Brief Article
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World J Diabetes. Dec 15, 2013; 4(6): 372-377
Published online Dec 15, 2013. doi: 10.4239/wjd.v4.i6.372
Influence of physiological and supraphysiological hyperinsulinemia on skin microcirculation in healthy volunteers
Michal Krčma, Daniela Čechurová, Jitka Brožová, Zdeněk Jankovec, Silvie Lacigová, Michal Žourek, Zdeněk Rušavý
Michal Krčma, Daniela Čechurová, Jitka Brožová, Zdeněk Jankovec, Silvie Lacigová, Michal Žourek, Zdeněk Rušavý, Diabetology Centre, 1st Department of Clinic Medicine, Teaching Hospital and Medical Faculty Charles University, 32300 Plzen, Czech Republic
Author contributions: Krčma M and Rušavý Z designed the study and wrote the manuscript; Krčma M and Brožová J performed most of the experiments; Čechurová D, Jankovec Z, Lacigová S and Žourek M helped with the methods and took part in writing and revising the manuscript.
Supported by Ministry of Health, Czech Republic-Conceptual Development of Research Organization (Faculty Hospital in Pilsen-FNPl), No. 00669806
Correspondence to: Michal Krčma, MD, PhD, Diabetology Centre, 1st Department of Clinic Medicine, Teaching Hospital and Medical Faculty Charles University, Alej Svobody 80, 32300 Plzen, Czech Republic. krcmam@fnplzen.cz
Telephone: +42-377-103234 Fax: +42-377-103234
Received: June 3, 2013
Revised: October 30, 2013
Accepted: November 15, 2013
Published online: December 15, 2013
Processing time: 200 Days and 14.9 Hours
Abstract

AIM: To examine skin perfusion in dependency on insulinemia in healthy subjects.

METHODS: All volunteers were informed in detail about the procedures and signed informed consent. The protocol of this study was approved by the ethical committee. In our study, a two stage hyperinsulinemic euglycemic clamp was performed, with insulinemia 100 and 250 mIU/mL and glycemia 5.0 mmol/L (3% standard deviation). Before the clamp and in steady states, microcirculation was measured by laser Doppler flowmetry and transcutaneous oximetry and energy expenditure was measured by indirect calorimetry. Results (average and standard deviation) were evaluated with paired t-test.

RESULTS: Physiological (50 mIU/L) insulinemia led to higher perfusion in both tests; hyperemia after heating to 44%-1848% (984-2046) vs 1599% (801-1836), P < 0.05, half time of reaching peak perfusion after occlusion release 1.2 s (0.9-2.6) vs 4.9 s (1.8-11.4), P < 0.05. Supraphysiological (150 mIU/L) insulinemia led to even higher perfusion in both tests; hyperemia after heating to 44%-1937% (1177-2488) vs 1599% (801-1836), P < 0.005, half time to reach peak perfusion after occlusion release 1.0 s (0.7-1.1) vs 4.9 s (1.8-11.4), P < 0.005. A statistically significant increase occurred in tissue oxygenation in both insulinemia. The difference in perfusion and oxygenation between physiological and supraphysiological hyperinsulinemia was not statistically significant.

CONCLUSION: The post occlusive hyperemia test in accordance with heating test showed significantly increasing skin perfusion in the course of artificial hyperinsulinemia. This effect rises non-linearly with increasing insulinemia. Dependency on the dose was not statistically significant.

Keywords: Diabetes; Insulin; Laser Doppler flowmetry; Microcirculation

Core tip: Insulin mediated small vessel vasodilatation is a hot topic in microcirculation research. Our work describes skin microcirculation response to increasing insulinemia in the physiological and supraphysiological level. Simultaneous use of two laser Doppler flowmetry and transcutaneous oximetry was used for discriminating between total blood flow and perfusion of the nutritive bed. Both methods reveal increasing skin microcirculation perfusion due to insulin infusion with this effect rising non-linearly with increasing insulinemia.