Oxygen Penetration Through Full-Thickness Skin by Oxygen-Releasing Sutures for Skin Graft Transplantation

The transplantation of full-thickness skin grafts(FTSGs)is important for reconstructing skin barrier and promoting wound healing.Sufficient oxygen supply is closely related to the success of skin grafting.However,full-thickness oxygen delivery is limited by the poor oxygen permeability of skin.Oxygen-releasing sutures(O_(2)sutures)were developed to facilitate oxygen penetration through full-thickness skin.The O_(2)sutures delivered 100 times more oxygen than topical gaseous oxygen therapy at a 15 mm depth in the skin model.Under extreme hypoxia(<0.5%O_(2),v/v),O_(2)sutures could also promote endothelial cell proliferation.After the transplantation of FTSGs in mice,O_(2)sutures accelerated blood re-perfusion and increased the survival area of the skin graft.It is expected that O_(2)sutures will be adopted in clinical applications to increase the success rate of full-thickness skin transplantation.

Development of a hydrogen peroxide-responsive and oxygen-carrying nanoemulsion for photodynamic therapy against hypoxic tumors using phase inversion composition method

Photodynamic therapy(PDT)has become an attractive tumor treatment modality because of its noninvasive feature and low side effects.However,extreme hypoxia inside solid tumors severely impedes PDT therapeutic outcome.To overcome this obstacle,various strategies have been developed recently.Among them,in situ oxygen generation,which relies on the decom-position of tumor endogenous H_(2)O_(2),and oxygen delivery tactic using high oxygen loading capacity of hemoglobin or perfluorocarbons,have been widely studied.The in situ oxygen generation strategy has high specificity to tumors,but its oxygen-generating efficiency is lim-ited by the intrinsically low tumor H_(2)O_(2)level.In contrast,the oxygen delivery approach holds advantage of high oxygen loading efficiency,nevertheless lacks tumor specificity.In this work,we prepared a nanoemulsion system containing H_(2)O_(2)-responsive catalase,highly efficient ox-ygen carrier perfiuoropolyether(PFPE),and a near-infrared(NIR)light activatable photo-sensitizer IR780,to combine the high tumor specificity of the in situ oxygen generation strategy and the high efficiency of the oxygen delivery strategy.This concisely prepared nanoplatform exhibited enhanced and H_(2)O_(2)-controllable production of singlet oxygen under light excitation,satisfactory cytocompatibility,and ability to kill cancer cells under NIR light excitation.This highlights the potential of this novel nanoplatform for highly efficient and selective NIR light mediated PDT against hypoxic tumors.This research provides new insight into the design of intelligent nanoplatform for relieving tumor hypoxia and enhancing the oxygen-dependent PDT effects in hypoxic tumors.

Beneficial effects of splenectomy on liver regeneration in a rat model of massive hepatectomy

BACKGROUND: Small-for-size syndrome is a widely recognized clinical complication after living donor liver transplantation or extended hepatectomy due to inadequate liver mass. The purpose of this study was to investigate the role of splenectomy in rats after massive hepatectomy, a surrogate model of small-for-size graft. METHODS: Rats were divided into eight groups, each with 20 animals: 50% hepatectomy (50% Hx), 50% hepatectomy+ splenectomy (50% Hx+Sp), 60% Hx, 60% Hx+Sp, 70% Hx, 70% Hx+Sp, 90% Hx and 90% Hx+Sp. The following parameters were evaluated: liver function tests (ALT, AST and TBIL), liver regeneration ratio, DNA synthesis, proliferation cell nuclear antigen, hepatic oxygen delivery (HDO(2)) and hepatic oxygen consumption (HVO(2)). RESULTS: The liver regeneration ratio was enhanced in the Hx+Sp groups (P < 0.05). In addition, compared with the Hx groups, the Hx+Sp groups had better liver functions (P < 0.05). DNA synthesis and proliferation cell nuclear antigen were also increased in the Hx+Sp groups compared with the Hx groups (P < 0.05). Furthermore, in the Hx+Sp groups, HDO(2) and HVO(2) were increased over those in the Hx groups (P < 0.05), and were positively correlated with the liver regeneration ratio. CONCLUSIONS: Splenectomy significantly improved liver function, and enhanced DNA synthesis and proliferation cell nuclear antigen after massive hepatectomy in rats. This operation could be mediated through increased HDO(2), and HVO(2) which facilitate liver regeneration. (Hepatobiliary Pancreat Dis Int 2012;11:60-65)

Biomimetic Erythrocyte-Like Particles from Microfluidic Electrospray for Tissue Engineering

Microparticles have demonstrated value for regenerative medicine.Attempts in this field tend to focus on the development of intelligent multifunctional microparticles for tissue regeneration.Here,inspired by erythrocytes-associated self-repairing process in damaged tissue,we present novel biomimetic erythrocyte-like microparticles(ELMPs).These ELMPs,which are composed of extracellular matrix-like hybrid hydrogels and the functional additives of black phosphorus,hemoglobin,and growth factors(GFs),are generated by using a microfluidic electrospray.As the resultant ELMPs have the capacity for oxygen delivery and near-infrared-responsive release of both GFs and oxygen,they would have excellent biocompatibility and multifunctional performance when serving as microscaffolds for cell adhesion,stimulating angiogenesis,and adjusting the release profile of cargoes.Based on these features,we demonstrate that the ELMPs can stably overlap to fill a wound and realize controllable cargo release to achieve the desired curative effect of tissue regeneration.Thus,we consider our biomimetic ELMPs with discoid morphology and cargo-delivery capacity to be ideal for tissue engineering.

Postnatal hemodynamic changes in low-birth-weight and very-low-birth-weight infants during the first 72 h of life

Background Despite increasing investigation in the area of cardiovascular instability in preterm infants,huge gaps in knowledge remain. Study of the hemodynamic characteristics in this population is inadequate. Methods A one-center, prospective, observational longitudinal cohort study at a third level Neonatal Intensive Care Unit enrolled 86 preterm infants. Of these, 46 were low-birth-weight(LBW) newborns of a mean(SD) gestational age of 32.3(1.1) weeks and a birth weight of 2,031(1,684-2,320) g. Forty were very-low-birth-weight(VLBW) newborns with a gestational age of 28.4(1.5) weeks and a birth weight of 1,255(884-1,580) g. All infants underwent Doppler ultrasound examinations at 24, 48, and 72 h after birth. Results SMII, DO_2, MBP, LVCO, CI, and SVI in the VLBW infants were all significantly lower than the LBW infants, but SVRI was not different. Postnatal increases in MBP, SVRI were observed in VLBW and LBW groups that were not associated with changes in LVCO and DO_2. The postnatal pattern of SMII differed between the two groups. SMII increased with postnatal age in the LBW group and did not change significantly in the VLBW group. Conclusions SMII and DO_2 were significantly lower in VLBW neonates during the first 72 h of life, and there was a direct relationship between inotropy, DO_2, and birth weight over a range of maturities at birth. VLBW infants may be at higher risk for cardiac dysfunction when an additional challenge is encountered.[S Chin J Cardiol 2019;20(4):245-251]