Considerable impact of major air pollutants on hypertension in Guizhou province,southwest China

To the Editor:Air pollution can lead to respiratory and cardiovascular diseases(CVDs),and its impact on human health is very significant.Air particles less than 0.1µm can pass through the blood brain barrier,reach the brain,and enter the central nervous system,causing physiological and pathological changes.A study shows that long-term exposure to fine particulate matter(PM_(2.5))will increase the risk of CVDs among Chinese residents.^([1])Another study found that a short time exposure to low concentrations of air pollutants may also lead to the onset of acute coronary syndrome within one hour.^([2])A meta-analysis based on seven databases showed that environmental air pollution was positively correlated with elevated blood pressure and hypertension.^([3])Mounting evidence indicates that air pollution can cause cardiovascular and cerebrovascular diseases and affect human health furtherly.

Bionic peptide scaffold in situ polarization and recruitment of M2 macrophages to promote peripheral nerve regeneration

Tissue regeneration requires exogenous and endogenous signals,and there is increasing evidence that the exogenous microenvironment may play an even more dominant role in the complex process of coordinated multiple cells.The short-distance peripheral nerve showed a spontaneous regenerative phenomenon,which was initiated by the guiding role of macrophages.However,it cannot sufficiently restore long-distance nerve injury by itself.Based on this principle,we firstly constructed a proinflammatory model to prove that abnormal M2 expression reduce the guidance and repair effect of long-distance nerves.Furthermore,a bionic peptide hydrogel scaffold based on self-assembly was developed to envelop M2-derived regenerative cytokines and extracellular vesicles(EVs).The cytokines and EVs were quantified to mimic the guidance and regenerative microenvironment in a direct and mild manner.The bionic scaffold promoted M2 transformation in situ and led to proliferation and migration of Schwann cells,neuron growth and motor function recovery.Meanwhile,the peptide scaffold combined with CX3CL1 recruited more blood-derived M2 macrophages to promote long-distance nerve reconstruction.Overall,we systematically confirmed the important role of M2 in regulating and restoring the injury peripheral nerve.This bionic peptide hydrogel scaffold mimicked and remodeled the local environment for M2 transformation and recruitment,favoring long-distance peripheral nerve regeneration.It can help to explicate regulative effect of M2 may be a cause not just a consequence in nerve repair and tissue integration,which facilitating the development of pro-regenerative biomaterials.

Acellular nerve xenografts based on supercritical extraction technology for repairing long-distance sciatic nerve defects in rats

Compared to conventional artificial nerve guide conduits (NGCs) prepared using natural polymers or synthetic polymers, acellular nerve grafts (ACNGs) derived from natural nerves with eliminated immune components have natural bionic advantages in composition and structure that polymer materials do not have. To further optimize the repair effect of ACNGs, in this study, we used a composite technology based on supercritical carbon dioxide (scCO_(2)) extraction to process the peripheral nerve of a large mammal, the Yorkshire pig, and obtained an innovative Acellular nerve xenografts (ANXs, namely, CD + scCO_(2) NG). After scCO_(2) extraction, the fat and DNA content in CD + scCO_(2) NG has been removed to the greatest extent, which can better supported cell adhesion and proliferation, inducing an extremely weak inflammatory response. Interestingly, the protein in the CD + scCO_(2) NG was primarily involved in signaling pathways related to axon guidance. Moreover, compared with the pure chemical decellularized nerve graft (CD NG), the DRG axons grew naturally on the CD + scCO_(2) NG membrane and extended long distances. In vivo studies further revealed that the regenerated nerve axons had basically crossed the CD + scCO_(2) NG 3 weeks after surgery. 12 weeks after surgery, CD + scCO_(2) NG was similar to autologous nerves in improving the quality of nerve regeneration, target muscle morphology and motor function recovery and was significantly better than hollow NGCs and CD NG. Therefore, we believe that the fully decellularized and fat-free porcine ACNGs may be the most promising “bridge” for repairing human nerve defects at this stage and for some time to come.