Type 1 diabetes glycemic management: Insulin therapy, glucose monitoring, and automation

Despite innovations in insulin therapy since its discovery, most patients living with type 1 diabetes do not achieve sufficient glycemic control to prevent complications, and they experience hypoglycemia, weight gain, and major self-care burden. Promising pharmacological advances in insulin therapy include the refinement of extremely rapid insulin analogs, alternate insulin-delivery routes, liver-selective insulins, add-on drugs that enhance insulin effect, and glucose-responsive insulin molecules. The greatest future impact will come from combining these pharmacological solutions with existing automated insulin delivery methods that integrate insulin pumps and glucose sensors. These systems will use algorithms enhanced by machine learning, supplemented by technologies that include activity monitors and sensors for other key metabolites such as ketones. The future challenges facing clinicians and researchers will be those of access and broad clinical implementation.

Antidiabetic activities of Bolanthus spergulifolius (Caryophyllaceae) extracts on insulin-resistant 3T3-L1 adipocytes

Diabetes mellitus (DM) is a metabolic disorder with chronic hyperglycemia featured by metabolic outcomes owing to insufficient insulin secretion and/or insulin effect defect. It is critical to investigate new therapeutic approaches for T2DM and alternative, natural agents that target molecules in potential signal pathways. Medicinal plants are significant resources in the research of alternative new drug active ingredients. Bolanthus spergulifolius (B. spergulifolius) is one of the genera of the family Caryophyllaceae. In this study, it was explored the potential anti-diabetic effects in vitro of B. spergulifolius extracts on 3T3-L1 adipocytes. The total phenolic contents (TPC) of methanolic (MeOH), ethyl acettate (EA) and aqueous extracts of B. spergulifolius were evaluated via Folin-Ciocateau. B. spergulifolius extracts showing highly TPC (Aqueous< MeOH< EA) and their different concentrations were carried out on preadipocytes differentiated in to mature 3T3-L1 adipocytes to investigate their half-maximal (50%) inhibitory concentration (IC50) value by using Thiazolyl blue tetrazolium bromide (MTT) assay. The IC50 of MeOH, EA and Aqueous extracts were observed as 305.7 ± 5.583 μg/mL, 567.4 ± 3.008 μg/mL, and 418.3 ± 4.390 μg/mL and used for further experiments. A live/dead assay further confirmed the cytotoxic effects of MeOH, EA and Aqueous extracts (respectively, 69.75 ± 1.70%, 61.75 ± 1.70%, 70 ± 4.24%, and for all p< 0.05). Also, effects of extracts on lipid accumulation in mature 3T3-L1 adipocytes were evaluated by Oil-Red O staining assay. The extracts effectively decreased lipid-accumulation compared to untreated adipocytes (for all p< 0.05). Moreover, effect of extracts on apoptosis regulated by the Bax and Bcl-2 was investigated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The extracts significantly induced apoptosis by up-regulating pro-apoptotic Bax expression but down-regulated anti-apoptotic Bcl-2 gene expression compared to untreated adipocytes (for all p< 0.05). The Glut-4 expression linked with insulin resistance was determined by qRT-PCR, Western-blot analysis, and immunofluorescence staining. In parallel, the expression of Glut-4 in adipocytes treated with extracts was significantly higher compared to untreated adipocytes (for all p< 0.05). Extracts significantly suppressed cell migration after 30 h of wounding in a scratch-assay (for all p< 0.05). Cell morphology and diameter were further evaluated by phase-contrast microscopy, scanning electron microscopy, Immunofluorescence with F-Actin and Giemsa staining. The adipocytes treated with extracts partially lost spherical morphology and showed smaller cell-diameter compared to untreated adipocytes (for all p< 0.05). In conclusion, these results suggest that extracts of B. spergulifolius cause to an induce apoptosis, decrease lipid-accumulation, wound healing, up-regulating Glut-4 level and might contribute to reducing of insulin-resistance in DM.

The association of laminin levels with insulin resistance and non-alcoholic hepatosteatosis

Background Laminin, one of the largest glycoproteins of the basement membrane, is an important component of the extracellular matrix. Functions of the basement membrane include regulation of cell signaling behaviors and structural support. Laminin plays a critical role in the regulation of insulin action in muscle, liver, and adipose tissue. The study mainly investigates an association between the change in serum laminin levels and insulin resistance and non-alcoholic hepatosteatosis. Methods This prospective study included a total of 90 participants; 60 patients diagnosed with Grade 2–3 non-alcoholic hepatosteatosis and 30 age- and sex-matched healthy controls between December 2019 and December 2020. Routine laboratory tests including glucose, insulin, homeostatic model of assessment-insulin resistance (HOMA-IR), alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and C-reactive protein and laminin levels were measured in the serum of the patient and control groups. Enzyme-linked immunosorbent assay was used for the measurement of laminin levels. Results The median serum laminin levels were lower in patients with hepatic steatosis, compared to the control group (72 ng/L vs. 82 ng/L, respectively; p = 0.003). In the patients with insulin resistance, median laminin levels were lower, regardless of the presence of non-alcoholic hepatosteatosis (67 ng/L vs. 85 ng/L, respectively; p = 0.007). There was a weak, negative correlation between the laminin levels and HOMA-IR. Conclusions Our study results suggest that, although there is no exact link between laminin and non-alcoholic hepatosteatosis, serum laminin levels are lower in patients with insulin resistance by regulating the insulin effect through integrins.

Pyruvate accumulation may contribute to acceleration-induced impairment of physical and cognitive abilities: An experimental study

Background: Fatigue can be induced after acceleration exposure, however the mechanism of it is still unclear. The aim of the present study was to examine whether metabolites changes can decrease cognitive and physical function after acceleration. Methods: Graybiel scale and Fatigue Self-rating scale were used to assess the seasickness and fatigue degrees of eighty-seven male seafarers respectively after sailing. To test the effect of pyruvate on cognitive and physical functions, five different doses of pyruvate were administrated into rats. Insulin can reduce the accumulation of pyruvate. To observe the insulin effect on pyruvate, and cognitive, physical functions after acceleration, insulin administration or treatment of promoting insulin secretion was used. Physical and cognitive functions were assessed using Open Field test, Morris water maze and Loaded swimming test in animals. Results: Physical and cognitive abilities were decreased obviously, and Serum pyruvate level increased mostly in human and rats after acceleration. Compared to vehicle group, physical and cognitive abilities were significantly decreased after pyruvate administration. Besides, we found a significant decline in adenosine triphosphate concentration and pyruvate dehydrogenase activity in the hippocampus, prefrontal cortex, liver, and muscle of rats treated with acceleration or pyruvate injection, while insulin administration or treatment of promoting insulin secretion markedly alleviated this decline and the impairment of physical and cognitive abilities, compared to the control group. Conclusion: Our results indicates that pyruvate has a negative effect on physical and cognitive abilities after acceleration. Insulin can inhibit pyruvate accumulation and cognitive and physical function after acceleration exposure.

Potential Inhibitors of Protein Tyrosine Phosphatase (PTP1B) Enzyme: Promising Target for Type-II Diabetes Mellitus

Background: There has been growing interest in the development of highly potent and selective protein tyrosine phosphatase (PTP1B) inhibitors for the past 2-3 decades. Though most PTPs share a common active site motif, the interest in selective inhibitors, particularly against PTP1B is increasing to discover new chemical entities as antidiabetic agents. In the current paradigm to find potent and selective PTP1B inhibitors, which is currently considered as one of the best validated biological targets for non-insulin-dependent diabetic and obese individuals, resistance to insulin due to decreased sensitivity of the insulin receptor is a pathological factor and is also genetically linked, causing type II diabetes. Objectives: Insulin receptor sensitization is performed by a signal transduction mechanism via a selective protein tyrosine phosphatase (PTP1B). After the interaction of insulin with its receptor, autophosphorylation of the intracellular part of the receptor takes place, turning it into an active kinase (sensitization). PTP1B is involved in the desensitization of the receptor by dephosphorylation. PTP1b inhibitors delay the receptor desensitization, prolonging insulin effect and making PTP1B as a drug target for the treatment of diabetes II. Therefore, it has become a major target for the discovery of potent drugs for the treatment of type II diabetes and obesity. An attempt has been made in the present study to discuss the latest design and discovery of protein tyrosine phosphatase (PTP1B) inhibitors. Methods: Many PTP1B inhibitors such as diaminopyrroloquinazoline, triazines, pyrimido triazine derivatives, 2-(benzylamino)-1-phenylethanol, urea, acetamides and piperazinylpropanols, phenylsulphonamides and phenylcarboxamide, benzamido, arylcarboxylic acid derivatives, arylsupfonyl derivatives, thiazoles, isothiozolidiones and thiazolodinones have been discussed, citing the disease mechanisms. Results: The reader will gain an overview of the structure and biological activity of recently developed PTPs inhibitors. Conclusion: The co-crystallized ligands and the screened inhibitors could be used as a template for the further design of potent congeners.

Insulin Within the Arcuate Nucleus Has Paradoxical Effects on Nociception in Healthy and Diabetic Rats

Introduction: Broad neural circuits originate from the hypothalamic arcuate nucleus and project to many parts of the brain which are related to pain perception. Insulin receptors are found in the arcuate nucleus. Since nociception may be affected in type 1 diabetes, the present study aimed to investigate the intra-arcuate nucleus insulin role in pain perception in streptozotocin (STZ)-induced diabetic and healthy rats. Methods: Regular insulin was microinjected within the arcuate nucleus and the pain tolerance was measured using the hot plate and the tail-flick apparatus in diabetic rats. Results: The results showed that the arcuate nucleus suppression with lidocaine could increase thermal nociception in non-diabetic animals. Also, insulin within the arcuate nucleus decreased the acute thermal pain perception in these animals. STZ-induced diabetes produced hypoalgesia which the latency of these tests, progressively increased over time after induction of diabetes. Also, in the same animal group, intra-arcuate injection of insulin reduced the latency of nociception. Conclusion: Intra-arcuate insulin has paradoxical and controversial effects in healthy and diabetic rats’ nociception. These effects seem to be due to the insulin effect on releasing pro-opiomelanocortin and its deriv

Hypoglycemia and Islet Dysfunction Following Oral Glucose Tolerance Testing in Pancreatic-Insufficient Cystic Fibrosis

Context Oral glucose tolerance test (OGTT)-related hypoglycemia is common in pancreatic-insufficient cystic fibrosis (PI-CF), but its mechanistic underpinnings are yet to be established. Objective To delineate the mechanism(s) underlying OGTT-related hypoglycemia. Design and Setting We performed 180-minute OGTTs with frequent blood sampling in adolescents and young adults with PI-CF and compared results with those from a historical healthy control group. Hypoglycemia (Hypo[+]) was defined as plasma glucose &lt;65 mg/dL. We hypothesized that CF-Hypo[+] would demonstrate impaired early phase insulin secretion and persistent late insulin effect compared with control-Hypo[+], and explored the contextual counterregulatory response. Main Outcome Measure OGTT 1-hour and nadir glucose, insulin, C-peptide, and insulin secretory rate (ISR) incremental areas under the curve (AUC) between 0 and 30 minutes (early) and between 120 and 180 minutes (late), and Δglucagon120-180min and Δfree fatty acids (FFAs)120-180min were compared between individuals with CF and control participants with Hypo[+]. Results Hypoglycemia occurred in 15/23 (65%) patients with CF (43% female, aged 24.8 [14.6-30.6] years) and 8/15 (55%) control participants (33% female, aged 26 [21-38] years). The CF-Hypo[+] group versus the control-Hypo[+] group had higher 1-hour glucose (197 ± 49 vs 139 ± 53 mg/dL; P = 0.05) and lower nadir glucose levels (48 ± 7 vs 59 ± 4 mg/dL; P &lt; 0.01), while insulin, C-peptide, and ISR-AUC0-30 min results were lower and insulin and C-peptide, and AUC120-180min results were higher (P &lt; 0.05). Individuals with CF-Hypo[+] had lower Δglucagon120-180min and ΔFFA120-180min compared with the control-Hypo[+] group (P &lt; 0.01). Conclusions OGTT-related hypoglycemia in PI-CF is associated with elevated 1-hour glucose, impaired early phase insulin secretion, higher late insulin exposure, and less increase in glucagon and FFAs. These data suggest that hypoglycemia in CF is a manifestation of islet dysfunction including an impaired counterregulatory response.

P0986NO/CGMP PATHWAY MODULATES GLUCOSE UPTAKE VIA REGULATION OF SIRT1 DEACETYLASE EXPRESSION AND ACTIVITY IN PODOCYTES EXPOSED TO HIGH GLUCOSE CONCENTRATIONS

Background and Aims Glomerular podocytes have become the aim of the extensive research in diabetes because of their importance in the development of diabetic nephropathy. High glucose concentration affects podocyte metabolism and function leading to the development of insulin resistance. Moreover, it decreases deacetylase SIRT1 protein amount and activity, leading to abolition of insulin effect on glucose uptake into the cells. The aim of our study was to examine the involvement of NO/cGMP pathway in the regulation of sirtuin 1 (SIRT1) protein expression and activity in podocytes, in the context of high-glucose induced insulin resistance. This work was supported by grant from the National Science Centre (2016/23/B/NZ4/03448). Method Experiments were performed in primary rat podocytes cultured with normal (NG, 11.1 mM) or high (HG, 30 mM) glucose concentrations for 5 days. RT-PCR and immunodetection methods were used to detect mRNA and protein expressions. Glucose uptake was measured by the addition of 1 µCi/well of 2-deoxy-(1,2-3H)-D-glucose uptake diluted in non-radioactive dglucose (50 µM final concentration) with or without 300 nM insulin. SIRT1 activity was determined with a SIRT1 Fluorometric Kit according to the manufacturer’s instructions. SIRT1 expression was modified by transfection with SIRT1 siRNA. To examine the effect of NO/cGMP pathway activity on SIRT1, cells were incubated in the presence of SNAP, a mimetic of nitric oxide synthase activity (NOS), and 8-Br-cGMP, protein kinase G (PKG) activator. We also used L-NAME – NOS inhibitor, and Rp-8-Br-cGMPs, PKG inhibitor. Results SIRT1 protein expression and activity were decreased in podocytes exposed to high glucose concentrations. We showed that in the presence of SNAP and 8-Br-cGMP, SIRT1 protein amount and activity were increased, leading also to enhancement of basal and insulin-dependent glucose uptake. In podocytes, transfected with SIRT1 siRNA, treatment with NO/cGMP pathway activators SNAP or 8-Br-cGMP increased glucose uptake. NO/cGMP pathway inhibitors exerted opposite effects on SIRT1 protein level and activity as well as on glucose uptake. Insulin action on glucose uptake into podocytes cultivated in the presence of normal glucose concentrations was abolished after NO/cGMP pathway inhibition. Conclusion We found that impairment of insulin effect on glucose uptake in HG-exposed podocytes, which was associated with SIRT1 downregulation, may be prevented by NO-dependent signaling modulation.

Effect of Insulin on Proximal Tubules Handling of Glucose: A Systematic Review

Renal proximal tubules reabsorb glucose from the glomerular filtrate and release it back into the circulation. Modulation of glomerular filtration and renal glucose disposal are some of the insulin actions, but little is known about a possible insulin effect on tubular glucose reabsorption. This review is aimed at synthesizing the current knowledge about insulin action on glucose handling by proximal tubules. Method. A systematic article selection from Medline (PubMed) and Embase between 2008 and 2019. 180 selected articles were clustered into topics (renal insulin handling, proximal tubule glucose transport, renal gluconeogenesis, and renal insulin resistance). Summary of Results. Insulin upregulates its renal uptake and degradation, and there is probably a renal site-specific insulin action and resistance; studies in diabetic animal models suggest that insulin increases renal SGLT2 protein content; in vivo human studies on glucose transport are few, and results of glucose transporter protein and mRNA contents are conflicting in human kidney biopsies; maximum renal glucose reabsorptive capacity is higher in diabetic patients than in healthy subjects; glucose stimulates SGLT1, SGLT2, and GLUT2 in renal cell cultures while insulin raises SGLT2 protein availability and activity and seems to directly inhibit the SGLT1 activity despite it activating this transporter indirectly. Besides, insulin regulates SGLT2 inhibitor bioavailability, inhibits renal gluconeogenesis, and interferes with Na+K+ATPase activity impacting on glucose transport. Conclusion. Available data points to an important insulin participation in renal glucose handling, including tubular glucose transport, but human studies with reproducible and comparable method are still needed.