordingly, there was an increase in the mRNA and protein levels of the mitochondrial fusion gene Opa1 and mitochondrial biogenesis genes Pgc1a and Essra, but Fis1, a fission gene, was downregulated. Low protein programming also impaired the mitochondrial function of the hepatocytes with a decrease in basal respiration ATP-linked respiration and proton leak. In summary, the present study suggests that the hepatic mitochondrial dysfunction induced by an in utero low protein diet might be a potential mechanism linking glucose intolerance and insulin resistance in adult offspring.

Modifying Dietary Protein Impacts mTOR Signaling and Brain Deposition of Amyloid β in a Knock-In Mouse Model of Alzheimer Disease

BackgroundAlzheimer disease (AD) is a neurodegenerative condition defined by the build-up of amyloid plaques in the brain and intraneuronal tangles of the protein tau. Autophagy is a cellular cleaning process involved in the degradation of proteins, including proteins directly responsible for amyloid plaques, but its activity is compromised in AD. The mechanistic target of rapamycin complex (mTORC) 1 inhibits autophagy when activated by amino acids. ObjectivesWe hypothesized that reducing amino acid intake by decreasing dietary protein could promote autophagy, which in turn could prevent amyloid plaque deposition in AD mice. MethodsHomozygote (2-mo-old) and heterozygote (4-mo-old) amyloid precursor protein NL-G-F mice, a model of brain amyloid deposition, were used in this study to test this hypothesis. Male and female mice were fed with isocaloric low-protein, control, or high-protein diets for 4 mo and killed for analysis. Locomotor performance was measured using the inverted screen test, and body composition was measured using EchoMRI. Samples were analyzed using western blotting, enzyme-linked immunosorbent assay, mass spectrometry, and immunohistochemical staining. ResultsmTORC1 activity in the cerebral cortex was inversely covaried with protein consumption in both homozygote and heterozygote mice. Low-protein diet improved metabolic parameters and restored locomotor performance only in male homozygous mice. Dietary protein adjustment did not affect amyloid deposition in homozygous mice. However, in the heterozygous amyloid precursor protein NL-G-F mice, amyloid plaque was lower in male mice consuming the low protein compared with that in mice fed with the control diet. ConclusionsThis study showed that reducing protein intake reduces mTORC1 activity and may prevent amyloid accumulation, at least in male mice. Moreover, dietary protein is a tool that can be used to change mTORC1 activity and amyloid deposition in the mouse brain, and the murine brain’s response to dietary protein is sex specific.

The CD45RA+ (Quiescent) Cellular Phenotype Is Overabundant Relative to the CD45RA- Phenotype within the Involuted Splenic T Cell Population of Weanling Mice Subjected to Wasting Protein-Energy Malnutrition

The objective of this investigation was to determine whether an imbalance between naive- and memory-phenotype cells occurs within CD4+ and/or CD8+ splenic T cell subsets in models of protein-energy malnutrition (PEM) which produce wasting disease (loss of ∼1.6% of body weight per day for 14 d) and profound depression in thymus-dependent immunity. Male and female weanling mice of disparate inbred strains, CBA/J and C57BL/6J, were allocated to the following groups: zero-time control (23 d old and 19 d old, respectively), ad libitum intake of a complete purified diet (19% crude protein, 17 kJ/g gross energy), restricted intake of the complete diet, and (C57BL/6J, only) ad libitum intake of an isocaloric low protein diet (0.6% crude protein). Surface expression of isoforms of CD45, a component of the T cell receptor complex, as well as of the accessory molecule, CD2, were assessed by flow cytometry of splenic mononuclear cell suspensions. Both major T cell subsets in the malnourished groups contained a significantly higher proportion of cells expressing the surface marker, CD45RA, than was found in the spleen cells of the control groups. CD45RA+ (naive-phenotype) T cells represent the extreme of quiescence and stringent activation requirements among thymic lymphocytes. The results provide the first clear evidence of a T cell subset imbalance in PEM which is consistent with depression in acquired immunity and which occurs, apart from antigenic challenge, in a site wherein immune responses take place. The T cell receptor complex may emerge as a focal point of the depressive influence of PEM on the competence of thymic lymphocytes.

Characterisation of the Paternal Influence on Intergenerational Offspring Cardiac and Brain Lipid Homeostasis in Mice.

There is growing evidence that poor paternal diet at the time of conception increase the risk of offspring developing a range of non-communicable metabolic diseases, such as obesity, diabetes and cardiovascular disease, in adulthood. We hypothesise that a paternal low protein-high carbohydrate diet perturbs offspring tissue lipid abundance through both sperm and seminal plasma-mediated mechanisms. To test our hypothesis, we fed male C57BL/6 mice either a control normal protein diet (NPD; 18% protein) or an isocaloric low protein diet (LPD; 9% protein) for a minimum of 8 weeks. We generated offspring through artificial insemination, in combination with vasectomised male mating. Using this approach, we derived offspring from either NPD or LPD sperm but in the presence of NPD or LPD seminal plasma. Using high resolution mass-spectrometry, we found that offspring derived from either LPD sperm or seminal fluid displayed perturbed cardiac and brain lipid abundance from just three weeks of age, typically associated with the altered abundance of tissue triglycerides. We also observed the differential sex-specific patterns of lipids between the control and experimental offspring's hearts and brains. These observations indicate that poor paternal diet at the time of conception affects offspring cardiac and brain lipid profiles in an age-, sex- and generation-specific manner.

Performance of Egg Laying Japanese Quail Hens Fed Low Protein Diet Supplemented with Protease and/or Formic Acid

This study aimed to decrease the cost of laying rations by lowering protein as it’s the most expensive constituent in the diet. So, the research stated to investigate the effect of incorporating protease and/or formic acid as feed additives into a low protein isocaloric diet of laying Japanese quail hens on the productive performance, some egg quality parameters and economic efficiency. It was performed on 120 of 5–6-week-old healthy Japanese quail hens (weighed 268g7.06±) and randomly distributed into five groups (3 replicates per group). G1 (control with basal layer quail diet 20% protein), G2 (17% protein diet without protease enzyme or formic acid), G3 (17% protein diet + 0.05% protease enzyme), G4 (17% protein diet + 0.5% formic acid), G5 (17% protein diet + 0.05% protease enzyme + 0.5% formic acid). The experimental period lasted for 12 weeks with two weeks of adaptation before this period. For each replicate, daily egg number, daily egg weight, and egg mass as well as weekly feed intake were recorded. At the end of each week, eggs were collected from each replicate to evaluate egg quality. Mean egg production, egg albumin %, eggshell % and egg yolk % in all groups do not differ significantly with control but G2 was numerically higher than control in egg production, egg mass, FCR, egg shell %, egg yolk % and feed intake. G2 significantly has the heavier egg weight among groups (p < 0.05) as the average egg weights were 11.77g and 12.48g in control and G2 respectively. G3 was being the highest in feed intake and egg albumin percent than the other groups. G4 was being the highest in eggshell percent. Triglycerides per the whole yolk were lower in all groups than in the control. Cholesterol (mg)/whole yolk was low in G2 and G3. FCR was improved in G5. G2 had the highest net revenue and economic efficiency (48 LE&114.3%) in compare with control (46 LE&106.98%), while the values were 47.1LE&107.3%, 43.3LE&101.4% and 46.2 LE&105.5% for groups G3, G4 and G5 respectively. It could be concluded that feeding laying Japanese quail hens on diet containing 17% protein without protease enzyme or formic acid did not differ significantly from those fed on a control diet containing 20% protein. Moreover, it showed the highest net revenue and numerical improvement than the control group regarding egg production, egg mass, FCR, eggshell %, egg yolk %, and cholesterol in egg yolk.

Paternal low protein diet perturbs inter-generational metabolic homeostasis in a tissue-specific manner in mice

The underlying mechanisms driving paternally-programmed metabolic disease in offspring remain poorly defined. We fed male C57BL/6 mice either a control normal protein diet (NPD; 18% protein) or an isocaloric low protein diet (LPD; 9% protein) for a minimum of 8 weeks. Using artificial insemination, in combination with vasectomised male mating, we generated offspring using either NPD or LPD sperm but in the presence of NPD or LPD seminal plasma. Offspring from either LPD sperm or seminal fluid display elevated body weight and tissue dyslipidaemia from just 3 weeks of age. These changes become more pronounced in adulthood, occurring in conjunction with altered hepatic metabolic and inflammatory pathway gene expression. Second generation offspring also display differential tissue lipid abundance, with profiles similar to those of first generation adults. These findings demonstrate that offspring metabolic homeostasis is perturbed in response to a suboptimal paternal diet with the effects still evident within a second generation.

The Yucatan minipig model: A new preclinical model of malnutrition induced by a low-calorie/low-protein diet

Severe malnutrition exposes patients to adverse outcomes and a higher mortality risk. The Yucatan minipig, closer to human physiology than murine models could be a pertinent and innovative experimental model for studying the physiopathology and consequences of severe malnutrition. The present study aimed to determine whether a low calorie/low protein diet (LC/LP) can reproduce marasmus malnutrition in minipigs, and to characterize body composition, gut microbiota, malnutrition-related blood parameters, and histological and molecular skeletal muscle patterns. Eleven Yucatan minipigs were subjected to two different diets: a standard control diet (ST) (n=5) and a LC/LP diet (n=6). LC/LP animals daily received 50% of an isocaloric low-protein diet (10.37MJ/kg, 8.6% protein). Body composition was measured by computed tomography (CT-scan) before (T0) and after 8 weeks of diet (T8). Trapezius and biceps femoris muscles were sampled at the end of protocol to perform histological and molecular analyses. Gut microbiota composition were was also analyzed at T0 and T8 in fecal samples. Eight weeks of LC/LP diet significantly reduced body weight (-12.3±9.5%, P=0.03) and gut microbiota richness (i.e. number of observed species) (-10.4±8.3%, P=0.014) compared to baseline. After 8 weeks, LC/LP animals exhibited a significant reduction of retroperitoneal fat and skeletal muscle surface areas (P=0.03 and P=0.047, respectively), whereas these parameters remained unchanged in ST animals. These reductions were associated with lower muscle fiber cross-sectional area (CSA) in trapezius (P<0.001) and biceps femoris (P=0.003) in LC/LP animals compared to ST. LC/LP diet promoted an increase of AMP kinase phosphorylation in trapezius and biceps femoris (P=0.05), but did not affect cytochrome c and COX IV protein content, markers of mitochondrial content. Gene and proteins involved in ubiquitin-proteasome system and apoptosis remained unchanged after 8 weeks of LC/LP diet both in trapezius and biceps femoris. All these findings support that this experimental minipig model of severe malnutrition is valid to mimic pathophysiological changes occurring in human protein-energy marasmus malnutrition and muscle atrophy associated with malnutrition, as observed in patients with secondary sarcopenia.

Effect of different protein diets on weight loss, inflammatory markers, and cardiometabolic risk factors in obese women.

Background:Reducing and maintaining body weight has become more important than ever as obesity is becoming increasingly common worldwide. This study was aimed to investigate the effects of diets with different protein contents administered to obese women on anthropometric measurements, inflammatory markers, and cardiometabolic risk factors.Materials and Methods:This randomized controlled trial was conducted with sixty volunteering obese women aged between 20 and 45 years. The subjects were divided into two groups in equal numbers. The high-protein (HP) group (n = 30) was administered an iso-caloric HP diet (25% protein, 30% fat, and 45% carbohydrate), and the control group (n = 30) an isocaloric low-protein diet (15% protein, 30% fat, and 55% carbohydrate), and both groups were followed up for 8 weeks. The subjects' descriptive data, anthropometric measurements, homeostatic model assessment-insulin resistance (HOMA-IR), lipid profiles, and high-sensitive C-reactive protein (hs-CRP), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) levels were analyzed.Results:There was no significant difference at baseline (except for low-density lipoprotein cholesterol [LDL-C]), and end-of-study (except for IL-6, systolic blood pressure [SBP], and diastolic blood pressure) values of parameters between the two groups; after adjusted for baseline measurements, a significant difference was observed between the groups for body weight, body mass index, waist circumference, HOMA-IR, LDL-C, hs-CRP, TNF-α, IL-6, and SBP (P = 0.004, P = 0.001, P = 0.003, P = 0.029, P = 0.004, P = 0.016, P = 0.004, P = 0.010, and P = 0.000, respectively) and were greater in the HP group than in the control group (P < 0.05).Conclusion:The HP diet was effective on improvement in HOMA-IR, SBP, LDL-C, hs-CRP, TNF-α, IL-6, and resulted in body weight loss.

Intrauterine Low-Protein Diet Exacerbates Abnormal Development of the Urinary System in Gen1-Mutant Mice

Background: Gen1 mutation can cause various phenotypes of congenital anomaly of the kidney and urinary tract (CAKUT). An intrauterine low-protein isocaloric diet can also cause CAKUT phenotypes in offspring. However, single factors such as gene mutation or abnormal environmental factor during pregnancy can only explain part of the pathogenesis of CAKUT. Objectives: A low-protein isocaloric diet was fed to Gen1-mutant mice throughout pregnancy to establish a Gen1-mutant mouse model exposed to a low-protein isocaloric intrauterine environment. The mice were divided into 4 groups: normal (22%) protein diet (ND) + wild-type mice (CON group), ND + Gen1^PB/+ mice (Gen1^PB/+ group), low (6%)-protein isocaloric diet (LD) + wild-type mice (LD group), and the LD + Gen1^PB/+ groups. Methods: The experimental design included observing proportion and distribution of CAKUT phenotypes of neonatal mice; evaluating the number of ureteric buds (UBs) on embryonic day (E) 11.5, the location of UBs on E11.5, and length of the common nephric duct (CND); isolating embryonic kidneys on E11.5 from the Gen1^PB/+ group and culturing embryonic kidneys in medium containing 10% serum or serum-free medium to observe the branching of UBs; and detecting the p-PLCγ, p-Akt, and p-ERK1/2 in UBs and CND on E11.5, as well as the apoptosis and proliferation of tissues by immunofluorescence staining. Results: We found that the incidence of CAKUT in offspring of Gen1^PB/+ mice under an intrauterine low-protein isocaloric diet environment was significantly increased, and a duplicated collecting system was the dominant phenotype of CAKUT. During the early stage of metanephric development, ectopic protrusion of UBs may appear and lower locations of UBs in Gen1^PB/+ mice under an intrauterine low-protein isocaloric diet environment and the number of UB branches in the serum-free culture condition significantly decreased. Further examination revealed that p-PLCγ signaling and tissue apoptosis were abnormal in UBs and the CND at the early stage of kidney development. Conclusions: The aforementioned findings suggest that an intrauterine low-protein isocaloric diet can aggravate the occurrence of CAKUT in Gen1-mutant mice, which might affect key steps in the metanephric development, such as the protrusion of UBs, which might be related to mediate UBs and CND apoptosis through p-PLCγ signaling.

Isocaloric low protein diet in a mouse model for vanishing white matter does not impact ISR deregulation in brain, but reveals ISR deregulation in liver

ABSTRACT Objective: Vanishing white matter (VWM) is a genetic brain white matter disorder caused by mutations in eIF2B. eIF2B is central in the integrated stress response (ISR), during which its activity is inhibited by various cellular stresses. VWM is a chronic progressive disease with episodes of rapid neurological deterioration provoked by stresses. VWM patients and VWM mouse models show ISR deregulation in brain, correlating with chronic disease development. ISR inhibition ameliorates the chronic disease in VWM mice. The subacute deteriorations have not been modeled yet. We hypothesized that ISR activation could worsen disease progression in mice and model the episodic neurological deterioration. Method: We chose to activate the ISR by subjecting wild-type (wt) and VWM mice to an isocaloric low protein diet. This model would allow us to investigate the contribution of ISR activation in subacute decline in VWM. Results: We found that the low protein diet did not significantly affect amino acid levels nor ISR levels in wt and VWM mouse brain. Our study serendipitously led to the discovery of increased levels of glycine, asparagine and Fgf21 mRNA in VWM mouse brain irrespective of the dietary protein content. Strikingly, the ISR was not activated by the low protein diet in the liver of VWM in contrast to wt mice, due to a modest ISR deregulation in this organ. Discussion: A model for subacute neurological deterioration in VWM was not established. Possibly, ISR deregulation in VWM results in reduced ISR responsiveness.

In utero low-protein-diet-programmed type 2 diabetes in adult offspring is mediated by sex hormones in rats†.

Sex steroids regulate insulin sensitivity and glucose metabolism. We had characterized a lean type 2 diabetes (T2D) rat model using gestational low-protein (LP) diet programming. Our objective was to identify if endocrine dysfunction leading to decreased sex hormone levels will precede the development of T2D and if steroid replacement will prevent the onset of the disease. Pregnant rats were fed control or isocaloric LP diet from gestational day 4 until delivery. Normal diet was given to all mothers after delivery and to pups after weaning. LP offspring developed glucose intolerance and insulin resistance at 4months. We measured sex steroid hormone profiles and expression of key genes involved in steroidogenesis in testis and ovary. Furthermore, one-month old rats were implanted with 90-day slow release T and E2 pellets for males and females, respectively. Glucose tolerance test (GTT) and euglycemic hyperinsulinemic clamp was performed at 4months. LP-programmed T2D males had low T levels and females had low E2 levels due to dysregulated gene expression during steroidogenesis in gonads. GTT and euglycemic hyperinsulinemic clamp showed that LP males and females were glucose intolerant and insulin resistant; however, steroid supplementation prevented the onset of glucose intolerance and insulin resistance. Rats that developed T2D by LP programming have compromised gonadal steroidogenesis leading to low T and E2 in males and females, respectively. Sex steroid supplementation prevented the onset of glucose intolerance and insulin resistance indicating low sex steroid levels could cause compromised glucose metabolism ultimately leading to T2D.

Maternal low protein diet induces persistent expression changes in metabolic genes in male rats.

BACKGROUNDPerinatal exposure to a poor nutritional environment predisposes the progeny to the development of metabolic disease at the adult age, both in experimental models and humans. Numerous adaptive responses to maternal protein restriction have been reported in metabolic tissues. However, the expression of glucose/fatty acid metabolism-related genes in adipose tissue and liver needs to be described.AIMTo evaluate the metabolic impact of perinatal malnutrition, we determined malnutrition-associated gene expression alterations in liver and adipose tissue.METHODSIn the present study, we evaluated the alterations in gene expression of glycolytic/Krebs cycle genes (Pyruvate dehydrogenase kinase 4 and citrate synthase), adipogenic and lipolytic genes and leptin in the adipose tissue of offspring rats at 30 d and 90 d of age exposed to maternal isocaloric low protein (LP) diet throughout gestation and lactation. We also evaluated, in the livers of the same animals, the same set of genes as well as the gene expression of the transcription factors peroxisome proliferator-activated receptor gamma coactivator 1, forkhead box protein O1 and hepatocyte nuclear factor 4 and of gluconeogenic genes.RESULTSIn the adipose tissue, we observed a transitory (i.e., at 30 d) downregulation of pyruvate dehydrogenase kinase 4, citrate synthase and carnitine palmitoyl transferase 1b gene expression. Such transcriptional changes did not persist in adult LP rats (90 d), but we observed a tendency towards a decreased gene expression of leptin (P = 0.052). The liver featured some gene expression alterations comparable to the adipose tissue, such as pyruvate dehydrogenase kinase 4 downregulation at 30 d and displayed other tissue-specific changes, including citrate synthase and fatty acid synthase upregulation, but pyruvate kinase downregulation at 30 d in the LP group and carnitine palmitoyl transferase 1b downregulation at 90 d. These gene alterations, together with previously described changes in gene expression in skeletal muscle, may account for the metabolic adaptations in response to maternal LP diet and highlight the occurrence of persistent transcriptional defects in key metabolic genes that may contribute to the development of metabolic alterations during the adult life as a consequence of perinatal malnutrition.CONCLUSIONWe conclude that perinatal malnutrition relays long-lasting transcriptional alterations in metabolically active organs, i.e., liver and adipose tissue.

In utero nutritional stress as a cause of obesity: Altered relationship between body fat, leptin levels and caloric intake in offspring into adulthood

AimsEmerging evidence suggests that during gestation the in utero environment programs metabolism and can increase risk of obesity in adult offspring. Our aim was to study how alterations in maternal diets during gestation might alter body weight evolution, circulating leptin levels and caloric intake in offspring, leading to changes in body composition. Materials and methodsWe fed gestating rats either a control diet (CD), high fat diet (HFD) or an isocaloric low protein diet (LPD), and examined the repercussions in offspring fed similar diets post-weaning on birth weight, body weight evolution, body composition, insulin sensitivity, glucose tolerance and in the relationship between plasma leptin concentration and caloric intake in offspring during growth and development. Key findsOffspring from dams fed LPD maintained reduced body weight with greater % lean mass and consumed fewer calories despite having leptin levels similar to controls. On the other hand, offspring from dams fed a HFD were insulin resistant and maintained increased body weight and % fat mass, while consuming more calories than controls despite elevated leptin concentrations. Therefore the uterine environment, modulated primarily through maternal nutrition, modified the relationship between circulating leptin levels, body fat, and caloric intake in the offspring, and dams fed a HFD produced offspring with excess adiposity, insulin resistance, and leptin resistance into adulthood. SignificanceOur data indicates that in utero environmental factors affected by maternal diet program alterations in the set point around which leptin regulates body weight in offspring into adulthood contributing to obesity.

Moderate Intensity Continuous Training versus High Intensity Interval Training in Growth Restricted Mice to Improve Cardiac Function: A Pilot Study

IntroductionGrowth‐restriction during postnatal development has been linked to increased cardiovascular disease risk in adulthood, with greater impairment seen in females. Growth‐restricted mice present with thinner left ventricle posterior and anterior walls, compromised diastolic function and reduced stroke volume and cardiac output. Regular aerobic exercise training can promote cardiovascular health and well‐being, with recent evidence suggesting high intensity interval training may be more cardio protective as compared to moderate intensity continuous training. The purpose of this investigation was to determine if high intensity interval training (HIIT) promoted cardiac health in postnatally growth‐restricted female mice as compared to traditional moderate intensity continuous training (MICT).MethodsTo induce postnatal growth‐restriction, FVB mouse dams were fed either a 20% protein control diet or an 8% low‐protein isocaloric diet beginning 2 weeks before mating. Only pups born to control‐fed dams were used and cross‐fostered to either a low‐protein fed dam to induce growth‐restriction (PUN) or a different control fed dam (CON). On postnatal (PN) day 21 all pups were weaned and fed a control diet. At PN33 mice were allocated to MICT (PUN n=4, CON n=3), HIIT (PUN n= 4, CON n= 3) or a corresponding sedentary group (MICT: sedentary PUN n= 5, sedentary CON n=4; or HIIT: sedentary PUN n= 5, sedentary CON n=4). The MICT protocol was defined as treadmill running 3 days/week for 12 weeks at 17 m/min at −16 degree decline for 28 minutes and the HIIT protocol was treadmill running 5 days/week for 8 weeks with alternating intervals of 8 mins at 85% and 2 mins at 55% of maximum workload for 60 minutes. At PN 128 (MICT) and PN 98 (HIIT) echocardiography and Doppler blood flow was utilized to measure cardiac structure and function under 1% isoflurane anesthesia. Statistical analysis was performed using GraphPad Prism 8, utilizing two‐way ANOVAs with an alpha level of .05 set a priori and if significant Tukey’s post hoc for multiple comparisons was conducted.ResultsSedentary PUN groups exhibited cardiac dysfunction as evident by reduced left ventricle (LV) area during systole (p=.0290), LV diameter during diastole (p=.0156) and systole (p=.0003) and LV volume during systole (p=.0191). Systolic function was compromised in the PUN sedentary group by impaired myocardial performance index (MPI) (p=.0049), ejection fraction (EF) (p=.0023), aortic ejection time (AET) (p=.0345) and fractional shortening (FS) (p=.0111). Diastolic impairment manifested as reductions in isovolumic relaxation time (IVRT) (p=.0102) and mitral valve deceleration time (MVDT) (p=&lt;.0001) in the PUN sedentary group. Both MICT and HIIT were able to reverse impairments as no significant differences were noted between exercised PUN groups and their CON counterparts.ConclusionMICT and HIIT both reversed the cardiac impairments caused by growth‐restriction. Impairments caused by growth‐restriction can be mitigated with exercise training. Importantly, exercise professionals have flexibility in prescribing exercise as both MICT and HIIT were shown to be effective.

Low protein diet and methyl-donor supplements modify testicular physiology in mice.

The link between male diet and sperm quality has received significant investigation. However, the impact diet and dietary supplements have on the testicular environment has been examined to a lesser extent. Here, we establish the impact of a sub-optimal low protein diet (LPD) on testicular morphology, apoptosis and serum fatty acid profiles. Furthermore, we define whether supplementing a LPD with specific methyl donors abrogates any detrimental effects of the LPD. Male C57BL6 mice were fed either a control normal protein diet (NPD; 18% protein; n = 8), an isocaloric LPD (LPD; 9% protein; n = 8) or an LPD supplemented with methyl donors (MD-LPD; choline chloride, betaine, methionine, folic acid, vitamin B12; n = 8) for a minimum of 7 weeks. Analysis of male serum fatty acid profiles by gas chromatography revealed elevated levels of saturated fatty acids and lower levels of mono- and polyunsaturated fatty acids in MD-LPD males when compared to NPD and/or LPD males. Testes of LPD males displayed larger seminiferous tubule cross section area when compared to NPD and MD-LPD males, while MD-LPD tubules displayed a larger luminal area. Furthermore, TUNNEL staining revealed LPD males possessed a reduced number of tubules positive for apoptosis, while gene expression analysis showed MD-LPD testes displayed decreased expression of the pro-apoptotic genes Bax, Csap1 and Fas when compared to NPD males. Finally, testes from MD-LPD males displayed a reduced telomere length but increased telomerase activity. These data reveal the significance of sub-optimal nutrition for paternal metabolic and reproductive physiology.

The 17β-oestradiol treatment minimizes the adverse effects of protein restriction on bone parameters in ovariectomized Wistar rats: Relevance to osteoporosis and the menopause.

ObjectivesInsufficient protein ingestion may affect muscle and bone mass, increasing the risk of osteoporotic fractures in the elderly, and especially in postmenopausal women. We evaluated how a low-protein diet affects bone parameters under gonadal hormone deficiency and the improvement led by hormone replacement therapy (HRT) with 17β-oestradiol.MethodsFemale Wistar rats were divided into control (C), ovariectomized (OVX), and 17β-oestradiol-treated ovariectomized (OVX-HRT) groups, which were fed a control or an isocaloric low-protein diet (LP; 6.6% protein; seven animals per group). Morphometric, serum, and body composition parameters were assessed, as well as bone parameters, mechanical resistance, and mineralogy.ResultsThe results showed that protein restriction negatively affected body chemical composition and bone metabolism by the sex hormone deficiency condition in the OVX group. The association between undernutrition and hormone deficiency led to bone and muscle mass loss and increased the fragility of the bone (as well as decreasing relative femoral weight, bone mineral density, femoral elasticity, peak stress, and stress at offset yield). Although protein restriction induced more severe adverse effects compared with the controls, the combination with HRT showed an improvement in minimizing these damaging effects, as it was seen that HRT had some efficacy in maintaining muscle and bone mass, preserving the bone resistance and minimizing some deleterious processes during the menopause.ConclusionProtein restriction has adverse effects on metabolism, leading to more severe menopausal symptoms, and HRT could minimize these effects. Therefore, special attention should be given to a balanced diet during menopause and HRT.Cite this article: Bone Joint Res 2019;8:573–581.

Perinatal protein restriction with postnatal catch-up growth leads to elevated p66Shc and mitochondrial dysfunction in the adult rat liver.

Epidemiological data suggest an inverse relationship between birth weight and long-term metabolic deficits, which is exacerbated by postnatal catch-up growth. We have previously demonstrated that rat offspring subject to maternal protein restriction (MPR) followed by catch-up growth exhibit impaired hepatic function and ER stress. Given that mitochondrial dysfunction is associated with various metabolic pathologies, we hypothesized that altered expression of p66Shc, a gatekeeper of oxidative stress and mitochondrial function, contributes to the hepatic defects observed in MPR offspring. To test this hypothesis, pregnant Wistar rats were fed a control (20% protein) diet or an isocaloric low protein (8%; LP) diet throughout gestation. Offspring born to control dams received a control diet in postnatal life, while MPR offspring remained on a LP diet (LP1) or received a control diet post weaning (LP2) or at birth (LP3). At four months, LP2 offspring exhibited increased protein abundance of both p66Shc and the cis-trans isomerase PIN1. This was further associated with aberrant markers of oxidative stress (i.e. elevated 4-HNE, SOD1 and SOD2, decreased catalase) and aerobic metabolism (i.e., increased phospho-PDH and LDHa, decreased complex II, citrate synthase and TFAM). We further demonstrated that tunicamycin-induced ER stress in HepG2 cells led to increased p66Shc protein abundance, suggesting that ER stress may underlie the programmed effects observed in vivo. In summary, because these defects are exclusive to adult LP2 offspring, it is possible that a low protein diet during perinatal life, a period of liver plasticity, followed by catch-up growth is detrimental to long-term mitochondrial function.

Paternal diet impairs F1 and F2 offspring vascular function through sperm and seminal plasma specific mechanisms in mice.

A low protein diet had minimal effects on paternal cardiovascular function or renin-angiotensin system activity. Paternal low protein diet modified F1 neonatal and adult offspring renin-angiotensin system activity and cardiovascular function in a sperm and/or seminal plasma specific manner. Paternal low protein diet modified F1male offspring testicular expression of central epigenetic regulators. Significant changes in F2 neonatal offspring growth and tissue angiotensin-converting enzyme activity were programmed by paternal low protein diet in a sperm and/or seminal plasma specific manner. Although the impact of maternal diet on adult offspring health is well characterized, the role that a father's diet has on his offspring's health remains poorly defined. We establish the significance of a sup-optimal paternal low protein diet for offspring vascular homeostasis and define the sperm and seminal plasma specific programming effects on cardiovascular health. Male C57BL6mice were fed either a control normal protein diet (NPD; 18% protein) or an isocaloric low protein diet (LPD; 9% protein) for a minimum of 7weeks. Using artificial insemination, in combination with vasectomized male mating, we generated offspring derived from either NPD or LPD sperm (devoid of seminal plasma) but in the presence of NPD or LPD seminal plasma (devoid of sperm). We observed that either LPD sperm or seminal fluid at conception impaired adult offspring vascular function in response to both vasoconstrictors and dilators. Underlying these changes in vascular function were significant changes in serum, lung and kidney angiotensin-converting enzyme (ACE) activity, established in F1 offspring from 3weeks of age, maintained into adulthood and present also within juvenile F2 offspring. Furthermore, we observed differential expression of multiple central renin-angiotensin system regulators in adult offspring kidneys. Finally, paternal diet modified the expression profiles of central epigenetic regulators of DNA methylation, histone modifications and RNA methylation in adult F1male testes. These novel data reveal the impact of sub-optimal paternal nutrition on offspring cardiovascular well-being, programming offspring cardiovascular function through both sperm and seminal plasma specific mechanisms over successive generations.