Enhanced microvasculature formation and patterning in iPSC-derived kidney organoids cultured in physiological hypoxia

Functional kidney organoids have the potential to be used in implantable kidney grafts for patients with end-stage kidney disease, because they have been shown to self-organize from induced pluripotent stem cells into most important renal structures. To date, however, long-term kidney organoid culture has not succeeded, as nephrons lose their phenotype after approximately 25 days. Furthermore, the renal structures remain immature with diminishing endothelial networks with low connectivity and limited organoid invasion. We hypothesized that introducing long-term culture at physiological hypoxia, rather than the normally applied non-physiological, hyperoxic 21% O2, could initiate angiogenesis, lead to enhanced growth factor expression and improve the endothelial patterning. We therefore cultured the kidney organoids at 7% O2 instead of 21% O2 for up to 25 days and evaluated nephrogenesis, VEGF-A expression and vascularization. Whole mount imaging revealed a homogenous morphology of the endothelial network with enhanced sprouting and interconnectivity when the kidney organoids were cultured in hypoxia. Three-dimensional quantification confirmed that the hypoxic culture led to an increased average vessel length, likely due to the observed upregulation of proangiogenic VEGF-A189 mRNA and downregulation of the antiangiogenic protein VEGF-A165b measured in hypoxia. This research indicates the importance of optimization of oxygen availability in organoid systems and the potential of hypoxic culture conditions in improving the vascularization of organoids.

Effect of Dexmedetomidine Combined with Ropivacaine on Cognitive Dysfunction and Inflammatory Response in Patients Undergoing Craniocerebral Surgery

Objective. To study the effects of dexmedetomidine in combination with ropivacaine in patients undergoing craniocerebral surgery and their efficiency on cognitive function and inflammatory response of patients. Methods. 100 patients undergoing craniocerebral surgery in our hospital from November 2018 to September 2020 were randomly selected and divided into a control group and an experimental group by drawing lots, with 50 cases in each group. Patients in the control group received routine anesthesia, while those in the experimental group received 1 μg/kg of dexmedetomidine combined with 0.5% of ropivacaine for anesthesia to compare the anesthesia onset time, analgesic time, postoperative awake time, Social Disability Screening Schedule (SDSS) cognitive function score after waking, visual analogue scale (VAS) pain score, Ramsay sedation score, incidence of adverse reactions, postoperative inflammatory factor expression levels, and changes in heart rate, oxygen saturation, and blood pressure at T0, T1, T2, T3, and T4 between the two groups. Results. The anesthesia onset time, SDSS cognitive function score after waking, VAS pain score, Ramsay sedation score, incidence of adverse reactions, and postoperative inflammatory factor expression levels in the experimental group were significantly lower than those in the control group ( P < 0.05 ). The analgesic time and postoperative awake time in the experimental group were significantly longer than those in the control group, with statistical significance ( P < 0.05 ). There were no statistically significant differences in the changes of heart rate, oxygen saturation, and blood pressure at T0, T1, T2, T3, and T4 between the two groups ( P > 0.05 ). Conclusion. Dexmedetomidine combined with ropivacaine has high application value in craniocerebral surgery.