Objective:This study aimed to investigate the effect of lipohypertrophy induced by insulin injection on blood glucose fluctuation in patients with type 1 diabetes mellitus.Methods:A total of 80 patients with type 1 diabetes mellitus were recruited between June 2021 and December 2021 from the First Affiliated Hospital of Nanjing Medical University. And these patients all received insulin injection more than six months. Lipohypertrophy was assessed by ultrasound scanning, and blood glucose fluctuation was evaluated using the flash glucose monitoring system(FGM). Univariate analysis and multivariate linear regression were used to analyze the relationship of lipohypertrophy and and core indicators of blood glucose fluctuation.Results:Compared with patients without lipohypertrophy, patients with lipohypertrophy had higher mean amplitude of glycemic excursions(MAGE), coefficient of variation(CV), mean of daily differences(MODD), standard deviation(SD) of blood glucose, time above range(TAR), and high blood glucose index(HBGI; all P<0.05), while time in range(TIR) of glucose markedly become lower( P<0.01). Moreover, multivariate linear regression analysis showed that lipohypertrophy detected by ultrasound was an independent influencing factor of TIR( β=-9.423, P=0.032), MAGE( β=1.114, P=0.039), CV( β=4.304, P=0.041), MODD( β=0.717, P=0.046) after adjusting for age at diagnosis, duration of insulin injection, fasting C-peptide, and daily dose of insulin per unit weight. Conclusion:Lipohypertrophy increases glycemic variability and imposes negative impact on glycemic control rate in patients type 1 diabetes mellitus.

Objective To explore whether the biocompatibility of phosphorylcholine (PC) modified alginate-chitosan microcapsules could be improved. Methods PC modified alginate-chitosan microcapsules were obtained by high-voltage electrostatic system.Bradford method was adopted to determine the adsorption amounts of bovine serum albumin by chitosan alone and PC modified chitosan.Alginate-chitosan-PC microcapsules (experimental group) and alginate-chitosan microcapsules ( control group) were respectively implanted into the peritoneal cavity of mice and retrieved 4 weeks after transplantation.Fibrosis of the capsules was evaluated by HE staining.Glucose stimulated insulin secretion (GSIS) assay was used to assess the insulin secretion response of encapsulated and nonencapsulated rat islets. Results The adsorption amount of protein was 189.4 μg/mg and 90.5 μg/mg respectively by chitosan alone and PC modified chitosan.The difference had statistical significance ( t =5.549, P ＜ 0.05 ).In contrast to the control group, the cellular reaction on the surface of the modified microcapsules was weaker, with no obvious fibrosis found.The insulin secreted by encapsulated islets and nonencapsulated islets was( 3.298 ± 1.680 ) μIU/ml VS (4.299 ± 1.159 ) μIU/ml ( t =1.096, P ＞ 0.05 ) in response to low-glucose stimulus and( 11.783 ± 4.175 ) μIU/ml VS ( 12.875 ± 2.268 ) μIU/ml ( t =0.514, P ＞ 0.05 ) in response to high-glucose stimulus.Conclusions PC can improve the biocompatibility of alginate-chitosan microcapsules, with no effect on the biological function of encapsulated islets.It may be more appropriate to use modified microcapsules encapsulating islets for transplantation.