Mesenchymal stem cell-derived exosomes: The dawn of diabetic wound healing

Chronic wound healing has long been an unmet medical need in the field of wound repair,with diabetes being one of the major etiologies.Diabetic chronic wounds(DCWs),especially diabetic foot ulcers,are one of the most threatening chronic complications of diabetes.Although the treatment strategies,drugs,and dressings for DCWs have made great progress,they remain ineffective in some patients with refractory wounds.Stem cell-based therapies have achieved specific efficacy in various fields,with mesenchymal stem cells(MSCs)being the most widely used.Although MSCs have achieved good feedback in preclinical studies and clinical trials in the treatment of cutaneous wounds or other situations,the potential safety concerns associated with allogeneic/autologous stem cells and unknown long-term health effects need further attention and supervision.Recent studies have reported that stem cells mainly exert their trauma repair effects through paracrine secretion,and exosomes play an important role in intercellular communication as their main bioactive component.MSC-derived exosomes(MSC-Exos)inherit the powerful inflammation and immune modulation,angiogenesis,cell proliferation and migration promotion,oxidative stress alleviation,collagen remodeling imbalances regulation of their parental cells,and can avoid the potential risks of direct stem cell transplantation to a large extent,thus demonstrating promising performance as novel"cell-free"therapies in chronic wounds.This review aimed to elucidate the potential mechanism and update the progress of MSC-Exos in DCW healing,thereby providing new therapeutic directions for DCWs that are difficult to be cured using conventional therapy.

An Assessment of the Diabetic Knowledge, Attitude, and Practice of School Teachers in Riyadh, Kingdom of Saudi Arabia

Background: Teachers are the cornerstone of the next generation and they are considered an important source of health information for students about diabetes. The objective of this study is to assess the knowledge, attitude, and practice (KAP) of teachers about diabetes mellitus (DM) and to identify the associated factors. Methods: Cross-sectional study design included a stratified random sample of male and female teachers from public and private schools in Riyadh city. A self-administered online questionnaire was developed. The data collection was from October to November 2019. Results: The study included 633 teachers. Overall, 57.2% of the surveyed teachers were knowledgeable about DM. Teachers aged between 51 and 60 years (p = 0.005), males (p = 0.018), PhD holders (p = 0.011), teaching science (p = 0.021), having more than 20 years of teaching experience (p = 0.001), diabetics (p < 0.001), and having family history of diabetes (p = 0.007) had the highest level of knowledge. Overall, positive attitude towards DM was reported among 53.1% of the teachers. Those with teaching experience between 11 and 15 years (p = 0.024), diabetics (p = 0.029), and having a diabetic student (p = 0.012) had more positive attitude towards diabetes. Good diabetes-related practice was observed among 54.3% of the teachers. Older (p < 0.001), having more than 20 years of teaching experience (p < 0.001), non-Saudi (p = 0.011), diabetic teachers with longer duration of the disease (p < 0.001), having family history of DM (p = 0.028), and principals (p = 0.002) had the highest level of good diabetes-related practice. Conclusion: The KAP of teachers in public and private schools in Riyadh about DM was sufficient in many aspects. However, targeting new young teachers should be a priority to raise awareness.

In Defense of the LDL Hypothesis

Both clinical and basic science studies during the last 30 years have emphasized the importance of cholesterol in the pathogenesis of atherosclerosis. There is a direct relationship between the level of circulating cholesterol (as LDLc remnant particles) and the incidence of cardiovascular events. However, this hypothesis has not gone unchallenged, both in social media and the scientific literature. This controversy has major consequences to the health of the public,?because atherosclerosis is the number one cause of morbidity and mortality in the Western World.?The proponents of the non-importance of atherosclerosis base their argument on certain studies. We have carefully examined these studies in order to address the validity of the challenges.?Each of these studies has its own deficiencies?as pointed out in this article. Overall, the evidence that cholesterol is not the primary underlying pathogenic factor causing heart attacks and strokes is based on a flawed interpretation of study results. These studies have several serious deficiencies including lost data, inadequate power, excessive drop outs, borderline significance, and lack of a control group. The conclusion that cholesterol is essential in the pathogenesis of atherosclerosis is critical for treating and preventing atherosclerosis and reducing the prevalence of cardiovascular disease.

Electrospun nanofibrous membranes meet antibacterial nanomaterials:From preparation strategies to biomedical applications

Electrospun nanofibrous membranes(eNFMs)have been extensively developed for bio-applications due to their structural and compositional similarity to the natural extracellular matrix.However,the emergence of antibiotic resistance in bacterial infections significantly impedes the further development and applications of eNFMs.The development of antibacterial nanomaterials substantially nourishes the engineering design of antibacterial eNFMs for combating bacterial infections without relying on antibiotics.Herein,a comprehensive review of diverse fabrication techniques for incorporating antibacterial nanomaterials into eNFMs is presented,encompassing an exhaustive introduction to various nanomaterials and their bactericidal mechanisms.Furthermore,the latest achievements and breakthroughs in the application of these antibacterial eNFMs in tissue regenerative therapy,mainly focusing on skin,bone,periodontal and tendon tissues regeneration and repair,are systematically summarized and discussed.In particular,for the treatment of skin infection wounds,we highlight the antibiotic-free antibacterial therapy strategies of antibacterial eNFMs,including(i)single model therapies such as metal ion therapy,chemodynamic therapy,photothermal therapy,and photodynamic therapy;and(ii)multimodel therapies involving arbitrary combinations of these single models.Additionally,the limitations,challenges and future opportunities of antibacterial eNFMs in biomedical applications are also discussed.We anticipate that this comprehensive review will provide novel insights for the design and utilization of antibacterial eNFMs in future research.

Association of high-density lipoprotein cholesterol and wound healing in patients with diabetic foot ulcers

To the Editor:Diabetic foot ulcers(DFUs)are an important cause of morbidity in patients with diabetes mellitus(DM).The prevalence of foot ulcers in patients with diabetes is 4%to 10%,with the lifetime incidence estimated to be between 19%and 34%.[1]DFUs have become a considerable burden on patients and the healthcare service system.However,the mechanism is not fully understood,and DFUs are still difficult to heal.High-density lipoproteins(HDL)are circulating particles composed of phospholipids,cholesterol,and proteins.HDL attracted lots of attention mainly because of its protective effect against the development of atherosclerosis.However,it has been shown that decreased HDL levels are correlated with an increased risk of DM and its complications.The association of HDL with DFUs has also received much attention.Lower levels of HDL cholesterol were associated with increased risk for foot ulceration in patients with diabetes(odds ratio 0.427,95%confidence interval[CI]0.228-0.799,P=0.008).[2]HDL cholesterol levels were also revealed to be an independent risk factor of lower-extremity amputation and wound-related death in patients with DFUs(hazard ratio[HR]0.30,95%CI 0.14-0.63,P=0.002).Therefore,there might be a potential correlation between HDL and wound healing.

Dynamic changes of wound-related miRNAs after application of autologous platelet-rich gel in diabetic wounds

To the Editor:Diabetic chronic cutaneous ulcers(DCUs)are among the most common and serious complications of diabetes mellitus.Diabetic foot ulcers are the most common type of DCU and are now considered a global epidemic.[1]The clinical prevention and treatment of DCUs are critical and have remained challenging for clinicians.With the exploration of topical treatment methods,autologous platelet-rich gel(APG)is regarded as an adjuvant therapy to promote wound healing,and it has been widely used for wound repair.[2]Some microRNAs that play a critical role in the whole wound healing process have been found in wound tissues,which we call wound-related miRNAs(wr-miRNAs).However,few studies have explored the dynamic changes of wr-miRNAs during APG treatment.Our study aimed to evaluate the efficacy of APG in treating diabetic wounds and explore the dynamic changes of wr-miRNAs during wound healing.

Consensus on the application of negative pressure wound therapy of diabetic foot wounds

Because China is becoming an aging society,the incidence of diabetes and diabetic foot have been increasing.Diabetic foot has become one of the main health-related killers due to its high disability and mortality rates.Negative pressure wound therapy(NPWT)is one of the most effective techniques for the treatment of diabetic foot wounds and great progress,both in terms of research and its clinical application,has been made in the last 20 years of its development.However,due to the complex pathogenesis and management of diabetic foot,irregular application of NPWT often leads to complications,such as infection,bleeding and necrosis,that seriously affect its treatment outcomes.In 2020,under the leadership of Burns,Trauma and Tissue Repair Committee of the Cross-Straits Medicine Exchange Association,the writing group for‘Consensus on the application of negative pressure wound therapy of diabetic foot wounds’was established with the participation of scholars from the specialized areas of burns,endocrinology,vascular surgery,orthopedics and wound repair.Drawing on evidence-based practice suggested by the latest clinical research,this consensus proposes the best clinical practice guidelines for the application and prognostic evaluation of NPWT for diabetic foot.The consensus aims to support the formation of standardized treatment schemes that clinicians can refer to when treating cases of diabetic foot.