Nanosilver alleviates foreign body reaction and facilitates wound repair by regulating macrophage polarization / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Foreign body reactions induced by macrophages often cause delay or failure of wound healing in the application of tissue engineering scaffolds. This study explores the application of nanosilver (NAg) to reduce foreign body reactions during scaffold transplantation. An NAg hybrid collagen-chitosan scaffold (NAg-CCS) was prepared using the freeze-drying method. The NAg-CCS was implanted on the back of rats to evaluate the effects on foreign body reactions. Skin tissue samples were collected for histological and immunological evaluation at variable intervals. Miniature pigs were used to assess the effects of NAg on skin wound healing. The wounds were photographed, and tissue samples were collected for molecular biological analysis at different time points post-transplantation. NAg-CCS has a porous structure and the results showed that it could release NAg constantly for two weeks. The NAg-CCS group rarely developed a foreign body reaction, while the blank-CCS group showed granulomas or necrosis in the subcutaneous grafting experiment. Both matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were reduced significantly in the NAg-CCS group. The NAg-CCS group had higher interleukin (IL)-10 and lower IL-6 than the blank CCS group. In the wound healing study, M1 macrophage activation and inflammatory-related proteins (inducible nitric oxide synthase (iNOS), IL-6, and interferon-‍γ (IFN-‍γ)) were inhibited by NAg. In contrast, M2 macrophage activation and proinflammatory proteins (arginase-1, major histocompatibility complex-II (MHC-II), and found in inflammatory zone-1 (FIZZ-1)) were promoted, and this was responsible for suppressing the foreign body responses and accelerating wound healing. In conclusion, dermal scaffolds containing NAg suppressed the foreign body reaction by regulating macrophages and the expression of inflammatory cytokines, thereby promoting wound healing.

One case of severe subcutaneous soft tissue infection caused by nonstandard insulin injection / 中华烧伤杂志

On January 1st 2018, a male 44 years old diabetic patient with subcutaneous soft tissue infection in right thigh was admitted to our hospital. The patient repeatedly used the same needle to inject insulin subcutaneously in the unsterilized right thigh, and his blood glucose was badly controlled in the long term. Severe subcutaneous soft tissue infection of the right thigh occurred after his fatigue, accompanied with ketoacidosis. Then he received conservative treatment in the local hospital for one month, but the infection persisted. After being transferred to our hospital, we highly suspected the diagnosis of necrotizing fasciitis according to previous test indicators and local B-ultrasound results, but suggestion of aggressive surgery was refused. So we treated him with conservative therapies using sensitive antibiotics and supportive remedies. The patient was basically healed after treatment of 1 month and he was recovered well during the follow-up 2 months after discharged from our hospital. This case emphasizes the importance of standard injection of insulin and early diagnosis of severe subcutaneous soft tissue infection.

Advances in the research of sensory nerve regeneration in tissue engineering skin / 中华烧伤杂志

Severe skin damage not only causes a mass of tissue defect, but also leads to the loss of various sensory functions. Tissue engineering skin provides a new way for high-quality wound repair, while there are still many problems in the recovery of sensory function, such as abnormality or loss of sensation of pain, touch, and temperature. Therefore, when tissue engineering skin is used to promote wound healing, regeneration and functional recovery of sensory nerve have attracted more and more attention. This article introduces the kind, distribution, regeneration, and factors influencing regeneration of sensory nerve in skin, and explores strategies in promoting regeneration of sensory nerve from dermal scaffold, seed cell, and neurturin of tissue engineering skin.

Experimental research on the compatibility of self-assembly nanofiber hydrogel from the amphipathic peptide containing IKVAV with olfactory ensheathing cells of rats / 生物医学工程学杂志

The present research was aimed to explore the biocompatibility of IKVAV self-assembling peptide nanofiber scaffold with olfactory ensheathing cells (OECs) of rats. The OECs were seeded onto the surface of coverslips covered with IKVAV self-assembling peptide nanofiber scaffold hydrogel (2D culture system), and implanted within IKVAV self-assembling peptide nanofiber scaffold hydrogel (3D culture system), respectively. The adhesion, viability of OECs were observed with inverted microscope. Then the characteristics for survival and adhesion of cells by image processing were observed, and statistical analysis on the number of S-100 positive cell, the area of the cell bodies and the perimeter of the cell and MTT method were carried out. It was found that the OECs could survive and migrate in IKVAV self-assembling peptide nanofiber scaffold. The result of the cell MTT exam, of the shape and quantity of cells had no significant difference compared to those of the OECs cultured with poly-L-lysine (PLL). It has been proved that IKVAV self-assembling peptide nanofiber scaffold has good biocompatibility with rat OECs.