Influence of Negative-Pressure Wound Therapy on Tissue Oxygenation in Diabetic Feet

Unveiling therapeutic potential: Adipose tissue-derived mesenchymal stem cells and their exosomes in the management of diabetes mellitus, wound healing, and chronic ulcers

Diabetes mellitus (DM) is a pervasive global health issue with substantial morbidity and mortality, often resulting in secondary complications, including diabetic wounds (DWs). These wounds, arising from hyperglycemia, diabetic neuropathy, anemia, and ischemia, afflict approximately 15% of diabetic patients, with a considerable 25% at risk of lower limb amputations. The conventional approaches for chronic and diabetic wounds management involves utilizing various therapeutic substances and techniques, encompassing growth factors, skin substitutes and wound dressings. In parallel, emerging cell therapy approaches, notably involving adipose tissue-derived mesenchymal stem cells (ADMSCs), have demonstrated significant promise in addressing diabetes mellitus and its complications. ADMSCs play a pivotal role in wound repair, and their derived exosomes have garnered attention for their therapeutic potential. This review aimed to unravel the potential mechanisms and provide an updated overview of the role of ADMSCs and their exosomes in diabetes mellitus and its associated complications, with a specific focus on wound healing.

Antibiotic bone cement accelerates diabetic foot wound healing: Elucidating the role of ROCK1 protein expression

Clinical studies indicate antibiotic bone cement with propeller flaps improves diabetic foot wound repair and reduces amputation rates, but the molecular mechanisms, particularly key proteins' role remain largely unexplored. This study assessed the efficacy of antibiotic bone cement for treating diabetic foot wounds, focusing on molecular impact on ROCK1. Sixty patients were randomized into experimental (EXP, n = 40) and control (CON, n = 20) groups, treated with antibiotic bone cement and negative pressure. Wound healing rate, amputation rate, wound secretion culture and C-reactive protein (CRP) changes, were monitored. Comprehensive molecular investigations were conducted and animal experiments were performed to further validate the findings. Statistical methods were employed to verify significant differences between the groups and treatment outcomes. The EXP group showed significant improvements in wound healing (χ 2 $$ {\chi}^2 $$ = 11.265, p = 0.004) and reduced amputation rates. Elevated levels of ROCK1, fibroblasts and VGF were observed in the trauma tissue post-treatment in the experimental group compared to pre-treatment and the control group (all p < 0.05). Improved trauma secretion culture and CRP were also noted in the EXP group (all p < 0.05). The study suggests that antibiotic bone cement enhances diabetic foot wound healing, possibly via upregulation of ROCK1. Further research is needed to elucidate the underlying molecular mechanisms and broader clinical implications.

Insights into the mechanisms of diabetic wounds: pathophysiology, molecular targets, and treatment strategies through conventional and alternative therapies

Diabetes mellitus is a prevalent cause of mortality worldwide and can lead to several secondary issues, including DWs, which are caused by hyperglycemia, diabetic neuropathy, anemia, and ischemia. Roughly 15% of diabetic patient's experience complications related to DWs, with 25% at risk of lower limb amputations. A conventional management protocol is currently used for treating diabetic foot syndrome, which involves therapy using various substances, such as bFGF, pDGF, VEGF, EGF, IGF-I, TGF-β, skin substitutes, cytokine stimulators, cytokine inhibitors, MMPs inhibitors, gene and stem cell therapies, ECM, and angiogenesis stimulators. The protocol also includes wound cleaning, laser therapy, antibiotics, skin substitutes, HOTC therapy, and removing dead tissue. It has been observed that treatment with numerous plants and their active constituents, including Globularia Arabica, Rhus coriaria L., Neolamarckia cadamba, Olea europaea, Salvia kronenburgii, Moringa oleifera, Syzygium aromaticum, Combretum molle, and Myrtus communis, has been found to promote wound healing, reduce inflammation, stimulate angiogenesis, and cytokines production, increase growth factors production, promote keratinocyte production, and encourage fibroblast proliferation. These therapies may also reduce the need for amputations. However, there is still limited information on how to prevent and manage DWs, and further research is needed to fully understand the role of alternative treatments in managing complications of DWs. The conventional management protocol for treating diabetic foot syndrome can be expensive and may cause adverse side effects. Alternative therapies, such as medicinal plants and green synthesis of nano-formulations, may provide efficient and affordable treatments for DWs.

Measuring In-Vivo Foot Perfusion Distal to a Near-Circumferential Negative Pressure Wound Therapy Dressing via Thermal Imaging

Background Negative pressure wound therapy (NPWT) has been shown to promote the healing of acute and chronic wounds. In our previous study, we demonstrated that a near-circumferential NPWT dressing provided "lift-off" on an in-vitro extremity model resulting in decreased pressure. We hypothesized that this decrease in pressure may increase perfusion distal to the NPWT dressing by increasing lymphatic drainage and venous flow. Methods In this study, we tested if a near-circumferential NPWT dressing caused any appreciable skin movement around the dressing. We then used a thermal imaging camera to test if there was an increase in perfusion to the foot when a near-circumferential NPWT dressing was placed around the lower leg and tested at various negative pressures. Finally, we wanted to see if an artificial "lift-off" mechanism would lead to an increase in perfusion. Results The skin was noted to stretch between the short ends of the NPWT dressing, consistent with our previously described "lift-off" mechanism. However, there was no correlation between negative pressure and perfusion to the foot in the other experiments. Conclusion This study demonstrated that a near-circumferential NPWT dressing may not have any appreciable effects on perfusion when applied on a healthy patient, however, future studies are needed to determine if similar results would be seen on a traumatized or otherwise compromised extremity.

Diabetic Wound-Healing Science

Diabetes mellitus is an increasingly prevalent chronic metabolic disease characterized by prolonged hyperglycemia that leads to long-term health consequences. It is estimated that impaired healing of diabetic wounds affects approximately 25% of all patients with diabetes mellitus, often resulting in lower limb amputation, with subsequent high economic and psychosocial costs. The hyperglycemic environment promotes the formation of biofilms and makes diabetic wounds difficult to treat. In this review, we present updates regarding recent advances in our understanding of the pathophysiology of diabetic wounds focusing on impaired angiogenesis, neuropathy, sub-optimal chronic inflammatory response, barrier disruption, and subsequent polymicrobial infection, followed by current and future treatment strategies designed to tackle the various pathologies associated with diabetic wounds. Given the alarming increase in the prevalence of diabetes, and subsequently diabetic wounds, it is imperative that future treatment strategies target multiple causes of impaired healing in diabetic wounds.

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.

Application of a simple skin stretching system and negative pressure wound therapy in repair of complex diabetic foot wounds

The management of complex diabetic foot wounds with large skin defects poses a challenge for surgeons. We presented a simple skin stretching system and negative pressure wound therapy for the repair of complex diabetic foot wounds to examine the effectiveness and safety.

A total of 16 patients with diabetic foot ulcers were retrospectively reviewed between January 2015 and October 2020. All patients underwent the treatment by 3 stages. In stage 2, these difficult-to-close wounds of diabetes foot were residual. This method was applied to the wounds with a median defect size of 20.42 cm² (range, 4.71–66.76 cm²).

The median time for closure of complex diabetic foot wounds was 14 days ranging from 8 to 19 days. With respect to the absolute rates of reduction, it was observed with a median of 1.86 cm²/day, ranging from 0.29 cm²/day to 8.35 cm²/day. In accordance with the localization of the defect, the patients were divided into 3 groups: side of the foot (37.5%), dorsum of the foot (50.0%), and others (12.5%). There was no statistical difference between side of the foot and dorsum of the foot in terms of the median defect size with P = 0.069 (Kruskal–Wallis test). Otherwise, there were statistically significant differences regarding the median time and the median absolute rates (P < 0.05; Kruskal–Wallis test). No severe complications were encountered in this study.

In summary, our results show that application of the simple skin stretching system and NPWT is an effective and safe approach to complex diabetic foot wounds. Nevertheless, more attention should be paid to the appropriate patient selection and intraoperative judgment to ensure wound closure and avoid undue complications.

3D scaffolds in the treatment of diabetic foot ulcers: New trends vs conventional approaches

Diabetic foot ulcer (DFU) is a serious complication of diabetes mellitus, affecting roughly 25% of diabetic patients and resulting in lower limb amputation in over 70% of known cases. In addition to the devastating physiological consequences of DFU and its impact on patient quality of life, DFU has significant clinical and economic implications. Various traditional therapies are implemented to effectively treat DFU. However, emerging technologies such as bioprinting and electrospinning, present an exciting opportunity to improve current treatment strategies through the development of 3D scaffolds, by overcoming the limitations of current wound healing strategies. This review provides a summary on (i) current prevention and treatment strategies available for DFU; (ii) methods of fabrication of 3D scaffolds relevant for this condition; (iii) suitable materials and commonly used molecules for the treatment of DFU; and (iv) future directions offered by emerging technologies.

Physical and biological properties of blend-electrospun polycaprolactone/chitosan-based wound dressings loaded with N-decyl-N, N-dimethyl-1-decanaminium chloride: An in vitro and in vivo study

Dual-pump electrospinning of antibacterial N-decyl-N, N-dimethyl-1-decanaminium-chloride (DDAC)-loaded polycaprolactone (PCL) nanofibers, and chitosan (CS)/polyethylene-oxide (PEO)-based wound dressings with hydrophilic and hydrophobic properties to eliminate and absorb pathogenic bacteria from wound surface besides antibacterial action and to support wound healing and accelerate its process. Physicochemical properties of the prepared nanofibrous mat as well as antibacterial, cytotoxicity, and cell compatibility were studied. The full-thickness excisional wound healing properties up to 3 weeks using hematoxylin and eosin and Masson-trichrome staining were investigated. Addition of DDAC to CS/PEO-PCL mats decreased the diameter of the nanofibers, which is a crucial property for wound healing as large surface area per volume ratio of nanofibers, in addition to proper cell adhesion, increases loading of DDAC in mats and leads to increased cell viability and eliminating Gram-positive bacteria at in vitro studies. In vivo studies showed DDAC-loaded CS/PEO-PCL mats increased epithelialization and angiogenesis and decreased the inflammation according to histological results. We demonstrated that hydrophobic PCL/DDAC mats, besides antibacterial properties of DDAC, absorbed and eliminated the hydrophobic pathological microorganisms, whereas the hydrophilic nanofibers consisted of CS/PEO, increased the cell adhesion and proliferation due to positive charge of CS. Finally, we were able to increase the wound healing quality by using multifunctional wound dressing. CS/PEO-PCL containing 8 wt % of DDAC nanofibrous mats is promising as a wound dressing for wound management due to the favorable interactions between the pathogenic bacteria and PCL/CS-based wound dressing.

Skin Hydration Level as a Predictor for Diabetic Wound Healing: A Retrospective Study

BACKGROUND

In the diabetic foot, the skin may crack and develop fissures, potentially increasing vulnerability to ulceration and infection. Therefore, maintaining adequate skin hydration may be crucial for diabetic wound healing. However, no clinical study has addressed this issue. This study aimed to determine and compare the effect of the skin hydration level on diabetic wound healing with that of the tissue oxygenation level, which is recognized as the most reliable parameter in predicting diabetic wound healing.

METHODS

This retrospective study included 263 diabetic patients with forefoot ulcers. Skin hydration and transcutaneous oxygen pressure data collected before and after percutaneous transluminal angioplasty were analyzed. Skin hydration and tissue oxygenation were graded as poor, moderate, or acceptable. Wound healing outcomes were graded as healed without amputation, minor amputation, or major amputation. Wound healing outcomes were compared using four parameters: skin hydration at baseline, transcutaneous oxygen pressure at baseline, post-percutaneous transluminal angioplasty skin hydration, and post-percutaneous transluminal angioplasty transcutaneous oxygen pressure.

RESULTS

Each of the four parameters exhibited statistically significant correlations with wound healing outcomes. In the concurrent analysis of both skin hydration and transcutaneous oxygen pressure, skin hydration was a dominant parameter (p = 0.0018) at baseline, whereas transcutaneous oxygen pressure was a dominant parameter (p < 0.0001) following percutaneous transluminal angioplasty.

CONCLUSIONS

Skin hydration level might be a useful predictor for diabetic wound healing. In particular, the skin hydration level before recanalization was found to be superior to transcutaneous oxygen pressure in predicting wound healing.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Treatment of Diabetic Foot Gangrene Using the STAGE Principle: A Case Series

Diabetic foot gangrene with lower extremity ischemia can preclude amputation. However, wound treatment principles based on the Wagner classification system are lacking. We proposed the STAGE principle for the surgical management of diabetic foot wounds. The STAGE principle guides surgical intervention during the wound treatment of diabetic foot ulcers and emphasizes that "based on anatomical layers, the management focuses on blood supply and includes layer-by-layer incision to the infected area, maintenance of effective wound drainage, and step-by-step treatment of the wound." We applied the STAGE principle for the treatment of 7 patients with an ankle brachial index <0.5 and Wagner grade 4 diabetic foot gangrene. The average ankle brachial index was 0.42 (0.32-0.48; SD = 0.06), and male patients smoked an average of 1.28 packs/day (0.4-2; SD = 0.63). The average wound duration was 45.86 days (14-63 days; SD = 18.46). The average wound healing time was 8.86 months (5-13 months; SD = 2.36). The follow-up time was 37.71 months (3-84 months; SD = 25.04; median = 36 months). Patient 1 received endovascular interventional therapy twice for the lower extremity artery, and the wound healed. After 3 months of follow-up, the patient exhibited recurrence. After the third application of endovascular interventional therapy for the lower extremity artery, the blood supply was improved, and the wound healed after 1 month. In summary, the treatment of 7 cases of diabetic foot gangrene with severe lower extremity ischemia using the STAGE principle resulted in remarkable efficacy.

Tissue Oxygenation and Negative-Pressure Wound Therapy When Applied to the Feet of Persons With Diabetes Mellitus: An Observational Study

PURPOSE

Our group has reported that negative-pressure wound therapy (NPWT) decreases tissue oxygenation by 84% in the foot of diabetic patients because the pad of the connecting drainage tube and foam sponge of the NPWT system compress the wound bed. The purpose of this study was to determine whether an NPWT modified dressing application reduces tissue oxygenation in the feet of persons with diabetes mellitus.

DESIGN

A prospective, clinical, observational study.

SUBJECTS AND SETTING

We enrolled 30 patients with diabetic mellitus; their mean age was 63.9 ± 11.2 years (mean ± standard deviation). All were cared for at the diabetic wound center at an academic tertiary medical center in South Korea between 2014 and January 2015.

METHODS

Transcutaneous partial oxygen pressures (TcpO2) were measured to determine tissue oxygenation levels beneath modified NPWT dressings. A TcpO2 sensor was fixed at the tarsometatarsal area of the contralateral unwounded foot. A negative pressure of -125 mm Hg was applied until TcpO2 reached a plateau state; values were measured before, during, and after the modified NPWT. The Wilcoxon' and Mann-Whitney U tests were used to compare differences between these measurements.

RESULTS

TcpO2 levels decreased by 26% during the modified NPWT. Mean TcpO2 values before, during, and after turning off the therapy were 54.3 ± 15.3 mm Hg, 41.6 ± 16.3 mm Hg, and 53.3 ± 15.6 mm Hg (P < .05), respectively.

CONCLUSION

Applying NPWT without the pad of the connecting drainage tube significantly reduces the amount of tissue oxygenation loss beneath foam dressings on the skin of the foot dorsum in diabetic patients.

Status of wound management in Korea

In spite of a period of intense economic, social, and political hardship following the Korean War, the Republic of Korea has made great strides in economic growth over the past half century, and also remarkable progress in the medical field. However, wound research has been slow to take off in South Korea. Meanwhile, as is the case in many countries in Western Europe and North America, South Korea is seeing a steady increase in its aged population. The growth in the geriatric population has in turn brought on more cases of chronic wounds. Though South Korea only began to recognize the importance of wound management in the early 2000s, it was fortunate enough to have sophisticated related industries, such as biotechnology and information technology, and brilliant, industrious, and eager wound researchers, contributing to rapid development of the field. The country has particular strengths in research for innovative cell-based treatments and products for managing wounds. Notwithstanding government policy ill-equipped to sufficiently support such advancement, better communication between experts and public officials will no doubt bring forth even more achievements in this very promising field. It is in this context that this article aims to summarize current wound management practices, research, training, product development, and government policies regarding wound management in South Korea as of the year 2017.