Translational insights on developmental origins of metabolic syndrome: Focus on fructose consumption

Effects of in utero exposure to Δ-9-tetrahydrocannabinol on cardiac extracellular matrix expression and vascular transcriptome in rhesus macaques

Delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis, remains a schedule I substance, thus safety data regarding the effects on the cardiovascular and prenatal health are limited. Importantly, there is evidence showing prenatal cannabis exposure can negatively impact fetal organ development, including the cardiovascular system. THC can cross the placenta and bind to cannabinoid receptors expressed in the developing fetus, including on endothelial cells. To understand the impact of prenatal THC exposure on the fetal cardiovascular system, we used our rhesus macaque model of prenatal daily edible THC consumption. Before conception, animals were acclimated to THC (2.5 mg/7 kg/day, equivalent to a heavy medical cannabis dose) and maintained on this dose daily throughout pregnancy. Fetal tissue samples were collected at gestational day 155 (full term is 168 days). Our model showed that in utero THC exposure was associated with a decreased heart weight-to-body weight ratio in offspring, warranting further mechanistic investigation. Histological examination of the fetal cardiac and vascular tissues did not reveal any significant effect of THC exposure on the maturity of collagen within the fetal heart or the aorta. Total collagen III expression and elastin production and organization were unchanged. However, bulk RNA-sequencing of vascular cells in the umbilical vein, umbilical artery, and fetal aorta demonstrated that THC alters the fetal vascular transcriptome and is associated with upregulated expression of genes involved in carbohydrate metabolism and inflammation. The long-term consequences of these findings are unknown but suggest that prenatal THC exposure may affect cardiovascular development in offspring.NEW & NOTEWORTHY Prenatal cannabis use is increasing and despite the public health relevance, there is limited safety data regarding its impact on offspring cardiovascular health outcomes. We used a translational, nonhuman primate model of daily edible Δ-9-tetrahydrocannabinol (THC) consumption during pregnancy to assess its effects on the fetal cardiovascular system. THC-exposed fetal vascular tissues displayed upregulation of genes involved in cellular metabolism and inflammation, suggesting that prenatal THC exposure may impact fetal vascular tissues.

Acetylcholinesterase Inhibitor Ameliorates Early Cardiometabolic Disorders in Fructose-Overloaded Rat Offspring

BACKGROUND

We investigate the role of galantamine on autonomic dysfunction associated with early cardiometabolic dysfunction in the offspring of fructose-overloaded rats.

METHODS

Wistar rats received fructose diluted in drinking water (10%) or water for 60 days prior to mating. Fructose overload was maintained until the end of lactation. The offspring (21 days after birth) of control and fructose-overloaded animals were divided into three groups: control (C), fructose (F) and fructose + galantamine (GAL). GAL (5 mg/kg) was administered orally until the offspring were 51 days old. Metabolic, hemodynamic and cardiovascular autonomic modulation were evaluated.

RESULTS

The F group showed decreased insulin tolerance (KITT) compared to the C and GAL groups. The F group, in comparison to the C group, had increased arterial blood pressure, heart rate and sympathovagal balance (LF/HF ratio) and a low-frequency band of systolic arterial pressure (LF-SAP). The GAL group, in comparison to the F group, showed increased vagally mediated RMSSD index, a high-frequency band (HF-PI) and decreased LF/HF ratio and variance in SAP (VAR-SAP) and LF-SAP. Correlations were found between HF-PI and KITT (r = 0.60), heart rate (r = -0.65) and MAP (r = -0.71).

CONCLUSIONS

GAL treatment significantly improved cardiovascular autonomic modulation, which was associated with the amelioration of cardiometabolic dysfunction in offspring of parents exposed to chronic fructose consumption.

Longitudinal Gut Microbiota Dysbiosis Underlies Olanzapine-Induced Weight Gain

Olanzapine is one of the most effective medicines available for stabilizing schizophrenia spectrum disorders. However, it has been reported to show the greatest propensity for inducing body weight gain and producing metabolic side effects, which cause a great burden in patients with psychiatric disorders. Since the gut microbiota has a profound impact on the initiation and development of metabolic diseases, we conducted a longitudinal study to explore its role in olanzapine-induced obesity and metabolic abnormalities. Female Sprague-Dawley rats were treated with different doses of olanzapine, and metabolic and inflammatory markers were measured. Olanzapine significantly induced body weight gain (up to a 2.1-fold change), which was accompanied by hepatic inflammation and increased plasma triglyceride levels (up to a 2.9-fold change), as well as gut microbiota dysbiosis. Subsequently, fuzzy c-means clustering was used to characterize three clusters of longitudinal trajectories for microbial fluctuations: (i) genera continuing to increase, (ii) genera continuing to decrease, and (iii) genera temporarily changing. Among them, Enterorhabdus (r = 0.38), Parasutterella (r = 0.43), and Prevotellaceae UCG-001 (r = 0.52) positively correlated with body weight gain. In addition, two MetaCyc metabolic pathways were identified as associated with olanzapine-induced body weight gain, including the superpathway of glucose and xylose degradation and the superpathway of l-threonine biosynthesis. In conclusion, we demonstrate that olanzapine can directly alter the gut microbiota and rapidly induce dysbiosis, which is significantly associated with body weight gain. This may suggest gut microbiota targets in future studies on metabolic abnormalities caused by olanzapine. IMPORTANCE Olanzapine is one of the most effective second-generation antipsychotics for stabilizing schizophrenia spectrum disorders. However, olanzapine has multiple drug-induced metabolic side effects, including weight gain. This study provides insight to the gut microbiota target in olanzapine-induced obesity. Specifically, we explored the longitudinal gut microbiota trajectories of female Sprague-Dawley rats undergoing olanzapine treatment. We showed that olanzapine treatment causes a dynamic alteration of gut microbiota diversity. Additionally, we identified three genera, Parasutterella, Enterorhabdus, and Prevotellaceae UCG-001, that may play an important role in olanzapine-induced obesity. In this case, the supply or removal of specific elements of the gut microbiota may represent a promising avenue for treatment of olanzapine-related metabolic side effects.

Reprogramming Effects of Postbiotic Butyrate and Propionate on Maternal High-Fructose Diet-Induced Offspring Hypertension

Maternal nutrition has a key role in the developmental programming of adult disease. Excessive maternal fructose intake contributes to offspring hypertension. Newly discovered evidence supports the idea that early-life gut microbiota are connected to hypertension later in life. Short-chain fatty acids (SCFAs), butyrate, and propionate are microbiota-derived metabolites, also known as postbiotics. The present study aimed to determine whether maternal butyrate or propionate supplementation can protect offspring from hypertension using a maternal high-fructose (HF) diet rat model. Female Sprague Dawley rats were allocated during pregnancy and lactation to (1) regular chow (ND); (2) 60% high-fructose diet (HF); (3) HF diet plus butyrate (HFB, 400 mg/kg/day); and (4) HF diet plus propionate (HFP, 200 mmol/L). Male offspring were sacrificed at 12 weeks of age. The maternal HF diet impaired the offspring’s BP, which was prevented by perinatal butyrate or propionate supplementation. Both butyrate and propionate treatments similarly increased plasma concentrations of propionic acid, isobutyric acid, and valeric acid in adult offspring. Butyrate supplementation had a more profound impact on trimethylamine N-oxide metabolism and nitric oxide parameters. Whilst propionate treatment mainly influenced gut microbiota composition, it directly altered the abundance of genera Anaerovorax, Lactobacillus, Macellibacteroides, and Rothia. Our results shed new light on targeting gut microbiota through the use of postbiotics to prevent maternal HF intake-primed hypertension, a finding worthy of clinical translation.

The Impact of Nutrient Intake and Metabolic Wastes during Pregnancy on Offspring Hypertension: Challenges and Future Opportunities

Hypertension can have its origin in early life. During pregnancy, many metabolic alterations occur in the mother that have a crucial role in fetal development. In response to maternal insults, fetal programming may occur after metabolic disturbance, resulting in programmed hypertension later in life. Maternal dietary nutrients act as metabolic substrates for various metabolic processes via nutrient-sensing signals. Different nutrient-sensing pathways that detect levels of sugars, amino acids, lipids and energy are integrated during pregnancy, while disturbed nutrient-sensing signals have a role in the developmental programming of hypertension. Metabolism-modulated metabolites and nutrient-sensing signals are promising targets for new drug discovery due to their pathogenic link to hypertension programming. Hence, in this review, we pay particular attention to the maternal nutritional insults and metabolic wastes affecting fetal programming. We then discuss the role of nutrient-sensing signals linking the disturbed metabolism to hypertension programming. This review also summarizes current evidence to give directions for future studies regarding how to prevent hypertension via reprogramming strategies, such as nutritional intervention, targeting nutrient-sensing signals, and reduction of metabolic wastes. Better prevention for hypertension may be possible with the help of novel early-life interventions that target altered metabolism.

Impaired insulin signaling at the bladder mucosa facilitates metabolic syndrome-associated bladder overactivity in rats with maternal and post-weaning fructose exposure

BACKGROUND/PURPOSE

Metabolic syndrome (MetS) and overactive bladder might share common pathophysiologies. Environmental fructose exposure during pre- and postnatal periods of rats may program MetS-associated bladder overactivity. We explored the dysregulated insulin signalling at bladder mucosa, as a common mechanism, in facilitating bladder overactivity in rats with MetS induced by maternal and post-weaning fructose diet.

METHODS

Male offspring of Sprague-Dawley rats were subject into 4 groups by maternal and post-weaning diets (i.e., Control/Control, Fructose/Control, Control/Fructose and Fructose/Fructose by diets). Micturition behavior was evaluated. Acidic ATP solution was used to elicit cystometric reflex along with insulin counteraction. Concentration-response curves to insulin were plotted. The canonical signalling pathway of insulin was evaluated in the bladder mucosal using Western blotting. Levels of detrusor cGMP and urinary NO₂ plus NO₃ were measured.

RESULTS

Male offspring with any fructose exposure presents traits of MetS and bladder overactivity. We observed all fructose exposure groups have the poor urodynamic response to insulin during ATP solution stimulation and poor insulin-activated detrusor relaxation in organ bath study. Compared to controls, the Control/Fructose and Fructose/Fructose groups showed the increased phosphorylation levels of IRS1 (Ser³⁰⁷) and IRS2 (Ser⁷³¹); thus, suppressed the downstream effectors and urinary NOx/detrusor cGMP levels. The Fructose/Control group showed the compensatory increase of phospho-AKT (Ser⁴⁷³) and phospho-eNOS/eNOS levels, but decreased in eNOS, phospho-eNOS, urinary NOx, and detrusor cGMP levels.

CONCLUSION

Our results show dysregulated insulin signalling at bladder mucosa should be a common mechanism of MetS-associated bladder overactivity programmed by pre-and postnatal fructose diet.

Maternal Fructose Intake, Programmed Mitochondrial Function and Predisposition to Adult Disease

Fructose consumption is now recognised as a major risk factor in the development of metabolic diseases, such as hyperlipidaemia, diabetes, non-alcoholic fatty liver disease and obesity. In addition to environmental, social, and genetic factors, an unfavourable intrauterine environment is now also recognised as an important factor in the progression of, or susceptibility to, metabolic disease during adulthood. Developmental trajectory in the short term, in response to nutrient restriction or excessive nutrient availability, may promote adaptation that serves to maintain organ functionality necessary for immediate survival and foetal development. Consequently, this may lead to decreased function of organ systems when presented with an unfavourable neonatal, adolescent and/or adult nutritional environment. These early events may exacerbate susceptibility to later-life disease since sub-optimal maternal nutrition increases the risk of non-communicable diseases (NCDs) in future generations. Earlier dietary interventions, implemented in pregnant mothers or those considering pregnancy, may have added benefit. Although, the mechanisms by which maternal diets high in fructose and the vertical transmission of maternal metabolic phenotype may lead to the predisposition to adult disease are poorly understood. In this review, we will discuss the potential contribution of excessive fructose intake during pregnancy and how this may lead to developmental reprogramming of mitochondrial function and predisposition to metabolic disease in offspring.

Maternal Supplementation of Probiotics, Prebiotics or Postbiotics to Prevent Offspring Metabolic Syndrome: The Gap between Preclinical Results and Clinical Translation

Metabolic syndrome (MetS) is an extremely prevalent complex trait and it can originate in early life. This concept is now being termed the developmental origins of health and disease (DOHaD). Increasing evidence supports that disturbance of gut microbiota influences various risk factors of MetS. The DOHaD theory provides an innovative strategy to prevent MetS through early intervention (i.e., reprogramming). In this review, we summarize the existing literature that supports how environmental cues induced MetS of developmental origins and the interplay between gut microbiota and other fundamental underlying mechanisms. We also present an overview of experimental animal models addressing implementation of gut microbiota-targeted reprogramming interventions to avert the programming of MetS. Even with growing evidence from animal studies supporting the uses of gut microbiota-targeted therapies start before birth to protect against MetS of developmental origins, their effects on pregnant women are still unknown and these results require further clinical translation.

Metabolic Syndrome: Lessons from Rodent and Drosophila Models

Overweight and obesity are health conditions tightly related to a number of metabolic complications collectively called “metabolic syndrome” (MetS). Clinical diagnosis of MetS includes the presence of the increased waist circumference or so-called abdominal obesity, reduced high density lipoprotein level, elevated blood pressure, and increased blood glucose and triacylglyceride levels. Different approaches, including diet-induced and genetically induced animal models, have been developed to study MetS pathogenesis and underlying mechanisms. Studies of metabolic disturbances in the fruit fly Drosophila and mammalian models along with humans have demonstrated that fruit flies and small mammalian models like rats and mice have many similarities with humans in basic metabolic functions and share many molecular mechanisms which regulate these metabolic processes. In this paper, we describe diet-induced, chemically and genetically induced animal models of the MetS. The advantages and limitations of rodent and Drosophila models of MetS and obesity are also analyzed.

The Impact of Gut Microbiome on Maternal Fructose Intake-Induced Developmental Programming of Adult Disease

Excessive or insufficient maternal nutrition can influence fetal development and the susceptibility of offspring to adult disease. As eating a fructose-rich diet is becoming more common, the effects of maternal fructose intake on offspring health is of increasing relevance. The gut is required to process fructose, and a high-fructose diet can alter the gut microbiome, resulting in gut dysbiosis and metabolic disorders. Current evidence from animal models has revealed that maternal fructose consumption causes various components of metabolic syndrome in adult offspring, while little is known about how gut microbiome is implicated in fructose-induced developmental programming and the consequential risks for developing chronic disease in offspring. This review will first summarize the current evidence supporting the link between fructose and developmental programming of adult diseases. This will be followed by presenting how gut microbiota links to common mechanisms underlying fructose-induced developmental programming. We also provide an overview of the reprogramming effects of gut microbiota-targeted therapy on fructose-induced developmental programming and how this approach may prevent adult-onset disease. Using gut microbiota-targeted therapy to prevent maternal fructose diet-induced developmental programming, we have the potential to mitigate the global burden of fructose-related disorders.

The Role of Selenoprotein Tissue Homeostasis in MetS Programming: Energy Balance and Cardiometabolic Implications

Selenium (Se) is an essential trace element mainly known for its antioxidant, anti-inflammatory, and anti-apoptotic properties, as it is part of the catalytic center of 25 different selenoproteins. Some of them are related to insulin resistance (IR) and metabolic syndrome (MetS) generation, modulating reactive oxygen species (ROS), and the energetic sensor AMP-activated protein kinase (AMPK); they can also regulate the nuclear transcription factor kappa-B (NF-kB), leading to changes in inflammation production. Selenoproteins are also necessary for the correct synthesis of insulin and thyroid hormones. They are also involved in endocrine central regulation of appetite and energy homeostasis, affecting growth and development. MetS, a complex metabolic disorder, can appear during gestation and lactation in mothers, leading to energetic and metabolic changes in their offspring that, according to the metabolic programming theory, will produce cardiovascular and metabolic diseases later in life. However, there is a gap concerning Se tissue levels and selenoproteins’ implications in MetS generation, which is even greater during MetS programming. This narrative review also provides an overview of the existing evidence, based on experimental research from our laboratory, which strengthens the fact that maternal MetS leads to changes in Se tissue deposits and antioxidant selenoproteins’ expression in their offspring. These changes contribute to alterations in tissues’ oxidative damage, inflammation, energy balance, and tissue function, mainly in the heart. Se imbalance also could modulate appetite and endocrine energy balance, affecting pups’ growth and development. MetS pups present a profile similar to that of diabetes type 1, which also appeared when dams were exposed to low-Se dietary supply. Maternal Se supplementation should be taken into account if, during gestation and/or lactation periods, there are suspicions of endocrine energy imbalance in the offspring, such as MetS. It could be an interesting therapy to induce heart reprogramming. However, more studies are necessary.

Maternal Fructose Intake Causes Developmental Reprogramming of Hepatic Mitochondrial Catalytic Activity and Lipid Metabolism in Weanling and Young Adult Offspring

Excess dietary fructose is a major public health concern, yet little is known about its influence on offspring development and later-life disease when consumed in excess during pregnancy. To determine whether increased maternal fructose intake could have long-term consequences on offspring health, we investigated the effects of 10% w/v fructose water intake during preconception and pregnancy in guinea pigs. Female Dunkin Hartley guinea pigs were fed a control diet (CD) or fructose diet (FD; providing 16% of total daily caloric intake) ad libitum 60 days prior to mating and throughout gestation. Dietary interventions ceased at day of delivery. Offspring were culled at day 21 (D21) (weaning) and at 4 months (4 M) (young adult). Fetal exposure to excess maternal fructose intake significantly increased male and female triglycerides at D21 and 4 M and circulating palmitoleic acid and total omega-7 through day 0 (D0) to 4 M. Proteomic and functional analysis of significantly differentially expressed proteins revealed that FD offspring (D21 and 4 M) had significantly increased mitochondrial metabolic activities of β-oxidation, electron transport chain (ETC) and oxidative phosphorylation and reactive oxygen species production compared to the CD offspring. Western blotting analysis of both FD offspring validated the increased protein abundances of mitochondrial ETC complex II and IV, SREBP-1c and FAS, whereas VDAC1 expression was higher at D21 but lower at 4 M. We provide evidence demonstrating offspring programmed hepatic mitochondrial metabolism and de novo lipogenesis following excess maternal fructose exposure. These underlying asymptomatic programmed pathways may lead to a predisposition to metabolic dysfunction later in life.

Regulation of Pancreatic β-Cell Mass by Gene-Environment Interaction

The main pathogenic mechanism of diabetes consists of an increase in insulin resistance and a decrease in insulin secretion from pancreatic β-cells. The number of diabetic patients has been increasing dramatically worldwide, especially in Asian people whose capacity for insulin secretion is inherently lower than that of other ethnic populations. Causally, changes of environmental factors in addition to intrinsic genetic factors have been considered to have an influence on the increased prevalence of diabetes. Particular focus has been placed on "gene-environment interactions" in the development of a reduced pancreatic β-cell mass, as well as type 1 and type 2 diabetes mellitus. Changes in the intrauterine environment, such as intrauterine growth restriction, contribute to alterations of gene expression in pancreatic β-cells, ultimately resulting in the development of pancreatic β-cell failure and diabetes. As a molecular mechanism underlying the effect of the intrauterine environment, epigenetic modifications have been widely investigated. The association of diabetes susceptibility genes or dietary habits with gene-environment interactions has been reported. In this review, we provide an overview of the role of gene-environment interactions in pancreatic β-cell failure as revealed by previous reports and data from experiments.

Early-Life Origins of Metabolic Syndrome: Mechanisms and Preventive Aspects

One of the leading global public-health burdens is metabolic syndrome (MetS), despite the many advances in pharmacotherapies. MetS, now known as "developmental origins of health and disease" (DOHaD), can have its origins in early life. Offspring MetS can be programmed by various adverse early-life conditions, such as nutrition imbalance, maternal conditions or diseases, maternal chemical exposure, and medication use. Conversely, early interventions have shown potential to revoke programming processes to prevent MetS of developmental origins, namely reprogramming. In this review, we summarize what is currently known about adverse environmental insults implicated in MetS of developmental origins, including the fundamental underlying mechanisms. We also describe animal models that have been developed to study the developmental programming of MetS. This review extends previous research reviews by addressing implementation of reprogramming strategies to prevent the programming of MetS. These mechanism-targeted strategies include antioxidants, melatonin, resveratrol, probiotics/prebiotics, and amino acids. Much work remains to be accomplished to determine the insults that could induce MetS, to identify the mechanisms behind MetS programming, and to develop potential reprogramming strategies for clinical translation.

Metabolic programming in offspring of mice fed fructose during pregnancy and lactation

Fructose (C6H12O6), also known as levulose, is a hexose. Chronic consumption of fructose may be associated with increased intrahepatic fat concentration and the development of insulin resistance as well as an increase in the prevalence of nonalcoholic fatty liver disease and hyperlipidemia during pregnancy. Despite the existence of many studies regarding the consumption of fructose in pregnancy, its effects on fetuses have not yet been fully elucidated. Therefore, the objective of this study was to evaluate the genetic and biochemical effects in offspring (male and female) of female mice treated with fructose during pregnancy and lactation. Pairs of 60-day-old Swiss mice were used and divided into three groups; negative control and fructose, 10%/l and 20%/l doses of fructose groups. After offspring birth, the animals were divided into six groups: P1 and P2 (males and females), water; P3 and P4 (males and females) fructose 10%/l; and P5 and P6 (males and females) fructose 20%/l. At 30 days of age, the animals were euthanized for genetic and biochemical assessments. Female and male offspring from both dosage groups demonstrated genotoxicity (evaluated through comet assay) and oxidative stress (evaluated through nitrite concentration, sulfhydril content and superoxide dismutase activity) in peripheral and brain tissues. In addition, they showed nutritional and metabolic changes due to the increase in food consumption, hyperglycemia, hyperlipidemia, and metabolic syndrome. Therefore, it is suggested that high consumption of fructose by pregnant female is harmful to their offspring. Thus, it is important to carry out further studies and make pregnant women aware of excessive fructose consumption during this period.

The high-fructose intake of dams during pregnancy and lactation exerts sex-specific effects on adult rat offspring metabolism

Experimental studies have demonstrated the effects of maternal fructose consumption during pregnancy and lactation on metabolic alterations in their offspring, especially male offspring. However, few studies have focused on female offspring after providing fructose in food to dam rats. Here, we studied whether offspring of both sexes were differentially affected by a maternal high-fructose diet (HFD). For this purpose, Sprague-Dawley rats were fed during pregnancy and lactation with a standard diet (SD) or a HFD (50% w/w). After weaning, offspring were fed an SD; 3 days later, dams were sacrificed, and their offspring were sacrificed on postnatal day 90. Body weight (BW), food and water intake (only for dams), and various biomarkers of metabolic syndrome were measured. When compared to the SD-fed dams, HFD-fed dams had a reduction in BW and food and water intake. Conversely, adiposity, liver weight, liver lipids, and plasma levels of glucose, insulin, cholesterol, triglycerides, and uric acid were increased in HFD-fed dams. Moreover, the BW, food consumption, weight of retroperitoneal fat pads, and liver lipids increased in female and male offspring of HFD-fed dams. Interestingly, the pups of HFD-fed mothers showed increased levels of leptin and insulin resistance and decreased levels of adiponectin which were more pronounced in male offspring than in female offspring. In contrast, a higher increase in BW was shown earlier in female offspring. Thus, high-fructose consumption by dams during pregnancy and lactation led to sex-specific developmental programming of the metabolic syndrome phenotype in adult offspring.

Animal Models for DOHaD Research: Focus on Hypertension of Developmental Origins

Increasing evidence suggests that fetal programming through environmental exposure during a critical window of early life leads to long-term detrimental outcomes, by so-called developmental origins of health and disease (DOHaD). Hypertension can originate in early life. Animal models are essential for providing convincing evidence of a causal relationship between diverse early-life insults and the developmental programming of hypertension in later life. These insults include nutritional imbalances, maternal illnesses, exposure to environmental chemicals, and medication use. In addition to reviewing the various insults that contribute to hypertension of developmental origins, this review focuses on the benefits of animal models in addressing the underlying mechanisms by which early-life interventions can reprogram disease processes and prevent the development of hypertension. Our understanding of hypertension of developmental origins has been enhanced by each of these animal models, narrowing the knowledge gap between animal models and future clinical translation.

Altered Gut Microbiota and Its Metabolites in Hypertension of Developmental Origins: Exploring Differences between Fructose and Antibiotics Exposure

Gut microbiota-derived metabolites, in particular short chain fatty acids (SCFAs) and their receptors, are linked to hypertension. Fructose and antibiotics are commonly used worldwide, and they have a negative impact on the gut microbiota. Our previous study revealed that maternal high-fructose (HF) diet-induced hypertension in adult offspring is relevant to altered gut microbiome and its metabolites. We, therefore, intended to examine whether minocycline administration during pregnancy and lactation may further affect blood pressure (BP) programmed by maternal HF intake via mediating gut microbiota and SCFAs. Pregnant Sprague-Dawley rats received a normal diet or diet containing 60% fructose throughout pregnancy and lactation periods. Additionally, pregnant dams received minocycline (50 mg/kg/day) via oral gavage or a vehicle during pregnancy and lactation periods. Four groups of male offspring were studied (n = 8 per group): normal diet (ND), high-fructose diet (HF), normal diet + minocycline (NDM), and HF + minocycline (HFM). Male offspring were killed at 12 weeks of age. We observed that the HF diet and minocycline administration, both individually and together, causes the elevation of BP in adult male offspring, while there is no synergistic effect between them. Four groups displayed distinct enterotypes. Minocycline treatment leads to an increase in the F/B ratio, but decreased abundance of genera Lactobacillus, Ruminococcus, and Odoribacter. Additionally, minocycline treatment decreases plasma acetic acid and butyric acid levels. Hypertension programmed by maternal HF diet plus minocycline exposure is related to the increased expression of several SCFA receptors. Moreover, minocycline- and HF-induced hypertension, individually or together, is associated with the aberrant activation of the renin-angiotensin system (RAS). Conclusively, our results provide a new insight into the support of gut microbiota and its metabolite SCAFs in the developmental programming of hypertension and cast new light on the role of RAS in this process, which will help prevent hypertension programmed by maternal high-fructose and antibiotic exposure.

Toxic AGEs (TAGE) theory: a new concept for preventing the development of diseases related to lifestyle

BACKGROUND

The habitual excessive intake of sugar (i.e., sucrose and high-fructose corn syrup), which has been implicated in the onset of diabetes mellitus, induces excessive production of glyceraldehyde, a metabolite produced during glucose and fructose metabolism, in hepatocytes, neuronal cells, and cardiomyocytes.

MAIN TEXT

Toxic advanced glycation end-products (toxic AGEs, TAGE) are formed from reactions between glyceraldehyde and intracellular proteins, and their accumulation contributes to various cellular disorders. TAGE leakage from cells affects the surrounding cells and increases serum TAGE levels, promoting the onset and/or development of lifestyle-related diseases (LSRD). Therefore, serum TAGE levels have potential as a novel biomarker for predicting the onset and/or progression of LSRD, and minimizing the effects of TAGE might help to prevent the onset and/or progression of LSRD. Serum TAGE levels are closely related to LSRD associated with the excessive ingestion of sugar and/or dietary AGEs.

CONCLUSIONS

The TAGE theory is also expected to open new perspectives for research into numerous other diseases.

Pediatric Non-Alcoholic Fatty Liver Disease: Nutritional Origins and Potential Molecular Mechanisms

Non-alcoholic fatty liver disease (NAFLD) is the number one chronic liver disease worldwide and is estimated to affect nearly 40% of obese youth and up to 10% of the general pediatric population without any obvious signs or symptoms. Although the early stages of NAFLD are reversible with diet and lifestyle modifications, detecting such stages is hindered by a lack of non-invasive methods of risk assessment and diagnosis. This absence of non-invasive means of diagnosis is directly related to the scarcity of long-term prospective studies of pediatric NAFLD in children and adolescents. In the majority of pediatric NAFLD cases, the mechanisms driving the origin and rapid progression of NAFLD remain unknown. The progression from NAFLD to non-alcoholic steatohepatitis (NASH) in youth is associated with unique histological features and possible immune processes and metabolic pathways that may reflect different mechanisms compared with adults. Recent data suggest that circulating microRNAs (miRNAs) are important new biomarkers underlying pathways of liver injury. Several factors may contribute to pediatric NAFLD development, including high-sugar diets, in utero exposures via epigenetic alterations, changes in the neonatal microbiome, and altered immune system development and mitochondrial function. This review focuses on the unique aspects of pediatric NAFLD and how nutritional exposures impact the immune system, mitochondria, and liver/gastrointestinal metabolic health. These factors highlight the need for answers to how NAFLD develops in children and for early stage-specific interventions.

Targeting on Gut Microbiota-Derived Metabolite Trimethylamine to Protect Adult Male Rat Offspring against Hypertension Programmed by Combined Maternal High-Fructose Intake and Dioxin Exposure

Gut microbiota-dependent metabolites, in particular trimethylamine (TMA), are linked to hypertension. Maternal 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure or consumption of food high in fructose (HFR) can induce hypertension in adult offspring. We examined whether 3,3-maternal dimethyl-1-butanol (DMB, an inhibitor of TMA formation) therapy can protect adult offspring against hypertension arising from combined HFR and TCDD exposure. Pregnant Sprague-Dawley rats received regular chow or chow supplemented with fructose (60% diet by weight) throughout pregnancy and lactation. Additionally, the pregnant dams received TCDD (200 ng/kg BW orally) or a corn oil vehicle on days 14 and 21 of gestation, and days 7 and 14 after birth. Some mother rats received 1% DMB in their drinking water throughout pregnancy and lactation. Six groups of male offspring were studied (n = 8 for each group): regular chow (CV), high-fructose diet (HFR), regular diet+TCDD exposure (CT), HFR+TCDD exposure (HRT), high-fructose diet+DMB treatment (HRD), and HFR+TCDD+DMB treatment (HRTD). Our data showed that TCDD exacerbates HFR-induced elevation of blood pressure in male adult offspring, which was prevented by maternal DMB administration. We observed that different maternal insults induced distinct enterotypes in adult offspring. The beneficial effects of DMB are related to alterations of gut microbiota, the increase in nitric oxide (NO) bioavailability, the balance of the renin-angiotensin system, and antagonization of aryl hydrocarbon receptor (AHR) signaling. Our findings cast new light on the role of early intervention targeting of the gut microbiota-dependent metabolite TMA, which may allow us to prevent the development of hypertension programmed by maternal excessive fructose intake and environmental dioxin exposure.

Post-weaning exposure to high-sucrose diet induces early non-alcoholic fatty liver disease onset and progression in male mice: role of dysfunctional white adipose tissue

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH) particularly among chronic consumers of added sugar-rich diets. However, the impact of early consumption of such diets on NAFLD onset and progression is unclear. Thus, this study sought to characterise metabolic factors involved in NAFLD progression in young mice fed with a high-sucrose diet (HSD). Male Swiss mice were fed HSD or regular chow (CTR) from weaning for up to 60 or 90 days. Obesity development, glucose homeostasis and serum biochemical parameters were determined at each time-point. At day 90, mice were euthanised and white adipose tissue (WAT) collected for lipolytic function assessment and liver for histology, gene expression and cytokines quantification. At day 60, HSD mice presented increased body mass, hypertriglyceridemia, peripheral insulin resistance (IR) and simple steatosis. Upon 90 days on diet, WAT from HSD mice displayed impaired insulin sensitivity, which coincided with increased fasting levels of glucose and free fatty acids (FFA), as well as NAFLD progression to NASH. Transcriptional levels of lipogenic genes, particularly stearoyl-CoA desaturase-1, were consistently increased, leading to hepatic leukocyte infiltration and pro-inflammatory cytokines spillover. Therefore, our dataset supports IR triggering in the WAT as a major factor for dysfunctional release of FFA towards portal circulation and consequent upregulation of lipogenic genes and hepatic inflammatory onset, which decisively concurred for NAFLD-to-NASH progression in young HSD-fed mice. Notwithstanding, this study forewarns against the early introduction of dietary sugars in infant diet, particularly following breastfeeding cessation.

Fast quantification of short-chain fatty acids in rat plasma by gas chromatography

Short-chain fatty acids (SCFAs) are the main metabolites of the intestinal flora and play an important role in the interaction between the intestinal flora and host metabolism. Therefore, reliable methods are needed to accurately measure SCFAs concentrations. SCFAs are commonly analyzed by gas chromatography-mass spectrometry (GC-MS), which requires lengthy sample treatments and a long run time. This study aimed to develop a fast GC method with formic acid pretreatment for SCFAs quantification in the plasma of rat. Baseline chromatographic resolution was achieved for three SCFAs (acetic, propionic, and butyric) within an analysis time of 10.5 min. The method exhibited good recovery for a wide range of concentrations with a low limit of detection for each compound. The relative standard deviations (RSDs) of all targeted compounds showed good intra- and interday precision (<10%). We used our method to measure SCFAs levels in plasma samples from rats fed with a high fructose diet (HFD) to test the accuracy of the developed method. It was shown that SCFAs are indeed affected negatively by a HFD (60% fructose). This method was successfully employed to accurately determine SCFAs in the rat plasma with minimum sample preparation. Results showed potential damage of HFD, which produced lower SCFAs. PRACTICAL APPLICATION: Increasingly, microbiota and gut health research are being conducted by many food scientists to elucidate the relationships among the factors of food components, particularly the nondigestible carbohydrates, food processing conditions, and potential health impact. This research provides a useful, rapid, and accurate method that can save time in the analysis of short-chain fatty acids, which are commonly analyzed in gut health research.

Fructose Consumption During Pregnancy Influences Milk Lipid Composition and Offspring Lipid Profiles in Guinea Pigs

Excess dietary fructose is a major public health concern (1-4). Evidence shows increased fructose intake can cause insulin resistance, hepatic de novo lipogenesis, hypertriglyceridemia, obesity and non-alcoholic fatty liver disease (NAFLD) (5-9). However, little is known about the effects of fructose during pregnancy and its influence on offspring development and predisposition to later-life disease. To determine whether moderately increased maternal fructose intake could have health consequences on offspring, we have investigated the effects of 10% w/v fructose water intake during preconception and pregnancy. Female Dunkin Hartley guinea pigs were fed a control diet (CD) or fructose diet (FD;10% kcal from fructose) ad-libitum 60 days prior to mating and throughout gestation. Offspring were culled at weaning, day 21 (d21). Compared to CD dams, FD dams had altered glucose metabolism and increased milk free fatty acid content. Matsuda-DeFronzo insulin sensitivity index (M-ISI) from OGTT plasma showed no significant difference in whole-body insulin sensitivity between FD and CD dams 60 days post-dietary intervention and during midgestation. Fetal exposure to increased maternal fructose resulted in offspring with significantly altered serum free fatty acids at days 0, 7, 14, and 21 [including pentadecanoic acid (15:0), dma16:0, margaric acid (17:0) palmitoleic acid, total omega-7 and total saturates], increased levels of uric acid and triglycerides were also observed at d21. We have demonstrated that increased fructose intake during pregnancy can cause significant changes in maternal metabolic function and milk composition, which alters offspring metabolism. Taken together, these changes in pregnancy outcomes and feto-maternal condition may underlie their offspring's predisposition to metabolic dysfunction during later-life.

Targeting on Gut Microbial Metabolite Trimethylamine-N-Oxide and Short-Chain Fatty Acid to Prevent Maternal High-Fructose-Diet-Induced Developmental Programming of Hypertension in Adult Male Offspring

SCOPE

Alterations of gut metabolites, such as SCFAs and trimethylamine (TMA), and microbial composition are associated with the development of hypertension. Whether maternal 3,3-dimethyl-1-butanol (DMB, an inhibitor for TMA formation) treatment or the predominant SCFA acetate supplementation can prevent programed hypertension induced by a high-fructose diet (HFD) exposure during pregnancy and lactation in adult male offspring is examined.

METHODS AND RESULTS

Male offspring are divided into four groups: ND, normal diet; HFD, 60% HFD; ACE, HFD plus 200 mmol L^-1 magnesium acetate in drinking water; and DMB: HFD plus 1% DMB in drinking water. Maternal HFD induces programed hypertension in adult male offspring, which is prevented by maternal acetate supplementation or DMB treatment. HFD-induced hypertension is relevant to increased plasma levels of TMA and acetate, and alterations of gut microbial composition. The protective effects of acetate supplementation are associated with decreased plasma TMA level and TMA-to-trimethylamine-N-oxide (TMAO) ratio, and increased renal expression of SCFA receptors. Maternal DMB treatment reduces plasma TMA, TMAO, acetate, and propionate levels.

CONCLUSION

Early intervention targeting on gut-microbiota-derived metabolites TMAO and SCFAs to reprogram hypertension may have significant impact to reduce the burden of hypertension.

Effects of Quercetin on Expression of Genes of Carbohydrate and Lipid Metabolism Enzymes in the Liver of Rats Receiving High-Fructose Ration

We studied the expression of genes encoding enzymes of carbohydrate and lipid metabolism ketohexokinase (Khk), glucokinase (Gck), pyruvate kinase (Pklr), acetyl-Co-carboxylase (Acaca), fatty acid synthase (Fasn), stearoyl-CoA desaturase (Scd), and their transcription regulators ChREBP (Mlxipl), SREBP-1c (Srebf1), and PPARα (Ppara) in rat liver. Control group rats received a semisynthetic ration over 20 weeks. Experimental group 1 received a semisynthetic ration and 20% fructose solution instead of drinking water. Experimental group 2 rats received a semisynthetic ration with quercetin (0.1% fodder weight) and 20% fructose solution. Consumption of 20% fructose solution (experimental group 1) led to an increase in Scd expression in comparison with the control and did not affect the expression of other genes. Addition of quercetin to the ration (experimental group 2) led to a decrease in the expression of Khk, Gck, Fasn, Scd, Mlxipl, and Ppara genes in comparison with experimental group 1. The results suggest that quercetin reduced the expression of genes of carbohydrate and lipid metabolism enzymes in the liver of rats receiving high-fructose ration.

The Good, the Bad, and the Ugly of Pregnancy Nutrients and Developmental Programming of Adult Disease

Maternal nutrition plays a decisive role in developmental programming of many non-communicable diseases (NCDs). A variety of nutritional insults during gestation can cause programming and contribute to the development of adult-onset diseases. Nutritional interventions during pregnancy may serve as reprogramming strategies to reverse programming processes and prevent NCDs. In this review, firstly we summarize epidemiological evidence for nutritional programming of human disease. It will also discuss evidence from animal models, for the common mechanisms underlying nutritional programming, and potential nutritional interventions used as reprogramming strategies.

The Double-Edged Sword Effects of Maternal Nutrition in the Developmental Programming of Hypertension

Hypertension is a growing global epidemic. Developmental programming resulting in hypertension can begin in early life. Maternal nutrition status has important implications as a double-edged sword in the developmental programming of hypertension. Imbalanced maternal nutrition causes offspring's hypertension, while specific nutritional interventions during pregnancy and lactation may serve as reprogramming strategies to reverse programming processes and prevent the development of hypertension. In this review, we first summarize the human and animal data supporting the link between maternal nutrition and developmental programming of hypertension. This review also presents common mechanisms underlying nutritional programming-induced hypertension. This will be followed by studies documenting nutritional interventions as reprogramming strategies to protect against hypertension from developmental origins. The identification of ideal nutritional interventions for the prevention of hypertension development that begins early in life will have a lifelong impact, with profound savings in the global burden of hypertension.

Maternal Administration of Probiotic or Prebiotic Prevents Male Adult Rat Offspring against Developmental Programming of Hypertension Induced by High Fructose Consumption in Pregnancy and Lactation

Excessive intake of fructose is associated with hypertension. Gut microbiota and their metabolites are thought to be associated with the development of hypertension. We examined whether maternal high-fructose (HF) diet-induced programmed hypertension via altering gut microbiota, regulating short-chain fatty acids (SCFAs) and their receptors, and mediating nutrient-sensing signals in adult male offspring. Next, we aimed to determine whether early gut microbiota-targeted therapies with probiotic Lactobacillus casei and prebiotic inulin can prevent maternal HF-induced programmed hypertension. Pregnant rats received 60% high-fructose (HF) diet, with 2 × 10⁸ CFU/day Lactobacillus casei via oral gavage (HF+Probiotic), or with 5% w/w long chain inulin (HF+prebiotic) during pregnancy and lactation. Male offspring (n = 7–8/group) were assigned to four groups: control, HF, HF+Probiotic, and HF+Prebiotic. Rats were sacrificed at 12 weeks of age. Maternal probiotic Lactobacillus casei and prebiotic inulin therapies protect against hypertension in male adult offspring born to fructose-fed mothers. Probiotic treatment prevents HF-induced hypertension is associated with reduced plasma acetate level and decreased renal mRNA expression of Olfr78. While prebiotic treatment increased plasma propionate level and restored HF-induced reduction of Frar2 expression. Maternal HF diet has long-term programming effects on the adult offspring’s gut microbiota. Probiotic and prebiotic therapies exerted similar protective effects on blood pressure but they showed different mechanisms on modulation of gut microbiota. Maternal HF diet induced developmental programming of hypertension, which probiotic Lactobacillus casei or prebiotic inulin therapy prevented. Maternal gut microbiota-targeted therapies could be reprogramming strategies to prevent the development of hypertension caused by maternal consumption of fructose-rich diet.

Developmental Programming of the Metabolic Syndrome: Can We Reprogram with Resveratrol?

Metabolic syndrome (MetS) is a mounting epidemic worldwide. MetS can start in early life, in a microenvironment that is now known as the developmental origins of health and disease (DOHaD). The concept of DOHaD also offers opportunities for reprogramming strategies that aim to reverse programming processes in early life. Resveratrol, a polyphenolic compound has a wide spectrum of beneficial effects on human health. In this review, we first summarize the epidemiological and experimental evidence supporting the developmental programming of MetS. This review also presents an overview of the evidence linking different molecular targets of resveratrol to developmental programming of MetS-related disorders. This will be followed by studies documenting resveratrol as a reprogramming agent to protect against MetS-related disorders. Further clinical studies are required in order to bridge the gap between animal models and clinical trials in order to establish the effective dose and therapeutic duration for resveratrol as a reprogramming therapy on MetS disorders from developmental origins.

Saliva biomarkers in neurological disorders: A "spitting image" of brain health?

In this issue of the Biomedical Journal, we learn how biomarkers in saliva may be able to provide insight into the health of the brain and the central nervous system. We also discover how computational modeling can help to identify potential epitopes for vaccine development against Chlamydia, the world's most common sexually transmitted infection.