The bioengineering of perfusable endocrine tissue with anastomosable blood vessels.

Organ transplantation is a definitive treatment for endocrine disorders, but donor shortages limit the use of this technique. The development of regenerative therapies would revolutionize the treatment of endocrine disorders. As is the case for harvested organs, the ideal bioengineered graft would comprise vascularized endocrine tissue, contain blood vessels that could be anastomosed to host vessels, have stable blood flow, and be suitable for transplantation into various sites. Here, we describe a transplantable endocrine tissue graft that was fabricated byex vivoperfusion of tricultured cell sheets (isletß-cells, vascular endothelial cells (vECs), and mesenchymal stem cells (MSCs)) on a vascularized tissue flap ofin vivoorigin. The present study has three key findings. First, mild hypothermic conditions enhanced the success ofex vivoperfusion culture. Specifically, graft construction failed at 37 °C but succeeded at 32 °C (mild hypothermia), and endocrine tissue fabricated under mild hypothermia contained aggregations of isletß-cells surrounded by dense vascular networks. Second, the construction of transplantable endocrine tissue byex vivoperfusion culture was better achieved using a vascular flap (VF) than a muscle flap. Third, the endocrine tissue construct generated using a VF could be transplanted into the rat by anastomosis of the graft artery and vein to host blood vessels, and the graft secreted insulin into the host's circulatory system for at least two weeks after transplantation. Endocrine tissues bioengineered using these techniques potentially could be used as novel endocrine therapies.

External pressure dynamics promote kidney viability and perfusate filtration during ex vivo kidney perfusion.

Normothermic machine perfusion (NMP) has not yet been established as a technique for preserving organs for a day. A key contributing factor to the same is that the perfusing solutions cannot circulate continuously and evenly in the organs. Here, we conceived a method of applying intermittent air pressure from outside the organ to assist its circulatory distribution during perfusion. We used a perfusion culture system while applying external pressure to culture rat kidneys and compared the circulatory distribution in the kidneys, changes in tissue morphology due to injury, and perfusate filtration. The intermittent pressurization (IMP) (-) group showed markedly poorer circulation on the upper side compared with that in the lower side, alongside histological damage. On the other hand, the IMP (+) group showed improved circulation in the upper side and had lesser histological damage. Furthermore, the IMP (+) group maintained the ability to filter perfusate for 24 h. In transplantation medicine and regenerative medicine research, this method has the potential to contribute to more efficient organ preservation and more functional tissue regeneration in the future.

Application of the Caprini Risk Assessment Model for Evaluating Postoperative Deep Vein Thrombosis in Patients Undergoing Plastic and Reconstructive Surgery.

BACKGROUND: The optimal approach for assessing the risk of venous thromboembolism (VTE) in patients undergoing plastic surgery is yet to be established. This study aimed to determine the validity of the Caprini Risk Assessment Scale in identifying patients undergoing plastic surgery who are at a high risk of developing VTE. METHODS: Between December 2014 and November 2015, we enrolled 90 patients. Risk factors for VTE were assessed at baseline. The Caprini Risk Assessment Model was used to stratify patients into Caprini <4, Caprini 5-6, Caprini 7-8, and Caprini >8 groups before examination. We preoperatively screened for deep vein thrombosis (DVT) using duplex ultrasound. During operation, surgical duration and blood loss were recorded. Duplex ultrasound was repeated 2 and 7 days postoperatively to evaluate for DVT. We used a univariate analysis to determine risk factors for postoperative VTE. Confounding predictors were finally tested using a multivariate logistic regression analysis. RESULTS: One patient had preoperative DVT and was excluded from the study. Eighty-nine patients were included in the final analyses. Of the 89 patients, 7 (8%) developed postoperative DVT. Mean age, body mass index, Caprini score, and surgical duration were significantly higher in patients who developed postoperative DVT. Variables associated with increased risk of postoperative DVT using univariate analysis were Caprini scores of 7-8 and >8. Multivariate logistic regression analysis finally identified Caprini scores 7-8 [odds ratio (OR) 13, 95% confidence interval (CI) 1.67-101.98, P = 0.014] and >8 (OR 19.5, 95% CI 1.02-371.96, P = 0.048) to be independently associated with postoperative DVT. CONCLUSIONS: Although the incidence of postoperative DVT is relatively low among patients undergoing plastic surgery, Caprini scores can be used to predict postoperative VTE complications.