Effect Of Insulin Research Articles

Neuroprotective Effect of Insulin on Rat Cortical Neurons in Oxidative Stress Is Mediated by Autophagy and Apoptosis Inhibition in vitro

Neuroprotective Effect of Insulin on Rat Cortical Neurons in Oxidative Stress Is Mediated by Autophagy and Apoptosis Inhibition in vitro

Abstract P133: NaCl And Insulin Regulate Urate Transporter 1 Via Phosphorylation

Objective: Hyperuricemia frequently associates with hypertension and diabetes. Previously, we demonstrated that insulin positively regulates urate transporter 1 (URAT1) in renal proximal tubules; yet the detailed mechanisms remain unclear. We here investigated the role of phosphorylation as a potential mechanism regulating URAT1. Methods: We screened potential phosphorylation sites in HEK cells expressing human URAT1 using phospho-Akt substrate motif antibody. Identified sites were confirmed by in vitro kinase assay and the creation of site-specific phosphorylation antibodies. Functional significance of identified sites was evaluated by cell surface biotinylated assay and Western blotting. As upstream signals, we tested the effects of insulin and NaCl in HEK cells expressing URAT1. Results: Western blot using phospho-Akt substrate motif antibody indicated that URAT1 was phosphorylated in HEK cells. Motif search identified two potential phosphorylation sites, T350 and T408 located at the intracellular regions. In ADP-glo assay, phosphorylation of URAT1 by Akt was significantly reduced when both sites were mutated to non-phosphorylatable Ala (T350A/T408A). T408A but not T350A showed decreased N-glycosylation in Western blotting. Biotinylated Western blotting confirmed that the cell-surface expression was significantly reduced in T408A-URAT1, indicating that T408 phosphorylation regulates URAT1 trafficking. Phosphorylation of T408 was confirmed by creating phospho-specific antibodies against this site. As an upstream signaling, insulin increased URAT1 at the cell surface in HEK cells, an effect that was not observed in T408A-URAT1. In kinase screen, we found that Sgk1, PKA, and PKG also phosphorylate URAT1-T408 besides Akt. NaCl increased Sgk1 and T408 phosphorylation, which resulted in increased cell surface URAT1 levels in HEK cells. In contrast, NaCl did not alter cell surface URAT1 levels in HEK cells expressing T408A-URAT1. Conclusion: These data indicate that insulin and NaCl promote membrane trafficking of URAT1 through T408 phosphorylation via Akt and SGK1, respectively. This mechanism could contribute to the co-occurrence of hyperuricemia in patients with hypertension and diabetes.

Evaluation of serum adiponectin and lipid profile in patients with acne vulgaris

Background Acne vulgaris is a chronic inflammatory disease of the pilosebaceous unit and is among the most common dermatological conditions worldwide. Adipokines are bioactive molecules secreted by adipocytes. Adiponectin is the most abundant adipokine. It has multiple properties, which includes sensitization of insulin, anti-inflammatory, and antiatherogenic effect. Objectives This study aims to evaluate serum adiponectin and lipid profile levels in patients with acne vulgaris and their correlation with each other and disease severity. Patients and methods This is a case-control study, conducted on a total of 90 patients with acne vulgaris and matched age, sex, and body mass index 70 healthy controls. Serum adiponectin and lipid profile levels were evaluated in all subjects. Results Total cholesterol (TC), total triglycrides (TG) and low density lipoprotein (LDL) were significantly higher in acne vulgaris cases, while high density lipoprotein (HDL) was statistically significant lower in cases compared to controls. Adiponectin concentration was significantly higher in acne vulgaris cases when compared to control group with positive correlations with female gender, disease severity, TC, LDL and significant negative correlation with HDL. Conclusions Adiponectin may play a role in the pathogenesis of acne vulgaris and may affect its severity. Evaluation of all acne patients for lipid profile and advice for healthy diets as an adjuvant method to acne treatment.

Glucose metabolism, hippocampal subfields and cognition in first-episode and never-treated schizophrenia

BackgroundPrevious studies have indicated that glucose metabolism and altered hippocampal structure and function play a pivotal role in cognitive deficits in schizophrenia (SZ). This study was designed to explore the inter-relationship between glucose metabolism, hippocampal subfield volume, and cognitive function in the antipsychotics-naive first episode (ANFE) SZ patients. MethodsWe chose the fasting insulin, glucose, and insulin resistance (HOMA-IR) index as biomarkers of glucose metabolism. Cognitive function was assessed by the MATRICS Consensus Cognitive Battery (MCCB). The hippocampal subfield volume, glucose metabolism biomarkers, and cognitive function were evaluated in 43 ANFE SZ and 29 healthy controls (HCs). ResultsCompared with HCs, SZ patients had higher fasting blood glucose and insulin levels and HOMA-IR (all p < 0.05). Correlation analysis revealed that category fluency performance was positively associated with fasting glucose level. Fasting insulin or HOMA-IR was positively associated with the hippocampal subfield volume in patients (all p<0.05). Moreover, the spatial span index score was associated with the volume of the right presubiculum, subiculum, and right hippocampal tail. In addition, multiple regression analysis found that the interaction effects of insulin × right fimbria or insulin × left fimbria were independent predictors of the MCCB total score. ConclusionsOur findings suggest that abnormal glucose metabolism and cognitive decline occur in the early stage of SZ. The interaction between abnormal glucose metabolism and hippocampal subfields was associated with cognitive functions in SZ.

Comparison between the Effects of Ultrasound Guided Local Insulin Injections versus Hydrodissection of Normal Saline in Carpal Tunnel Syndrome Patients with Diabetes Mellitus

Background Hydrodissection is a minimally invasive procedure of injecting fluid into anatomic spaces to facilitate dissection and adhesiolysis in peripheral nerve entrapments. The near-nerve local insulin injection is thought to promote neuronal growth and regeneration, and could be important in restoring nerve function following metabolic or vascular damage. Aim of the Work to compare the short-term effects of insulin and normal saline local injections in the treatment of patients with diabetes mellitus who have mild-to-moderate carpal tunnel syndrome. Patients and Methods A comparative study was conducted on 30 carpal tunnel syndrome patients with diabetes mellitus during recruited from Ain Shams University Hospital, Neurosonology, neurology department during the period January 2020 to March 2021 according to the regulation of Ain Shams University ethical and scientific committee. The privacy of participants and confidentiality of the data were guaranteed during various phases of the study. Results the Hydrodissection (10 ml of normal saline) of the median nerve is significantly effective in the treatment of mild to moderate carpal tunnel syndrome in patients with diabetes mellitus and alleviates the symptoms of CTS. Also the study showed that the local insulin injection (10 IU of NPH) alone is significantly effective in the management of mild to moderate carpal tunnel syndrome of diabetic patients, which shows significant response within two weeks of follow up. The study shows that Hydrodissection is slightly superior to insulin for treatment of CTS. Furthermore our current study compares the failure rate of both treatment modalities which implies that Hydrodissection group are less failure rate than insulin group, but this difference is insignificant due small sample size of both groups. Conclusion Hydrodissection and local insulin injection are effective methods in the management of mild to moderate Carpal Tunnel Syndrome of diabetic patients with superiority of ultrasound guided hydrodissection to Insulin. It is noteworthy this study is considered a pioneer in comparing HD and Insulin in managing CTS.

Comparison between Serum Vaspin in Chronic Kidney Disease and with Hepatitis C Virus and Normal Control Group

Abstract Background Chronic kidney disease ―CKD|| patients have insulin secretion disorders and resistance to insulin effects, that is responsible for the development of cardiovascular proceedings. Vaspin is an adipcytokine that regulates glucose and lipid metabolism. Aim and objectives To compare serum level of Vaspin in Chronic kidney disease&amp; chronic hepatitis C patients group and normal control group. Subjects and Methods This study is comparative case - control study, was conducted at in Ain shams university hospitals &amp; El Zaitoun Specialized hospital on patients attending gastroenterology and hepatology clinic and nephrology clinic0. Result There was high statistically significant difference between the studied groups as regard vaspin. Conclusion Diabetic nephropathy‖ patients presented a significant increased levels of serum Vaspin when compared to levels to control, serum Vaspin are protective roles. Also, vaspin could be used as specific predictors for liver fibrosis in CHC patients with and without diabetes.

Myo-inositol alters the effects of glucose, leptin and insulin on placental palmitic acid and oleic acid metabolism.

Well-regulated placental palmitic acid (PA) and oleic acid (OA) metabolism is vital for optimal placental function and fetal development, but dysregulation occurs with gestational diabetes (GDM). We hypothesized that such dysregulation might arise from increased maternofetal glucose, leptin or insulin concentrations present in GDM, and that dysregulated PA and OA lipid metabolism could be moderated by myo-inositol, a natural polyol and potential GDM intervention. Placental explants from 21 women were incubated with stable isotope-labelled 13 C-PA or 13 C-OA for 48h. Explants were treated with glucose (5, 10mm) or leptin (13nm) or insulin (150nm) in combination with myo-inositol (0.3, 30, 60μm). Forty-seven 13 C-PA lipids and 37 13 C-OA lipids were measured by liquid chromatography-mass spectrometry (LCMS). Compared with controls (5mm glucose), glucose (10mm) increased 19 13 C-OA lipids and nine 13 C-PA lipids, but decreased 13 C-OA phosphatidylethanolamine 38:5 and 13 C-PA phosphatidylethanolamine 36:4. The effects of leptin and insulin were less prominent than glucose, with leptin increasing 13 C-OA acylcarnitine 18:1, and insulin increasing four 13 C-PA triacylglycerides. Most glucose, leptin and insulin-induced alterations in lipids were attenuated by co-incubation with myo-inositol (30 or 60μm), with attenuation also occurring in all subgroups stratified by GDM status and fetal sex. However, glucose-induced increases in acylcarnitine were not attenuated by myo-inositol and were even exaggerated in some instances. Myo-inositol therefore appears to generally act as a moderator, suppressing the perturbation of lipid metabolic processes by glucose, leptin and insulin in placenta in vitro. Whether myo-inositol protects the fetus and pregnancy from unfavourable outcomes requires further research. KEY POINTS: Incubation of placental explants with additional glucose, or to a lesser extent insulin or leptin, alters the placental production of 13 C-lipids from 13 C-palmitic acid (PA) and 13 C-oleic acid (OA) in vitro compared with untreated controls from the same placenta. Co-incubation with myo-inositol attenuated most alterations induced by glucose, insulin or leptin in 13 C-lipids, but did not affect alterations in 13 C-acylcarnitines. Alterations induced by glucose and leptin in 13 C-PA triacylglycerides and 13 C-PA phospholipids were influenced by fetal sex and gestational diabetes status, but were all still attenuated by myo-inositol co-incubation. Insulin differently affected 13 C-PA triacylglycerides and 13 C-PA phospholipids depending on fetal sex, with alterations also attenuated by myo-inositol co-incubation.

Circulating Concentrations of Cathelicidin Anti-Microbial Peptide (CAMP) Are Increased during Oral Glucose Tolerance Test.

Recent investigation has revealed the significant role of Cathelicidin antimicrobial peptide (CAMP) in infection defense and innate immunity processes in adipose tissue. Meanwhile, knowledge of its regulation and functions in metabolic contexts as an adipokine remains sparce. The present study investigated the postprandial regulation of circulating CAMP levels during oral glucose tolerance tests (OGTTs). Eighty-six metabolically healthy volunteers participated in a standardized 75 g-2 h-OGTT setting. The effects of exogenous glucose, insulin, and incretins on CAMP expression in human adipocyte culture (cell-line SGBS) were studied in vitro. CAMP concentrations in blood serum samples were measured by ELISA techniques and adipocyte gene expression levels were quantified by real-time PCR. Of note, base-line CAMP serum quantities were negatively correlated with HDL cholesterol levels as well as with the anti-inflammatory adipokine adiponectin. During the 2 h following glucose ingestion, a significant rise in circulating CAMP concentrations was observed in considerable contrast to reduced quantities of fatty acid binding proteins (FABP) 2 and 4 and dipeptidyl peptidase 4 (DPP4). In SGBS adipocytes, neither differing glucose levels nor insulin or incretin treatment significantly induced CAMP mRNA levels. According to our data, glucose represents a positive postprandial regulator of systemic CAMP. This effect apparently is not mediated by the regulatory impact of glucose metabolism on adipocyte CAMP expression.

Analysis of Cell Glycogen with Quantitation and Determination of Branching Using Liquid Chromatography-Mass Spectrometry.

Glycogen is a highly branched biomacromolecule that functions as a glucose buffer. It is involved in multiple diseases such as glycogen storage disorders, diabetes, and even liver cancer, where the imbalance between biosynthetic and catabolic enzymes results in structural alterations and abnormal accumulation of glycogen that can be toxic to cells. Accurate and sensitive glycogen quantification and structural determination are prerequisites for understanding the phenotypes and biological functions of glycogen under these conditions. In this research, we furthered cell glycogen characterization by presenting a highly sensitive method to measure the glycogen content and degree of branching. The method employed a novel fructose density gradient as an alternative to the traditional sucrose gradient to fractionate glycogen from cell mixtures using ultracentrifugation. Fructose was used to avoid the large glucose background, allowing the method to be highly quantitative. The glycogen content was determined by quantifying 1-phenyl-3-methyl-5-pyrazolone (PMP)-derivatized glucose residues obtained from acid-hydrolyzed glycogen using ultra-high-performance liquid chromatography/triple quadrupole mass spectrometry (UHPLC/QqQ-MS). The degree of branching was determined through linkage analysis where the glycogen underwent permethylation, hydrolysis, PMP derivatization, and UHPLC/QqQ-MS analysis. The new approach was used to study the effect of insulin on the glycogen phenotypes of human hepatocellular carcinoma (Hep G2) cells. We observed that cells produced greater amounts of glycogen with less branching under increasing insulin levels before reaching the cell's insulin-resistant state, where the trend reversed and the cells produced less but higher-branched glycogen. The advantage of this method lies in its high sensitivity in characterizing both the glycogen level and the structure of biological samples.

A Review on Diabetes Mellitus its Types, Pathophysiology, Epidermiology and its Global Burden

The spread of obesity and unhealthy lifestyles has contributed to a significant and increasing disease burden associated with diabetes in all countries worldwide. According to recent estimates, the worldwide prevalence of diabetes in 2013 was recorded at 382 million individuals, with projections indicating a significant increase to 592 million by the year 2035. The categorization of diabetes based on its aetiology has gained widespread acceptance in the scientific community. There are two primary classifications of diabetes, namely type 1 and type 2. Type 2 diabetes is the predominant kind, constituting a majority proportion (&gt;85%) of the overall prevalence of diabetes. Both types of diabetes have the potential to result in a range of problems affecting several bodily systems. These complications can manifest as microvascular endpoints such as retinopathy, nephropathy, and neuropathy, as well as macrovascular endpoints including ischemic heart disease, stroke, and peripheral vascular disease. Diabetes is a significant public health concern because to its association with premature morbidity, death, diminished life expectancy, and substantial financial and societal burdens. Diabetes mellitus is a chronic metabolic illness characterised by heterogeneity and a complex pathophysiology. The condition is distinguished by increased amounts of glucose in the bloodstream, known as hyperglycemia, which arises from irregularities in either the production of insulin or the effectiveness of insulin, or both. Traditionally, diabetes has been classified into three distinct types: Type 1 DM, also known as insulin-dependent diabetes mellitus (IDDM), characterised by the body's inability to make insulin, necessitating the administration of insulin by injections or the use of an insulin pump. This condition is commonly referred to as "juvenile diabetes" in medical literature. Type 2 diabetes mellitus, also known as non-insulin dependent diabetes mellitus (NIDDM), arises due to the presence of insulin resistance. This condition occurs when cells are unable to effectively utilise insulin, either with or without a complete absence of insulin. This particular classification was once denoted as "adult-onset diabetes". The third primary category is gestational diabetes, which manifests when women who do not have a prior medical history of diabetes experience elevated levels of blood glucose throughout their pregnancy. It is plausible that it may occur prior to the onset of type 2 diabetes mellitus. This article explores the various forms, pathophysiology, epidemiology, and global burden associated with the topic under discussion.

Expression of visfatin in the ovarian follicles of prepubertal and mature gilts and in vitro effect of gonadotropins, insulin, steroids, and prostaglandins on visfatin levels

Recent studies have demonstrated that visfatin participates in the regulation of female reproduction. Due to the lack of data concerning the level of visfatin in the ovarian follicles of pigs, one of the most economically important livestock species, the aim of this study was to investigate the expression and localisation of visfatin and the follicular fluid concentration in the ovarian follicles of prepubertal and mature gilts. We also aimed to examine the in vitro effects of gonadotropins (LH, FSH), insulin, progesterone (P4), oestradiol (E2), prostaglandin E2 (PGE2) and F2α (PGF2α) on visfatin levels. In the present study, we have demonstrated that visfatin expression is dependent on the maturity of the animals and the stage of ovarian follicle development. Visfatin signal was detected in individual follicular compartments from primordial to antral follicles and even in atretic follicles. We have shown that the expression of visfatin in granulosa cells was higher than in theca cells. The level of visfatin is upregulated by LH, FSH, E2, and P4 and downregulated by insulin, while prostaglandins have modulatory effects, dependent on the dose and type of ovarian follicular cells. To summarise, our research has shown that visfatin is widely expressed in the ovarian follicles of prepubertal and mature pigs, and its expression is regulated by gonadotropins, insulin, steroids, and prostaglandins, suggesting that visfatin appears to be an important intra‐ovarian factor that could regulate porcine ovarian follicular function.

Insulin Can Delay Neutrophil Extracellular Trap Formation In Vitro-Implication for Diabetic Wound Care?

Diabetes is a worldwide evolving disease with many associated complications, one of which is delayed or impaired wound healing. Appropriate wound healing strongly relies on the inflammatory reaction directly after injury, which is often altered in diabetic wound healing. After an injury, neutrophils are the first cells to enter the wound site. They have a special defense mechanism, neutrophil extracellular traps (NETs), consisting of released DNA coated with antimicrobial proteins and histones. Despite being a powerful weapon against pathogens, NETs were shown to contribute to impaired wound healing in diabetic mice and are associated with amputations in diabetic foot ulcer patients. The anti-diabetic drugs metformin and liraglutide have already been shown to regulate NET formation. In this study, the effect of insulin was investigated. NET formation after stimulation with PMA (phorbol myristate acetate), LPS (lipopolysaccharide), or calcium ionophore (CI) in the presence/absence of insulin was analyzed. Insulin led to a robust delay of LPS- and PMA-induced NET formation but had no effect on CI-induced NET formation. Mechanistically, insulin induced reactive oxygen species, phosphorylated p38, and ERK, but reduced citrullination of histone H3. Instead, bacterial killing was induced. Insulin might therefore be a new tool for the regulation of NET formation during diabetic wound healing, either in a systemic or topical application.

Evaluation of Vitamin D in Patients with Type 2 Diabetes Mellites

Background: Type 2 diabetes mellitus is a chronic metabolic condition caused by either a reduction in insulin secretion and/or effect. It affects more than 90% of all diabetic patients. Diabetes is a complex illness that is brought on by a number of genetic and environmental (diet and lifestyle) risk factors working together. On average, one person dies from diabetes-related complications every eight seconds throughout the world. Also, according to a recent International Diabetic Federation (IDF) survey, 537 million persons aged 20-79 years are now living with diabetes worldwide. It is expected to increase to 783 million (12.2%) by 2045. Furthermore, 240 million individuals globally have undiagnosed diabetes. Therefore, there is a rising interest in studying the possible therapeutic value of fat-soluble micronutrients like vitamin D for preventing or controlling type 2 diabetes mellitus. Aim of Study: The present study was designed to evaluate levels of vitamin D in patients with type 2 diabetes mellitus. Patients and Methods: To achieve this aim, in a case-control study conducted in Diyala governorate at Baqubah Teaching Hospital and Balad Ruz General Hospital from first of January to the end of March 2023, the study included 60 patients with type 2 diabetes mellitus (30 males and 30 females). On the other hand, 30 people as a control group of both sexes (15 males and 15 females) were taken, and the ages of the two groups ranged between 30 and 65 years. The information about patients in this study was retrieved from the patients themselves through a direct interview with them, according to a prepared questionnaire. In the present study, blood samples were collected from each participant for estimation of vitamin D by (ELISA), HbA1c by (Cobas), lipid profile by (colorimetric methods) and calculated BMI. Results: The mean ± Standard Deviation (SD) of vitamin D levels for the type 2 diabetes group were (11.16± 2.18) ng /ml, with a highly significant decrease (p &lt; 0.001) when compared with control group (20.73± 3.64) ng /ml. The mean ± SD of HbA1c level for the type 2 diabetes group was (8.88± 1.86) %, with a highly significant increase (p &lt; 0.001) when compared with control (5.59 0.45) %. The mean ± SD of cholesterol, TG, and LDL-C levels for the type 2 diabetes group were (161.48± 21.70) mg/dl, (203.40± 8.16) mg/dl and (81.15± 21.62) mg/dl, respectively, with a highly significant increase (p &lt; 0.001) when compared with the control group (105.77± 12.50) mg/dl, (191.73± 8.70) mg/dl, and (22.96± 13.38) mg/dl, respectively. The mean ± SD of HDL-C levels for the type 2 diabetes group was (39.66± 2.52) mg/dl and control (44.46± 4.82) mg/dl, with a highly significant decrease when compared with the control group. The mean ± SD of BMI for the type 2 diabetes group was (27.20± 4.25) and control (26.66± 2.30), respectively, with no significant difference (p &lt; 0.05) when comparing the two groups. Conclusion: The current study concluded that Vitamin D levels showed a highly significant decrease in patients with uncontrolled type 2 diabetes mellitus when compared with those in the control group.

Insulin Controls Clock Gene Expression in the Liver of Goldfish Probably via Pi3k/Akt Pathway.

The liver circadian clock plays a pivotal role in driving metabolic rhythms, being primarily entrained by the feeding schedule, although the underlying mechanisms remain elusive. This study aimed to investigate the potential role of insulin as an intake signal mediating liver entrainment in fish. To achieve this, the expression of clock genes, which form the molecular basis of endogenous oscillators, was analyzed in goldfish liver explants treated with insulin. The presence of insulin directly increased the abundance of per1a and per2 transcripts in the liver. The dependency of protein translation for such insulin effects was evaluated using cycloheximide, which revealed that intermediate protein translation is seemingly unnecessary for the observed insulin actions. Furthermore, the putative interaction between insulin and glucocorticoid signaling in the liver was examined, with the results suggesting that both hormones exert their effects by independent mechanisms. Finally, to investigate the specific pathways involved in the insulin effects, inhibitors targeting PI3K/AKT and MEK/ERK were employed. Notably, inhibition of PI3K/AKT pathway prevented the induction of per genes by insulin, supporting its involvement in this process. Together, these findings suggest a role of insulin in fish as a key element of the multifactorial system that entrains the liver clock to the feeding schedule.

Insulin alleviates lipopolysaccharide-induced cognitive impairment via inhibiting neuroinflammation and ferroptosis

Neuroinflammation is regarded to be a key mediator in cerebral diseases with attendant cognitive decline. Ferroptosis, characterized by iron-dependent lipid peroxidation, participates in neuroinflammation and cognitive impairment. Recent studies have revealed insulin's neuroprotective effects and involvement in the regulation of numerous central functions. But the effect of insulin on cognitive impairment induced by neuroinflammation has been rarely explored. In this study, we constructed a cognitive impairment model by intracerebroventricular injection of lipopolysaccharide (LPS) and a single dosage of insulin was mixed in the LPS solution to explore the potential mechanisms through which insulin treatment could improve LPS-induced cognitive dysfunction. At 24 h after treatment, we found that insulin treatment significantly improved LPS-induced cognitive decline, neuronal injuries, and blood-brain barrier (BBB) disruption. Insulin treatment could also inhibit the LPS-induced activation of microglia and astrocytes, and the release of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the hippocampus. Furthermore, insulin treatment inhibited LPS-induced ferroptosis in the hippocampus by decreasing iron accumulation levels, regulating ferroptosis-related proteins including transferrin, glutathione peroxidase 4 (GPX4), ferritin heavy chin 1 (FTH1) and cystine/glutamate antiporter (xCT), inhibiting oxidative stress injuries and lipid peroxidation in the hippocampus. In conclusion, our finding that insulin treatment could alleviate LPS-induced cognitive impairment by inhibiting neuroinflammation and ferroptosis provides a new potential therapeutic method to ameliorate cognitive decline.

Multi Objective Nonlinear Model Predictive Control of Diabetes Models Considering the Effects of Insulin and Exercise

Rigorous multiobjective nonlinear model predictive control on the diabetes model incorporating single and multiple control strategies. The amount of glucose is minimized with the Bergman model considering the effects of insulin and exercise. The optimization language pyomo is used in conjunction with the state-of-the-art global optimization solvers IPOPT and Baron. Pareto surfaces are generated. When some optimal control profiles were found to exhibit sharp spikes, an activation factor involving the hyperbolic tangent function was used. It is observed that a greater amount of glucose minimization is achieved when more control procedures were incorporated. This demonstrates that it is more beneficial to use multiple control strategies

Synergistic Effect of Substance P with Insulin and Insulin-Like Growth Factor-I on Epithelial Migration of the Transformed Human Corneal Epithelial Cells (SV-40)

On the cornea, daily epithelial resurfacing is a critical process to prevent the loss of normal function, ocular morbidity, corneal structure, and vision loss. There are several components to wound healing, including cellular attachment, migration, and growth. To develop a treatment for corneal epithelial healing, we studied the effect of substance P (SP) on corneal epithelial cell migration using a cell culture system of either transformed human corneal epithelial cells (SV-40), or rabbit corneal epithelial cells (SIRC). We investigated the effect of SP with insulin and insulin-like growth factor-I (IGF-1). We found that SP is synergistic with insulin and IGF-1 on the stimulation of transformed human corneal epithelial migration in a cell culture system, as well as in rabbit SIRC cells. The addition of either SP, insulin, or IGF-1 alone did not greatly affect epithelial migration, while the combination of SP and insulin or SP and IGF-1 markedly stimulated epithelial migration in a dose-dependent manner. The synergistic effects of SP with insulin and SP with IGF-1 were inhibited by the addition of the SP-specific inhibitor (CP96345). However, the effect of insulin and IGF-1 alone were not inhibited by the NK-1-specific inhibitor (CP96345). Our results are consistent with the need for the involvement of the neuropeptide SP in corneal epithelial wound healing of diabetic corneas where nerve-ending dropout occurs. Additionally, almost identical results were obtained with human and rabbit corneal epithelial cells. These results suggest that the maintenance of the normal integrity of the corneal epithelium might be regulated by both humoral and neural factors.

Effect of insulin on bone formation ability of rat alveolar bone marrow mesenchymal stem cells.

The alveolar bone marrow mesenchymal stem cells (ABM-MSCs) play an important role in oral bone healing and regeneration. Insulin is considered to improve impaired oral bones due to local factors, systemic factors and pathological conditions. However, the effect of insulin on bone formation ability of ABM-MSCs still needs to be elucidated. The aim of this study was to determine the responsiveness of rat ABM-MSCs to insulin and to explore the underlying mechanism. We found that insulin promoted ABM-MSCs proliferation in a concentration-dependent manner, in which 10-6 M insulin exerted the most significant effect. 10-6 M insulin significantly promoted the type I collagen (COL-1) synthesis, alkaline phosphatase (ALP) activity, osteocalcin (OCN) expression and mineralized matrix formation in ABM-MSCs, significantly enhanced the gene and protein expressions of intracellular COL-1, ALP and OCN. Acute insulin stimulation significantly promoted insulin receptor (IR) phosphorylation, insulin receptor substrate-1 (IRS-1) protein expression and mammalian target of rapamycin (mTOR) phosphorylation, but chronic insulin stimulation decreased these values, while inhibitor NT219 could attenuate these responses. When seeded on β-tricalcium phosphate (β-TCP), ABM-MSCs adhered and grew well, during the 28-day culture period, ABM-MSCs+β-TCP+10-6 M Insulin group showed significantly higher extracellular type I collagen amino-terminus prolongation peptide (TPINP) content, ALP activity, OCN secretion, Ca and P concentration. When implanted subcutaneously in severe combined immunodeficient mice for 1 month, the ABM-MSCs+β-TCP+10-6 M Insulin group obtained the most bone formation and blood vessels. These results showed that insulin promoted the proliferation and osteogenic differentiation of ABM-MSCs in vitro, and enhance osteogenesis and angiogenesis of ABM-MSCs in vivo. Inhibition studies demonstrated that the insulin-induced osteogenic differentiation of ABM-MSCs was dependent of insulin/mTOR signaling. It suggests that insulin has a direct anabolic effect on ABM-MSCs.

Endothelial Insulin Resistance Exacerbates Experimental Periodontitis

Epidemiological studies suggest that the severity of periodontitis is higher in people with diabetes than in healthy individuals. Insulin resistance might play a crucial role in the pathogenesis of multiple diabetic complications and is reportedly induced in the gingiva of rodents with type 2 diabetes; however, the molecular mechanisms underlying the pathogenesis of diabetes-related periodontitis remain unclear. Therefore, we aimed to investigate whether endothelial insulin resistance in the gingiva may contribute to the pathogenesis of periodontitis as well as elucidate its underlying molecular mechanisms. We demonstrated that insulin treatment downregulated lipopolysaccharide (LPS)–induced or tumor necrosis factor α (TNFα)–induced VCAM1 expression in endothelial cells (ECs) via the PI3K/Akt activating pathway, resulting in reduced cellular adhesion between ECs and leukocytes. Hyperglycemia-induced selective insulin resistance in ECs diminished the effect of insulin on LPS- or TNFα-stimulated VCAM1 expression. Vascular endothelial cell–specific insulin receptor knockout (VEIRKO) mice exhibited selective inhibition of the PI3K/Akt pathway in the gingiva and advanced experimental periodontitis-induced alveolar bone loss via upregulation of Vcam1, Tnfα, Mcp-1, Rankl, and neutrophil migration into the gingiva compared with that in the wild-type (WT) mice despite being free from diabetes. We also observed that insulin-mediated activation of FoxO1, a downstream target of Akt, was suppressed in the gingiva of VEIRKO and high-fat diet (HFD)–fed mice, hyperglycemia-treated ECs, and primary ECs from VEIRKO. Further analysis using ECs transfected with intact and mutated FoxO1, with mutations at 3 insulin-mediated phosphorylation sites (T24A, S256D, S316A), suggested that insulin-mediated regulation of VCAM1 expression and cellular adhesion of ECs with leukocytes was attenuated by mutated FoxO1 overexpression. These results suggest that insulin resistance in ECs may contribute to the progression of periodontitis via dysregulated VCAM1 expression and cellular adhesion with leukocytes, resulting from reduced activation of the PI3K/Akt/FoxO1 axis.

The effect of hormones insulin and glucagon on ubiquitin modifications elucidated by proteomics in liver cells

AimsInsulin action is intertwined with changing levels of glucose and counter-regulatory hormone glucagon. While insulin lowers blood sugar level, glucagon raises it by promoting the breakdown of the stored glycogen in liver and releases glucose into the bloodstream. The hormones insulin and glucagon are key in the pathogenesis of type 2 diabetes (T2D). Insulin resistance is a primary predisposing factor for diabetes. Phosphorylation of insulin signaling molecules is altered in the insulin-resistant state. However, ubiquitin (Ub) modifications in insulin-resistant state are relatively understudied. To dissect the underlying mechanisms, we performed a proteomics study on hepatoma cells to study the regulation of ubiquitination by insulin and glucagon. Materials and methodsWe performed western blotting, immunoprecipitations, and affinity pull down using tandem Ub binding entities (TUBE) reagents on hepatoma cells treated with insulin or glucagon. Next, we performed MS/MS analysis on Ub-linkage specific affinity pull down samples. Gene ontology analysis and protein-protein interaction network analysis was performed using DAVID GO and STRING db, respectively. Key findingsThe ubiquitination pattern of total Ub, K48-linked Ub, and K63-linked Ub was altered with the treatment of hormones insulin and glucagon. Ubiquitination in immunoprecipitated samples showed enrichment with total Ub and K48-linked Ub but not with K63-linked Ub. Ubiquitination by treatment with hormones mainly enriched key signaling pathways MAPK, Akt, oxidative stress etc. SignificanceOur study identified key altered proteins and signal transduction pathways which aids in understanding the mechanisms of hormonal action on ubiquitination and identify new therapeutic targets for T2D.