Polska Elzbieta, Kolodjaschna Julia, Berisha Fatmire, Malec Maria M, Simader Christian, Bayerle-Eder Michaela, Roden Michael, Schmetterer Leopold
Department of Clinical Pharmacology, Division of Opthalmo-Pharmacology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
Diabetes Care. 2006 Sep;29(9):2034-8. doi: 10.2337/dc06-0134.
The aim of the present study was to investigate the effect of intravenous C-peptide infusion on ocular blood flow in patients with type 1 diabetes under euglycemic conditions.
The study was performed in a randomized, placebo-controlled, double-masked, two-way, crossover design in 10 type 1 diabetic patients. C-peptide was intravenously administered at two different dosages (dosage 1: 25 pmol . kg(-1) . min(-1) bolus followed by 5 pmol . kg(-1) . min(-1) continuous infusion; dosage 2: six times higher than dosage 1), each for 60 min. Physiologic saline solution was used as a control for C-peptide on a different study day. On both study days, euglycemic clamps were performed. To assess retinal blood flow, laser Doppler velocimetry (blood flow velocities) and retinal vessel analyzer (vessels diameters) measurements were performed. Laser interferometric measurements of fundus pulsation were used to assess pulsatile choroidal blood flow. Blood velocities in the ophthalmic artery were measured using color Doppler imaging.
Eight patients (two female and six male) completed the study according to the protocol and without adverse events. One patient developed an anaphylactic reaction to C-peptide, which resolved without sequelae. The following results originate from the remaining eight subjects. Systemic hemodynamic parameters remained stable during both study days. Infusion of C-peptide did not affect any ocular hemodynamic parameter.
The data of the present study indicate that exogenous C-peptide exerts no effect on ocular hemodynamic parameters in type 1 diabetic patients under euglycemic conditions. The maximum detectable change in these parameters was <25%.
本研究旨在探讨在血糖正常的情况下，静脉输注C肽对1型糖尿病患者眼部血流的影响。
本研究采用随机、安慰剂对照、双盲、双向交叉设计，纳入10例1型糖尿病患者。C肽以两种不同剂量静脉给药（剂量1：25 pmol·kg⁻¹·min⁻¹推注，随后以5 pmol·kg⁻¹·min⁻¹持续输注；剂量2：比剂量1高6倍），每种剂量输注60分钟。在不同的研究日，使用生理盐溶液作为C肽的对照。在两个研究日，均进行了血糖正常钳夹试验。为评估视网膜血流，进行了激光多普勒测速（血流速度）和视网膜血管分析仪（血管直径）测量。使用眼底搏动的激光干涉测量法评估脉络膜搏动血流。使用彩色多普勒成像测量眼动脉中的血流速度。
8例患者（2例女性和6例男性）按照方案完成了研究，且未发生不良事件。1例患者对C肽发生过敏反应，反应消退后未留后遗症。以下结果来自其余8名受试者。在两个研究日，全身血流动力学参数均保持稳定。输注C肽未影响任何眼部血流动力学参数。
本研究数据表明，在血糖正常的情况下，外源性C肽对1型糖尿病患者的眼部血流动力学参数无影响。这些参数的最大可检测变化<25%。
