Improved pharmacokinetic and pharmacodynamic profiles of insulin analogues using InsuPatch, a local heating device.

BACKGROUND: Previous studies have shown that heating the insulin injection site may accelerate insulin absorption. We investigated the pharmacological profile of insulin administered with InsuPatch, a local skin-heating device. METHODS: In this randomized, crossover study carried out in 56 subjects with type 1 diabetes treated with insulin pump [mean age 32 ± 13.5 years; 23 women; HbA1c :7.8 ± 0.9% (62 ± 10 mmol/mol) (mean+/-standard deviation)]. Euglycemic glucose clamps were performed after administration of 0.15 units/kg of short-acting insulin analogues. Each subject underwent three clamp procedures: two with the InsuPatch device (day 1 and day 3) and one without the device (day 1 control). The primary endpoints were the following: (1) the change in the area under the curve (AUC) of insulin during the first 60 min post-insulin bolus on day 1 with the InsuPatch device versus day 1 control and (2) parameters to assess the safety of using the device. RESULTS: The area under the curve of insulin during the initial 60 min (insulin AUC(0-60)) after insulin bolus was increased by 29.7 ± 7% on day 1 InsuPatch versus day 1 control (p < 0.01). Maximal post-insulin bolus concentration was 57 mU/L on day 1 InsuPatch versus 47.6 mU/L on day 1 control (p < 0.01). On day 3 InsuPatch, insulin AUC(0-60) was increased by 27.9 ± 72% versus day 1 InsuPatch (p < 0.01). Maximal insulin concentration was 70.4 mU/L versus 57 mU/L, respectively (p = 0.05). CONCLUSIONS: The use of the heating device upon administration of short-acting insulin analogues in pump-treated type 1 diabetic patients was found to enhance insulin absorption. This heating device may therefore serve to achieve better meal insulin coverage.

Improved Postprandial Glucose Control Using the InsuPad Device in Insulin-Treated Type 2 Diabetes: Injection Site Warming to Improve Glycemic Control.

BACKGROUND: Delays in the time-action profiles of premeal boluses of rapid-acting insulin analogs contribute to early postmeal hyperglycemia in patients with diabetes. We tested whether applying local heat to skin around the injection site to increase the rate of insulin absorption reduces postprandial hyperglycemia in patients with type 2 diabetes. METHODS: Fourteen patients with type 2 diabetes (4 females; age 61.6 ± 8.4 years, HbA1c 8.42 ± 1.13%; BMI 29.10 ± 5.61 kg/m(2)) on intensified insulin therapy underwent 5-hour meal tolerance tests (MTTs) with a standardized liquid meal after an overnight fast on 2 study days. Subjects injected 0.2 U/kg of insulin aspart or lispro subcutaneously into the abdominal skin on both days with and without the use of the InsuPad device. RESULTS: Following the premeal bolus injection of rapid-acting insulin analog, infusion site warming led to a rise in plasma insulin levels to peak concentrations that were significantly earlier than without skin warming (mean ± SD 52 ± 26.7 vs 80 ± 51.3 minutes, P < .005) as well as increase in plasma insulin levels during the first hour after injection (mean ± SD 63.5 ± 32.7 IU vs 48.0 ± 25.0 uU.min/ml, P = .019). As a result, the area under the curve of the postprandial glucose excursion during the first 2 hours (the primary study outcome) and the entire 5 hours after the meal were significantly reduced (P = .007 and P = .03, respectively) with skin warming around the injection site. DISCUSSION AND CONCLUSIONS: Use of the InsuPad to increase the rate of insulin absorption provides an effective means to achieve better control of postmeal glucose excursions in type 2 diabetic patients receiving premeal injections of rapid-acting insulin analogs.

Plasmodium vivax merozoite surface protein PvMSP-3 beta is radically polymorphic through mutation and large insertions and deletions.

Plasmodium vivax causes the majority of malaria outside of sub-Saharan Africa and is an important burden for affected countries. The recent spread of drug-resistant P. vivax strains in these countries has led to renewed pressure for the development of a P. vivax vaccine. The complex life cycle of P. vivax presents many potential vaccine targets, but among the most promising candidates are subunits of the surface coat that surrounds the merozoite, the parasite stage that infects erythrocytes and initiates much of the pathology of malaria. Although the genes for several constituents of the P. vivax surface coat have now been cloned and sequenced, little is known about the extent to which these proteins vary between populations, an important consideration in vaccine development. The merozoite surface protein MSP-3beta is a member of a family of related merozoite surface proteins, all of which contain a central alanine-rich domain that is predicted to form a coiled-coil tertiary structure. We have sequenced the PvMSP-3 beta gene from P. vivax isolates originating in Central and South America, Asia and the Pacific. In this first assessment of PvMSP-3 beta variation between populations, we discovered widespread and significant diversity, mostly within the alanine-rich central region. We observed frequent differences in PvMSP-3 beta gene size, caused by the insertion and/or deletion of several large sequence blocks, as well as numerous single nucleotide polymorphisms and smaller scale insertions and deletions. Despite this high level of sequence diversity, certain physical properties of the encoded protein are maintained, particularly the ability to form coiled-coil tertiary structures, suggesting that although PvMSP-3 beta varies widely, it is under functional constraints. The implications for PvMSP-3 beta function and vaccine development are discussed.