Insulin glulisine in the management of diabetes

Insulin: evolution of insulin formulations and their application in clinical practice over 100 years

The first preparation of insulin extracted from a pancreas and made suitable for use in humans after purification was achieved 100 years ago in Toronto, an epoch-making achievement, which has ultimately provided a life-giving treatment for millions of people worldwide. The earliest animal-derived formulations were short-acting and contained many impurities that caused adverse reactions, thereby limiting their therapeutic potential. However, since then, insulin production and purification improved with enhanced technologies, along with a full understanding of the insulin molecule structure. The availability of radio-immunoassays contributed to the unravelling of the physiology of glucose homeostasis, ultimately leading to the adoption of rational models of insulin replacement. The introduction of recombinant DNA technologies has since resulted in the era of both rapid- and long-acting human insulin analogues administered via the subcutaneous route which better mimic the physiology of insulin secretion, leading to the modern basal-bolus regimen. These advances, in combination with improved education and technologies for glucose monitoring, enable people with diabetes to better meet individual glycaemic goals with a lower risk of hypoglycaemia. While the prevalence of diabetes continues to rise globally, it is important to recognise the scientific endeavour that has led to insulin remaining the cornerstone of diabetes management, on the centenary of its first successful use in humans.

Analysis of the local dynamics of human insulin and a rapid-acting insulin analog by hydrogen/deuterium exchange mass spectrometry

Human insulin and insulin lispro (lispro), a rapid-acting insulin analog, have identical primary structures, except for the transposition of a pair of amino acids. This mutation results in alterations in their higher order structures, with lispro dissociating more easily than human insulin. In our previous study performed using hydrogen/deuterium exchange mass spectrometry (HDX/MS), differences were observed in the rates and levels of deuteration among insulin analog products, which were found to be related to their self-association stability. In this study, we carried out peptide mapping of deuterated human insulin and lispro to determine the regions responsible for these deuteration differences and to elucidate the type of structural changes that affect their HDX reactivity. We identified A3-6 and B22-24 as the 2 regions that showed distinct differences in the number of deuterium atoms incorporated between human insulin and lispro. These regions contain residues that are thought to participate in hexamerization and dimerization, respectively. We also determined that over time, the differences in deuteration levels decreased in A3-6, whereas they increased in B22-24, suggesting a difference in the dynamics between these 2 regions. This article is part of a Special Issue entitled: Mass spectrometry in structural biology.

Evolution of insulin development: focus on key parameters

INTRODUCTION

Although insulin products and treatment strategies have improved significantly, clinical challenges still exist. Meeting glycemic goals while minimizing glucose variability and hypoglycemia is of utmost importance when considering existing insulin therapies and designing investigational insulin treatments.

METHODS

A PubMed search identified relevant, peer-reviewed articles related to the evolution of insulin development for this nonsystematic review. Search terms included "animal insulin," "synthetic insulin," "regular human insulin," "insulin lispro," "insulin aspart," "insulin glulisine," "insulin glargine," "insulin detemir," "insulin degludec," "biphasic human insulin," "insulin premixes," "ultra-long acting," "oral insulin," and "inhaled insulin."

RESULTS

While the discovery of animal insulin significantly decreased mortality rates from diabetes, issues with availability and large variability between batches led to difficulty in determining proper doses and, subsequently, challenges in achieving glycemic control and avoiding hypoglycemia. The development of synthetic insulin created a more readily available supply, but hypoglycemia still persisted. Recombinant DNA technology solved insulin production problems and allowed for the development of better retarding agents, but pharmacokinetic/pharmacodynamic profiles still did not mimic natural insulin. Insulin premixes offered improved glycemic control, decreased intrapatient variability versus self-mixing, and required fewer injections per day; however, patient adherence remained a problem due to the need to inject 30-60 minutes before a meal for optimal control. This prompted the development of rapid-acting insulin analogs that could be injected right before a meal and long-acting insulin analogs with flatter time-action profiles.

CONCLUSION

Despite advances in insulin development, a need to provide more physiologic basal insulin coverage and reduce hypoglycemic risk in patients with diabetes remains. Newer insulin analogs and more convenient routes of insulin delivery have shown promising safety and efficacy results. Many patients with diabetes have not reached glycemic goals on currently available insulins. Additional studies are necessary to tailor optimal insulin delivery strategies to specific subsets of diabetes patients.

Uncovering undetected hypoglycemic events

Hypoglycemia is the rate-limiting factor that often prevents patients with diabetes from safely and effectively achieving their glycemic goals. Recent studies have reported that severe hypoglycemia is associated with a significant increase in the adjusted risks of major macrovascular events, major microvascular events, and mortality. Minor hypoglycemic episodes can also have serious implications for patient health, psychological well being, and adherence to treatment regimens. Hypoglycemic events can impact the health economics of the patient, their employer, and third-party payers. Insulin treatment is a key predictor of hypoglycemia, with one large population-based study reporting an overall prevalence of 7.1% (type 1 diabetes mellitus) and 7.3% (type 2 diabetes mellitus) in insulin-treated patients, compared with 0.8% in patients with type 2 diabetes treated with an oral sulfonylurea. Patients with type 1 diabetes typically experience symptomatic hypoglycemia on average twice weekly and severe hypoglycemia once annually. The progressive loss of islet cell function in patients with type 2 diabetes results in a higher risk of both symptomatic and unrecognized hypoglycemia over time. Patients with diabetes who become hypoglycemic are also more susceptible to developing defective counter-regulation, also known as hypoglycemia awareness autonomic failure, which is life-threatening and must be aggressively addressed. In patients unable to recognize hypoglycemia symptoms, frequent home monitoring or use of continuous glucose sensors are critical. Primary care physicians play a key role in the prevention and management of hypoglycemia in patients with diabetes, particularly in those requiring intensive insulin therapy, yet physicians are often unaware of the multitude of consequences of hypoglycemia or how to deal with them. Careful monitoring, adherence to guidelines, and use of optimal treatment combinations are all important steps toward improving care in patients with diabetes. The most important goals are for primary care physicians to recognize that every patient treated with antihyperglycemic medications is at risk of iatrogenic hypoglycemia and to ask patients about hypoglycemia at every visit.