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.

Impaired wound healing associated with recurrent Staphylococcus aureus infection and unresolved inflammation are hallmarks of nonhealing diabetic foot ulcers (DFUs). Perforin-2, an innate immunity molecule against intracellular bacteria, limits cutaneous infection and dissemination of S. aureus in mice. Here, we report the intracellular accumulation of S. aureus in the epidermis of DFUs with no clinical signs of infection due to marked suppression of perforin-2. S. aureus residing within the epidermis of DFUs triggers AIM2 inflammasome activation and pyroptosis. These findings were corroborated in mice lacking perforin-2. The effects of pyroptosis on DFU clinical outcomes were further elucidated in a 4-week longitudinal clinical study in patients with DFUs receiving standard care. Increased AIM2 inflammasome and ASC-pyroptosome coupled with induction of IL-1β were found in nonhealing DFUs compared with healing DFUs. Our findings revealed that perforin-2 suppression, intracellular S. aureus accumulation, and associated induction of pyroptosis contribute to healing inhibition and prolonged inflammation in patients with DFUs.

Fibrotic disease, which is implicated in almost half of all deaths worldwide, is the result of an uncontrolled wound healing response to injury in which tissue is replaced by deposition of excess extracellular matrix, leading to fibrosis and loss of organ function. A plethora of genome-wide association studies, microarrays, exome sequencing studies, DNA methylation arrays, next-generation sequencing, and profiling of noncoding RNAs have been performed in patient-derived fibrotic tissue, with the shared goal of utilizing genomics to identify the transcriptional networks and biological pathways underlying the development of fibrotic diseases. In this review, we discuss fibrosing disorders of the skin, liver, kidney, lung, and heart, systematically (1) characterizing the initial acute injury that drives unresolved inflammation, (2) identifying genomic studies that have defined the pathologic gene changes leading to excess matrix deposition and fibrogenesis, and (3) summarizing therapies targeting pro-fibrotic genes and networks identified in the genomic studies. Ultimately, successful bench-to-bedside translation of observations from genomic studies will result in the development of novel anti-fibrotic therapeutics that improve functional quality of life for patients and decrease mortality from fibrotic diseases.

Intracellular pathogens including Staphylococcus aureus contribute to the non‐healing phenotype of chronic wounds. Lactobacilli, well known as beneficial bacteria, are also reported to modulate the immune system, yet their role in cutaneous immunity remains largely unknown. We explored the therapeutic potential of bacteria‐free postbiotics, bioactive lysates of lactobacilli, to reduce intracellular S. aureus colonization and promote healing. Fourteen postbiotics derived from various lactobacilli species were screened, and Latilactobacillus curvatus BGMK2‐41 was selected for further analysis based on the most efficient ability to reduce intracellular infection by S. aureus diabetic foot ulcer clinical isolate and S. aureus USA300. Treatment of both infected keratinocytes in vitro and infected human skin ex vivo with BGMK2‐41 postbiotic cleared S. aureus . Keratinocytes treated in vitro with BGMK2‐41 upregulated expression of antimicrobial response genes, of which DEFB4 , ANG , and RNASE7 were also found upregulated in treated ex vivo human skin together with CAMP exclusively upregulated ex vivo. Furthermore, BGMK2‐41 postbiotic treatment has a multifaceted impact on the wound healing process. Treatment of keratinocytes stimulated cell migration and the expression of tight junction proteins, while in ex vivo human skin BGMK2‐41 increased expression of anti‐inflammatory cytokine IL‐10, promoted re‐epithelialization, and restored the epidermal barrier via upregulation of tight junction proteins. Together, this provides a potential therapeutic approach for persistent intracellular S. aureus infections.

Advancements in pathology have given rise to software applications intended to minimize human error and improve efficacy of image analysis. Still, the subjectivity of image quantification performed manually and the limitations of the most ubiquitous tissue stain analysis software requiring parameters tuned by the observer, reveal the need for a highly accurate, automated nuclear quantification software specific to immunohistochemistry, with improved precision and efficiency compared with the methods currently in use. We present a method for the quantification of immunohistochemical biomarkers in keratinocyte nuclei proposed to overcome these limitations, contributing sensitive shape-focused segmentation, accurate nuclear detection, and automated device-independent color assessment, without observer-dependent analysis parameters.

Venous leg ulcers (VLUs) are the most common cause of leg ulcers, yet only 44% heal with standard-of-care treatment, highlighting the critical need for better understanding of their cellular pathology. We used both bulk and single-cell RNA sequencing (scRNA-seq) to identify molecular mechanisms and cellular functions contributing to VLU pathophysiology. scRNA-seq of chronic VLUs revealed impairments in immune, lymph endothelial, and endothelial cells, along with underlying signaling pathways. Next, bulk RNA-seq was performed alongside weekly wound assessments over 4 weeks in patients with VLUs receiving standard care, classifying them as healers or nonhealers on the basis of ≥50% closure. Transcriptomes of healing and nonhealing VLUs were compared with those of human acute wounds, revealing marked suppression of inflammatory response, lymphangiogenesis, and angiogenesis in nonhealing VLUs. In contrast, healing VLUs resembled the gene expression signature of physiological, acute wound healing. Reduced inflammatory response underlined the nonhealing VLU signature, associated with impaired leukocyte transmigration and egress, with suppression of the activity of multiple kinases. Bioinformatic analyses pinpointed PTEN (phosphatase and TENsin homolog) as a master regulator of these processes and signaling pathways. Increased PTEN protein expression was confirmed in nonhealing compared with healing VLUs. Furthermore, pharmacological PTEN inhibition enhanced immune response and pro-inflammatory signals, angiogenesis, and lymphangiogenesis, which resulted in accelerated acute wound closure in mice. These findings support PTEN as a key regulator of the nonhealing VLU phenotype controlling multiple processes responsible for impaired wound healing and highlight its potential use as a therapeutic target to promote wound closure in VLUs.