Co-treatment Of Insulin Research Articles

The effect of intra-nasal co-treatment with insulin and growth factor-rich serum on behavioral defects, hippocampal oxidative-nitrosative stress, and histological changes induced by icv-STZ in a rat model.

Impaired insulin and growth factor functions are thought to drive many alterations in neurodegenerative diseases like dementia and seem to contribute to oxidative stress and inflammatory responses. Recent studies revealed that nasal growth factor therapy could induce neuronal and oligodendroglia protection in rodent brain damage induction models. Impairment of several growth factors signaling was reported in neurodegenerative diseases. So, in the present study, we examined the effects of intranasal co-treatment of insulin and a pool of growth factor-rich serum (GFRS) which separated from activated platelets on memory, and behavioral defects induced by intracerebroventricular streptozotocin (icv-STZ) rat model also investigated changes in the hippocampal oxidative-nitrosative state and histology. We found that icv-STZ injection (3 mg/kg bilaterally) impairs spatial learning and memory in Morris Water Maze, leads to anxiogenic-like behavior in the open field arena, and induces oxidative-nitrosative stress, neuroinflammation, and neuronal/oligodendroglia death in the hippocampus. GFRS (1µl/kg, each other day, 9 doses) and regular insulin (4 U/40 µl, daily, 18 doses) treatments improved learning, memory, and anxiogenic behaviors. The present study showed that co-treatment (GFRS + insulin with respective dose) has more robust protection against hippocampal oxidative-nitrosative stress, neuroinflammation, and neuronal/oligodendroglia survival in comparison with the single therapy. Memory and behavioral improvements in the co-treatment of insulin and GFRS could be attributed to their effects on neuronal/oligodendroglia survival and reduction of neuroinflammation in the hippocampus.

Forkhead box protein O1 (FoxO1) regulates lipids metabolism and cell proliferation mediated by insulin and PI3K-Akt-mTOR pathway in goose primary hepatocytes

In order to explore the role of forkhead box protein O1 (FoxO1) in the lipid metabolism and cell proliferation, goose primary hepatocytes were isolated and incubated with insulin or PI3K-Akt-mTOR pathway dual inhibitor NVP-BEZ235, and then transfected with FoxO1 interference plasmid. The related parameters of lipid metabolism and cell proliferation were measured. The results firstly showed that FoxO1 interference increased the intracellular TG and lipids concentration (P < 0.05); and increased the proliferative index (PI), cell DNA synthesis, protein expression of Cyclin D1 in goose primary hepatocytes (P < 0.05). Secondly, the co-treatment of insulin and FoxO1 interference increased the mRNA level and protein content of Cyclin D1 (P < 0.05); however, there was no significant difference between the insulin treatment and the co-treatment of insulin and miR-FoxO1 interference in the intracellular TG and lipids concentration and PI (P > 0.05). Lastly, the decrease of intracellular TG and lipids concentration and PI induced by NVP-BEZ235 was up-regulated by FoxO1 interference significantly (P < 0.05). In summary, FoxO1 could regulate the lipids metabolism and cell proliferation mediated by PI3K-Akt-mTOR signaling pathway in goose primary hepatocytes. Further investigations are required to highlight the potential role of FoxO1 in the lipid metabolism and cell proliferation mediated by insulin in goose primary hepatocyte.

Induction of anxiolytic, antidepressant and analgesic effects by Shiff base of (E)-3-(1H-imidazol-4-yl)-2-((2-oxoindolin-3-ylidene)amino)propanoic acid derivatives in diabetic rats.

Diabetes mellitus is a metabolic disorder with several psychological problems such as anxiety, depression, and pain sense. This study aimed to evaluate the effect of Schiff base on the modulation of anxiety, depression, and pain behaviors in diabetic rats. Anxiety, depression, and pain behaviors were evaluated by elevated plus maze (EPM), forced swim test (FST), and hot-plate test, respectively. The results indicated that induction of diabetes decreased time spent in open arms (OAT) in the EPM whereas injection of insulin (1ml/kg), glibenclamide (5mg/kg), and Schiff base II (100mg/kg) increased OAT in the EPM. So, induction of diabetes in rats caused an anxiogenic effect that this effect reversed by drug treatment. Interestingly, co-treatment of insulin and glibenclamide along with an ineffective dose of Schiff base II potentiated anxiolytic behavior in diabetic rats. Furthermore, induction of diabetes increased immobility time in the FST but administration of insulin (1ml/kg), glibenclamide (5mg/kg), and Schiff base II (25, 50, and 100mg/kg) decreased immobility time in the FST which indicated depressant effect in diabetic rats without drug-treatment and antidepressant effect in diabetic rats with drug-treatment. Additionally, induction of diabetes decreased latency in the hot-plate test while injection of insulin (1ml/kg), glibenclamide (5mg/kg), Schiff base I (50mg/kg), and Schiff base II (25, 50, and 100mg/kg) enhanced latency in the hot-plate test which revealed hyperalgesic effect in diabetic rats without drug-treatment and analgesic effect in diabetic rats with drug-treatment. Consequently, induction of diabetes-induced anxiogenic, depressant, and hyperalgesia effects that administration of insulin, glibenclamide, Schiff bases I, and II reversed these effects.

Mechanisms Underlying the Synergistic Action of Insulin and Growth Hormone on IGF-I and -II Expression in Grass Carp Hepatocytes.

In mammals, insulin is known to modify growth hormone (GH)-induced IGF-I expression at the hepatic level, which also contributes to the functional crosstalk between energy homeostasis and somatotropic axis. However, the studies on the comparative aspects of this phenomenon are limited and the mechanisms involved have not been fully characterized. Using a serum-free culture of grass carp hepatoctyes, the functional interaction between GH and insulin on hepatic expression of IGF-I and -II was examined in a fish model. In carp hepatocytes, GH could up-regulate IGF-I and -II mRNA expression via the JAK2/STAT5, MEK/ERK and PI3K/Akt pathways. These stimulatory effects were mimicked by insulin via activation of the PI3K/Akt but not MEK/ERK and P38 MAPK cascades. Although insulin did not activate JAK2 and STAT5 at hepatocyte level, insulin-induced IGF-I and -II mRNA expression were highly dependent on the normal functioning of JAK2/STAT5 pathway. In parallel experiments, insulin co-treatment was found to markedly enhance IGF-I and -II responses induced by GH and these potentiating effects were mediated by insulin receptor (InsR) but not IGF-I receptor. Interestingly, co-treatment with GH also enhanced insulin-induced InsR phosphorylation with a current elevation in protein:protein interaction between GH receptor and phosphorylated InsR and these stimulatory effects were noted with further enhancement in STAT5, ERK1/2 and Akt phosphorylation at hepatocyte level. Consistent with these findings, the potentiating effects of GH and insulin co-treatment on IGF-I and -II mRNA expression were found to be suppressed/abolished by inhibiting JAK2/STAT5, MEK/ERK and PI3K/Akt but not P38 MAPK pathways. These results, as a whole, suggest that insulin and GH can act in a synergistic manner in the carp liver to up-regulate IGF-I and -II expression through protein:protein interaction at the receptor level followed by potentiation in post-receptor signaling.

EFFECT OF EXPERIMENTAL DYSGLYCEMIA ON UNDER-CARBOXYLATED OSTEOCALCIN PRODUCTION IN HUMAN PRIMARY OSTEOBLAST-LIKE CELL CULTURES.

The undercarboxylated form of osteocalcin (ucOC) and osteoprotegerin (OPG) are bone-derived molecules involved in the endocrine crosstalk governing the bone, the adipose tissue and the pancreas. In addition, glucocorticoids are major determinants of both insulin resistance and osteoporosis. We aimed to investigate the response of ucOC and OPG to dysglycemia and/or dexamethasone (DXM) in primary human osteoblastic cell (HOC) cultures. Third-passage sub-confluent primary HOC cultures were treated with glucose: 2.8 mmol/L, 5.6 mmol/L, 11.1 mmol/L and 28 mmol/L, respectively. Alternatively, HOC cultures were subjected to DXM 1 μmol/L. In more complex experiments, HOC cultures were pre-treated with glucose (5.6 mmol/L) with/without insulin (1 pmol/L) followed by DXM (1 μmol/L). 24-hours post-treatment, culture medium ucOC and OPG were measured by ELISA. ucOC production differed significantly (p<0.05) between cell groups, decreasing in a dose-dependent manner as glucose concentration in the medium increased. Insulin prevented this effect. OPG levels appeared not to be significantly influenced by the hyperglycemic culture medium and were not related to ucOC concentration (p>0.05). Addition of DXM resulted in significantly lower ucOC concentrations compared to vehicle-treated cells (p<0.05). However, the effect of insulin co-treatment on ucOC was not counteracted by DXM (p<0.05). An obvious alteration of OC production/metabolism was observed as glucose levels changed in the bone microenvironment, to potentially be involved in diabetes-related osteopenia. DXM suppressed ucOC levels however not in insulin-rich environment.

Markers of β-Cell Failure Predict Poor Glycemic Response to GLP-1 Receptor Agonist Therapy in Type 2 Diabetes.

To assess whether clinical characteristics and simple biomarkers of β-cell failure are associated with individual variation in glycemic response to GLP-1 receptor agonist (GLP-1RA) therapy in patients with type 2 diabetes. We prospectively studied 620 participants with type 2 diabetes and HbA1c ≥58 mmol/mol (7.5%) commencing GLP-1RA therapy as part of their usual diabetes care and assessed response to therapy over 6 months. We assessed the association between baseline clinical measurements associated with β-cell failure and glycemic response (primary outcome HbA1c change 0-6 months) with change in weight (0-6 months) as a secondary outcome using linear regression and ANOVA with adjustment for baseline HbA1c and cotreatment change. Reduced glycemic response to GLP-1RAs was associated with longer duration of diabetes, insulin cotreatment, lower fasting C-peptide, lower postmeal urine C-peptide-to-creatinine ratio, and positive GAD or IA2 islet autoantibodies (P ≤ 0.01 for all). Participants with positive autoantibodies or severe insulin deficiency (fasting C-peptide ≤0.25 nmol/L) had markedly reduced glycemic response to GLP-1RA therapy (autoantibodies, mean HbA1c change -5.2 vs. -15.2 mmol/mol [-0.5 vs. -1.4%], P = 0.005; C-peptide <0.25 nmol/L, mean change -2.1 vs. -15.3 mmol/mol [-0.2 vs. -1.4%], P = 0.002). These markers were predominantly present in insulin-treated participants and were not associated with weight change. Clinical markers of low β-cell function are associated with reduced glycemic response to GLP-1RA therapy. C-peptide and islet autoantibodies represent potential biomarkers for the stratification of GLP-1RA therapy in insulin-treated diabetes.

Reduced Intracellular Drug Accumulation in Drug-Resistant Leukemia Cells is Not Only Solely Due to MDR-Mediated Efflux but also to Decreased Uptake.

Expression of ABC family transporter proteins that promote drug efflux from cancer cells is a widely observed mechanism of multi-drug resistance of cancer cells. Cell adaptation in long-term culture of HL60 leukemic cells in the presence of chemotherapy leads to induction and maintenance of the ABC transporters expression, preventing further accumulation of drugs. However, we found that decreased accumulation of drugs and fluorescent dyes also contributed by a reduced uptake by the resistant cells. Confocal time-lapse microscopy and flow cytometry revealed that fluid-phase endocytosis was diminished in drug-resistant cells compared to drug-sensitive cells. Drug uptake was increased by insulin co-treatment when cells were grown in methylcellulose and monitored under the microscope, but not when cultured in suspension. We propose that multi-drug resistance is not only solely achieved by enhanced efflux capacity but also by supressed intake of the drug, offering an alternative target to overcome drug resistance or potentiate chemotherapy.

TNF-αand IFN-s-Dependent Muscle Decay Is Linked to NF-κB- and STAT-1α-StimulatedAtrogin1andMuRF1Genes in C2C12 Myotubes

TNF-α was shown to stimulate mitogenicity in C2C12 myoblasts. Selected cytokines TNF-α, IFNα, or IFNγ reduced the expression of myosin heavy chain (MyHC IIa) when given together. Molecular mechanisms of cytokine activities were controlled by NF-κB and JAK/STAT signaling pathways, as metabolic inhibitors, curcumin and AG490, inhibited some of TNF-α and IFNα/IFNγ effects. Insulin was hardly antagonistic to TNF-α- and IFNα/IFNγ-dependent decrease in MyHC IIa protein expression. Cytokines used individually or together also repressed myogenesis of C2C12 cells. Moreover, TNF-α- and IFNα/IFNγ-dependent effects on C2C12 myotubes were associated with increased activity of Atrogin1 and MuRF1 genes, which code ubiquitin ligases. MyHC IIa gene activity was unaltered by cytokines. Inhibition of NF-κB or JAK/STAT with specific metabolic inhibitors decreased activity of Atrogin1 and MuRF1 but not MyHC IIa gene. Overall, these results suggest cooperation between cytokines in the reduction of MyHC IIa protein expression level via NF-κB/JAK/STAT signaling pathways and activation of Atrogin1 and MuRF1 genes as their molecular targets. Insulin cotreatment or pretreatment does not protect against muscle decay induced by examined proinflammatory cytokines.

Synergistic effect of curcumin and insulin on muscle cell glucose metabolism

Curcumin is a major phenolic compound of Curcuma longa, which has long been used in traditional Indian medicine. Recently, curcumin has been reported to have antihyperglycemic activity in animal models. However, the molecular basis of this action has not been adequately described. In the present study, curcumin was observed to contain a high level of polyphenols and strong antioxidant activity. Then, the antihyperglycemic effect of curcumin was examined for various signaling pathways using C 2C 12 mouse myoblast cells. From this, curcumin treatment strongly induced glucose uptake and the phosphorylation of AMPK (AMP-activated protein kinase)/ACC (acetyl-CoA carboxylase), but not PI3-kinase (phosphoinositide 3-kinase)/Akt. Interestingly, the co-treatment of insulin and curcumin produced a mutual synergistic activation of both AMPK/ACC and PI3-kinase/Akt pathways. On the other hand, the synergism could not be observed from the co-treatment of insulin and EGCG. It suggests that the two signaling pathways can crosstalk each other in a case-sensitive manner upon the treatment of antioxidant polyphenols. Further, these results were consistent with the findings of GLUT4 translocation to the cell surface. Our findings indicate that curcumin can promote AMPK activation and glucose uptake with increased insulin sensitivity in muscle cells as a potential anti-diabetic therapeutic agent.

Treatment with insulin inhibits poly(ADP-ribose)polymerase activation in a rat model of endotoxemia

In critically ill patients various conditions may lead to the activation of poly(ADP-ribose) polymerase (PARP). By promoting cellular energetic dysfunction, and by enhancing pro-inflammatory gene expression, PARP activation significantly contributes to the pathogenesis of shock. PARP activation is usually triggered by DNA strand breakage, which is typically the result of the overproduction of various reactive oxidant species. One of the pathophysiological conditions associated with PARP activation is hyperglycemia, where the reactive species are produced from the mitochondria and other cellular sources. In the present study we tested whether endotoxin-induced PARP activation and pro-inflammatory mediator production can be modified by insulin therapy. Rats subjected to bacterial lipopolysaccharide (LPS) with or without insulin co-treatment were studied. LPS-induced PARP activation in circulating lymphocytes was measured by flow cytometry, tumor necrosis factor alpha (TNF-α) production was measured by ELISA. The direct effect of insulin on the PARP activity of mononuclear leukocytes and human umbilical vein endothelial cells (HUVEC) in elevated glucose conditions was tested in vitro. LPS-induced significant hyperglycemic response activated PARP in circulating lymphocytes and induced TNF-α production. Insulin treatment prevented LPS-induced hyperglycemic response, blocked PARP activation and blunted LPS-induced TNF-α response. Insulin treatment caused a slight reduction in the PARP activity of mononuclear cells and HUVECs in vitro. We demonstrate that insulin treatment blocks LPS-induced PARP activation in vivo. We propose that this effect is mainly indirect, and occurs due to the prevention of stress induced hyperglycemia, with a direct cellular effect of insulin playing a potential minor supplemental role. The current findings may have significant implications in the context of the emerging concept of tight glycemic control and insulin treatment for critically ill patients.

Ovarian response, embryo production and hormonal profile in superovulated goats treated with insulin

The influence of insulin on ovarian response and embryo production was investigated in 30 mixed breed goats, divided randomly into three equal ( n=10) groups. Goats in Group 1 (control) were superovulated using 20 IU FSH i.m. in six divided descending doses, i.e. 4/4, 3/3 and 3/3 IU at 12 h interval for three consecutive days and were not given insulin treatment. Goats in Group 2 (insulin pretreatment) were pretreated with long acting purified bovine insulin 0.2 IU/kg body weight per day s.c. on Days 7, 8 and 9 of the estrous cycle prior to initiation of superovulatory treatment as in Group 1. Animals in Group 3 (insulin cotreatment) were treated as in Group I, but in addition received long acting purified bovine insulin 0.2 IU/kg body weight per day s.c. as a cotreatment along with the first, third and fifth FSH treatments on three consecutive days. Total ovarian response (corpus luteum and unovulated large follicle (UOLF)) was significantly ( P<0.05) higher in insulin pretreatment (17.90±3.08) than in the cotreatment (11.50±2.34) and control (11.90±1.87) groups. The number of UOLF was significantly higher ( P<0.05) in the insulin pretreatment (10.2±1.67) than the cotreatment (4.9±1.14) and control (3.6±1.09) groups. The mean transferable quality of embryos did not differ significantly among treatments. Progesterone concentration on the day of PGF 2α treatment was not different ( P>0.05) between the insulin treatment groups (5.28±0.79; 5.30±0.66 ng/ml). Estradiol-17β concentration was significantly ( P<0.05) higher on the day of PGF 2α treatment in both the insulin treatment groups (36.67±6.40; 34.33±4.33 pg/ml) as compared to the control group (20.00±2.73 pg/ml). There is ample evidence to indicate beneficial effect of insulin on folliculogenesis and steroidogenesis in superovulated goats.

Effect of bST co-treatment with FSH or PMSG on trans-vaginal ultrasound-guided oocyte retrieval in calves

The influence of insulin on ovarian response and embryo production was investigated in 30 mixed breed goats, divided randomly into three equal (n=10) groups. Goats in Group 1 (control) were superovulated using 20 IU FSH i.m. in six divided descending doses, i.e. 4/4, 3/3 and 3/3 IU at 12 h interval for three consecutive days and were not given insulin treatment. Goats in Group 2 (insulin pretreatment) were pretreated with long acting purified bovine insulin 0.2 IU/kg body weight per day s.c. on Days 7, 8 and 9 of the estrous cycle prior to initiation of superovulatory treatment as in Group 1. Animals in Group 3 (insulin cotreatment) were treated as in Group I, but in addition received long acting purified bovine insulin 0.2 IU/kg body weight per day s.c. as a cotreatment along with the first, third and fifth FSH treatments on three consecutive days. Total ovarian response (corpus luteum and unovulated large follicle (UOLF)) was significantly (P<0.05) higher in insulin pretreatment (17.90±3.08) than in the cotreatment (11.50±2.34) and control (11.90±1.87) groups. The number of UOLF was significantly higher (P<0.05) in the insulin pretreatment (10.2±1.67) than the cotreatment (4.9±1.14) and control (3.6±1.09) groups. The mean transferable quality of embryos did not differ significantly among treatments. Progesterone concentration on the day of PGF2α treatment was not different (P>0.05) between the insulin treatment groups (5.28±0.79; 5.30±0.66 ng/ml). Estradiol-17β concentration was significantly (P<0.05) higher on the day of PGF2α treatment in both the insulin treatment groups (36.67±6.40; 34.33±4.33 pg/ml) as compared to the control group (20.00±2.73 pg/ml). There is ample evidence to indicate beneficial effect of insulin on folliculogenesis and steroidogenesis in superovulated goats.