Sarah J. Glastras

Effect of GLP-1 Receptor Activation on Offspring Kidney Health in a Rat Model of Maternal Obesity

Maternal obesity is associated with an increased risk of chronic disease in offspring, including type 2 diabetes (T2D). Exendin-4 (Exd-4) activates the glucagon like peptide-1 (GLP-1) receptor thereby decreasing serum glucose levels and body weight. In addition, Exd-4 has been shown to reduce renal and cardiac complications in experimental models of T2D. We hypothesized that treatment with Exd-4 would ameliorate the detrimental effects of maternal and diet-induced obesity on renal characteristics in offspring. Female Sprague-Dawley rats were fed either normal or high-fat diet (HFD) for 6 weeks prior to pregnancy, during pregnancy and lactation, and their offspring were weaned to normal or HFD. The offspring were randomized to Exd-4 or placebo from weaning and their kidneys harvested at Week 9. We found that the kidneys of offspring from obese mothers, regardless of postnatal diet, had significantly increased markers of inflammation, oxidative stress and fibrosis. Exd-4 ameliorated the negative renal effects of maternal obesity and in particular, reduced renal inflammation, oxidative stress and fibrosis. In conclusion, maternal obesity has persisting effects on renal structure in the offspring. GLP-1 analogues are potentially useful for protecting against the deleterious effects of maternal obesity on renal physiology in offspring.

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.

FXR expression is associated with dysregulated glucose and lipid levels in the offspring kidney induced by maternal obesity.

BackgroundMaternal obesity is associated with dysregulation of glucose and lipid metabolism with consequent exposure of the fetus to an abnormal metabolic milieu. It is recognized that maternal obesity predisposes offspring to chronic kidney disease (CKD). We aimed to determine whether the nuclear Farnesoid X receptor (FXR), known to play a role in maintaining homeostasis of glucose and lipid metabolism, is involved in renal injury in offspring of obese mothers.MethodsMaternal obesity was established in a rat model by feeding dams with high-fat diet prior to and during pregnancy and lactation. The offspring’s kidneys were examined at postnatal Day 1and Day 20. Human kidney 2 (HK2) cells were exposed to high glucose with or without the FXR agonist GW4064 or when FXR mRNA was silenced.ResultsGlucose intolerance in the offspring of obese mothers was evident at weaning, with associated downregulation of renal FXR expression and upregulation of monocyte chemoattractant protein-1 (MCP-1) and transforming growth factor-β1 (TGF-β1). HK2 cells exposed to high glucose had reduced FXR expression and increased MCP-1, TGF-β1, fibronectin and collagen IV expression, which was reversed in the presence of GW4064. FXR-silenced HK2 cells had amplified pro-inflammatory and pro-fibrotic markers under high glucose conditions.ConclusionsMaternal obesity influences renal expression of pro-inflammatory and fibrotic factors that predispose the offspring to CKD. This was associated with the downregulation of the renal FXR expression suggesting a potential protective role for FXR.

Use of metformin earlier in pregnancy predicts supplemental insulin therapy in women with gestational diabetes

The use of metformin in gestational diabetes is safe and effective, yet some women require additional insulin therapy to achieve glycaemic targets. We found a significant association between earlier gestational age at initiation of metformin therapy and the necessity for supplemental insulin in women treated with metformin during pregnancy.

Central Functions of Glucagon-like Peptide-1: Roles in Energy Regulation andNeuroprotection

The identification of the glucagon-like peptide-1 receptor in the central nervous system has led to an array of studies exploring the functions of central GLP-1 signalling. Originally identified as a gastrointestinal incretin hormone responsible for the potentiation of insulin secretion following ingestion of nutrients, the role of GLP-1 has been expanded to include specific neural activities. Two distinct actions of GLP-1 receptor activation in the brain have been identified, namely the regulation of appetite via promotion of satiety, as well as anti-inflammatory and anti-apoptotic activity to promote neuronal cell survival. Both of these features are now being exploited clinically, with GLP-1 receptor agonists, initially designed and marketed for the treatment of hyperglycaemia in type 2 diabetes, now being directed towards use in obesity and as potential neuroprotective agents. This review gives a summary of the functional role of GLP-1 in the central nervous system, in terms of promoting satiety, modulating food intake and aiding in the regulation of peripheral glycaemia. In addition, the molecular mechanisms underpinning the beneficial effects of central GLP-1 receptor agonist therapy in protecting against neuronal cell inflammation and death, including neurodegenerative processes, are described.

Maternal Obesity Promotes Diabetic Nephropathy in Rodent Offspring.

Maternal obesity is known to increase the risk of obesity and diabetes in offspring. Though diabetes is a key risk factor for the development of chronic kidney disease (CKD), the relationship between maternal obesity and CKD has not been clearly defined. In this study, a mouse model of maternal obesity was employed to determine the impact of maternal obesity on development of diabetic nephropathy in offspring. 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 diet. At postnatal Week 8, offspring were randomly administered low dose streptozotocin (STZ, 55 mg/kg/day for five days) to induce diabetes. Assessment of renal damage took place at postnatal Week 32. We found that offspring of obese mothers had increased renal fibrosis, inflammation and oxidative stress. Importantly, offspring exposed to maternal obesity had increased susceptibility to renal damage when an additional insult, such as STZ-induced diabetes, was imposed. Specifically, renal inflammation and oxidative stress induced by diabetes was augmented by maternal obesity. Our findings suggest that developmental programming induced by maternal obesity has implications for renal health in offspring. Maternal obesity should be considered a risk factor for CKD.

The renal consequences of maternal obesity in offspring are overwhelmed by postnatal high fat diet

Aims/Hypothesis 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. Methods 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. Results 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. Conclusion 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.

Association Between Glycemic Variability, HbA1c, and Large-for-Gestational-Age Neonates in Women With Type 1 Diabetes

Fetal exposure to hyperglycemia is a major determinant of large-for-gestational-age (LGA; birth weight >90th centile for gender) neonates (1), yet targets for glycemic control beyond the first trimester in type 1 diabetes (T1D) pregnancy remain controversial. As HbA1c represents a summary measure of glycemic control, it might not adequately reflect acute glucose fluctuations or glycemic variability (GV) that contributes to excess fetal growth. Moreover, neonates born to women who attain HbA1c <6% (42 mmol/mol) in the third trimester of pregnancy have an LGA prevalence of 25% (2), with associated adverse perinatal outcomes (3). In contrast to HbA1c, continuous glucose monitoring (CGM) allows precise observation of GV. Several studies have demonstrated an association between higher GV and increased birth weight (1,4,5). The capability of GV compared with HbA1c to identify women likely to have LGA neonates is, however, unclear. We evaluated the association between various measures of GV, HbA1c, and LGA neonates in T1D pregnancy. Twenty-one pregnant women with T1D were recruited over a 2-year period, and measurements of HbA1c and GV (EasyGV, University …

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.

Identification of Patients With Diabetes Who Benefit Most From a Health Coaching Program in Chronic Disease Management, Sydney, Australia, 2013

Introduction Chronic disease management programs (CDMPs) that include health coaching can facilitate and coordinate diabetes management. The aim of this study was to assess changes in patients’ general knowledge of diabetes, self-reported health status, diabetes distress, body mass index (BMI), and glycemic control after enrollment in a face-to-face CDMP group health coaching session (with telephone follow-up) compared with participation in telephone-only health coaching, during a 12-month period. Methods Patients with diabetes were enrolled in a health coaching program at Royal North Shore Hospital, Sydney, Australia, in 2013. Questionnaires were administered at baseline and at 3, 6, and 12 months, and the results were compared with baseline. Glycemic control, measured with glycated hemoglobin A1c (HbA1c) and BMI, were measured at baseline and 12 months. Results Overall, 238 patients attended a face-to-face CDMP session with telephone follow-up (n = 178) or participated in telephone-only health coaching (n = 60). We found no change in BMI in either group; however, HbA1c levels in patients with baseline above the current recommended target (>7%) decreased significantly from 8.5% (standard deviation [SD], 1.0%) to 7.9% (SD, 1.0%) (P = .03). Patients with the lowest self-reported health status at baseline improved from 4.4 (SD, 0.5) to 3.7 (SD, 0.9) (P = .001). Diabetes knowledge improved in all patients (24.4 [SD, 2.4] to 25.2 [SD, 2.4]; P < .001), and diabetes distress decreased among those with the highest levels of distress at baseline (3.0 [SD, 0.4] vs 3.8 [SD, 0.6]; P = .003). Conclusion Diabetes health coaching programs can improve glycemic control and reduce diabetes distress in patients with high levels of these at baseline.