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22 result(s) for "Glastras, Sarah J."
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Maternal obesity increases the risk of metabolic disease and impacts renal health in offspring
Obesity, together with insulin resistance, promotes multiple metabolic abnormalities and is strongly associated with an increased risk of chronic disease including type 2 diabetes (T2D), hypertension, cardiovascular disease, non-alcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD). The incidence of obesity continues to rise in astronomical proportions throughout the world and affects all the different stages of the lifespan. Importantly, the proportion of women of reproductive age who are overweight or obese is increasing at an alarming rate and has potential ramifications for offspring health and disease risk. Evidence suggests a strong link between the intrauterine environment and disease programming. The current review will describe the importance of the intrauterine environment in the development of metabolic disease, including kidney disease. It will detail the known mechanisms of fetal programming, including the role of epigenetic modulation. The evidence for the role of maternal obesity in the developmental programming of CKD is derived mostly from our rodent models which will be described. The clinical implication of such findings will also be discussed.
Kidney outcomes are altered by preconception weight modulation in rodent mothers with obesity
Obesity increases the risk of chronic kidney disease. We have previously demonstrated the benefits of preconception maternal weight loss on fertility and pregnancy outcomes in a mouse model of maternal obesity. Here, we elucidate if preconception weight loss, either by diet modification or the glucose-like peptide 1 agonist liraglutide, used in the treatment of diabetes and obesity, improves maternal kidney outcomes in late gestation. C57BL/6 female mice were fed either a high-fat-diet (HFD) or a chow (control) diet for 8 weeks. To induce pre-pregnancy weight loss, HFD-fed dams were switched to chow diet (HFD-C) or administered liraglutide (0.3 mg/kg subcutaneous) whilst continuing on HFD (HFD-L). Liraglutide was discontinued one week prior to mating. HFD-V mice continued on HFD, with saline injections. A group of HFD-fed dams were ‘diet switched’ to chow after conception (post-conception, HFD-PC). Maternal body weight and glucose tolerance were measured: (1) preconception and (2) during late gestation followed by blood, urine and kidney collection. Serum creatinine, urinary creatinine and albumin, kidney tissue gene expression and protein were measured. In the preconception period, HFD-L and HFD-C mothers have lower urine albumin:creatinine ratios (UACR) and fatty acid synthase (FAS) protein expression ( P  < 0.005 vs. HFD-V). At late gestation, kidneys of HFD-V and HFD-PC dams have increased gene expression of insulin receptor and FAS ( P  < 0.05) and higher UACR compared to controls ( P  < 0.01). In the HFD-PC group, kidneys show increased mRNA and protein expression of metabolic and oxidative stress markers (FAS, 8-OHdG vs. control, P  < 0.05, P  < 0.0001 respectively). The preconception intervention groups with liraglutide, or diet change show reduced oxidative stress (protein expression of 8-OHdG, P  < 0.05 vs. HFD), mRNA and protein expression of FAS ( P  < 0.05 vs. HFD), protein expression of fibrosis markers (collagen IV, fibronectin vs. HFD, P  < 0.05), and UACR ( P  < 0.05 vs. HFD). This study suggests that preconception weight loss benefits maternal kidney health during pregnancy, superior to diet intervention once already pregnant.
Low-dose hydralazine during gestation reduces renal fibrosis in rodent offspring exposed to maternal high fat diet
Maternal high fat diet (HFD) promotes chronic kidney disease (CKD) in offspring. This is in accordance with the theory of fetal programming, which suggests adverse conditions occurring in utero predispose offspring to chronic conditions later in life. DNA methylation has been proposed as a key mechanism by which fetal programming occurs and is implicated in CKD progression. DNA demethylating drugs may interrupt the fetal programming of CKD by maternal obesity. Hydralazine, an antihypertensive agent, demethylates DNA at low doses which do not reduce blood pressure. We used a mouse model of maternal obesity to determine whether gestational administration of low-dose hydralazine to mothers can prevent CKD in offspring. C57BL/6 dams received HFD or chow from 6 weeks prior to mating and were administered subcutaneous hydralazine (5mg/kg) or saline thrice weekly during gestation. Male offspring were weaned to chow and were sacrificed at either postnatal week 9 or week 32. Biometric and metabolic parameters, renal global DNA methylation, renal structural and functional changes and markers of fibrosis, oxidative stress and inflammation were measured in offspring at weeks 9 and 32. In week 9 offspring, maternal HFD consumption did not significantly alter anthropometric or metabolic parameters, or renal global DNA methylation. Week 32 offspring had increased renal global DNA methylation, together with albuminuria, glomerulosclerosis, renal fibrosis and oxidative stress. Administration of low-dose hydralazine to obese mothers during gestation reduced renal global DNA methylation and renal fibrotic markers in week 32 offspring. Gestational hydralazine reduced renal global DNA methylation in offspring of obese mothers and attenuated maternal obesity-induced renal fibrosis. These data support the use of low-dose hydralazine as a demethylating agent to prevent CKD arising in offspring due to maternal HFD consumption.
The renal consequences of maternal obesity in offspring are overwhelmed by postnatal high fat diet
Developmental programming induced by maternal obesity influences the development of chronic disease in offspring. In the present study, we aimed to determine whether maternal obesity exaggerates obesity-related kidney disease. Female C57BL/6 mice were fed high-fat diet (HFD) for six weeks prior to mating, during gestation and lactation. Male offspring were weaned to normal chow or HFD. At postnatal Week 8, HFD-fed offspring were administered one dose streptozotocin (STZ, 100 mg/kg i.p.) or vehicle control. Metabolic parameters and renal functional and structural changes were observed at postnatal Week 32. HFD-fed offspring had increased adiposity, glucose intolerance and hyperlipidaemia, associated with increased albuminuria and serum creatinine levels. Their kidneys displayed structural changes with increased levels of fibrotic, inflammatory and oxidative stress markers. STZ administration did not potentiate the renal effects of HFD. Though maternal obesity had a sustained effect on serum creatinine and oxidative stress markers in lean offspring, the renal consequences of maternal obesity were overwhelmed by the powerful effect of diet-induced obesity. Maternal obesity portends significant risks for metabolic and renal health in adult offspring. However, diet-induced obesity is an overwhelming and potent stimulus for the development of CKD that is not potentiated by maternal obesity.
Tirzepatide for the treatment of adults living with concurrent type 1 diabetes and overweight or obesity (TZP-T1D): a double-blind, placebo-matched randomised controlled trial protocol
IntroductionThe increasing prevalence of overweight and obesity among individuals with type 1 diabetes (T1D) complicates glycaemic management and escalates insulin resistance, necessitating innovative therapeutic strategies. Tirzepatide, a dual agonist for glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide receptors, shows promise in managing weight and glycaemic control in type 2 diabetes but is unexplored in the context of T1D. This double-blind, placebo-controlled randomised trial will evaluate the efficacy of tirzepatide in adults with T1D and overweight/obesity over 32 weeks.Methods and analysis60 participants (aged 18–70 years) with a body mass index ≥27 kg/m2 and HbA1c≤10% will be randomised 1:1 to receive either tirzepatide or a placebo, alongside standard insulin therapy. The primary outcome is the change in body weight (%). Secondary measures include change in HbA1c (%), proportion of body weight lost (>5%, >10%, >15% and >20%), changes in insulin dosage, time in range by continuous glucose monitoring (CGM) criteria and severity of comorbidities. Compliance, adverse events and medication interactions will be closely monitored, with adjustments made for tolerability. Patient-reported outcomes and experiences will be measured to capture the benefits of glycaemic management, weight management and quality of life. To compare the means of body weight reduction (%) between the tirzepatide and control groups, an independent samples t-test will be employed under the assumption that data are normally distributed. Secondary outcome measures will be analysed by Student’s t-test. All data will be reported as group means with confidence intervals, with default statistical significance assumed at p<0.05.Ethics and disseminationEthical approval has been obtained from the Northern Sydney Local Health District’s Human Research Ethics Committee (approval ID #2024/ETH00180).Trial registration numberNCT06180616.
Mouse Models of Diabetes, Obesity and Related Kidney Disease
Multiple rodent models have been used to study diabetic kidney disease (DKD). The purpose of the present study was to compare models of diabetes and obesity-induced metabolic syndrome and determine differences in renal outcomes. C57BL/6 male mice were fed either normal chow or high fat diet (HFD). At postnatal week 8, chow-fed mice were randomly assigned to low-dose streptozotocin (STZ, 55 mg/kg/day, five consecutive days) or vehicle control, whereas HFD-fed mice were given either one high-dose of STZ (100 mg/kg) or vehicle control. Intraperitoneal glucose tolerance tests were performed at Week 14, 20 and 30. Urinary albumin to creatinine ratio (ACR) and serum creatinine were measured, and renal structure was assessed using Periodic Acid Schiff (PAS) staining at Week 32. Results showed that chow-fed mice exposed to five doses of STZ resembled type 1 diabetes mellitus with a lean phenotype, hyperglycaemia, microalbuminuria and increased serum creatinine levels. Their kidneys demonstrated moderate tubular injury with evidence of tubular dilatation and glycogenated nuclear inclusion bodies. HFD-fed mice resembled metabolic syndrome as they were obese with dyslipidaemia, insulin resistance, and significantly impaired glucose tolerance. One dose STZ, in addition to HFD, did not worsen metabolic features (including fasting glucose, non esterified fatty acid, and triglyceride levels). There were significant increases in urinary ACR and serum creatinine levels, and renal structural changes were predominantly related to interstitial vacuolation and tubular dilatation in HFD-fed mice.
The Role of the Gut Microbiome in Diabetes and Obesity-Related Kidney Disease
Diabetic kidney disease (DKD) is a progressive disorder, which is increasing globally in prevalence due to the increased incidence of obesity and diabetes mellitus. Despite optimal clinical management, a significant number of patients with diabetes develop DKD. Hence, hitherto unrecognized factors are likely to be involved in the initiation and progression of DKD. An extensive number of studies have demonstrated the role of microbiota in health and disease. Dysregulation in the microbiota resulting in a deficiency of short chain fatty acids (SCFAs) such as propionate, acetate, and butyrate, by-products of healthy gut microbiota metabolism, have been demonstrated in obesity, type 1 and type 2 diabetes. However, it is not clear to date whether such changes in the microbiota are causative or merely associated with the diseases. It is also not clear which microbiota have protective effects on humans. Few studies have investigated the centrality of reduced SCFA in DKD development and progression or the potential therapeutic effects of supplemental SCFAs on insulin resistance, inflammation, and metabolic changes. SCFA receptors are expressed in the kidneys, and emerging data have demonstrated that intestinal dysbiosis activates the renal renin-angiotensin system, which contributes to the development of DKD. In this review, we will summarize the complex relationship between the gut microbiota and the kidney, examine the evidence for the role of gut dysbiosis in diabetes and obesity-related kidney disease, and explore the mechanisms involved. In addition, we will describe the role of potential therapies that modulate the gut microbiota to prevent or reduce kidney disease progression.
Liraglutide-Driven Weight Loss Modulates Placental Remodeling in Obese Pregnancies in Mice
The placenta stands at the maternal-fetal interface and is a key organ regulating the intrauterine environment. In pregnancies exposed to obesity, placental function, signaling, and nutrient handling are adversely altered. Pre-conception weight loss is a potential intervention to alter an obesogenic milieu of pregnancy, which we investigated in a mouse model of maternal obesity using diet or administration of the glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide. Pre-pregnancy weight loss in high-fat diet (HFD)-fed dams was induced in the pre-pregnancy period by switching diet from HFD to chow diet or administering liraglutide (0.3 mg/kg/day subcutaneously for 4 weeks) whilst continuing HFD. In addition, a group of HFD-fed dams were switched to chow diet post-conception. The metabolomic profile and gene expression within the placenta was compared at day 18-20 of gestation. H NMR spectroscopy metabolomic analysis of placenta of HFD mice showed an altered amino acid metabolomic profile, with lower aspartate, glutamate, and glutamine levels compared to the placenta of chow-fed mice ( < 0.05). Meanwhile, gene expression analysis identified both oxidative stress and inflammation in the placentas of HFD-fed dams. Whilst dietary modification alone was sufficient to reduce markers of oxidative stress and inflammation, liraglutide treatment modulated pathological changes, including placental metabolic stress but not inflammation. These findings highlight the importance of dietary or pharmacological interventions in the pre- or immediate post-conception period, with pre-conception offering a critical window to reduce aberrant placental changes induced by obesity.
Are newly introduced criteria for the diagnosis of gestational diabetes mellitus associated with improved pregnancy outcomes and/or increased interventions in New South Wales, Australia? A population-based data linkage study
IntroductionThe incidence of gestational diabetes mellitus (GDM) is increasing in Australia, influenced by changed diagnostic criteria. We aimed to identify whether the diagnostic change was associated with improved outcomes and/or increased obstetric interventions using state-wide data in New South Wales (NSW), Australia.Research design and methodsPerinatal and hospital data were linked for singleton births, 33–41 weeks’ gestation, 2006–2015, NSW. An adjusted Poisson model was used to split pregnancies from 2011 onwards into those that would have been diagnosed under the old criteria (‘previous GDM’) and newly diagnosed cases (‘additional GDM’). We compared actual rates of total and early (<39 weeks) planned births, cesareans, and maternal and neonatal adverse outcomes for GDM-diagnosed pregnancies using three predicted scenarios, where the ‘additional GDM’ group was assumed to have the same rates as: the ‘previous GDM’ group <2011 (scenario A); the ‘non-GDM’ group <2011 (scenario B); or the ‘non-GDM’ group ≥2011 (scenario C).ResultsGDM incidence more than doubled over the study period, with an inflection point observed at 2011. For those diagnosed with GDM since 2011, the actual incidence of interventions (planned births and cesareans) and macrosomia was consistent with scenario A, which meant higher intervention rates, but lower rates of macrosomia, than those with no GDM. Incidence of neonatal hypoglycemia was lower than scenario A and closer to the other scenarios. There was a reduction in perinatal deaths among those with GDM, lower than that predicted by all scenarios, indicating an improvement for all with GDM, not only women newly diagnosed. Incidence of maternal and neonatal morbidity indicators was within the confidence bounds for all three predicted scenarios.ConclusionsOur study suggests that the widely adopted new diagnostic criteria for GDM are associated with increased obstetric intervention rates and lower rates of macrosomic babies, but with no clear impacts on maternal or neonatal morbidity.
Therapeutic Potential for Beta-3 Adrenoreceptor Agonists in Peripheral Arterial Disease and Diabetic Foot Ulcers
Annually, peripheral arterial disease is estimated to cost over USD 21 billion and diabetic foot disease an estimated at USD 9–13 billion. Mirabegron is a TGA-approved beta-3 adrenoreceptor agonist, shown to be safe and effective in the treatment of overactive bladder syndrome by stimulating bladder smooth muscle relaxation. In this review, we discuss the potential use of beta-3 adrenoreceptor agonists as therapeutic agents repurposed for peripheral arterial disease and diabetic foot ulcers. The development of both conditions is underpinned by the upregulation of oxidative stress pathways and consequential inflammation and hypoxia. In oxidative stress, there is an imbalance of reactive oxygen species and nitric oxide. Endothelial nitric oxide synthase becomes uncoupled in disease states, producing superoxide and worsening oxidative stress. Agonist stimulation of the beta-3 adrenoreceptor recouples and activates endothelial nitric oxide synthase, increasing the production of nitric oxide. This reduces circulating reactive oxygen species, thus decreasing redox modification and dysregulation of cellular proteins, causing downstream smooth muscle relaxation, improved endothelial function and increased angiogenesis. These mechanisms lead to endothelial repair in peripheral arterial disease and an enhanced perfusion in hypoxic tissue, which will likely improve the healing of chronic ulcers.