Altered tissue oxygen tension responsiveness in diabetes

Pregnancy and post-partum muscle and cerebral oxygenation during intermittent exercise in gestational diabetes: A pilot study

OBJECTIVE

This pilot, prospective, observational, cohort study aimed to examine, for the first time, the in vivo alterations in the oxygenation of the forearm skeletal muscles and the prefrontal lobes during intermittent exercise in women diagnosed with gestational diabetes mellitus (GDM), during and after pregnancy.

STUDY DESIGN

Nine pregnant women, diagnosed with GDM, performed a 3-min intermittent handgrip exercise protocol (at 35% of Maximal Voluntary Contraction) during pregnancy (mean 27th gestational week) and following labor (mean 71 weeks). During the protocol, muscle and cerebral oxygenation were assessed with near-infrared spectroscopy. Resting vascular parameters [carotid intima-media thickness (cIMT) and hemodynamic parameters (using rheocardiography)], and hematological/biochemical parameters during pregnancy and after delivery have been compared.

RESULTS

Although changes were observed in certain hematological parameters (p< 0.05), cIMT and hemodynamic parameters were not altered post-partum. In addition, both muscle and cerebral oxygenation parameters during handgrip were not significantly altered post-partum.

CONCLUSIONS

Despite significant changes in specific hematological parameters in women with GDM, impairments in muscle and cerebral oxygenation during exercise remained at one year after labor. These results indicate that alterations in vascular parameters and muscle/cerebral oxygenation associated with GDM do not entirely reverse post-partum. Future studies are needed to examine which interventions will lead to improvements in microvascular parameters and prevent type 2 diabetes.

Transepidermal oxygen flux during arterial occlusion using ratiometric luminescence imaging

BACKGROUND

A physiological oxygen transport through a circulatory and microcirculatory system is essential for execution of cellular functions. Several pathological conditions e.g. infections, ischemia, cancer, diabetes, hypertension or chronic wounds show a change of oxygen distribution and oxygen tension in cellular microenvironment. Additionally complex operative procedures in order to reconstruct tissue defects require a reliable monitoring of microcirculation.

OBJECTIVE

Target of this study was to evaluate skin oxygenation during an ischemia-reperfusion experiment using transepidermal oxygen flux imaging.

METHODS

Twelve patients at the Department of Plastic and Reconstructive surgery of the University hospital of Regensburg underwent to elective hand operations. During the operation a tourniquet is standardly set on the upper arm to create ischemia in order to facilitate the operative procedure. Measurements were performed at the different time intervals: in rest, under ischemia and after reperfusion.

RESULTS

The transepidermal oxygen flux increased during the ischemic condition compared to normal condition and decreased to a lower value during reperfusion (rest: 0.043±0.007, ischemia: 0.063±0.014, reperfusion: 0.030±0.028).

CONCULSION

Transepidermal oxygen flux imaging by ratiometric luminescence imaging seems to be a reliable tool to assess skin oxygenation. However dynamic changes seem to be more informative than absolute thresholds. Further investigations are necessary to prove these promising results.