[Research advances on the role of microRNA engineered exosomes in diabetic wounds]

Diabetic wounds are a common complication in patients with diabetes, which is difficult to treat. Current treatment methods for diabetic wounds include debridement, functional dressing coverage, negative pressure therapy, bone cement filling, and skin grafting, etc. MicroRNA (miRNA) engineered exosomes have shown promising potential in diabetic wound repair due to the ability to alleviate inflammation, stimulate angiogenesis, and promote collagen deposition and re-epithelialization. Related researches are being actively carred out. This paper reviews the pathophysiological characteristics of diabetic wounds, the characteristics of miRNA and exosomes, the engineering methods for exosomes loaded with miRNA, and the mechanism of miRNA engineered exosomes in promoting healing of diabetic wounds, aiming to provide a reference basis for the future clinical application of miRNA engineered exosomes in diabetic wounds.

MiR-431 promotes cardiomyocyte proliferation by targeting FBXO32 expression

BACKGROUND

The induction of cardiomyocyte (CM) proliferation is a promising approach for cardiac regeneration following myocardial injury. MicroRNAs (miRNAs) have been reported to regulate CM proliferation. In particular, miR-431 expression decreases during cardiac development, according to Gene Expression Omnibus (GEO) microarray data. However, whether miR-431 regulates CM proliferation has not been thoroughly investigated.

METHODS

We used integrated bioinformatics analysis of GEO datasets to identify the most significantly differentially expressed miRNAs. Real-time quantitative PCR and fluorescence in situ hybridization were performed to determine the miRNA expression patterns in hearts. Gain- and loss-of-function assays were conducted to detect the role of miRNA in CM proliferation. Additionally, we detected whether miR-431 affected CM proliferation in a myocardial infarction model. The TargetScan, miRDB and miRWalk online databases were used to predict the potential target genes of miRNAs. Luciferase reporter assays were used to study miRNA interactions with the targeting mRNA.

RESULTS

First, we found a significant reduction in miR-431 levels during cardiac development. Then, by overexpression and inhibition of miR-431, we demonstrated that miR-431 promotes CM proliferation in vitro and in vivo, as determined by immunofluorescence assays of 5-ethynyl-2'-deoxyuridine (EdU), pH3, Aurora B and CM count, whereas miR-431 inhibition suppresses CM proliferation. Then, we found that miR-431 improved cardiac function post-myocardial infarction. In addition, we identified FBXO32 as a direct target gene of miR-431, with FBXO32 mRNA and protein expression being suppressed by miR-431. FBXO32 inhibited CM proliferation. Overexpression of FBXO32 blocks the enhanced effect of miR-431 on CM proliferation, suggesting that FBXO32 is a functional target of miR-431 during CM proliferation.

CONCLUSION

In summary, miR-431 promotes CM proliferation by targeting FBXO32, providing a potential molecular target for preventing myocardial injury.

[Clinical effects of antibiotic bone cement combined with free anterolateral thigh flap in sequential treatment of diabetic foot ulcer]

Objective: To investigate the clinical effects of antibiotic bone cement combined with free anterolateral thigh flap in sequential treatment of diabetic foot ulcer (DFU) wounds. Methods: A retrospective observational study was conducted. From August 2018 to August 2021, 15 patients with DFU who met the inclusion criteria were admitted to the Affiliated Hospital of Zunyi Medical University, including 12 males and 3 females, aged 42-65 years, with a history of type 2 diabetes for 5-19 years. All the wounds of patients were complicated with local bone, muscle, or tendon defects or exposure. The wounds were covered with antibiotic bone cement after debridement in stage Ⅰ+free anterolateral thigh chimeric perforator flap (perforator flap+muscle flap) or simple free anterolateral thigh flap grafting in stage Ⅱ. The defect area of the wound after bone cement removal and debridement was 9.0 cm×5.0 cm-20.0 cm×7.0 cm, the incision area of the flap was 10.0 cm×5.0 cm-22.0 cm×7.0 cm, and the incision area of the muscle flap was 5.0 cm×3.0 cm-8.0 cm×4.0 cm. The donor sites of flaps were sutured directly. During follow-up, the situations of donor site healing and flap survival were observed. At the last follow-up, the texture and shape of the flap, the presence of new ulcers on both limbs, and the walking ability of the patient were observed. Results: During the follow-up of 8 to 21 months after operation in stage Ⅱ, the donor sites healed well with only residual linear scar; flaps in 14 patients survived completely, and the flap in 1 patient developed partial necrosis at 3 weeks after stage Ⅱ surgery, which was healed after debridement and skin grafting. At the last follow-up, the flaps were good in texture and appearance, there were no new ulcers in the affected limb or opposite limb, and the patients had no obvious impairment in daily walking function. Conclusions: To repair DFU wounds with antibiotic bone cement combined with free anterolateral thigh flap can rapidly control the infection, achieving a high survival rate of flap after operation with no obvious impairment in daily walking function of patients.

[Research advances on the application of free flaps in repairing diabetic foot ulcers]

Free flaps have been successfully used in the repair of diabetic foot ulcers (DFUs), which can reduce amputation rate, maintain normal gait of patients, and improve life quality of patients. However, there are still many challenges in the repair of DFUs with free flaps, and many problems need to be solved. This paper summarizes the selection of patients, preoperative cautions, types of flaps, methods of vascular anastomosis, clinical effects, and existing problems in using free skin flaps for repairing DFUs.

[Discussion on surgical treatment mode of diabetic foot wounds]

Diabetic foot wounds have a high incidence and uneven therapeutic effect, so it is necessary to explore the suitable treatment mode of diabetic foot wounds. The existing surgical treatment modes for diabetic foot wounds include the multi-disciplinary team (MDT) cooperation mode and the "five-in-one comprehensive limb salvage" treatment mode. These two modes have their own advantages, but are inconvenient to some extent. In response to this problem, the author's team proposed the wound surgical integrated treatment (WSIT) mode based on years of experience in repairing diabetic foot wounds, emphasizing the perioperative management by MDT, and the local wound management by WSIT team, which significantly improved the diagnosis and treatment efficiency of patients with diabetic foot wounds.