Raloxifene Ameliorates Glucosamine-Induced Insulin Resistance in Ovariectomized Rats

Osteoarthritis (OA) and osteoporosis (OP) are common among older women, especially postmenopausal women. Glucosamine (GlcN) is a common medication for OA, but it may induce insulin resistance and β-cell dysfunction, especially if ovarian hormones are lacking. Raloxifene (RLX) is a selective estrogen receptor modulator and also an OP drug. Previously, we found that estrogen could improve GlcN-induced insulin resistance in ovariectomized (OVX) rats. Here, we further hypothesized that RLX, similarly to estrogen, can ameliorate GlcN-induced insulin resistance in OVX rats. We used GlcN to induce insulin resistance in OVX rats as a model for evaluating the protective effects of RLX in vivo. We used a pancreatic β-cell line, MIN-6, to study the mechanisms underlying the effect of RLX in GlcN-induced β-cell dysfunction in vitro. Increases in fasting plasma glucose, insulin, and homeostasis model assessments of insulin resistance in OVX Sprague Dawley rats treated with GlcN were reversed by RLX treatment (n = 8 in each group). Skeletal muscle GLUT-4 increased, liver PEPCK decreased, pancreatic islet hypertrophy, and β-cell apoptosis in OVX rats treated with GlcN was ameliorated by RLX. The negative effects of GlcN on insulin secretion and cell viability in MIN-6 cells were related to the upregulation of reticulum (ER) stress-associated proteins (C/EBP homologous protein, phospho-extracellular signal-regulated kinase, phospho-c-JunN-terminal kinase), the expression of which was reduced by RLX. Pretreatment with estrogen receptor antagonists reversed the protective effects of RLX. GlcN can induce insulin resistance, β-cell dysfunction, and apoptosis in OVX rats and increase ER stress-related proteins in β-cells, whereas RLX can reverse these adverse effects. The effects of RLX act mainly through estrogen receptor α; therefore, RLX may be a candidate drug for postmenopausal women with OA and OP.

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Visceral Adiposity Index is associated with Insulin Resistance, impaired Insulin Secretion, and β-cell dysfunction in subjects at risk for Type 2 Diabetes

Diabetes Epidemiology and Management ◽

10.1016/j.deman.2021.100013 ◽

2021 ◽

pp. 100013

Author(s):

Froylan David Martínez-Sánchez ◽

Valerie Paola Vargas-Abonce ◽

Andrea Rocha-Haro ◽

Romina Flores-Cardenas ◽

Milagros Fernández-Barrio ◽

...

Keyword(s):

Insulin Resistance ◽

Type 2 Diabetes ◽

At Risk ◽

Insulin Secretion ◽

Visceral Adiposity ◽

Visceral Adiposity Index ◽

Β Cell ◽

Cell Dysfunction ◽

Impaired Insulin

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5-Bromoprotocatechualdehyde Combats against Palmitate Toxicity by Inhibiting Parkin Degradation and Reducing ROS-Induced Mitochondrial Damage in Pancreatic β-Cells

Antioxidants ◽

10.3390/antiox10020264 ◽

2021 ◽

Vol 10 (2) ◽

pp. 264

Author(s):

Seon-Heui Cha ◽

Chunying Zhang ◽

Soo-Jin Heo ◽

Hee-Sook Jun

Keyword(s):

Cell Loss ◽

Cellular Damage ◽

Mitochondrial Morphology ◽

Protective Effects ◽

Β Cells ◽

Β Cell ◽

Zebrafish Model ◽

Cell Dysfunction ◽

Glucose Stimulated Insulin Secretion

Pancreatic β-cell loss is critical in diabetes pathogenesis. Up to now, no effective treatment has become available for β-cell loss. A polyphenol recently isolated from Polysiphonia japonica, 5-Bromoprotocatechualdehyde (BPCA), is considered as a potential compound for the protection of β-cells. In this study, we examined palmitate (PA)-induced lipotoxicity in Ins-1 cells to test the protective effects of BPCA on insulin-secreting β-cells. Our results demonstrated that BPCA can protect β-cells from PA-induced lipotoxicity by reducing cellular damage, preventing reactive oxygen species (ROS) overproduction, and enhancing glucose-stimulated insulin secretion (GSIS). BPCA also improved mitochondrial morphology by preserving parkin protein expression. Moreover, BPCA exhibited a protective effect against PA-induced β-cell dysfunction in vivo in a zebrafish model. Our results provide strong evidence that BPCA could be a potential therapeutic agent for the management of diabetes.

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The association of insulinemic potential of diet and lifestyle with the risk of insulin-related disorders: a prospective cohort study among participants of Tehran Lipid and Glucose Study

Diabetology & Metabolic Syndrome ◽

10.1186/s13098-021-00674-z ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Ebrahim Mokhtari ◽

Hossein Farhadnejad ◽

Farshad Teymoori ◽

Parvin Mirmiran ◽

Fereidoun Azizi

Keyword(s):

Insulin Resistance ◽

Dietary Intakes ◽

Β Cells ◽

Β Cell ◽

Food Frequency ◽

Cell Dysfunction ◽

The Mean ◽

Diet And Lifestyle ◽

Activity Information ◽

Insulin Insensitivity

Abstract Background We aim to assess the association of empirical dietary (EDIH) and lifestyle (ELIH) index for hyperinsulinemia with the risk of insulin resistance, hyperinsulinemia, insulin sensitivity, and β-cell dysfunction in Iranian adults. Methods In this prospective study, a total of 1244 men and women aged ≥ 20 years were selected among participants of the Tehran lipid and glucose study and followed for 3.2 years. Dietary intakes were assessed using a valid semi-quantitative food frequency questionnaire. Dietary and lifestyle insulinemic potential indices were calculated using dietary intake, body mass index, and physical activity information. Multivariable logistic regression was used to estimate the associated risk of a 3-year incidence of insulin-related disorders. Results The mean ± SD age and BMI of all eligible participants (42.7% males) were 43.0 ± 13.0 and 27.4 ± 4.9 in the study's baseline. After adjusting for all potential confounders, participants in the highest tertile of ELIH score had a greater risk of developing hyperinsulinemia (OR:2.42, 95%CI:1.52–3.86, P for trend = < 0.001), insulin resistance (OR:2.71, 95%CI:1.75–4.18, P for trend = < 0.001) and insulin insensitivity (OR:2.65, 95%CI: 1.72–4.10, P for trend = < 0.001) compared with those in the lowest tertile. However, the risk of incident β-cell dysfunction was lower in individuals with a higher score of ELIH in comparison to those with the lowest score (OR:0.30, 95%CI:0.19–0.45, P for trend = < 0.001). Conclusions Empirical lifestyle index for hyperinsulinemia was directly associated with insulin resistance, insulin insensitivity, and hyperinsulinemia and was inversely associated with β-cells dysfunction.

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Association of hearing impairment with insulin resistance, β-cell dysfunction and impaired fasting glucose before onset of diabetes

Diabetic Medicine ◽

10.1111/dme.13096 ◽

2016 ◽

Vol 33 (9) ◽

pp. 1275-1282 ◽

Cited By ~ 2

Author(s):

M. Seo ◽

Y.-S. Lee ◽

S.-S. Moon

Keyword(s):

Insulin Resistance ◽

Hearing Impairment ◽

Impaired Fasting Glucose ◽

Fasting Glucose ◽

Β Cell ◽

Cell Dysfunction ◽

Onset Of Diabetes

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The role of vitamin D in the development of type 2 diabetes

Voprosy detskoj dietologii ◽

10.20953/1727-5784-2021-1-44-52 ◽

2021 ◽

Vol 19 (1) ◽

pp. 44-52

Author(s):

A.P. Shumilov ◽

◽

M.Yu. Semchenkova ◽

D.S. Mikhalik ◽

T.G. Avdeeva ◽

...

Keyword(s):

Insulin Resistance ◽

Type 2 Diabetes ◽

Vitamin D ◽

Inverse Relationship ◽

Biological Mechanisms ◽

Β Cell ◽

Cell Dysfunction ◽

Vitamin D Levels

Vitamin D plays an important role in decreasing the risk of developing type 2 diabetes by influencing calcium metabolism, thereby reducing β-cell dysfunction and preventing insulin resistance. The findings of research works are contradictory enough, although some of them demonstrated an inverse relationship between vitamin D levels and the incidence of type 2 diabetes. The article describes the biological mechanisms of relationships between vitamin D levels and type 2 diabetes, reviews the results of the studies conducted and summarizes the available data. Key words: vitamin D, type 2 diabetes mellitus, insulin resistance

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Ameliorative effect of low-dose spironolactone on obesity and insulin resistance is through replenishment of estrogen in ovariectomized rats

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2018-0416 ◽

2019 ◽

Vol 97 (1) ◽

pp. 65-74 ◽

Cited By ~ 1

Author(s):

Lawrence A. Olatunji ◽

Oluwaseun A. Adeyanju ◽

Olugbenga S. Michael ◽

Taofeek O. Usman ◽

Rita C. Tostes ◽

...

Keyword(s):

Insulin Resistance ◽

Low Dose ◽

Glycogen Synthase ◽

Mass Gain ◽

Ovariectomized Rats ◽

Atherogenic Dyslipidemia ◽

Beneficial Effects ◽

Ovx Rats ◽

Ameliorative Effect ◽

Hormonal Therapies

Women have a lower incidence of cardiovascular diseases (CVD) than men at a similar age but the reverse is the case after menopause, indicating a possible protective effect of estrogen on cardiometabolic function. Although various hormonal therapies have been formulated to combat the CVD risks in postmenopausal state, the beneficial effects have not been consistent. Obesity with insulin resistance (IR) is closely linked to CVD risks while ovariectomized rodents have been shown to mimic a state of obesity and IR. We therefore hypothesized that low-dose spironolactone would ameliorate obesity and IR in estrogen-deprived rats by replenishing estrogen and suppressing elevated glycogen synthase kinase-3 (GSK-3). Ten-week-old female Wistar rats were divided into 4 groups: sham-operated (SHM), spironolactone (SPL; 0.25 mg/kg), and ovariectomized (OVX) rats treated with or without spironolactone daily for 8 weeks. Results showed that estrogen deprivation through ovariectomy caused increased body mass gain and visceral adiposity that are accompanied by increased HOMA-IR, HOMA-β, 1-hour postload glucose, glucose intolerance, platelet/lymphocyte ratio, plasma insulin, atherogenic dyslipidemia, uric acid, GSK-3, corticosterone, and aldosterone and depressed 17β-estradiol. However, treatment of OVX rats with spironolactone ameliorated all these effects. Taken together, the results demonstrate that treatment with low-dose spironolactone improves obesity and IR, which appears to involve replenishment of estrogen and suppression of GSK-3 along with circulating mineralocorticoid and glucocorticoid. The findings imply a positive cardiometabolic effect of low-dose spironolactone usage in estrogen-deprived conditions.

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Analysis of compensatory β-cell response in mice with combined mutations of Insr and Irs2

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00430.2006 ◽

2007 ◽

Vol 292 (6) ◽

pp. E1694-E1701 ◽

Cited By ~ 17

Author(s):

Jane J. Kim ◽

Yoshiaki Kido ◽

Philipp E. Scherer ◽

Morris F. White ◽

Domenico Accili

Keyword(s):

Insulin Resistance ◽

Type 2 Diabetes ◽

Insulin Secretion ◽

Cell Response ◽

Cell Mass ◽

Comprehensive Treatment ◽

Β Cell ◽

Cell Dysfunction ◽

Impaired Insulin

Type 2 diabetes results from impaired insulin action and β-cell dysfunction. There are at least two components to β-cell dysfunction: impaired insulin secretion and decreased β-cell mass. To analyze how these two variables contribute to the progressive deterioration of metabolic control seen in diabetes, we asked whether mice with impaired β-cell growth due to Irs2 ablation would be able to mount a compensatory response in the background of insulin resistance caused by Insr haploinsufficiency. As previously reported, ∼70% of mice with combined Insr and Irs2 mutations developed diabetes as a consequence of markedly decreased β-cell mass. In the initial phases of the disease, we observed a robust increase in circulating insulin levels, even as β-cell mass gradually declined, indicating that replication-defective β-cells compensate for insulin resistance by increasing insulin secretion. These data provide further evidence for a heterogeneous β-cell response to insulin resistance, in which compensation can be temporarily achieved by increasing function when mass is limited. The eventual failure of compensatory insulin secretion suggests that a comprehensive treatment of β-cell dysfunction in type 2 diabetes should positively affect both aspects of β-cell physiology.

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