The discovery of insulin revisited: lessons for the modern era

Potential of Vitamin D and l-Cysteine Co-supplementation to Downregulate Mammalian Target of Rapamycin: A Novel Therapeutic Approach to Diabetes

Diabetes, a metabolic disease associated with an increased health care burden and mortality, is currently on the rise. Both upregulation of the mammalian target of rapamycin (mTOR) and decreased levels of vitamin D (VD) and l-cysteine (LC) have been associated with diabetes. The overactivation of mTOR leads to insulin desensitization and metabolic dysfunction including uncontrolled hyperglycemia. This review summarizes various studies that have shown an inhibitory effect of VD or LC on mTOR activity. Findings from preclinical studies suggest that optimizing the VD and LC status in patients with diabetes can result in mTOR suppression, which has the potential to protect these individuals from microvascular and macrovascular complications while enhancing the regulation of their blood glucose. Given this information, finding ways to suppress mTOR signaling and also increasing VD and LC status is a possible therapeutic approach that might aid patients with diabetes. Future clinical trials are needed to investigate whether VD and LC co-supplementation can successfully downregulate mTOR and can be used as adjuvant therapy in patients with diabetes.

The Up-to-date Treatment for Diabetes and Prevention of its Complications

Diabetes mellitus, characterized by high blood glucose due to inadequate insulin action, comprises two main types: type 1, an autoimmune disease, and type 2, marked by insulin resistance. This review provides a comprehensive overview of diabetes management and treatment advancements. Effective diabetes management includes maintaining blood glucose levels within normal ranges and monitoring HbA1c, a marker reflecting average glucose levels over the past few months. Historically, the discovery of insulin in 1921 revolutionized diabetes treatment, significantly extending patient life expectancy. Current treatment strategies encompass diet, exercise, and pharmacotherapy. The diet involves a balanced intake of carbohydrates, proteins, and fats, while exercise, including aerobic and resistance training, improves insulin sensitivity and glucose control. Pharmacotherapy options include insulin therapy and oral hypoglycemic agents, like metformin and empagliflozin, each with specific mechanisms of action. Innovative treatments include SGLT2 inhibitors and GLP-1 receptor agonists, which aid in glucose control and offer additional benefits like weight loss and improved cardiovascular outcomes. Continuous glucose monitoring (CGM) and insulin pumps represent technological advancements enhancing glycemic control through real-time monitoring and automated insulin delivery. We must pay attention to diabetes-related stigma, which we should overcome by advocacy. The diabetes education programs at Juntendo University Hospital aim to improve patient self-management through comprehensive diet, exercise, and medication education. We emphasize the importance of integrating the latest research and societal support to enable diabetic patients to lead healthy, fulfilling lives.

Efficacy and safety of once-weekly insulin versus once-daily insulin in patients with type 1 and type 2 diabetes mellitus: an updated meta-analysis of randomized controlled trials

Background

This meta-analysis was performed to obtain a comprehensive overview of the differences between once-weekly basal insulin (including icodec and basal insulin Fc) and once-daily basal insulin (including glargine and degludec) in patients with type 1 and type 2 diabetes mellitus.

Methods

PubMed, EMBASE, and Cochrane Library were systematically searched for eligible studies up to 2 January 2024.

Results

A total of 12 studies were included, comprising 5,895 patients, with 3,104 (52.7%) using once-weekly insulin and 2,791 (47.3%) using once-daily insulin. In the pooled data, glycated hemoglobin (HbA1c) change from baseline [mean difference (MD) -0.11%; 95% confidence interval (CI) -0.20 to -0.01%] and the odds of achieving an end-of-trial HbA1c <7% (OR 1.41, 95% CI 1.13, 1.77) demonstrated a significantly good glycemic control in the once-weekly insulin group, especially in insulin-naïve type 2 diabetics or patients using icodec. Body weight increase for once-weekly insulin was 0.43 kg compared to controls (95% CI 0.09 to 0.76 kg). In addition, once-weekly insulin was correlated with a higher risk of level 1 hypoglycemia (OR 1.42, 95% CI 1.26 to 1.6). There was no significant difference in fasting plasma glucose (MD 2.46 mg/dL; 95% CI -2.60 to 7.52 mg/dL), time in range (MD 2.03%; 95% CI -0.50 to 4.56%), and level 2 or 3 hypoglycemic events (OR 1.19; 95% CI 0.93 to 1.53).

Conclusions

Once-weekly basal insulin is safe and effective in modestly reducing HbA1c with similar level 2 or 3 hypoglycemic events compared to once-daily insulin, although the risk of level 1 hypoglycemia and weight gain was slightly increased.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, Identifier CRD42024496812.

Frederick G Banting (1891-1941): A Pioneer in Diabetes Treatment

The discovery of insulin by Frederick G Banting and his colleagues in 1921 marked a pivotal moment in medical history. Born in Ontario, Canada, in 1891, Banting's childhood was impacted by the death of his closest friend, Jane, who died of diabetes mellitus at a young age. This personal tragedy profoundly influenced him to choose a career in medicine and fueled his determination to find a cure for diabetes. This journey led to the discovery of Insulin with the help of Charles H Best and John JR Macleod, resulting in a Nobel Prize for this work. Their discoveries set the stage for advancements in clinical medicine and biotechnology, including developing recombinant insulin over 50 years later.

Intranasal Insulin Eases Autism in Rats via GDF-15 and Anti-Inflammatory Pathways

In rat models, it is well-documented that chronic administration of propionic acid (PPA) leads to autism-like behaviors. Although the intranasal (IN) insulin approach is predominantly recognized for its effects on food restriction, it has also been shown to enhance cognitive memory by influencing various proteins, modulating anti-inflammatory pathways in the brain, and reducing signaling molecules such as interleukins. This study seeks to explore the potential therapeutic benefits of IN insulin in a rat model of autism induced by PPA. Thirty male Wistar albino rats were categorized into three cohorts: the control group, the PPA-induced autism (250 mg/kg/day intraperitoneal PPA dosage for five days) group, treated with saline via IN, and the PPA-induced autism group, treated with 25 U/kg/day (250 µL/kg/day) insulin via IN. All treatments were administered for 15 days. After behavioral testing, all animals were euthanized, and brain tissue and blood samples were collected for histopathological and biochemical assessments. Following insulin administration, a substantial reduction in autism symptoms was observed in all three social behavior tests conducted on the rats. Moreover, insulin exhibited noteworthy capabilities in decreasing brain MDA, IL-2, IL-17, and TNF-α levels within autism models. Additionally, there is a notable elevation in the brain nerve growth factor level (p < 0.05) and GDF-15 (p < 0.05). The assessment of cell counts within the hippocampal region and cerebellum revealed that insulin displayed effects in decreasing glial cells and inducing a significant augmentation in cell types such as the Purkinje and Pyramidal cells. The administration of insulin via IN exhibits alleviating effects on autism-like behavioral, biochemical, and histopathological alterations induced by PPA in rats. Insulin-dependent protective effects show anti-inflammatory, anti-oxidative, and neuroprotective roles of insulin admitted nasally.

Activation and modulation of the AGEs-RAGE axis: Implications for inflammatory pathologies and therapeutic interventions - A review

Chronic inflammation is a common foundation for the development of many non-communicable diseases, particularly diabetes, atherosclerosis, and tumors. The activation of the axis involving Advanced Glycation End products (AGEs) and their receptor RAGE is a key promotive factor in the chronic inflammation process, influencing the pathological progression of these diseases. The accumulation of AGEs in the body results from an increase in glycation reactions and oxidative stress, especially pronounced in individuals with diabetes. By binding to RAGE, AGEs activate signaling pathways such as NF-κB, promoting the release of inflammatory factors, exacerbating cell damage and inflammation, and further advancing the formation of atherosclerotic plaques and tumor development. This review will delve into the molecular mechanisms by which the AGEs-RAGE axis activates chronic inflammation in the aforementioned diseases, as well as strategies to inhibit the AGEs-RAGE axis, aiming to slow or halt the progression of chronic inflammation and related diseases. This includes the development of AGEs inhibitors, RAGE antagonists, and interventions targeting upstream and downstream signaling pathways. Additionally, the early detection of AGEs levels and RAGE expression as biomarkers provides new avenues for the prevention and treatment of diabetes, atherosclerosis, and tumors.

Lessons From Insulin: Policy Prescriptions for Affordable Diabetes and Obesity Medications

Escalating insulin prices have prompted public scrutiny of the practices of drug manufacturers, pharmacy benefit managers, health insurers, and pharmacies involved in production and distribution of medications. As a result, a series of policies have been proposed or enacted to improve insulin affordability and foster greater equity in access. These policies have implications for other diabetes and obesity therapeutics. Recent legislation, at both the state and federal level, has capped insulin out-of-pocket payments for some patients. Other legislation has targeted drug manufacturers directly in requiring rebates on drugs with price increases beyond inflation rates, an approach that may restrain price hikes for existing medications. In addition, government negotiation of drug pricing, a contentious issue, has gained traction, with the Inflation Reduction Act of 2022 permitting limited negotiation for certain high expenditure drugs without generic or biosimilar competition, including some insulin products and other diabetes medications. However, concerns persist that this may inadvertently encourage higher launch prices for new medications. Addressing barriers to competition has also been a priority such as through increased enforcement against anticompetitive practices (e.g., "product hopping") and reduced regulatory requirements for biosimilar development and market entry. A novel approach involves public production, exemplified by California's CalRx program, which aims to provide biosimilar insulins at significantly reduced prices. Achieving affordable and equitable access to insulin and other diabetes and obesity medications requires a multifaceted approach, involving state and federal intervention, ongoing policy evaluation and refinement, and critical examination of corporate influences in health care.

Out-of-pocket expenses and rationing of insulin and diabetes supplies: findings from the 2022 T1International cross-sectional web-based survey

Introduction

Continue investigating Out-of-Pocket Expenses (OoPEs) and rationing of insulin and diabetes supplies, including impacts of the COVID-19 pandemic, for people with type 1 diabetes (T1D).

Methods

A cross-sectional web-based survey was conducted in English and advertised by T1International's global network of patient advocates from May through September 2022. Participants provided monthly OoPEs and rationing frequency for insulin and supplies, impacts of the COVID-19 pandemic, and open-ended comments.

Results

In the seven most represented countries, mean monthly OoPEs were highest in the United States, followed by Panama, Canada, and India, and were much lower in the United Kingdom, Germany, and Sweden. OoPEs were highest for participants with partial healthcare coverage, followed by those with no healthcare coverage. The COVID-19 pandemic negatively impacted access and/or affordability of insulin and/or supplies for over half of participants. Globally, 19.5% reported insulin rationing and 36.6% reported rationing glucose testing supplies. Qualitative analysis of open-ended responses identified themes such as 'mental health impacts' and 'limits to life choices.'

Discussion

High OoPEs lead to rationing of insulin and supplies for many people with T1D globally. Healthcare systems improvements and price reductions of insulin and supplies are needed to ensure adequate, equitable access for all.

Insulin's Legacy: A Century of Breakthroughs and Innovation

The clinical use of insulin to treat diabetes started just over 100 years ago. The past century has witnessed remarkable innovations in insulin therapy, evolving from animal organ extracts to bioengineered human insulins with ultra-rapid onset or prolonged action. Insulin delivery systems have also progressed to current automated insulin delivery systems. In this review, we discuss the history of insulin and the pharmacology and therapeutic indications for a variety of available insulins, especially newer analog insulins. We highlight recent advances in insulin pump therapy and review evidence on the therapeutic benefits of automated insulin delivery. As with any form of progress, there have been setbacks, and insulin has recently faced an affordability crisis. We address the challenges of insulin accessibility, along with recent progress to improve insulin affordability. Finally, we mention research on glucose-responsive insulins and hepato-preferential insulins that are likely to shape the future of insulin therapy.

An organism-wide atlas of hormonal signaling based on the mouse lemur single-cell transcriptome

Hormones mediate long-range cell communication and play vital roles in physiology, metabolism, and health. Traditionally, endocrinologists have focused on one hormone or organ system at a time. Yet, hormone signaling by its very nature connects cells of different organs and involves crosstalk of different hormones. Here, we leverage the organism-wide single cell transcriptional atlas of a non-human primate, the mouse lemur (Microcebus murinus), to systematically map source and target cells for 84 classes of hormones. This work uncovers previously-uncharacterized sites of hormone regulation, and shows that the hormonal signaling network is densely connected, decentralized, and rich in feedback loops. Evolutionary comparisons of hormonal genes and their expression patterns show that mouse lemur better models human hormonal signaling than mouse, at both the genomic and transcriptomic levels, and reveal primate-specific rewiring of hormone-producing/target cells. This work complements the scale and resolution of classical endocrine studies and sheds light on primate hormone regulation.

Type 1 diabetes: A new vision of the disease based on endotypes

Diagnosis and management of type 1 diabetes (T1D) have remained largely unchanged for the last several years. The management of the disease remains primarily focused on its phenotypical presentation and less on endotypes, namely the specific biological mechanisms behind the development of the disease. Furthermore, the treatment of T1D is essentially universal and indiscriminate-with patients administering insulin at varying dosages and frequencies to maintain adequate glycaemic control. However, it is now well understood that T1D is a heterogeneous disease with many different biological mechanisms (i.e. endotypes) behind its complex pathophysiology. A range of factors, including age of onset, immune system regulation, rate of β-cell destruction, autoantibodies, body weight, genetics and the exposome are recognised to play a role in the development of the condition. Patients can be classified into distinct diabetic subtypes based on these factors, which can be used to categorise patients into specific endotypes. The classification of patients into endotypes allows for a greater understanding of the natural progression of the disease, giving rise to more accurate and patient-centred therapies and follow-up monitoring, specifically for other autoimmune diseases. This review proposes 6 unique endotypes of T1D based on the current literature. The recognition of these endotypes could then be used to direct therapeutic modalities based on patients' individual pathophysiology.

The liver-derived exosomes stimulate insulin gene expression in pancreatic beta cells under condition of insulin resistance

Introduction

An insufficient functional beta cell mass is a core pathological hallmark of type 2 diabetes (T2D). Despite the availability of several effective pharmaceuticals for diabetes management, there is an urgent need for novel medications to protect pancreatic beta cells under diabetic conditions. Integrative organ cross-communication controls the energy balance and glucose homeostasis. The liver and pancreatic islets have dynamic cross-communications where the liver can trigger a compensatory beta cell mass expansion and enhanced hormonal secretion in insulin-resistant conditions. However, the indispensable element(s) that foster beta cell proliferation and insulin secretion have yet to be completely identified. Exosomes are important extracellular vehicles (EVs) released by most cell types that transfer biological signal(s), including metabolic messengers such as miRNA and peptides, between cells and organs.

Methods

We investigated whether beta cells can take up liver-derived exosomes and examined their impact on beta cell functional genes and insulin expression. Exosomes isolated from human liver HepG2 cells were characterized using various methods, including Transmission Electron Microscopy (TEM), dynamic light scattering (DLS), and Western blot analysis of exosomal markers. Exosome labeling and cell uptake were assessed using CM-Dil dye. The effect of liver cell-derived exosomes on Min6 beta cells was determined through gene expression analyses of beta cell markers and insulin using qPCR, as well as Akt signaling using Western blotting.

Results

Treatment of Min6 beta cells with exosomes isolated from human liver HepG2 cells treated with insulin receptor antagonist S961 significantly increased the expression of beta cell markers Pdx1, NeuroD1, and Ins1 compared to the exosomes isolated from untreated cells. In line with this, the activity of AKT kinase, an integral component of the insulin receptor pathway, is elevated in pancreatic beta cells, as represented by an increase in AKT's downstream substrate, FoxO1 phosphorylation.

Discussions

This study suggests that liver-derived exosomes may carry a specific molecular cargo that can affect insulin expression in pancreatic beta cells, ultimately affecting glucose homeostasis.

Narrative review of the role of technology in pediatric diabetes: from testing blood glucose to subcutaneous automated therapy and hope for cure

Background and Objective

Type 1 diabetes, the most common cause of diabetes in pediatrics, is defined by the hyperglycemia that results from the permanent autoimmune damage to the pancreas. The Diabetes Control and Complications Trial (DCCT) demonstrated that strict glycemic control targeting lower HbA1c goals can both delay the onset and progression of its complications that include diabetic neuropathy, nephropathy, retinopathy, and increased cardiovascular events. Our primary objective is to review the literature available regarding the technology applied for the treatment of diabetes, not only aiding patients' quality of life but addressing its effects on hypoglycemia and reduced risk of the long-term complications. It will synthesize the evolution of glucose monitoring devices; the development of insulin: from animal to recombinant engineering, smart insulin in the future; the development of algorithm-driven insulin delivery devices, the closed loop system/artificial pancreas; and the future utilization of technology to support islet cell transplant with the goal of a long-term cure. Emphasis will be made on what is known about the impact on its outcomes in children and adolescents.

Methods

A literature search was conducted using PubMed for publications from 1985 to present. Keywords used: type 1 diabetes, children, adolescents, pediatrics, continuous glucose monitoring (CGM), insulin pumps. Referenced articles include other reviews, current care guidelines as supported by cross sectional studies, cohort studies and randomized clinical trials.

Key Content and Findings

Understanding the pathophysiology of type 1 diabetes has led to the design of technology that facilitates glucose monitoring and insulin administration in a personalized manner. The current technology has improved outcomes and quality of life by decreasing hypoglycemic events and decreasing risk of long-term metabolic complications. Barriers remain, for children and adults, often driven by patient's preference as well as their understanding of the limitations of what they are wearing.

Conclusions

With the progressive evolution of this technology, it is now realistic to lower the burden of diabetes self-management while reducing hypoglycemia and risk of complications that otherwise impact daily life from academics, physical activity, career choices and even life expectancy.

Signaling pathways and intervention for therapy of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) represents one of the fastest growing epidemic metabolic disorders worldwide and is a strong contributor for a broad range of comorbidities, including vascular, visual, neurological, kidney, and liver diseases. Moreover, recent data suggest a mutual interplay between T2DM and Corona Virus Disease 2019 (COVID-19). T2DM is characterized by insulin resistance (IR) and pancreatic β cell dysfunction. Pioneering discoveries throughout the past few decades have established notable links between signaling pathways and T2DM pathogenesis and therapy. Importantly, a number of signaling pathways substantially control the advancement of core pathological changes in T2DM, including IR and β cell dysfunction, as well as additional pathogenic disturbances. Accordingly, an improved understanding of these signaling pathways sheds light on tractable targets and strategies for developing and repurposing critical therapies to treat T2DM and its complications. In this review, we provide a brief overview of the history of T2DM and signaling pathways, and offer a systematic update on the role and mechanism of key signaling pathways underlying the onset, development, and progression of T2DM. In this content, we also summarize current therapeutic drugs/agents associated with signaling pathways for the treatment of T2DM and its complications, and discuss some implications and directions to the future of this field.

Evaluation of physicochemical parameters, acute and subchronic toxicities, and anti-diabetic activity of Spondias venulosa (Engl.) Mart. ex Engl. leaf extract on alloxan-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Spondias venulosa is a medicinal plant whose leaves are popularly used for decades in Northeast Nigeria as a first-choice medicinal plants for the treatment of diabetes. This claim has not been proven scientifically.

AIM OF THE STUDY

The present study was carried out to determine the physicochemical profiles, acute, sub-chronic toxicities, and antidiabetic activity the leaf extract in alloxan-induced diabetic rats.

MATERIALS AND METHODS

The physicochemical parameters of S. venulosa leaves, acute, subchronic toxicities, and antidiabetic activity in alloxan-induced diabetic rats were determined using standard procedures. All physicochemical parameters were carried out triplicate. Acute and subchronic toxicity studies were carried out following OECD guidelines by administering maximum extract dose of 2000 mg/kg orally to Wistar rats. Subchronic toxicity and antidiabetic studies were carried out in rats of opposite sexes at doses 300, 600, and 1200 mg/kg (orally).

RESULTS

Results obtained showed that the moisture content, water soluble extractive, and organic matter had values of 4.98 ± 1.01, 12.04 ± 1.24 and 1.01 ± 0.01% w/w respectively. The metallic contents of the methanol leaf extract revealed the presence of zinc with value of 12.01 ± 1.01 ppm (normal range:< 100 mg/kg DM) and copper with value of 6.24 ± 2.14 ppm (normal range:< 30 mg/kg DM). Oral median lethal dose (LD₅₀) was estimated to be greater than 2000 mg/kg since the extract did not produce any sign of toxicity or death in short term while, subchronic toxicity study showed that there was no significant weight loss in the rats after 28 days of extract administration. All hematology and biochemical parameters showed no elevated values when compared to the control group (p < 0.05). Histopathological examinations of major organs do not show signs of organ damages which indicate that the extract was safe at the doses administered. Oral administration of extract doses for 30 days reduced blood glucose levels in alloxan-induced diabetic rats in dose-dependent manner compared (p < 0.05) to standard drug (Glibenclamide).

CONCLUSIONS

Our study showed some physicochemical parameters of S. venulosa leaf which are essential for its identification from closely related species in traditional medicine. The study further showed that S. venulosa methanol leaf extract possessed antidiabetic activity, thus, justifying its use for the treatment of diabetes in Nigeria. However, there is need to identify and investigate the bioactive compound(s) responsible for the activity towards drug discovery.

Dietary Methionine Restriction Improves Gastrocnemius Muscle Glucose Metabolism through Improved Insulin Secretion and H19/IRS-1/Akt Pathway in Middle-Aged Mice

Methionine restriction (MR) improves glucose metabolism. In skeletal muscle, H19 is a key regulator of insulin sensitivity and glucose metabolism. Therefore, this study aims to reveal the underlying mechanism of H19 upon MR on glucose metabolism in skeletal muscle. Middle-aged mice were fed MR diet for 25 weeks. Mouse islets β cell line β-TC6 cells and mouse myoblast cell line C2C12 cells were used to establish the apoptosis or insulin resistance model. Our findings showed that MR increased B-cell lymphoma-2 (Bcl-2) expression, deceased Bcl-2 associated X protein (Bax), cleaved cysteinyl aspartate-specific proteinase-3 (Caspase-3) expression in pancreas, and promoted insulin secretion of β-TC6 cells. Meanwhile, MR increased H19 expression, insulin Receptor Substrate-1/insulin Receptor Substrate-2 (IRS-1/IRS-2) value, protein Kinase B (Akt) phosphorylation, glycogen synthase kinase-3β (GSK3β) phosphorylation, and hexokinase 2 (HK2) expression in gastrocnemius muscle and promoted glucose uptake in C2C12 cells. But these results were reversed after H19 knockdown in C2C12 cells. In conclusion, MR alleviates pancreatic apoptosis and promotes insulin secretion. And MR enhances gastrocnemius muscle insulin-dependent glucose uptake and utilization via the H19/IRS-1/Akt pathway, thereby ameliorating blood glucose disorders and insulin resistance in high-fat-diet (HFD) middle-aged mice.

Equity should be fundamental to the emergence of innovation

The ability of artificial intelligence to perpetuate bias at scale is increasingly recognized. Recently, proposals for implementing regulation that safeguards such discrimination have come under pressure due to the potential of such restrictions stifling innovation within the field. In this formal comment, we highlight the potential dangers of such views and explore key examples that define this relationship between health equity and innovation. We propose that health equity is a vital component of healthcare and should not be compromised to expedite the advancement of results for the few at the expense of vulnerable populations. A data-centered future that works for all will require funding bodies to incentivize equity-focused AI, and organizations must be held accountable for the differential impact of such algorithms post-deployment.

Urinary insulin signaling pathway related proteins may serve as potential biomarkers for monitoring diabetes mellitus without hypertension and hyperlipidemia

The insulin signaling pathway plays an important role in the development of diabetes mellitus. The expression of insulin signaling pathway related proteins in the urine of diabetic patients has not been reported. The aim of this study was to analyze and verify the expression of insulin signaling pathway related proteins in the urine of diabetic patients without hypertension and hyperlipidemia, and to explore their clinical application value. Based on data-independent acquisition proteomics technology and bioinformatics, the urinary protein expression profile of diabetic patients without hypertension and hyperlipidemia was established. Western blot and enzyme-linked immunoassay were performed to verify the expression of insulin signaling pathway related proteins in the urine of diabetic patients. Sixteen proteins related to the insulin signaling pathway were screened in urine, and 7 of them were differentially expressed in the urine of diabetic patients without hypertension and hyperlipidemia. Further quantitative analysis showed that the downregulation of protein kinase CAMP-dependent type II regulatory subunit α, growth factor receptor bound protein 2, and guanine nucleotide-binding protein G(s) in the urine of diabetic patients without hyperlipidemia and hypertension was consistent with the preliminary screening results. In this exploratory study, we detected the expression of insulin signaling pathway related proteins in the urine of diabetic patients without hypertension and hyperlipidemia. protein kinase CAMP-dependent type II regulatory subunit α, growth factor receptor bound protein 2, and guanine nucleotide-binding protein G(s) in the urine of diabetic patients were downregulated, which was associated with diabetes. They may be promising noninvasive biomarkers for monitoring diabetes.

Cerebrovascular insulin receptors are defective in Alzheimer's disease

Central response to insulin is suspected to be defective in Alzheimer's disease. As most insulin is secreted in the bloodstream by the pancreas, its capacity to regulate brain functions must, at least partly, be mediated through the cerebral vasculature. However, how insulin interacts with the blood-brain barrier and whether alterations of this interaction could contribute to Alzheimer's disease pathophysiology both remain poorly defined. Here, we show that human and murine cerebral insulin receptors (INSRs), particularly the long isoform INSRα-B, are concentrated in microvessels rather than in the parenchyma. Vascular concentrations of INSRα-B were lower in the parietal cortex of subjects diagnosed with Alzheimer's disease, positively correlating with cognitive scores, leading to a shift towards a higher INSRα-A/B ratio, consistent with cerebrovascular insulin resistance in the Alzheimer's disease brain. Vascular INSRα was inversely correlated with amyloid-β plaques and β-site APP cleaving enzyme 1, but positively correlated with insulin-degrading enzyme, neprilysin and P-glycoprotein. Using brain cerebral intracarotid perfusion, we found that the transport rate of insulin across the blood-brain barrier remained very low (<0.03 µl/g·s) and was not inhibited by an insulin receptor antagonist. However, intracarotid perfusion of insulin induced the phosphorylation of INSRβ that was restricted to microvessels. Such an activation of vascular insulin receptor was blunted in 3xTg-AD mice, suggesting that Alzheimer's disease neuropathology induces insulin resistance at the level of the blood-brain barrier. Overall, the present data in post-mortem Alzheimer's disease brains and an animal model of Alzheimer's disease indicate that defects in the insulin receptor localized at the blood-brain barrier strongly contribute to brain insulin resistance in Alzheimer's disease, in association with β-amyloid pathology.

Association of subclass distribution of insulin antibody with glucose control in insulin-treated type 2 diabetes mellitus: a retrospective observational study

Objective

To examine the distribution and effects of the subclass of insulin antibodies on glucose control and side events in patients with type 2 diabetes treated with premixed insulin analog.

Methods

A total of 516 patients treated with premixed insulin analog were sequentially enrolled from the First Affiliated Hospital of Nanjing Medical University from June 2016 to August 2020. Subclass-specific insulin antibodies (IAs) (IgG1-4, IgA, IgD, IgE, and IgM) were detected in IA-positive patients by electrochemiluminescence. We analyzed glucose control, serum insulin, and insulin-related events between IA-positive and IA-negative groups, as well as among patients with different IA subclasses.

Results

Overall, 98 of 516 subjects (19.0%) were positive for total IAs after premixed insulin analog therapy; of these participants, 92 had subclass IAs, and IgG-IA was the predominant subclass, followed by IgE-IA. IAs were associated with serum total insulin increase and local injection-site reactions but not glycemic control and hypoglycemia. In the subgroup analysis in patients with IA-positive, the IgE-IA and IA subclass numbers were more associated with increased serum total insulin levels. Additionally, IgE-IA might be correlated more strongly with local responses and weakly with hypoglycemia, while IgM-IA might be correlated more strongly with hypoglycemia.

Conclusion

We concluded that IAs or IA subclasses might be associated with unfavorable events in patients receiving premixed insulin analog therapy, which can be used as an adjunctive monitoring indicator in clinical insulin trials.

The insulin signaling pathway a century after its discovery: Sexual dimorphism in insulin signaling

Since practically a century ago, the insulin pathway was discovered in both vertebrates and invertebrates, implying an evolutionarily ancient origin. After a century of research, it is now clear that the insulin signal transduction pathway is a critical, flexible and pleiotropic pathway, evolving into multiple anabolic functions besides glucose homeostasis. It regulates paramount aspects of organismal well-being like growth, longevity, intermediate metabolism, and reproduction. Part of this diversification has been attained by duplications and divergence of both ligands and receptors riding on a common general signal transduction system. One of the aspects that is strikingly different is its usage in reproduction, particularly in male versus female development and fertility within the same species. This review highlights sexual divergence in metabolism and reproductive tract differences, the occurrence of sexually "exaggerated" traits, and sex size differences that are due to the sexes' differential activity/response to the insulin signaling pathway.

Skeletal muscle HSF1 prevents insulin resistance by improving glucose utilization

The regulation of muscle glucose utilization has significant potential for the treatment of type 2 diabetes mellitus (T2DM) and obesity. Heat shock factor 1 (HSF1) is involved in cellular metabolism and regulation of muscle metabolism. However, it is unclear how HSF1 regulates muscle glucose metabolism. In the present study, the development of obesity in mice was associated with HSF1 downregulation. Serum samples and muscle biopsies were obtained from obese and healthy humans. Fasting glucose and insulin levels and the homeostasis model assessment of insulin resistance value showed that obesity was associated with insulin resistance. The skeletal muscle level of HSF1 was decreased in obese and ob/ob mice. HSF1 was selectively over-expressed in the skeletal muscles of high fat diet (HFD)-fed mice. Muscle HSF1 over-expression successfully triggered glycolytic-to-oxidative myofiber switch and increased fatty acid metabolism and insulin sensitivity in the skeletal muscles of HFD-fed mice. Moreover, HSF1 improved energy expenditure and blocked muscle accumulation of triglycerides in HFD-fed mice. Consequently, muscle HSF1 mitigated the impaired muscle insulin signaling and insulin resistance in HFD-fed mice. In conclusion, T2DM and obesity in HFD-fed mice may be treated with selective HSF1-directed programming of exercise-like effects in skeletal muscle. These findings may aid the development of a new therapeutic approach for obesity and T2DM.

Insulin pumps in children - a systematic review

BACKGROUND

Insulin pump therapy is a real breakthrough in managing diabetes Mellitus, particularly in children. It can deliver a tiny amount of insulin and decreases the need for frequent needle injections. It also helps to maintain adequate and optimal glycemic control to reduce the risk of metabolic derangements in different tissues. Children are suitable candidates for pump therapy as they need a more freestyle and proper metabolic control to ensure adequate growth and development. Therefore, children and their caregivers should have proper education and training and understand the proper use of insulin pumps to achieve successful pump therapy. The pump therapy continuously improves to enhance its performance and increase its simulation of the human pancreas. Nonetheless, there is yet a long way to reach the desired goal.

AIM

To review discusses the history of pump development, its indications, types, proper use, special conditions that may enface the children and their families while using the pump, its general care, and its advantages and disadvantages.

METHODS

We conducted comprehensive literature searches of electronic databases until June 30, 2022, related to pump therapy in children and published in the English language.

RESULTS

We included 118 articles concerned with insulin pumps, 61 were reviews, systemic reviews, and meta-analyses, 47 were primary research studies with strong design, and ten were guidelines.

CONCLUSION

The insulin pump provides fewer needles and can provide very tiny insulin doses, a convenient and more flexible way to modify the needed insulin physiologically, like the human pancreas, and can offer adequate and optimal glycemic control to reduce the risk of metabolic derangements in different tissues.

Analysis of curative effect of insulin external application on burn wounds of diabetic patients with different depths

To explore the curative effect of insulin external application on burn wounds of diabetic patients with different depths. A retrospective analysis of 114 diabetic burn patients in the First Hospital of Hebei Medical University from June 2019 to June 2022. According to the different treatment methods, they were divided into study group (insulin therapy) and control group (conventional therapy) with 57 cases in each. The wound healing time, dressing changes, scar healing after wound healing and adverse events were compared between two groups. Pain level, serum inflammatory factors, vascular endothelial growth factor (VEGF) and oxidative stress factors before and after treatment were compared. The wound healing time (17.23 ± 2.18 vs 20.31 ± 2.09 days) and the number of dressing changes (7.01 ± 1.23 vs 8.93 ± 1.32 times) in study group were significantly lower than those in control group (P < 0.05). Before treatment, there was no difference in pain level, VEGF, interleukin-1 (IL-1), tumour necrosis factor-α (TNF-α), malondialdehyde (MDA) and superoxide dismutase (SOD) between two groups (P > 0.05). However, the pain level, scar healing, IL-1, TNF-a and MDA in study group were significantly lower than those in control group after treatment (P < 0.05). And the VEGF and SOD in study group was significantly higher than that in control group (P < 0.05). External application of insulin can shorten the wound healing time of diabetic patients with different depths, reduce the number of dressing changes, promote scar healing after wound healing, relieve pain and reduce the level of inflammatory factors, which is worthy of clinical promotion.

The continuum of insulin development viewed in the context of a collaborative process toward leveraging science to save lives: Following the trail of publications and patents one century after insulin's first use in humans

Nearly 100 years ago, diabetes, a disease expected to reach global prevalence of at least 10% within the decade, was a fatal diagnosis. This year of 2022 marks a century since insulin, a lifesaving treatment for those living with diabetes, was purified, tested in humans, and brought to the bedside through widespread commercial production, thus saving countless lives. Insulin's arrival to the world stage was acknowledged with the 1923 Nobel Prize in Physiology or Medicine for "the discovery of insulin", the first among several Prizes awarded to honor scientific work on insulin. This initial awarding has been the subject of significant controversy since, as numerous other scientists paved the way towards the ultimate success, and priority for the true "discovery of insulin" has been argued for many other scientists. The intention and regulations around the Nobel Prize nomination and award process presented herein offer insight into the 1923 Nobel prize designation for the Toronto group, which distinguished itself in the accomplishment by their success in purifying insulin from pancreatic extract and in bringing insulin to worldwide production and the homes of those who needed it. However, a continuous, collaborative process involving contributors spanning centuries and continents was required for the development, rather than discovery, of insulin therapy and its benefits to humanity. This should be the story's enduring legacy. The prior 100 years have witnessed a series of significant innovations in insulin development and therapeutics, but both a cure for diabetes and equitable insulin access remain out of reach and require inspired attention and continuous diligent efforts.

[The insulin receptor discovery is 50 years old - A review of achieved progress]

The isolation of insulin from the pancreas and its purification to a degree permitting its safe administration to type 1 diabetic patients were accomplished 100 years ago at the University of Toronto by Banting, Best, Collip and McLeod and constitute undeniably one of the major medical therapeutic revolutions, recognized by the attribution of the 1923 Nobel Prize in Physiology or Medicine to Banting and McLeod. The clinical spin off was immediate as well as the internationalization of insulin's commercial production. The outcomes regarding basic research were much slower, in particular regarding the molecular mechanisms of insulin action on its target cells. It took almost a half-century before the determination of the tri-dimensional structure of insulin in 1969 and the characterization of its cell receptor in 1970-1971. The demonstration that the insulin receptor is in fact an enzyme named tyrosine kinase came in the years 1982-1985, and the crystal structure of the intracellular kinase domain 10 years later. The crystal structure of the first intracellular kinase substrate (IRS-1) in 1991 paved the way for the elucidation of the intracellular signalling pathways but it took 15 more years to obtain the complete crystal structure of the extracellular receptor domain (without insulin) in 2006. Since then, the determination of the structure of the whole insulin-receptor complex in both the inactive and activated states has made considerable progress, not least due to recent improvement in the resolution power of cryo-electron microscopy. I will here review the steps in the development of the concept of hormone receptor, and of our knowledge of the structure and molecular mechanism of activation of the insulin receptor.

Mutations in melanocortin-4 receptor: From fish to men

Melanocortin-4 receptor (MC4R), expressed abundantly in the hypothalamus, is a critical regulator of energy homeostasis, including both food intake and energy expenditure. Shortly after the publication in 1997 of the Mc4r knockout phenotypes in mice, including increased food intake and severe obesity, the first mutations in MC4R were reported in humans in 1998. Studies in the subsequent two decades have established MC4R mutation as the most common monogenic form of obesity, especially in early-onset severe obesity. Studies in animals, from fish to mammals, have established the conserved physiological roles of MC4R in all vertebrates in regulating energy balance. Drug targeting MC4R has been recently approved for treating morbid genetic obesity. How the MC4R can be exploited for animal production is highly worthy of active investigation.

The Noble and Often Nobel Role Played by Insulin-Focused Research in Modern Medicine

Since diabetes was first described over 3,000 years ago, clinicians and scientists alike have sought ever improving treatments en route to a cure. As we approach the 100th anniversary of insulin's first therapeutic use, this article will recount the glorious history associated with research surrounding insulin's isolation, purification, cloning, and subsequent modification. The discovery path we will relate tells the story of many relentless and passionate investigators pursuing ground-breaking research. The fruits of their labor include several Nobel Prizes, new technology, and, more importantly, ever improving treatments for one of humankind's greatest medical scourges.

Structural principles of insulin formulation and analog design: A century of innovation

BACKGROUND

The discovery of insulin in 1921 and its near-immediate clinical use initiated a century of innovation. Advances extended across a broad front, from the stabilization of animal insulin formulations to the frontiers of synthetic peptide chemistry, and in turn, from the advent of recombinant DNA manufacturing to structure-based protein analog design. In each case, a creative interplay was observed between pharmaceutical applications and then-emerging principles of protein science; indeed, translational objectives contributed to a growing molecular understanding of protein structure, aggregation and misfolding.

SCOPE OF REVIEW

Pioneering crystallographic analyses-beginning with Hodgkin's solving of the 2-Zn insulin hexamer-elucidated general features of protein self-assembly, including zinc coordination and the allosteric transmission of conformational change. Crystallization of insulin was exploited both as a step in manufacturing and as a means of obtaining protracted action. Forty years ago, the confluence of recombinant human insulin with techniques for site-directed mutagenesis initiated the present era of insulin analogs. Variant or modified insulins were developed that exhibit improved prandial or basal pharmacokinetic (PK) properties. Encouraged by clinical trials demonstrating the long-term importance of glycemic control, regimens based on such analogs sought to resemble daily patterns of endogenous β-cell secretion more closely, ideally with reduced risk of hypoglycemia.

MAJOR CONCLUSIONS

Next-generation insulin analog design seeks to explore new frontiers, including glucose-responsive insulins, organ-selective analogs and biased agonists tailored to address yet-unmet clinical needs. In the coming decade, we envision ever more powerful scientific synergies at the interface of structural biology, molecular physiology and therapeutics.

Insulin: A 100-Year-Old Discovery With a Fascinating History

Diabetes has been known since antiquity. We present here a historical perspective on the concepts and ideas regarding the physiopathology of the disease, on the progressive focus on the pancreas, in particular on the islets discovered by Langerhans in 1869, leading to the iconic experiment of Minkowski and von Mering in 1889 showing that pancreatectomy in a dog induced polyuria and diabetes mellitus. Subsequently, multiple investigators searched for the active substance of the pancreas and some managed to produce extracts that lowered blood glucose and decreased polyuria in pancreatectomized dogs but were too toxic to be administered to patients. The breakthrough came 100 years ago, when the team of Frederick Banting, Charles Best, and James Collip working in the Department of Physiology headed by John Macleod at the University of Toronto managed to obtain pancreatic extracts that could be used to treat patients and rescue them from the edge of death by starvation, the only treatment then available. This achievement was quickly recognized by the Nobel Prize in Physiology or Medicine to Banting and Macleod in 1923. At 32, Banting remains the youngest awardee of this prize. Here we discuss the work that led to the discovery and its main breakthroughs, the human characters involved in an increasingly dysfunctional relationship, the controversies that followed the Nobel Prize, and the debate as to who actually "discovered" insulin. We also discuss the early commercial development and progress in insulin crystallization in the decade or so following the Nobel Prize.

A Century of Progress in Diabetes Care with Insulin: A History of Innovations and Foundation for the Future

The year 2021 marks the 100th anniversary of the discovery of insulin, which has greatly changed the lives of people with diabetes and become a cornerstone of advances in medical science. A rapid bench-to-bedside application of the lifesaving pancreatic extract and its immediate commercialization was the result of a promising idea, positive drive, perseverance, and collaboration of Banting and colleagues. As one of the very few proteins isolated in a pure form at that time, insulin also played a key role in the development of important methodologies and in the beginning of various fields of modern science. Since its discovery, insulin has evolved continuously to optimize the care of people with diabetes. Since the 1980s, recombinant DNA technology has been employed to engineer insulin analogs by modifying their amino acid sequence, which has resulted in the production of insulins with various profiles that are currently used. However, unmet needs in insulin treatment still exist, and several forms of future insulins are under development. In this review, we discuss the past, present, and future of insulin, including a history of ceaseless innovations and collective intelligence. We believe that this story will be a solid foundation and an unerring guide for the future.

C-peptide enhances glucagon secretion in response to hyperinsulinemia under euglycemic and hypoglycemic conditions

Several studies have associated the presence of residual insulin secretion capability (also referred to as being C-peptide positive) with lower risk of insulin-induced hypoglycemia in patients with type 1 diabetes (T1D), although the reason is unclear. We tested the hypothesis that C-peptide infusion would enhance glucagon secretion in response to hyperinsulinemia during euglycemic and hypoglycemic conditions in dogs (5 male/4 female). After a 2-hour basal period, an intravenous (IV) infusion of insulin was started, and dextrose was infused to maintain euglycemia for 2 hours. At the same time, an IV infusion of either saline (SAL) or C-peptide (CPEP) was started. After this euglycemic period, the insulin and SAL/CPEP infusions were continued for another 2 hours, but the glucose was allowed to fall to approximately 50 mg/dL. In response to euglycemic-hyperinsulinemia, glucagon secretion decreased in SAL but remained unchanged from the basal period in CPEP condition. During hypoglycemia, glucagon secretion in CPEP was 2 times higher than SAL, and this increased net hepatic glucose output and reduced the amount of exogenous glucose required to maintain glycemia. These data suggest that the presence of C-peptide during IV insulin infusion can preserve glucagon secretion during euglycemia and enhance it during hypoglycemia, which could explain why T1D patients with residual insulin secretion are less susceptible to hypoglycemia.

Role of Insulin in Health and Disease: An Update

Insulin is a polypeptide hormone mainly secreted by β cells in the islets of Langerhans of the pancreas. The hormone potentially coordinates with glucagon to modulate blood glucose levels; insulin acts via an anabolic pathway, while glucagon performs catabolic functions. Insulin regulates glucose levels in the bloodstream and induces glucose storage in the liver, muscles, and adipose tissue, resulting in overall weight gain. The modulation of a wide range of physiological processes by insulin makes its synthesis and levels critical in the onset and progression of several chronic diseases. Although clinical and basic research has made significant progress in understanding the role of insulin in several pathophysiological processes, many aspects of these functions have yet to be elucidated. This review provides an update on insulin secretion and regulation, and its physiological roles and functions in different organs and cells, and implications to overall health. We cast light on recent advances in insulin-signaling targeted therapies, the protective effects of insulin signaling activators against disease, and recommendations and directions for future research.