Mehmet Demircan

Background: This study introduces an experimental model of a large, full-thickness skin defect and evaluates how adipose-derived stem cells characterized by high self-renewal and differentiation capacity affect both wound healing and the wound microenvironment when delivered using two different local application methods. Materials and Methods: In this preclinical study, we established an excisional full-thickness skin defect model involving approximately 30% of the total body surface area (TBSA). Five experimental groups were formed, each containing equal numbers of male and female rats: (1) subdermal ADSC injection (ADSC-I) (n = 8), (2) application of an acellular dermal matrix (ADM) seeded with ADSCs (n = 8) (ADSC-ADM), (3) ADM alone (n = 8), (4) subdermal saline injection (n = 8) (SS-I), and (5) an untreated skin-defect sham group (n = 8). Wound healing and wound microenvironment parameters were assessed at regular intervals using macroscopic and microscopic evaluations, as well as various quantitative measurements. The study was terminated when complete wound closure was achieved in all animals of at least one experimental group. Results: The most favorable healing outcomes were observed in the two ADSC-treated groups. More favorable microenvironmental conditions in the stem cell groups were detected from day 14 onward. Complete closure of the dermal defects occurred by day 32 in the ADSC-I group, whereas none of the other groups achieved full wound closure within the study period. Conclusions: Local application of adipose-derived stem cells may accelerate wound healing by favorably modulating the wound microenvironment.

Necrotizing enterocolitis (NEC) is a severe and often catastrophic gastrointestinal emergency that predominantly affects neonates, especially those born prematurely, and is associated with high rates of morbidity and mortality. Despite its significant clinical impact, the precise etiology and molecular pathogenesis of NEC remain incompletely understood. In this study, we conducted global transcriptomic profiling using high-throughput RNA sequencing in 11 premature neonates diagnosed with NEC, following rigorous inclusion and exclusion criteria. Compared to healthy controls, we identified 1,204 differentially expressed genes (DEGs), including 636 upregulated and 568 downregulated transcripts. Notably, genes involved in hypoxia-induced apoptosis (e.g., HIF1 AAS3, HIF1 AAS1), the caspase cascade (BCL2, BCL6, CASP5, CASP7), and inflammation (IL1RAP, IL6ST, TNFAIP3, TNFRSF10 A, TLR6, TLR10) were significantly upregulated. In contrast, IL18, a key modulator of inflammatory responses, was downregulated. Interestingly, several genes encoding selenoproteins (GPX1, GPX4, SELENON, SELENOM, SELENOF, SELENOW, SELENOT) were also downregulated, suggesting molecular evidence of selenium deficiency. Gene ontology and pathway enrichment analyses revealed widespread dysregulation in pathways related to hypoxia response, systemic inflammation, coagulation, antimicrobial defense, mitochondrial function, autophagy, selenium metabolism, and apoptosis. Collectively, our findings provide novel insights into the molecular underpinnings of NEC in premature infants and suggest that systemic hypoxia, oxidative stress, selenium deficiency, and programmed cell death contribute significantly to its pathogenesis.

In this study, we investigated the effects of 3 different burn dressing treatments, including experimental, silver, and modern dressing materials, on systemic oxidative stress in rats with severe scald burns within the first 96 h. The rats were divided into five groups: a burn group (n = 10), a polylactic membrane group (n = 10), a silver sulfadiazine group (n = 10), a curcumin group (n = 10), and a control group (n = 10), consisting of equal numbers of female and male rats. In the first 4 groups, 30% of the rats’ total body surface area was scalded at 95°C. The burn group was not treated. Each group was treated with group-name dressing material. The control group was neither treated nor burned. The rats were sacrificed, and blood and tissue samples were obtained at the 96th hour when severe effects of oxidative stress developed postburns. Systemic inflammatory biomarkers and oxidative stress parameters were examined. In addition, apoptosis and organ damage in liver, kidney, lung, and skin tissues were evaluated biochemically and histopathologically. When the parameters were statistically analyzed, we found that the systemic levels of oxidative stress and inflammatory damage to liver, kidney, and lung tissues were lower in the 3 treated groups than in the burn group. We believe that the dressing material’s efficacy in the treatment of severe burns may be dependent on its ability to combat oxidative stress and inflammation.

Although a slight imbalance between oxidative and antioxidative mediators is part of normal physiology that enables cell aging and the removal of dead cells, burns disturb this equilibrium locally and systemically. Topical burn dressings may attenuate local and systemic oxidative stress and positively influence the post-burn clinical course. This review integrated knowledge regarding the impact of burn dressings on oxidative stress. Using keywords and in-text searches, literature was identified from PubMed, Google Scholar, and Google articles, and studies on local or topical applications of wound dressings and associated oxidative stress were selected. As im-balances between oxidative mediators and antioxidative agents significantly contribute to organ dysfunction and healing disturbance, we investigated oxidative stress on organs, metabolic changes, clinical results, and oxidative parameters influenced by applied dressings. We found positive local and systemic effects of external burn dressings in laboratory and animal tests; however, such studies were rare in humans. Nevertheless, we identified successful cases of semi-occlusive, occlusive, and biologically active dressings that reduce oxidative stress in hu-man burns. In particular, we highlight promising clinical and laboratory results from lac-tate-releasing dressings. Our review provides an invaluable resource for future development and clinical applications of burn dressings.

Congenital diaphragmatic hernia (CDH) is an anomaly characterized by a defect in the diaphragm, leading to the passage of intra-abdominal organs into the thoracic cavity. Herein, the presented work analyzes the global gene expression profiles in nine CDH and one healthy newborn. All of the patients had left posterolateral (Bochdalek) diaphragmatic hernia, operated via an abdominal approach, and stomach and bowels in the thorax cavity. Some patients also had additional anomalies. A total of 560 differentially regulated genes were measured. Among them, 11 genes showed significant changes in expression associated with lung tissue, vascular structure development, and vitamin A metabolism, which are typical ontologies related to CDH etiology. Among them, SLC25A24 and RAB3IL1 are involved in angiogenesis, HIF1A and FOXC2-AS1 are related with the alveolus, MAGI2-AS3 is associated with the diaphragm, LHX4 and DHH are linked with the lung, and BRINP1, FZD9, WNT4, and BLOC1S1-RDH5 are involved in retinol. Besides, the expression levels of some previously claimed genes with CDH etiology also showed diverse expression patterns in different patients. All these indicated that CDH is a complex, multigenic anomaly, requiring holistic approaches for its elucidation.

Over time, we have come to recognize a very complex network of physiological changes enabling wound healing. An immunological process enables the body to distinguish damaged cells and begin a cleaning mechanism by separating damaged proteins and cells with matrix metalloproteinases, a complement reaction, and free radicals. A wide variety of cell functions help to rebuild new tissue, dependent on energy provision and oxygen supply. Like in an optimized “bio-reactor,” disturbance can lead to prolonged healing. One of the earliest investigated local factors is the pH of wounds, studied in close relation to the local perfusion, oxygen tension, and lactate concentration. Granulation tissue with the wrong pH can hinder fibroblast and keratinocyte division and proliferation, as well as skin graft takes. Methods for influencing the pH have been tested, such as occlusion and acidification by the topical application of acidic media. In most trials, this has not changed the wound’s pH to an acidic one, but it has reduced the strong alkalinity of deeper or chronic wounds. Energy provision is essential for all repair processes. New insights into the metabolism of cells have changed the definition of lactate from a waste product to an indispensable energy provider in normoxic and hypoxic conditions. Neovascularization depends on oxygen provision and lactate, signaling hypoxic conditions even under normoxic conditions. An appropriate pH is necessary for successful skin grafting; hypoxia can change the pH of wounds. This review describes the close interconnections between the local lactate levels, metabolism, healing mechanisms, and pH. Furthermore, it analyzes and evaluates the different possible ways to support metabolism, such as lactate enhancement and pH adjustment. The aim of wound treatment must be the optimization of all these components. Therefore, the role of lactate and its influence on wound healing in acute and chronic wounds will be assessed.

: Over time, we have come to recognize a very complex network of physiological changes enabling wound healing. An immunological process enables the body to distinguish damaged cells and begin a cleaning mechanism by separating damaged proteins and cells with matrix metallopro-teinases, a complement reaction, and free radicals. A wide variety of cell functions help to rebuild new tissue, dependent on energy provision and oxygen supply. Like in an optimized "biorector," disturbance can lead to prolonged healing. One of the earliest investigated local factors is the pH of wounds, studied in close relation to the local perfusion, oxygen tension, and lactate concentration. Granulation tissue with the wrong pH can hinder fibroblast and keratinocyte division and pro-liferation, as well as skin graft takes. Methods for influencing the pH have been tested, such as occlusion and acidification by the topical application of acidic media. In most trials, this has not changed the wound's pH to an acidic one, but it has reduced the strong alkalinity of deeper or chronic wound. Energy provision is essential for all repair processes. New insights into the metabolism of cells have changed the definition of lactate from a waste product to an indispensable energy provider in normoxic and hypoxic conditions. Neovascularization depends on oxygen provision and lactate, signaling hypoxic conditions even under normoxic conditions. An appropriate pH is necessary for successful skin grafting; hypoxia can change the pH of wounds. This review describes the close interconnections between the local lactate levels, metabolism, healing mechanisms, and pH. Furthermore, it analyzes and evaluates the different possible ways to support metabolism, such as lactate enhancement and pH adjustment. The aim of wound treatment must be the optimization of all these components. Therefore, the role of lactate and its influence on wound healing in acute and chronic wounds will be assessed.

Gürünlüoğlu S, et al. Pediatr Gastroenterol Hepatol Nutr. 2021 Mar;24(2):173-186. https://doi.org/10.5223/pghn.2021.24.2.173