Development Of Hyperinsulinemia Research Articles

Relationships between nonalcoholic fatty liver disease and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) and non-alcoholic fatty liver disease (NAFLD) are two common non-infectious pathologies. Their frequency and medico-social significance have increased significantly over the past decades and reflect the effects of radical changes in human lifestyle on human health in a transgenerational aspect. Due to absence a complete understanding of the etiology and pathogenesis of PCOS and NAFLD, modern medicine still does not have etiopathogenetic methods of treating these frequent diseases. Considering epidemiological and pathogenetic data PCOS and NAFLD can be regarded as related pathologies, which creates the prospect of improving the effectiveness of their management if the joint approach to scientific research and implementation of their results in medical practice is applied.The purpose of the review is to summarize the current scientific data on the common pathophysiological and clinical relationships between PCOS and NAFLD, which can contribute to improving the effectiveness management of both diseases.Pathogenetic relationships between PCOS and NAFLD are bidirectional. According to current data, it seems possible to consider PCOS as a significant risk factor for the development of NAFLD in women of reproductive age both in the presence of excess weight and with normal body weight.As is known, that liver is involved in the clearance of androgens by the formation of sex steroid-binding globulin, as well as in the inactivation of insulin. Disruption of these metabolic processes due to liver pathology can lead to the development or strengthening of biochemical and clinical hyperandrogenism and the development of hyperinsulinemia and insulin resistance (IR).Conclusions. The presence of fatty liver and especially steatohepatitis deepens the hormonal disorders inherent in PCOS (primarily, an increase of free androgens, IR and ovulatory dysfunction), as well as potentiates and accelerates the development of cardiometabolic complications, including atherogenic dyslipidemia, dysglycemia, metabolic syndrome and cardiovascular complications. Early detection of NAFLD in women with PCOS, regardless of the presence of obesity, may improve the effectiveness of PCOS management and prevention of its cardiometabolic risks.

TNF-α Antagonizes the Effect of Leptin on Insulin Secretion through FOXO1-Dependent Transcriptional Suppression of LepRb in INS-1 Cells.

Proinflammatory cytokines play a causal role in the development of hyperinsulinemia and T2MD. FOXO1, a transcription factor which is known to enhance proinflammation, was recently shown to be involved in obesity-induced β cell dysfunction. However, molecular mechanisms for the association remained elusive. In this study, we first found that both leptin (10 nM) and TNF-α (20 ng/ml) significantly inhibited glucose-stimulated insulin secretion (GSIS) of INS-1E cells. When in combination, the GSIS function of INS-1E cells was significantly increased compared with that of the leptin alone treatment, indicating that TNF-α attenuated the inhibiting effect of leptin on GSIS of INS-1E cells. Similarly, we found that TNF-α has the same inhibitory effect on leptin in regulating insulin synthesis and secretion, and the survival and apoptosis of insulin cells. Further studies showed that TNF-α blocks leptin pathway by reducing the expression of leptin receptor (LepRb, also called OBRb) and inhibiting the activation of STAT3, a key molecule involved in the leptin signaling pathway in INS-1E cells. Besides, the downregulated expression of phosphorylated FOXO1 was found to be involved in the possible mechanism of TNF-α. Overexpression of constitutively active FOXO1 markedly aggravated the LepRb reduction by TNF-α treatment of INS-1E cells, and the endogenous FOXO1 knockdown abolished the effect of TNF-α on INS-1E cells. Furthermore, we have proved that FOXO1 could directly bind to the promoter of LepRb as a negative transcription regulator. Taken together, the results of this study reveal that TNF-α-induced LepRb downregulated in pancreatic β cells and demonstrate that transcriptional reduction of FOXO1 might be the primary mechanism underlying TNF-α promoting INS-1E leptin resistance and β cell dysfunction. Conclusions. Our current studies based on INS-1E cells in vitro indicate that the inflammatory factor TNF-α plays an important role in the development of INS-1E leptin resistance and glucose metabolism disorders, probably through FOXO1-induced transcription reduction of LepRb promoter in pancreatic β cells, and FOXO1 may be a novel target for treating β cell dysfunction in obesity-induced hyperinsulinemia and T2DM.

Risk Assessment and Determination of Factors That Cause the Development of Hyperinsulinemia in School-Age Adolescents

Background and Objectives: Hyperinsulinemia and insulin resistance are not synonymous; if the risk of developing insulin resistance in adolescents is monitored, they do not necessarily have hyperinsulinemia. It is considered a condition of pre-diabetes and represents a condition of increased risk of developing DM (diabetes mellitus); it can exist for many years without people having the appropriate symptoms. This study aims to determine the risk of developing hyperinsulinemia at an early age in adolescents by examining which factors are crucial for its occurrence. Materials and Methods: The cross-sectional study lasting from 2019 to 2021 (2 years) was realized at the school children’s department in the Valjevo Health Center, which included a total of 822 respondents (392 male and 430 female) children and adolescents aged 12 to 17. All respondents underwent a regular, systematic examination scheduled for school children. BMI is a criterion according to which respondents are divided into three groups. Results: After summary analyzes of OGTT test respondents and calculated values of HOMA-IR (homeostatic model assessment for insulin resistance), the study showed that a large percentage of respondents, a total of 12.7%, are at risk for hyperinsulinemia. The research described in this paper aimed to use the most popular AI (artificial intelligence) model, ANN (artificial neural network), to show that 13.1% of adolescents are at risk, i.e., the risk is higher by 0.4%, which was shown by statistical tests as a significant difference. Conclusions: It is estimated that a model using three different ANN architectures, based on Taguchi’s orthogonal vector plans, gives more precise and accurate results with much less error. In addition to monitoring changes in each individual’s risk, the risk assessment of the entire monitored group is updated without having to analyze all data.

CHARACTERISTICS OF METABOLIC PROCESSES IN THE FORMATION OF MENSTRUAL FUNCTION DISORDERS IN ADOLESCENT GIRLS WITH OBESITY

Іntroduction. Today, a quarter of the population of economically developed countries has a body weight that is 15% larger than the norm. According to various authors, the timely onset of menarche in women with various forms of obesity and reproductive dysfunction is observed in 31% of cases only.
 Obesity results in insulin resistance, which in its turn results in hyperinsulinemia. The main reason of the connection of insulin resistance with reproductive function disorders consists in the specific influence of insulin on ovaries. Insulin suppresses apoptosis, binding to receptors of various growth factors that promotes long existence of atresizing follicles. In the pathogenesis of the metabolic syndrome, along with the development of hyperinsulinemia and insulin resistance, a significant role belongs to the imbalance of adipocytokines, one of which is adiponectin.
 The aim is to analyze metabolic processes in the formation of menstrual dysfunction in adolescent girls with obesity to improve diagnostic methods of menstrual disorders.
 Material and methods. Clinical and laboratory examination of adolescent girls aged 12-18 years was held, among which 79 had obesity and complaints about menstrual dysfunction (the main group); 31 with normal body weight and regular menstrual cycle (the control group).
 Research methods: general clinical, biochemical (indicators of lipid and carbohydrate metabolism were determined), instrumental (ultrasound), statistical.
 Results. It was found that 53.3% of the girls from the main group had the beginning of the first menstruation after 14 years, delayed menstruation from 42 days to 6 days, duration 2.1 ± 0.05 days, which was significantly shorter, the volume of 10.2 ± 0.05; 0.4 points (average 1-2 pads per day) was significantly lower (p <0.05).
 Ultrasound showed uterine hypoplasia in almost every second girl in the main group - 36 (45.46%).
 Hyperleptinemia and leptin resistance was found in obesity of the first degree 34.8 ± 1.75, in obesity of the second degree 37.15 ± 2.12, in obesity of the third degree 40.64 ± 2.0. It was 14.35 ng / ml in the control group, p<0,01.
 Hyperleptinemia in the main group was accompanied by hyperinsulinemia in 26% of cases and insulin resistance. The relationship between low values of adiponectin and elevated body mass index in patients of the main group was established, which was confirmed by the results of correlation analysis (adiponectin & body mass index: ρ = -0.74).
 Analysis of the results revealed a decrease of A/L level in the main group by 4.3 times. Based on our own results, the A/L and HOMA-AD models can be considered more accurate for determining insulin resistance.
 Conclusions. 1. Changes of the menstrual cycle in overweight girls were found.
 
 The association of adipokines secretion disorders is characterized by hyperleptinemia, leptin resistance, decreased Adiponectin / Leptin index and hypoadiponectinemia, which, in combination with insulin resistance, indicates the participation of adipokines in the genesis of oligomenorrhea.
 The algorithm of adolescents’ treatment with menstrual dysfunction on the background of obesity must include the calculation of Adiponectin/Leptin and HOMA-AD, which will make it possible to avoid overdiagnosis of insulin resistance.

Impaired Insulin Clearance as the Initial Regulator of Obesity-Associated Hyperinsulinemia: Novel Insight Into the Underlying Mechanism Based on Serum Bile Acid Profiles.

To investigate the roles of insulin clearance and insulin secretion in the development of hyperinsulinemia in obese subjects and to reveal the association between insulin clearance and bile acids (BAs). In cohort 1, insulin secretion, sensitivity, and endogenous insulin clearance were evaluated with an oral glucose tolerance test in 460 recruited participants. In cohort 2, 81 participants underwent an intravenous glucose tolerance test and a hyperinsulinemic-euglycemic clamp to assess insulin secretion, endogenous and exogenous insulin clearance, and insulin sensitivity. Based on insulin resistance levels ranging from mild to severe, obese participants without diabetes were further divided into 10 quantiles in cohort 1 and into tertiles in cohort 2. Forty serum BAs were measured in cohort 2 to examine the association between BAs and insulin clearance. All obese participants had impaired insulin clearance, and it worsened with additional insulin resistance in obese subjects without diabetes. However, insulin secretion was unchanged from quantile 1 to 3 in cohort 1, and no difference was found in cohort 2. After adjustments for all confounding factors, serum-conjugated BAs, especially glycodeoxycholic acid (GDCA; β = -0.335, P = 0.004) and taurodeoxycholic acid (TDCA; β = -0.333, P = 0.003), were negatively correlated with insulin clearance. The ratio of unconjugated to conjugated BAs (β = 0.335, P = 0.002) was positively correlated with insulin clearance. Hyperinsulinemia in obese subjects might be primarily induced by decreased insulin clearance rather than increased insulin secretion. Changes in circulating conjugated BAs, especially GDCA and TDCA, might play an important role in regulating insulin clearance.

How Western Diet And Lifestyle Drive The Pandemic Of Obesity And Civilization Diseases.

Westernized populations are plagued by a plethora of chronic non-infectious degenerative diseases, termed as “civilization diseases”, like obesity, diabetes, cardiovascular diseases, cancer, autoimmune diseases, Alzheimer's disease and many more, diseases which are rare or virtually absent in hunter-gatherers and other non-westernized populations. There is a growing awareness that the cause of this amazing discrepancy lies in the profound changes in diet and lifestyle during recent human history. This paper shows that the transition from Paleolithic nutrition to Western diets, along with lack of corresponding genetic adaptations, cause significant distortions of the fine-tuned metabolism that has evolved over millions of years of human evolution in adaptation to Paleolithic diets. With the increasing spread of Western diet and lifestyle worldwide, overweight and civilization diseases are also rapidly increasing in developing countries. It is suggested that the diet-related key changes in the developmental process include an increased production of reactive oxygen species and oxidative stress, development of hyperinsulinemia and insulin resistance, low-grade inflammation and an abnormal activation of the sympathetic nervous system and the renin-angiotensin system, all of which play pivotal roles in the development of diseases of civilization. In addition, diet-related epigenetic changes and fetal programming play an important role. The suggested pathomechanism is also able to explain the well-known but not completely understood close relationship between obesity and the wide range of comorbidities, like type 2 diabetes mellitus, cardiovascular disease, etc., as diseases of the same etiopathology. Changing our lifestyle in accordance with our genetic makeup, including diet and physical activity, may help prevent or limit the development of these diseases.

Enhanced PDGF signaling in gestational diabetes mellitus is involved in pancreatic β-cell dysfunction

Gestational diabetes mellitus (GDM) is often accompanied by the development of hyperinsulinemia as an adaptation to increased insulin demand, but this subsequently causes insulin resistance. Loss of function in pancreatic β-cells further aggravates the development of GDM. The level of serum platelet-derived growth factor (PDGF) reportedly increases in GDM patients. The present study investigated whether enhanced PDGF signaling directly causes β-cell dysfunction during gestation. Serum PDGF levels were negatively correlated with β-cell function in GDM patients. Administration of PDGF-BB disrupted glucose tolerance and β-cell function without inducing apoptosis in gestational mice but had no similar effect in non-gestational mice. The β-cell-specific genes encoding insulin synthesis proteins were decreased in the islets of PDGF-BB-treated gestational mice. In vitro experiments using INS1 insulinoma cells showed that PDGF-BB promoted cell proliferation, whereas it downregulated β-cell-specific genes. Taken together, these findings suggested that PDGF reduces β-cell function during gestation possibly through β-cell dedifferentiation.

Adipokines and C-peptide in overweight and obese pregnant women.

The aim of the study was to evaluate the levels of adipokines such as adiponectin, resistin, leptin as well as C-peptide in overweight and obese pregnant women. The adipokines and C-peptide concentrations were measured in the group of 38 overweight/obese pregnant women (BMI > 25 kg/m2) and in 42 pregnant women of normal weight (BMI < 25 kg/m2) with ELISA tests between 24th and 34th weeks of gestation. The overweight/obese women compared to lean ones were characterized by significantly higher concentrations of leptin (43.44 ± 31.41 vs. 21.29 ± 12.67 ng/mL, p = 0.0001) and C-peptide (2.77 ± 1.88 vs. 2.25 ± 1.42 ng/mL, p = 0.034). There were no significant differences between groups in resistin (17.39 ± 7.59 vs. 15.76 ± 6.64 ng/mL, NS) and adiponectin (6.93 ± 3.52 vs. 8.07 ± 6.53 μg/mL, NS) levels. In the overweight/obese patients, no relationships between the adipokines, C-peptide and CRP concentrations were found. BMI was negatively correlated with the resistin levels (R = -0.406, p = 0.011). The significant correlation between leptin and C-peptide concentrations was observed in the study group (R = 0.517, p = 0.012). In the control group, the negative correlation between adiponectin concentrations and BMI was shown (R = -0.446, p = 0.003). The higher levels of leptin in the overweight and obese pregnant women seem to reflect the leptin resistance condition and the higher levels of C-peptide in this group is suggestive for hyperinsulinemia. The positive correlation between C-peptide and leptin levels but not with resistin and adiponectin might confirm the role of leptin in the hyperinsulinemia development in overweight and obesity during pregnancy.

Resolution of glucose intolerance in long-term high-fat, high-sucrose-fed mice.

The high-fat, high-sucrose diet (HFSD)-fed C57Bl/6 mouse is a widely used model of prediabetes. However, studies typically implement a relatively short dietary intervention lasting between 4 and 16 weeks; as a result, little is known about how a long-term HFSD influences the metabolic profile of these mice. Therefore, the aim of this investigation was to examine the effects of consuming a HFSD for 42 weeks on the development of hyperinsulinaemia and glucose intolerance in male C57Bl/6 mice. Two cohorts of HFSD mice were studied at independent institutes and they underwent an oral glucose tolerance test (OGTT) with measures of plasma insulin and free fatty acids (FFA). Age-matched chow-fed control mice were also studied. The HFSD-fed mice were hyperinsulinaemic and grossly obese, being over 25 g heavier than chow-fed mice, which was due to a marked expansion of subcutaneous adipose tissue. This was associated with a 3-fold increase in liver lipid content. Glucose tolerance, however, was either the same or better than control mice due to the preservation of glucose disposal as revealed by a dynamic stable isotope-labelled OGTT. In addition, plasma FFAs were suppressed to lower levels in HFSD mice during the OGTT. In conclusion, we have made the paradoxical observation that long-term HFSD feeding results in the resolution of glucose intolerance in the C57Bl/6 mouse. Mechanistically, we propose that the gross expansion of subcutaneous adipose tissue increases the glucose disposal capacity of the HFSD-fed mouse, which overcomes the prevailing insulin resistance to improve glucose tolerance.

Glucocorticoid receptor polymorphism in obesity and glucose homeostasis.

Glucocorticoid receptor (GR) activity plays a significant role in the etiology of obesity and is essential for glucose homeostasis, the development of hyperinsulinaemia and subsequent increased fat deposition. Several polymorphisms in the GR gene have been described, and at least three of them seem to be associated with altered glucocorticoid sensitivity and changes in glucose homeostasis, and other metabolic parameters. The N363S polymorphism has been associated with increased sensitivity to glucocorticoides, increased insulin response to dexamethasone and increased plasma glucose level. BclI polymorphism is associated with increased abdominal obesity, hyperinsulinaemia and increased insulin resistance. Another polymorphism, ER22/23EK, in contrast to the others, is associated with relative resistance to glucocoricides actions and more beneficial metabolic profile-lower insulin resistance level, decreased lower cardiovascular risk and subseuent prolongation of life time. More research is still needed to understand the mechanisms behind these associations at the molecular level.

Insulin Production and Resistance in Different Models of Diet-Induced Obesity and Metabolic Syndrome.

The role of the liver and the endocrine pancreas in development of hyperinsulinemia in different types of obesity remains unclear. Sedentary rats (160 g) were fed a low-fat-diet (LFD, chow 13% kcal fat), high-fat-diet (HFD, 35% fat), or HFD+ 30% ethanol+ 30% fructose (HF-EFr, 22% fat). Overnight-fasted rats were culled after one, four or eight weeks. Pancreatic and hepatic mRNAs were isolated for subsequent RT-PCR analysis. After eight weeks, body weights increased three-fold in the LFD group, 2.8-fold in the HFD group, and 2.4-fold in the HF-EFr (p < 0.01). HF-EFr-fed rats had the greatest liver weights and consumed less food during Weeks 4–8 (p < 0.05). Hepatic-triglyceride content increased progressively in all groups. At Week 8, HOMA-IR values, fasting serum glucose, C-peptide, and triglycerides levels were significantly increased in LFD-fed rats compared to that at earlier time points. The greatest plasma levels of glucose, triglycerides and leptin were observed in the HF-EFr at Week 8. Gene expression of pancreatic-insulin was significantly greater in the HFD and HF-EFr groups versus the LFD. Nevertheless, insulin: C-peptide ratios and HOMA-IR values were substantially higher in HF-EFr. Hepatic gene-expression of insulin-receptor-substrate-1/2 was downregulated in the HF-EFr. The expression of phospho-ERK-1/2 and inflammatory-mediators were greatest in the HF-EFr-fed rats. Chronic intake of both LFD and HFD induced obesity, MetS, and intrahepatic-fat accumulation. The hyperinsulinemia is the strongest in rats with the lowest body weights, but having the highest liver weights. This accompanies the strongest increase of pancreatic insulin production and the maximal decrease of hepatic insulin signaling, which is possibly secondary to hepatic fat deposition, inflammation and other factors.

Abstract P3-05-06: A nude mouse model of diet-induced-obesity to study the mechanisms of resistance to aromatase inhibitor letrozole in MCF-7Ca xenografts

Abstract Obesity has been identified as one of the risk factor for breast cancer progression. However the mechanisms underlying this link are not completely understood. Specifically, breast cancer patients who are overweight, obese or have excess abdominal fat have increased risk of local or distant (metastasis) recurrence and cancer related death. Furthermore, breast cancer patients gain weight during treatment, especially those who receive hormone depletion therapies, are at increased risk of developing obesity and metabolic syndrome as survivors. Importantly, the presence of obesity may influence the resistance of breast cancer to existing treatments, such as aromatase inhibitors (AIs). In an effort to understand the effect of obesity on the growth of hormone dependent breast cancer tumors, we fed ovariectomized athymic nude mice a diet containing 45% kcal fat (45% of the total calories coming from the fat in the diet) and low fat (10% kcal fat) diet. We also used a standard chow diet to compare with our previous results. We saw that mice fed 45%kcal fat diet had a higher rate of tumor growth (p=0.04) compared to mice that were fed 10% kcal fat containing diet or chow diet. In addition, the mice fed 45% kcal fat had higher body weight, fasting insulin (as measured by C-peptide ELISA) and high fasting glucose levels. Glucose tolerance test (IP-GTT) demonstrated that mice fed high fat diet exhibited reduced glucose tolerance as measured by high AUCglucose in high fat versus low fat or chow diet. There was no statistically significant difference between the chow diet and the low fat diet. Next, we examined the effect of insulin on the growth of MCF-7Ca cells in response to E2 or letrozole. When co-treated with 2μM of exogenous insulin (in otherwise serum starved condition), the growth of MCF-7Ca cells was not stimulated by E2 at 1nM. However, at lower does, the combination of insulin with E2 stimulated cell growth more than E2 alone. This suggests that insulin makes MCF-7Ca breast cancer cells hypersensitive to mitogenic effects of E2. Hypersensitivity to E2 is one of the suggested mechanisms of resistance to endocrine therapy. Furthermore, response to anti-proliferative effects of letrozole was also abrogated in presence of insulin (2μM). This was more pronounced at lower dose of letrozole. These results suggest that the presence of insulin makes MCF-7Ca cells less responsive to E2 and letrozole. Furthermore, tumors of mice fed with high-fat diet also had higher activation of MAPK and Akt, suggesting induction of growth factor receptor pathways. Exogenous insulin treatment of MCF-7Ca cells also resulted in reduction of ERα protein levels and increase in p-IR, p-IGFR and p-Akt. These results suggest that diet-induced obesity may result in acquisition of resistance to letrozole due to development of hyperinsulinemia. We hypothesized that the presence of obesity can augment adaptation of cancer cells and impact the mechanism. This may be the result of a dramatically different hormonal milieu upon development of obesity. Citation Format: Amanda Schech, Stephen Yu, Preeti Shah, Olga Goloubeva, Angela Brodie, Saranya Chumsri, Gauri Sabnis. A nude mouse model of diet-induced-obesity to study the mechanisms of resistance to aromatase inhibitor letrozole in MCF-7Ca xenografts [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-05-06.

Controversies of the assesment and management of polycystic ovary syndrome in adolescents

The diagnosis of polycystic ovary syndrome (PCOS) in adolescents is difficult as the pathological criteria used in adults like menstrual irregularities, acne, hirsutism and polycystic ovarian morphology could be normal physiological findings during puberty; in addition the syndrome is heterogeneous and there is limited high quality evidence. [1-3] Three international conferences have been held reporting different criteria for diagnosis of PCOS in women [Table ​[Table1].1]. [4-6] The 2011 Australian PCOS evidence-based guideline [1], the 2012 international evidence-based workshop [2] and the 2013 Endocrine Society Clinical Practice Guideline [3] highlight the issues of applying adult criteria to diagnose PCOS in adolescents. Table 1 Diagnostic criteria for PCOS in women All criteria require exclusion of other conditions: non-classic congenital adrenal hyperplasia, hypothyroidism, Cushing syndrome, hyperprolactinemia or androgen producing tumours which can cause a PCOS-like picture. Although diagnosis of PCOS is based on its reproductive manifestations, it is a metabolic disorder. PCOS adolescents are at a high risk of having or developing glucose tolerance abnormalities, dyslipidemia and hypertension. Insulin resistance and the consequent development of hyperinsulinaemia seem to be the central pathophysiological mechanism that links PCOS to its associated metabolic derangements; this can occur independent of weight status. Obesity, which is commonly associated with PCOS, exaggerates insulin abnormalities. Adolescents with PCOS should have evaluation of glucose homeostasis and insulin resistance at diagnosis. PCOS management should include a multidisciplinary team and should be individualized depending on the predominant complaint and weight status. Lifestyle modifications should be the first line treatment in the presence of overweight, obesity and/or insulin resistance. Metformin can also be added. Cyclical progesterone withdrawn bleed or cyclical oral contraceptive pills are used for menstrual irregularities. Antiandrogens like spironolactone and oral contraceptive pills are used for hirsutism. Permanent treatment with laser or electrolysis is usually advised after a course of antiandrogens. Various aspects of adolescent PCOS will be discussed based on illustrative cases.

Comparison of Glucose and Lipid Metabolism Abnormality during Nilotinib, Imatinib and Dasatinib Therapy – Results of Enigma 2 Study

Abstract Background: Recently we have published results of pilot study on CML patients demonstrating fast development of hyperinsulinaemia, peripheral insulin resistance, hypoadiponectinaemia and hypercholesterolemia during nilotinib therapy. Aims: To analyze results from follow up multicenter study “ENIGMA 2” with the aim to confirm or to exclude results from the pilot study, as well as to analyze whether these abnormalities are detected in control groups of patients treated with other TKIs - imatinib and dasatinib. Methods: Patients received intensive laboratory workup before the start of TKI and after 3 month of therapy. This included fasting insulin, glucose, adiponectin and lipid serum concentration, HbA1c and oral glucose tolerance test. Patients with TKI treatment interruption for &gt;2 weeks and/or dose reduction for &gt; 25% were excluded. Results: Between 2/2011-6/2014 in 5 centers 37 CML patients initiated therapy with nilotinib, 18 with imatinib and 8 with dasatinib. After 3 months patients treated with nilotinib developed significant hypersinulinaemia and hyperglycaemia as result of fast development of peripheral insulin resistance. This was proved by significant increase in HOMA-2 index during 3 months of nilotinib therapy (mean – 1.4 vs. 1.8; p = 0.0023). Moreover, we have proved significant decrease of adiponectin (major insulin sensitizer) concentration as well as significant increase in total and LDL cholesterol concentration after 3 month of nilotinib treatment. Details are presented in Table. Contrary – none of these abnormalities were detected in the control group of patients treated with imatinib and dasatinib, including any change in insulin resistance measured by HOMA-2 index (means – 0.9 vs. 1.3; p = 0.1046 and 1.1 vs. 1.1; p = 0.9255). Moreover, administration of imatinib (and probably also dasatinib, however only limited data are available at this moment) leads to increase of adiponectin concentration, which serves as major insulin sensitizer in peripheral tissues. Conclusions: Our study proved fast development of peripheral insulin resistance already during the first 3 months of nilotinib therapy as underlying cause of glucose and secondary also lipid metabolism impairment during this treatment. Moreover, this was not proved for patients treated with imatinib and dasatinb and significant increase in adiponectin concentration during imatinib (and probably dasatinib) therapy could at least partly explain observed amelioration of diabetes 2 during its administration described in some studies Supported by the CELL – the Czech Leukemia Study Group – for life Table. NILOTINIB THERAPY (n=37) Start Month 3 p mean (range) mean (range) Fasting glucose [mmol/l] 5.3 (4.5-6.7) 5.7 (4.6-8.2) &lt;0.0001 Fasting insulin [mU/l] 11.2 (2.4-28.3) 14,1 (2.5-32.7) 0.0037 Fasting C-peptide [pmol/ml] 0.73 (0.53-1.78) 0.76 (0.76-3.31) 0.4953 Fasting HbA1c [mmol/mol] 38.9 (24.0-55.0) 38.2 (25.0-57.0) 0.3900 Fasting adiponectin [mg/l] 16.6 (2.1-45.1) 8.6 (2.6-22.4) 0.0019* Total cholesterol [mmol/l] 4.8 (2.5-6.7) 5.9 (4.4-7.9) &lt;0.0001 LDL cholesterol [mmol/l] 2.8 (1.1-4.9) 3.6 (2.1-5.7) &lt;0.0001 IMATINIB THERAPY (n=18) Start Month 3 p mean (range) mean (range) Fasting glucose [mmol/l] 5.5 (4.4-7.7) 5.6 (4.2-6.4) 0.7567 Fasting insulin [mU/l] 6.7 (2.0-19.0) 9.8 (2.0-37.80) 0.1369 Fasting C-peptide [pmol/ml] 0.77 (0.25-1.55) 0.72 (0.27-1.78) 0.4569 Fasting HbA1c [mmol/mol] 44.8 (33.0-59.0) 41.1 (30.0-55.0) 0.005 Fasting adiponectin [mg/l] 10.8 (2.1-25.7) 26.1 (6.0-45.2) &lt;0.0001** Total cholesterol [mmol/l] 5.1 (3.3-7.1) 4,7 (2.6-7.1) 0.1123 LDL cholesterol [mmol/l] 3.1 (1.7-4.7) 2.7 (1.2-4.7) 0.064 DASATINIB THERAPY (n=8) Start Month 3 p mean (range) mean (range) Fasting glucose [mmol/l] 5.8 (4.6-6.8) 5.3 (3.3-6.7) 0.1764 Fasting insulin [mU/l] 8.1 (2.5-19.3) 8.4 (2.6-17.9) 0.8815 Fasting C-peptide [pmol/ml] 0.63 (0.16-1.11) 0.60 (0.24-1.03) 0.8223 Fasting HbA1c [mmol/mol] 38.8 (31.0-51.0) 37.8 (30.0-56.0) 0.684 Fasting adiponectin [mg/l] 17.3 (9.2-26.7) 12.9 (5.5-21.4) 0.0106*** Total cholesterol [mmol/l] 4.0 (3.0-5.0) 4.5 (3.6-5.8) 0.0831 LDL cholesterol [mmol/l] 2.2 (1.6-3.0) 2.5 (1.9-3.3) 0.1140 *number of paired measurements = 24 **number of paired measurements = 12 ***number of paired measurements = 3 Disclosures Zdenek: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Klamova:Novartis and Bristol Myers-Squibb: Consultancy, Honoraria. Mayer:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Abstract 621: Effect of diet-induced obesity on MCF-7Ca xenografts grown in ovariectomized athymic nude mice

Abstract Obesity has been identified as one of the risk factor for breast cancer progression. However the mechanisms underlying this link are not completely understood. Specifically, breast cancer patients who are overweight, obese or have excess abdominal fat have increased risk of local or distant (metastasis) recurrence and cancer related death. Furthermore, breast cancer patients gain weight during treatment, especially those who receive hormone depletion therapies, are at increased risk of developing obesity and metabolic syndrome in surviving patients. Importantly, the presence of obesity may influence the resistance of breast cancer to existing treatments, such as aromatase inhibitors (AIs). In an effort to understand the effect of obesity on the growth of hormone dependent breast cancer tumors, we fed ovariectomized athymic nude mice a diet containing 45% kcal fat (45% of the total calories coming from the fat in the diet) and low fat (10% kcal fat) diet. We saw that mice fed with 45%kcal fat diet had a higher rate of tumor growth (p=0.04) compared to mice that were fed with 10% kcal fat containing diet. In addition, the mice fed with 45% kcal fat had higher body weight and also higher level of insulin, as measured by C-peptide ELISA. Next, we examined the effect of insulin on the growth of MCF-7Ca cells in response to E2 or letrozole. When co-treated with 2μM of exogenous insulin (in otherwise serum starved condition), the growth of MCF-7Ca cells was not stimulated by E2 at 1nM. However, at lower does, the combination of insulin with E2 stimulated cell growth more than E2 alone. This suggests that insulin makes MCF-7Ca breast cancer cells hypersensitive to mitogenic effects of E2. Hypersensitivity to E2 is one of the suggested mechanisms of resistance to endocrine therapy. Furthermore, response to anti-proliferative effects of letrozole was also abrogated in presence of insulin (2μM). This was more pronounced at lower dose of letrozole. These results suggest that the presence of insulin makes MCF-7Ca cells less responsive to E2 and letrozole. Furthermore, tumors of mice fed with high-fat diet also had higher activation of MAPK and Akt, suggesting induction of growth factor receptor pathways. Exogenous insulin treatment of MCF-7Ca cells also resulted in reduction of ERα protein levels and increase in p-MAPK and p-AKt. These results suggest that diet-induced obesity may result in acquisition of resistance to letrozole due to development of hyperinsulinemia. We hypothesized that the presence of obesity can augment adaptation of cancer cells and impact the mechanism. This may be the result of a dramatically different hormonal milieu upon development of obesity. Citation Format: Gauri J. Sabnis, Olga Goloubeva, Preeti Shah, Saranya Chumsri, Angela Brodie. Effect of diet-induced obesity on MCF-7Ca xenografts grown in ovariectomized athymic nude mice. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 621. doi:10.1158/1538-7445.AM2014-621

The relation of leptin and soluble leptin receptor levels with metabolic and clinical parameters in obese and healthy children

We investigated the relation of serum leptin, soluble leptin receptor (sLR) and free leptin index (FLI) with metabolic and anthropometric parameters in obese and healthy children. Height, weight, waist circumference (WC), fasting serum glucose, insulin, lipid profile, leptin and sLR levels of 35 obese children and 36 healthy children were measured and FLI was calculated as the ratio of leptin to sLR. In obese children, serum leptin and FLI were found significantly higher, while sLR level was significantly lower than the healthy children. Comparison of obese children regarding the insulin resistance showed significantly higher serum leptin and FLI in the insulin resistant group; however sLR level was not different between the insulin resistant and non-resistant obese children. In obese children, sLR was not correlated with any of the metabolic parameters except total cholesterol, while FLI was significantly and positively correlated with BMI, WC, TC, fasting insulin, and HOMA-IR. However, regression analysis confirmed that the HOMA-IR was the only independent variable significantly correlated with FLI in obese children. Findings of this study suggest that in obese children and adolescents (i) serum leptin and FLI were found significantly higher, while sLR level was significantly lower than the healthy children, (ii) increased FLI might be a compensatory mechanism for increasing leptin effect in peripheral tissue, (iii) FLI is a more accurate marker to evaluate leptin resistance than leptin or sLR alone, and (iv) increased FLI may contribute toward the development of hyperinsulinemia and insulin resistance.

Malondialdehyde regulates glucose-stimulated insulin secretion in murine islets via TCF7L2-dependent Wnt signaling pathway

Evidence showed strong relations between malondialdehyde (MDA) levels and different pathological stages of diabetes. Here, an explicit system with freshly isolated islets and precisely controlled MDA gradient was employed to investigate the physiological effect of MDA on GSIS. Promoter analysis, pathway mapping, Q-PCR profiling, and siRNA verification were performed to clarify the intracellular signaling pathways. MDA at a moderately high level (5 and 10μM) promoted GSIS and accompanied with ATP/ADP ratio, cytosolic Ca2+ level, and key regulators (GK, GLUT2, PDX1, and UCP2) changes in islets. Both upstream (PI3K and p-AKT) and downstream (TCF7L2 and TCF7) factors of Wnt pathway showed greatest changes. Knockdown of TCF7L2 blocked the MDA-induced GSIS elevation. These results indicated that MDA acted as a signaling messenger and regulated islet GSIS mainly through Wnt pathway. Therefore, the elevated MDA level and up-regulated Wnt signaling pathway could be an etiological factor in the development of hyperinsulinemia and type 2 diabetes.

The role of acute hyperinsulinemia in the development of cardiac arrhythmias

Patients with perturbed metabolic control are more prone to develop cardiac rhythm disturbances. The main purpose of the present preclinical study was to investigate the possible role of euglycemic hyperinsulinemia in development of cardiac arrhythmias. Euglycemic hyperinsulinemia was induced in conscious rabbits equipped with a right ventricular pacemaker electrode catheter by hyperinsulinemic euglycemic glucose clamp (HEGC) applying two different rates of insulin infusion (5 and 10mIU/kg/min) and variable rate of glucose infusion to maintain euglycemia (5.5 ± 0.5mmol/l). The effect of hyperinsulinemia on cardiac electrophysiological parameters was continuously monitored by means of 12-lead surface ECG recording. Arrhythmia incidence was determined by means of programmed electrical stimulation (PES). The possible role of adrenergic activation was investigated by determination of plasma catecholamine levels and intravenous administration of a beta adrenergic blocking agent, metoprolol. All of the measurements were performed during the steady-state period of HEGC and subsequent to metoprolol administration. Both 5 and 10mIU/kg/min insulin infusion prolonged significantly QTend, QTc, and Tpeak-Tend intervals. The incidence of ventricular arrhythmias generated by PES was increased significantly by euglycemic hyperinsulinemia and exhibited linear relationship to plasma levels of insulin. No alteration on plasma catecholamine levels could be observed; however, metoprolol treatment restored the prolonged QTend, QTc, and Tpeak-Tend intervals and significantly reduced the hyperinsulinemia-induced increase of arrhythmia incidence. Euglycemic hyperinsulinemia can exert proarrhythmic effect presumably due to the enhancement of transmural dispersion of repolarization. Metoprolol treatment may be of benefit in hyperinsulinemia associated with increased incidence of cardiac arrhythmias.

Deletion of Skeletal Muscle SOCS3 Prevents Insulin Resistance in Obesity

Obesity is associated with chronic low-grade inflammation that contributes to defects in energy metabolism and insulin resistance. Suppressor of cytokine signaling (SOCS)-3 expression is increased in skeletal muscle of obese humans. SOCS3 inhibits leptin signaling in the hypothalamus and insulin signal transduction in adipose tissue and the liver. Skeletal muscle is an important tissue for controlling energy expenditure and whole-body insulin sensitivity; however, the physiological importance of SOCS3 in this tissue has not been examined. Therefore, we generated mice that had SOCS3 specifically deleted in skeletal muscle (SOCS MKO). The SOCS3 MKO mice had normal muscle development, body mass, adiposity, appetite, and energy expenditure compared with wild-type (WT) littermates. Despite similar degrees of obesity when fed a high-fat diet, SOCS3 MKO mice were protected against the development of hyperinsulinemia and insulin resistance because of enhanced skeletal muscle insulin receptor substrate 1 (IRS1) and Akt phosphorylation that resulted in increased skeletal muscle glucose uptake. These data indicate that skeletal muscle SOCS3 does not play a critical role in regulating muscle development or energy expenditure, but it is an important contributing factor for inhibiting insulin sensitivity in obesity. Therapies aimed at inhibiting SOCS3 in skeletal muscle may be effective in reversing obesity-related glucose intolerance and insulin resistance.

Abstract 18803: Myeloid Derived S100/calgranulins Promotes Visceral Obesity, Diabetes and Calcific Aortic Valve Disease in Transgenic Mice

Circulating serum levels of human S100/calgranulins have been associated with diabetes, coronary artery disease and increased cardiovascular mortality in clinical studies. To test whether S100/calgranulins are biomarker of inflammation or directly mediate disease, we generated a novel humanized mouse with transgenic expression of human S100/calgranulin by expression of a bacterial artificial chromosome of the human S100/calgranulin gene cluster containing genes and regulatory elements for S100A8/9 and S100A12 (60kb) in C57BL6 mice. F3 animals of the hBAC-S100 mice their wild type (WT) control littermate mice on regular rodent chow diet or on high fat diet (HFD) were studied. Results: hBac-100 mice express human S100A12 in circulating myeloid cells and S100A12 was present in the serum of hBAC-S100 mice (25 ng/ml serum), but was not detected in WT mice. Moreover, serum IL-6 was elevated in hBAC-S100 mice at age 3 and 12 month. hBAC-S100 mice developed increased visceral adiposity after 12 months on regular chow diet (25% vs 12% body fat upon DEXA scanning, p&lt;0.05), or after 3 months on HFD. White adipose tissue (WAT) of lean hBAC-S100 age 4 weeks showed increased expression of T- and B cell marker and no macrophage marker compared to WT, followed by increase in gene expression for F4/80, CD68 and MCP-1 in obese hBAC-S100. Importantly, impaired oral glucose tolerance and hyperinsulinemia preceded the onset of adiposity in hBAC-S100 mice. Metabolic cage studies indicate reduced oxygen consumption and CO2 production as one mechanism leading to adiposity. This phenotype was attenuated in hBAC-S100 mice lacking RAGE. Moreover, 12-months old hBAC-S100 mice develop calcification of the aortic valve leafleat with presence of osteoblast-like cells in the ascending aortic media upon staining with Alizarin Red S. In vivo ECHO showed abnormal mitral valve doppler flow with reduced ratio of early (E) to atrial (A) filling (E/A ratio 0.85 and 1.22, p=0.03) indicative of diastolic dysfunction. Conclusion: Circulating myeloid derived human S100/calgranulin is sufficient to induce a sustained inflammatory state and is associated with the development of hyperinsulinemia, impaired glucose tolerance, adiposity and aortic valve calcification.