Cells can release lipid bilayer vesicles of endosomal and plasma membrane origin, which are known as exosomes or extracellular vesicles (EVs). EVs contain diverse shuttling lipids, RNA and transmembrane proteins, and play an important role in communicating between neighboring or distant cells. Breast cancer is the most commonly diagnosed malignancy, with over 2 million new cases in 2018, and is the leading cause of cancer mortality in women all over the world. Some observational studies have suggested that breast cancer is more likely to develop among women who have type 2 diabetes; the association is clear in postmenopausal women. Moreover, women with type 2 diabetes diagnosed before, at the same time, or after breast cancer diagnosis, have decreased overall survival compared to women without diabetes. The most recent medical studies provide more clues as to why breast cancer is more common and has poorer prognosis in type 2 diabetes patients, by pointing out the role of insulin-resistant adipocytes in the etiopathology. Here, we demonstrate how insulin-resistant adipocytes engage crosstalk with breast cancer cells through EVs in the microenvironment and drive the tumor cells to be more metastatic and aggressive. These progression mechanisms and the effects of insulin-resistant adipocytes on breast cancer cells require Bromodomain and ExtraTerminal (BET) proteins – an important epigenetic pathway. Targeting this pathway may help reduce morbidity and mortality of women with breast cancer and type 2 diabetes.

Obesity, one of the most serious health problems of the 21st century, often occurs as a result of an imbalance between energy intake and energy expenditure. Dietary lipids play an important role in the development of obesity, partly because they represent the richest source of energy amongst all macronutrients. It is, however, not only the amount of consumed lipids, but also the composition of fatty acids, which strongly influences health effects of a particular diet. Saturated fatty acids (SFA) are generally considered as unhealthy due to their pro-inflammatory and lipotoxic properties, while monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) represent a healthier alternative, as they are more readily oxidized and do not disrupt biochemical properties of cellular membranes. Amongst PUFA, PUFA of n-3 series (Omega-3) represent an utterly unique class of lipids that have been documented to protect against cardiovascular disease and dyslipidemia in men and improve insulin sensitivity and glucose tolerance primarily in animal models of obesity. Some molecular mechanisms of Omega-3 action have been already uncovered, such as the modification of biological membranes composition, activation of various transcription factors and membrane receptors, and their role as precursors for...

Insulin resistance (IR) is considered to be an important factor influencing the progression of atherosclerosis and is associated with higher morbidity and mortality. IR is a common feature of diabetes mellitus Type 2 and obesity. Many authors consider IR being the crucial abnormality of the metabolic syndrome which is characterized by the essential hypertension, hyperliproteinemia, visceral obesity, endothel dysfunction and many other abnormalities. Impaired insulin action (IR) is also described in diabetes mellitus Type 1, however this phenomenon has not been fully explained. The subjects of dissertation thesis was directed on the IR importance in diabetic Type 1 patients as well as on the renin angiotensin system inhibition in patients with IR and metabolic syndrome with impaired glucose homeostasis. Hyperinsulinemic euglycemic clamp is used in combination with indirect calorimetry to estimate the IR in vivo in humans. In our project we focused on a) the existence of the metabolic inflexibility phenomenon in type 1 diabetic patients b) the methodological evaluation of the hyperinsulinemic euglycemic clamp procedure in the same group c) the influence of renin angiotensin system inhibition with angiotensin II type 1 receptor inhibitor telmisartan in patients with metabolic syndrome and impaired glucose...

Objectives To evaluate the effectiveness of pharmacist-physician collaboration in the treatment of type 2 diabetes mellitus (DM) with severe insulin resistance, using 500 U/mL concentrated regular insulin (U-500) in a primary care clinic that is not staffed by an endocrinologist. Methods A retrospective chart review was conducted searching for patients who were prescribed U-500 insulin from January 1, 2008 through December 31, 2014. Subjects were included in the analysis if the pharmacist initiated U-500 insulin therapy, received treatment for at least 6 months, and who attended at least one follow-up visit with the pharmacist. Anyone who received U-500 insulin before the initial pharmacist consultation, managed by an endocrinologist, or who was missing follow-up hemoglobin A1c (HbA1c) laboratory values during the follow-up period was excluded. The primary endpoint was the change in HbA1c from U-500 initiation to 6 months later. Secondary endpoints included changes in weight, confirmed hypoglycemia events, changes in other anti-DM medications and the number of pharmacist and primary care physician visits during the follow-up period. Results Eighty-one patients were identified and screened, and 44 patients were included in the analysis. Baseline HbA1c (mean ± standard deviation) was 9.7% ± 1.6% and decreased to 8.6% ± 1.6% after 6 months of follow-up, representing a reduction of 1.1% (95% confidence interval -1.6 to -0.6, P < 0.001). Body weight increased (mean ± standard deviation) by 6.7 ± 15.1 lb from baseline (P = 0.005). The frequency of confirmed hypoglycemia events was low (0.8 events per patient). Treatment with metformin was preserved, whereas most other DM medications were discontinued. A similar number of pharmacist and physician follow-up visits were completed by the end of the study period (2.0 and 2.7 visits, respectively; P = 0.805). Conclusions Initiation of U-500 insulin by clinical pharmacists collaborating with primary care physicians results in improved DM control in patients with severe insulin resistance. Our findings suggest this interprofessional partnership provides an alternative referral approach for primary care physicians when endocrinology services are absent or limited.

Impairments in insulin sensitivity can occur in patients with chronic kidney disease (CKD). Correction of metabolic acidosis has been associated with improved insulin sensitivity in CKD, suggesting that metabolic acidosis may directly promote insulin resistance. Despite this, the effect of acid or alkali loading on insulin sensitivity in a rodent model of CKD (remnant kidney) has not been directly investigated. Such studies could better define the relationship between blood pH and insulin sensitivity. We hypothesized that in remnant kidney rats, acid or alkali loading would promote loss of pH homeostasis and consequently decrease insulin sensitivity. To test this hypothesis, we determined the impact of alkali (2 wk) or acid (5-7 days) loading on plasma electrolytes, acid-base balance, and insulin sensitivity in either sham control rats, 2/3 nephrectomized rats, or 5/6 nephrectomized rats. Rats with 5/6 nephrectomy had the greatest response to insulin followed by rats with 2/3 nephrectomy and sham control rats. We found that treatment with 0.1 M sodium bicarbonate solution in drinking water had no effect on insulin sensitivity. Acid loading with 0.1 M ammonium chloride resulted in significant reductions in pH and plasma bicarbonate. However, acidosis did not significantly impair insulin sensitivity. Similar effects were observed in Zucker obese rats with 5/6 nephrectomy. The effect of renal mass reduction on insulin sensitivity could not be explained by reduced insulin clearance or increased plasma insulin levels. We found that renal mass reduction alone increases sensitivity to exogenous insulin in rats and that this is not acutely reversed by the development of acidosis.

Skeletal muscle insulin resistance is a major characteristic of obesity and type 2 diabetes. Although obesity-mediated inflammation is causally associated with insulin resistance, the underlying mechanism is unclear. Our lab and others have shown that a chronic low-grade inflammation takes place in skeletal muscles during diet-induced obesity, as evidenced by increased macrophage markers and pro-inflammatory cytokine levels. Interleukin (IL)-10 is a Th2-type cytokine that inhibits the synthesis and activity of pro-inflammatory cytokines and counteracts the Toll-like receptor-mediated inflammation. Our lab has previously demonstrated the preventive role of IL-10 against insulin resistance. Here, I have analyzed the effects of IL-10 on the skeletal muscle glucose metabolism and myogenesis in three different insulin resistant states (high fat diet-induced, leptin-deficiency-induced and aging-induced). The first model involved long-term (16 weeks) high-fat diet (HFD) feeding that resulted in markedly obese and hyperglycemic mice, representative of obese type 2 diabetic subjects. In mice overexpressing IL-10 specifically in the skeletal muscle (MIL10), we observed improved whole-body and skeletal muscle insulin sensitivity as compared to wild-types after long-term high fat diet feeding. The improved insulin sensitivity in the skeletal muscle was due to increased Akt signaling and decreased muscle inflammation. Leptin is an important adipocyte-derived hormone that is elevated in obesity, and it regulates numerous physiological functions including the energy balance and inflammation. Thus, my second model examined the effects of muscle-specific overexpression of IL-10 on glucose metabolism in the hyperphagic, leptin-deficient ob/ob mice. We detected improved whole-body insulin sensitivity compared to the control mice. My third model examined the effects of increased IL-10 expression using MIL10 mice during aging-induced insulin resistance. In 18-month old MIL10 mice, we found enhanced whole-body and skeletal muscle insulin sensitivity due to improved insulin signaling and decreased muscle inflammation as compared to wild-type mice. Last, to test whether direct signaling of IL-10 on skeletal muscle is responsible for the beneficial effects of IL-10 on muscle glucose metabolism, I generated mice lacking IL-10 receptor 1 type chain selectively in skeletal muscle (M-IL10R-/-). We observed more prominent muscle inflammation and whole-body insulin resistance in HFD-fed M-IL10R-/- mice as compared to wild-type mice. Interestingly, when studying insulin resistance in the IL-10 transgenic mouse models, we identified a consistent increased lean mass phenotype, and conversely decreased lean mass in the HFD-fed M-IL10R-/- mice. Quantitative RT-PCR on HFD-fed MIL10 group muscles to measure myogenesis-related gene expression identified a correlation between lean mass and both IL-10 and MyoD mRNA expression levels. In support of this, I showed that IL-10 caused an increase in in vitro cultured myoblast proliferation rates. Together, these results highlight the potential benefits of IL-10 expression not only in muscle glucose metabolism but also in maintaining muscle mass during insulin resistant states. Overall, these results demonstrate that selective expression of IL-10 in skeletal muscle suppresses inflammation, improves glucose metabolism and muscle growth in obese and aging mice, and further establishes that these effects are at least partially mediated by direct activation of IL-10 signaling in skeletal muscle.

Obesity has in recent times become a more serious health issue and was estimated to affect over 650 million people world-wide in 2016. Furthermore, the list of obesity-associated diseases is countless, many of which have severe consequences. Type 2 diabetes (T2D) is such a disease, and it was estimated to be over 1.5 million new cases in America alone in 2015. It is thought that insulin resistance development which causes T2D is associated with a low-level chronic inflammation in the adipose tissue. The inflammatory state is caused by the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) which is secreted by macrophages. To further understand the complexity of the underlying mechanisms of both the adipocytes as well as the macrophages, mathematical models are being developed in the fields of systems biology. However, as of now, no mathematical model has been developed which can explain the association between chronic inflammation and the development of insulin resistance. Because of this, a first model will be presented which is able to describe the mechanisms of insulin resistance development caused by chronic inflammation. The model was fitted to data from intraperitoneal glucose tolerance test in mice and yielded a cost below the threshold of chi-square test, which suggests that the model cannot be rejected. Furthermore, the model was expanded, introducing more complexity in the intracellular cascade reaction of an activated macrophage. Once again, the model was fitted to the same data and yielded a cost below the threshold of chi-square test. Uncertainty tests were made to further validate the models and showed a low uncertainty for both models. These results increase the understanding regarding the association between adipocytes and macrophages, in the role of insulin resistance caused by chronic inflammation. This increased knowledge can help, for instance, in the development of new drugs which are able to prevent the development of insulin resistance and T2D.

The prevalence of obesity, which is considered as a disease, has been increasing uncontrollably over the last two decades. Obesity is a state of disregulated energy homeostasis characterized by hypothalamic resistance to adiposity signals (insulin and leptin). While many factors are involved in the development of obesity, excess dietary fat has been proposed as one of the main causal factors. This causes disrupted energy homeostasis by inducing both leptin and insulin resistance in the central nervous system. Although brain tissue was considered to be insulin independent for a long time, insulin is now recognized to have important functions in the brain in the regulation of feeding behavior, energy expenditure and peripheral metabolism to maintain energy homeostasis. Recently, our lab discovered that insulin has an anorectic effect when it is applied into the central nucleus of the amygdala (CeA), a response that is similar to its effect when it is intracerebroventricularly (icv) administered into the hypothalamus. Our lab also demonstrated that rats fed a high fat diet lost the anorectic response to CeA insulin and became insulin resistant. These data suggested that insulin signaling in the amygdala had an important role in controlling food intake and energy expenditure in similar ways to the hypothalamus. It also suggests that a high fat diet inhibits amygdala insulin signaling in the CeA. Both in vitro cell culture and in vivo animal studies have been used to investigate the effects of dietary fats on insulin signaling in neuronal cells and in the amygdala. Using both hypothalamic GT1-7 cells and primary amygdala cells in culture, the saturated fatty acid palmitic acid was shown to inhibit insulin signaling (Akt phosphorylation). This response appears to be related to the activation of PKC-θ since the inhibitory effect of palmitic acid on Akt phosphorylation was greater in GT1-7 cells transfected with PKC-θ compared to wild type cells and was abolished in GT1-7 cells transfected with PKC-θ siRNA. Further investigations in vivo confirmed that insulin stimulated Akt and mTOR signaling in the CeA of rats and that the insulin stimulation of Akt phosphorylation, but not mTOR phosphorylation, was inhibited in rats fed a high fat diet for 3 days or by infusing palmitic acid into the CeA for 3 days. These experiments also identified that fatty acid and insulin signaling in the CeA differentially affected Akt and mTOR signaling in the hypothalamus and suggest that these neural connections might be important components of the neural pathways through which insulin in the amygdala affects food intake and peripheral metabolism. This research has provided novel insight into the effects of dietary fats on insulin signaling in an area of the brain, the CeA, that is now recognized to have effects on energy balance and peripheral metabolism.

Doctor Educationis / Diabetes has since been a global epidemic; an estimated 5.0 million deaths of diabetes in the world have been recorded; one in 11 adults have diabetes (415 million); and by 2040, one adult in 10 (642 million) will have diabetes. In Africa, more than two thirds of people with diabetes are undiagnosed, and 42 million have diabetes in the Sub-Saharan region with 324 877 adult deaths in South Africa (IDF, 2015). The global prevalence (age-standardized) of diabetes has nearly doubled since 1980, rising from 4.7% to 8.5% in the adult population. This reflects an increase associated with risk factors such as overweight or obese (WHO, 2016). Medicinal plants on the other hand, have played a significant role in the treatment and prevention of diabetes for centuries. In South Africa, indigenous medicinal plants have increasingly been used in the treatment of diabetes. In this study, a new anti-diabetes herbal compound named Jiang Tang 2016 (JT2016), made of three well researched South African indigenous medicinal plants is investigated for its hypoglycemic effects in HFD/STZ induced diabetic SD rats. These plants have been used for centuries in the indigenous system of medicine against various ailments, they are easily accessible, they grow in abundance, and are economically sustainable

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21253号 / 医博第4371号 / 新制||医||1029(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 横出 正之, 教授 浅野 雅秀, 教授 松本 智裕 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM