Are Heat Shock Proteins an Important Link between Type 2 Diabetes and Alzheimer Disease?

Type 2 diabetes (T2D) and Alzheimer's disease (AD) are growing in prevalence worldwide. The development of T2D increases the risk of AD disease, while AD patients can show glucose imbalance due to an increased insulin resistance. T2D and AD share similar pathological features and underlying mechanisms, including the deposition of amyloidogenic peptides in pancreatic islets (i.e., islet amyloid polypeptide; IAPP) and brain (ß-Amyloid; Aß). Both IAPP and Aß can undergo misfolding and aggregation and accumulate in the extracellular space of their respective tissues of origin. As a main response to protein misfolding, there is evidence of the role of heat shock proteins (HSPs) in moderating T2D and AD. HSPs play a pivotal role in cell homeostasis by providing cytoprotection during acute and chronic metabolic stresses. In T2D and AD, intracellular HSP (iHSP) levels are reduced, potentially due to the ability of the cell to export HSPs to the extracellular space (eHSP). The increase in eHSPs can contribute to oxidative damage and is associated with various pro-inflammatory pathways in T2D and AD. Here, we review the role of HSP in moderating T2D and AD, as well as propose that these chaperone proteins are an important link in the relationship between T2D and AD.

MPA given orally during the first trimester for threatened miscarriage carries no specific risk for foetal abnormalities albeit the rate is higher than non-threatened pregnancies.

This observational study examines the outcomes of pregnancies arising in women referred for infertility, where those who experienced threatened miscarriage were treated with medroxyprogesterone acetate (MPA) tablets. The 14-year study period covers comprehensive real-time data entries into the validated electronic database including details of the infertility management, pregnancy outcomes and any foetal anomalies among the infants, each being tracked and recorded. Of 4057 clinical pregnancies, 1343 received MPA for threatened miscarriage; 934 (69.6 %) of which continued to livebirths. These were compared with the remaining 2714 clinical pregnancies without threatened miscarriage or MPA and which resulted in 2075 (76.5 %) livebirths. There were 134 developmental abnormalities recorded among the 3009 livebirths of which 78 (2.6 %) were categorised appropriate for the Western Australian Developmental Abnormalities Register; WARDA. These comprised 55 in the MPA group, 36 of which were categorised as serious (being 2.7 % of clinical pregnancies and 3.9 % of births). In the group without MPA, there were 79 abnormalities, of which 42 were categorised as serious (being 1.7 % of clinical pregnancies and 2.2 % of births). Specifically, there were no cases of androgenisation noted among the female infants. The abnormality rates were low overall and well within the annual WARDA ranges. We cautiously suggest that oral MPA can be considered for studies throughout pregnancy including the early first trimester to assess a potential role in reducing miscarriage, as well as advanced pregnancies to evaluate a potential role in reducing stillbirths and preterm delivery.

The Evolving Concept of Poor-Prognosis for Women Undertaking IVF and the Notion of Growth Hormone as an Adjuvant; A Single-Center Viewpoint.

IVF is currently regarded as a successful new technology with the number of IVF children currently well over 8 million worldwide. This has been achieved by an explosive plethora of facilities. However, from its earliest history, IVF has been beset by poor-prognosis on a treatment cycle basis, an aspect which has been a constant feature for the majority of treatments to this stage. The 2019 Australian and New Zealand Assisted Reproduction Database (ANZARD) report shows that IVF clinics have live birth productivity rates (from combined initiated fresh and frozen cycles) ranging from 9.3 to 33.2%. Over the past 40 years there have been a number of innovations which have steadily moved the success rates forward, but progress is held back by an intransigent group of women who can be classified as being poor-prognosis from one or more adverse factors, namely advanced age (>40 years), poor ovarian response (POR) to ovarian stimulation, inability to generate high quality blastocyst-stage embryos, recurrent implantation failure, or recurrent early pregnancy losses. A number of strategies are variously applied including the use of recombinant growth hormone (GH) adjuvant therapy. Our retrospective studies at PIVET over the past decade show a 6.2-fold chance of live birth for fresh cycle embryo transfers following GH injections of 1-1.5 IU daily given for 3-6 weeks in the lead-up to the trigger for ovum pick-up. We have also recently reported the live birth rates from frozen embryo transfers utilizing those blastocyst embryos generated under GH influence and showed the live birth rate was 2.7-fold higher in a carefully matched poor-prognosis group. This experience has been compared to the total 42 GH studies reported since the year 2000, the majority matching those of PIVET with significant increases in both oocyte and embryo utilization rates but only ~50% are followed by elevated live birth rates. We argue that this discrepancy relates to failure in addressing other causes of poor-prognosis along with the wastage of transferring more than a single embryo in the fresh cycle, when ANZARD data indicates a significantly higher chance of live birth from frozen embryo transfers.

Effects of High-Fat Diet on eHSP72 and Extra-to-Intracellular HSP70 Levels in Mice Submitted to Exercise under Exposure to Fine Particulate Matter.

Obesity, air pollution, and exercise induce alterations in the heat shock response (HSR), in both intracellular 70 kDa heat shock proteins (iHSP70) and the plasmatic extracellular form (eHSP72). Extra-to-intracellular HSP70 ratio (H-index = eHSP70/iHSP70 ratio) represents a candidate biomarker of subclinical health status. This study investigated the effects of moderate- and high-intensity exercise in the HSR and oxidative stress parameters, in obese mice exposed to fine particulate matter (PM2.5). Thirty-day-old male isogenic B6129F2/J mice were maintained for 16 weeks on standard chow or high-fat diet (HFD). Then, mice were exposed to either saline or 50 µg of PM2.5 by intranasal instillation and subsequently maintained at rest or subjected to moderate- or high-intensity swimming exercise. HFD mice exhibited high adiposity and glucose intolerance at week 16th. HFD mice submitted to moderate- or high-intensity exercise were not able to complete the exercise session and showed lower levels of eHSP70 and H-index, when compared to controls. PM2.5 exposure modified the glycaemic response to exercise and modified hematological responses in HFD mice. Our study suggests that obesity is a critical health condition for exercise prescription under PM2.5 exposure.

Molecular mechanisms of ROS production and oxidative stress in diabetes.

Oxidative stress and chronic inflammation are known to be associated with the development of metabolic diseases, including diabetes. Oxidative stress, an imbalance between oxidative and antioxidative systems of cells and tissues, is a result of over production of oxidative-free radicals and associated reactive oxygen species (ROS). One outcome of excessive levels of ROS is the modification of the structure and function of cellular proteins and lipids, leading to cellular dysfunction including impaired energy metabolism, altered cell signalling and cell cycle control, impaired cell transport mechanisms and overall dysfunctional biological activity, immune activation and inflammation. Nutritional stress, such as that caused by excess high-fat and/or carbohydrate diets, promotes oxidative stress as evident by increased lipid peroxidation products, protein carbonylation and decreased antioxidant status. In obesity, chronic oxidative stress and associated inflammation are the underlying factors that lead to the development of pathologies such as insulin resistance, dysregulated pathways of metabolism, diabetes and cardiovascular disease through impaired signalling and metabolism resulting in dysfunction to insulin secretion, insulin action and immune responses. However, exercise may counter excessive levels of oxidative stress and thus improve metabolic and inflammatory outcomes. In the present article, we review the cellular and molecular origins and significance of ROS production, the molecular targets and responses describing how oxidative stress affects cell function including mechanisms of insulin secretion and action, from the point of view of possible application of novel diabetic therapies based on redox regulation.

The effect of cigarette smoking, alcohol consumption and fruit and vegetable consumption on IVF outcomes: a review and presentation of original data.

BACKGROUND: Lifestyle factors including cigarette smoking, alcohol consumption and nutritional habits impact on health, wellness, and the risk of chronic diseases. In the areas of in-vitro fertilization (IVF) and pregnancy, lifestyle factors influence oocyte production, fertilization rates, pregnancy and pregnancy loss, while chronic, low-grade oxidative stress may underlie poor outcomes for some IVF cases. METHODS: Here, we review the current literature and present some original, previously unpublished data, obtained from couples attending the PIVET Medical Centre in Western Australia. RESULTS: During the study, 80 % of females and 70 % of male partners completed a 1-week diary documenting their smoking, alcohol and fruit and vegetable intake. The subsequent clinical outcomes of their IVF treatment such as quantity of oocytes collected, fertilization rates, pregnancy and pregnancy loss were submitted to multiple regression analysis, in order to investigate the relationship between patients, treatment and the recorded lifestyle factors. Of significance, it was found that male smoking caused an increased risk of pregnancy loss (p = 0.029), while female smoking caused an adverse effect on ovarian reserve. Both alcohol consumption (ß = 0.074, p < 0.001) and fruit and vegetable consumption (ß = 0.034, p < 0.001) had positive effects on fertilization. CONCLUSION: Based on our results and the current literature, there is an important impact of lifestyle factors on IVF clinical outcomes. Currently, there are conflicting results regarding other lifestyle factors such as nutritional habits and alcohol consumption, but it is apparent that chronic oxidative stress induced by lifestyle factors and poor nutritional habits associate with a lower rate of IVF success.

Molecular Events Linking Oxidative Stress and Inflammation to Insulin Resistance and ß-Cell Dysfunction.

The prevalence of diabetes mellitus (DM) is increasing worldwide, a consequence of the alarming rise in obesity and metabolic syndrome (MetS). Oxidative stress and inflammation are key physiological and pathological events linking obesity, insulin resistance, and the progression of type 2 DM (T2DM). Unresolved inflammation alongside a "glucolipotoxic" environment of the pancreatic islets, in insulin resistant pathologies, enhances the infiltration of immune cells which through secretory activity cause dysfunction of insulin-secreting ß-cells and ultimately cell death. Recent molecular investigations have revealed that mechanisms responsible for insulin resistance associated with T2DM are detected in conditions such as obesity and MetS, including impaired insulin receptor (IR) signalling in insulin responsive tissues, oxidative stress, and endoplasmic reticulum (ER) stress. The aim of the present review is to describe the evidence linking oxidative stress and inflammation with impairment of insulin secretion and action, which result in the progression of T2DM and other conditions associated with metabolic dysregulation.

Alanyl-glutamine improves pancreatic ß-cell function following ex vivo inflammatory challenge.

Obesity-associated diabetes and concomitant inflammation may compromise pancreatic ß-cell integrity and function. l-glutamine and l-alanine are potent insulin secretagogues, with antioxidant and cytoprotective properties. Herein, we studied whether the dipeptide l-alanyl-l-glutamine (Ala-Gln) could exert protective effects via sirtuin 1/HUR (SIRT1/HUR) signalling in ß-cells, against detrimental responses following ex vivo stimulation with inflammatory mediators derived from macrophages (IMMs). The macrophages were derived from blood obtained from obese subjects. Macrophages were exposed (or not) to lipopolysaccharide (LPS) to generate a pro-inflammatory cytokine cocktail. The cytokine profile was determined following analysis by flow cytometry. Insulin-secreting BRIN-BD11 ß-cells were exposed to IMMs and then cultured with or without Ala-Gln for 24 h. Chronic insulin secretion, the l-glutamine-glutathione (GSH) axis, and the level of insulin receptor ß (IR-ß), heat shock protein 70 (HSP70), SIRT1/HUR, CCAAT-enhancer-binding protein homologous protein (CHOP) and cytochrome c oxidase IV (COX IV) were evaluated. Concentrations of cytokines, including interleukin 1ß (IL1ß), IL6, IL10 and tumour necrosis factor alpha (TNFα) in the IMMs, were higher following exposure to LPS. Subsequently, when ß-cells were exposed to IMMs, chronic insulin secretion, and IR-ß and COX IV levels were decreased, but these effects were partially or fully attenuated by the addition of Ala-Gln. The glutamine-GSH axis and HSP70 levels, which were compromised by IMMs, were also restored by Ala-Gln, possibly due to protection of SIRT1/HUR levels, and a reduction of CHOP expression. Using an ex vivo inflammatory approach, we have demonstrated Ala-Gln-dependent ß-cell protection mediated by coordinated effects on the glutamine-GSH axis, and the HSP pathway, maintenance of mitochondrial metabolism and stimulus-secretion coupling essential for insulin release.