Relationship between gene expression associated with cellular senescence in cells from discarded wound dressings and wound healing: A retrospective cohort study.

AIM: Senescent cells, inducing a senescence-associated secretory phenotype (SASP), lead to chronic inflammation in hard-to-heal wound tissue. However, eliminating senescent cells may impede normal wound healing due to their important role in the wound healing mechanism. Accordingly, we focused on wound exudates in hard-to-heal wounds, which contain many inflammation biomarkers consistent with SASP. Therefore, we hypothesized that senescent cells might be present in the exudates and induce chronic inflammation. This study investigated the relationship between gene expression associated with cellular senescence in exudates from pressure injuries and wound healing status. METHODS: This retrospective cohort study involved patients treated by a pressure injury team. We collected viable cells from wound dressings and analyzed gene expression. Pearson's correlation coefficient was calculated between cellular senescence and SASP expression. The relationship between the gene expression of cellular senescence and the wound area reduction rate by the following week was examined using a mixed-effects model. RESULTS: CDKN1A-related to cellular senescence-was expressed in 96.3 % of 54 samples, and CDKN1A expression and SASPs positively correlated (PLAU: r = 0.68 and TNF: r = 0.34). Low CDKN1A expression was statistically associated with a large wound area reduction rate (ß = 0.83, p < 0.01). CONCLUSIONS: Gene expression of both cellular senescence and SASP factor in wound dressings suggests the presence of cellular senescence. Senescent cells in wound dressings could be associated with delayed wound healing in the following week.

Efficacy of wearable vibration dressings on full-thickness wound healing in a hyperglycemic rat model.

Local low-frequency vibration promotes blood flow and wound healing in hard-to-heal diabetic foot ulcers (DFUs). However, vibration treatment is challenging in patients with DFUs due to wound management difficulties and low adherence. Consequently, developing wearable self-care devices becomes imperative for effective wound healing. This study introduces a wearable vibration dressing and assesses its impact on wound healing in hyperglycemic rats. Low-frequency vibration at 52 Hz was applied to the wound for 40 min/day in awake rats. Relative wound areas on post-wounding days (PWDs) 4-7 were significantly smaller and the wound closure rate was significantly higher in the vibration group than in the control group (p < 0.05, respectively). The total haemoglobin at baseline and after vibration on post-wounding day 7 was significantly larger in the vibration group than in the control group (p < 0.05). On PWD 7, the thickness of the granulation tissue was significantly higher in the vibration group than in the control group (p < 0.05). Moreover, the number of blood vessels at the wound site and vascular endothelial growth factor A protein expression were significantly higher in the vibration group than in the control group (p < 0.05, respectively). The ratio of (CD68+ /iNOS+ )/(CD163+ ) macrophages in the vibration group was significantly lower than that in the control group (p < 0.05). These results indicate the potential of wearable vibration dressings as new self-care devices that can promote angiogenesis and blood flow, improve inflammation, and enhance wound healing in DFUs.

Local low-frequency vibration accelerates healing of full-thickness wounds in a hyperglycemic rat model.

AIMS/INTRODUCTION: Local low-frequency vibration (LLFV) promotes vasodilation and blood flow, enhancing wound healing in diabetic foot ulcers with angiopathy. However, vibration-induced vasodilation does not occur, owing to chronic hyperglycemia and inflammation. We hypothesized that LLFV improves glycometabolism and inflammation, leading to vasodilation and angiogenesis in diabetic wounds. Therefore, this study investigated the effect of LLFV on wound healing in hyperglycemic rats, primarily focusing on glycometabolism, inflammation, vasodilation, and angiogenesis. MATERIALS AND METHODS: Streptozotocin-induced hyperglycemic Sprague-Dawley rats were used in this study. We applied LLFV to experimentally-induced wounds at 50 Hz and 0, 600, 1,000 or 1,500 mVpp for 40 min/day from post-wounding days (PWD) 1-14. RESULTS: The relative wound areas in the 600 and 1,000 mVpp groups on PWD 5-7 were significantly smaller than those at 0 mVpp. The expression of Glo-1 (1,500 mVpp) and Slc2A4 (1,000 and 1,500 mVpp) was upregulated on PWD 4 and 14, respectively. However, there was no difference in methylglyoxal expression levels in any group until PWD 14. At 1,000 mVpp, the expression of Tnfa on PWD 4, and that of Ptx3 and Ccl2 on PWD 14 was downregulated. Furthermore, the M1/M2 macrophage ratio was considerably decreased on both days. The expression of Nos3, Vegfa and vascular endothelial growth factor A was upregulated on PWD 4. In addition, vasodilation and angiogenesis were more obvious on PWD 14 with 1,000 mVpp. CONCLUSIONS: The results suggest that LLFV promotes wound healing, improves glycometabolism and inflammation, and enhances vasodilation and angiogenesis in hyperglycemic wounds.

A method for harvesting viable cells from wound dressings.

Wound fluid has been well studied for exploring protein biomarkers contained in it. However, cells in wound fluid have not received much attention due to the difficulty in their collection. Our study aimed to establish a method for collecting viable cells from discarded wound dressings. A protocol was designed to wash out nonadherent cells and detach adherent cells from silicone-faced foam wound dressings using trypsin-EDTA. The optimal concentration and incubation time of trypsin-EDTA for collecting equivalent proportions of different cell types to the original cell population were determined in vitro. Cell composition and gene expression changes in monocytes, lymphocytes, neutrophils, fibroblasts and keratinocytes were confirmed using immunocytochemistry and RNA-sequencing ex vivo. Full-thickness wounds were created on 9-week-old male C57BL/6J mice. Wound fluid was collected, and half of it was applied to the wound dressings. The original cell population in the wound fluid and the cell population collected from wound dressings were compared. In the in vitro study, 0.25% trypsin-EDTA and 2.5-min incubation time were considered optimal for collecting adherent cells from wound dressings. In the ex vivo study, among all cell types, only CD3+ lymphocytes showed a significantly higher cell proportion in the collected group. The relative gene expression of the five selected cells showed no significant changes (p-value >0.05, |log2 fold change| < 1.5, differential gene expression analysis). Viable nonadherent and adherent cells were collected from wound dressings without altering gene expression and could be used in future studies for cellular analysis of wound fluid.

Skin properties of itching without symptoms and associated factors among older adults in long-term care facilities.

Since itching without rash frequently among older adults' population, study about skin properties of itching without rash is important to develop prevention methods. Therefore, this study explored the skin properties related to itching without rash and the factors associated with them. A correlation, predictive designs study was conducted at Indonesian Long-term Care (LTC) facilities. Skin properties including skin barrier function and skin inflammation were examined by photographs (macroscopic and microscopic), stratum corneum (SC) hydration, skin Potential of Hydrogen (pH), and skin blotting. Itching experience and skincare behavior were obtained by questionnaire. The itching-related skin properties and associated factors were analyzed. A total of 405 residents participated in this study, with mean age was 74 years. The prevalence of itching on the whole body was 69.1%, and 50.3% of those manifesting itching on the left forearm involved itching without macroscopic abnormalities (itching without rash). SC hydration, skin pH, albumin and nerve growth factor ß (NGFß) were associated with itching without rash (p = 0.007, 0.012, < 0.001, and < 0.001, respectively). Additionally, factors associated with skin properties were age, sex, sun exposure experience, skincare, and hygiene care in the linear regression analysis. Measurement of skin biomarkers using skin blotting was a possible objective measurement of itching skin properties without rash regardless of the environmental condition.

Identification of microRNAs responsive to shear loading in rat skin.

Pressure injuries (PIs) are localised skin injuries that result from pressure with or without shear force. Shear force is more destructive than pressure in clinical settings. Therefore, determining the critical external forces is important for selecting the appropriate care to prevent PIs. To quantitatively distinguish pressure and shear loading with high specificity, we focused on microRNAs (miRs). This study aimed to identify the miRs that are distinguishable between pressure with and without shear loading in rat skin. Microarray analysis identified six candidate miRs from the comparisons among the pressure, shear, and unloaded groups. We analysed the expression levels of the candidate miRs in the process of PI development using real-time reverse transcriptase polymerase chain reaction. In the pressure and shear groups, miR-92b expressions at 6 hours after loading were 2.3 ± 1.3 and 2.9 ± 1.0, respectively, which were significantly higher than those in the control group (P = .014 and .004, respectively). miR-877 expression at 6 hours after loading was significantly increased only in the shear group (2.8 ± 0.9) compared with the control group (P = .016). These results indicate that miR-92b and miR-877 are promising biomarkers to determine for which external force healthcare professionals should intervene.

Validity of skin blot examination for albumin and nerve growth factor ß to detect itching of the skin in Indonesian older adults.

AIM: Itching, a common skin disorder, impacts the quality of life of individuals. Itchy skin occurs more with increasing age and the prediction of itchy skin prognosis is necessary to provide good skincare. This study validated biomarkers in skin blotting to identify and measure itching sensation as well as conventional methods to measure skin barrier function. MATERIALS AND METHODS: From a cross-sectional study conducted in Long-term Care (LTC) facilities in Indonesia itching symptoms were obtained through a questionnaire. Skin conditions were assessed using photographs, stratum corneum (SC) hydration, skin pH, and skin blotting for biomarkers: albumin, interleukin 2 (IL2), nerve growth factor ß (NGFß), and thymic stromal lymphopoietin (TSLP). Association of skin measurements with the presence of skin blotting and trends analysis were conducted. RESULTS: Altogether, 564 LTC residents (average age, 70 years) participated. The SC hydration, skin pH, albumin, and NGFß were associated with the presence of itch (p value= <0.001, <0.001, <0.001, and <0.001, respectively). The signal levels of skin blotting biomarkers were higher in itch group than in the non-itch group. Additionally, the higher quantile of SC hydration was significantly associated with a lower intensity level of NGFß and TSLP (p value = 0.005, 0.003, respectively). The lower quantile of skin pH (better skin condition) was significantly associated with lower albumin, NGFß, and TSLP (p value = 0.048, 0.035, and <0.001, respectively). CONCLUSION: The albumin, NGFß, and TSLP could be a candidate for measurement of itchy skin among older adult with disrupted skin barrier function and local skin inflammation.

Skin characteristics associated with foot callus in people with diabetes: A cross-sectional study focused on desmocollin1 in corneocytes.

AIM: The purpose of this study was to investigate the degradation of desmocollin-1 (DSC1), a member of the desmosomal cadherin family in patients with diabetes, as well as the factors associated with the suppression of DSC1 degradation. METHODS: This cross-sectional study included 60 cases of foot callus involving 30 patients with diabetes (DM) and 30 matched volunteers without diabetes (non-DM). DSC1 degradation in samples from debrided calluses was analysed using western blotting. Skin hydration, a factor reported to suppress DSC1 degradation, was measured using a mobile moisture device. RESULTS: Full-length DSC1 (approximately 100 kDa) was detected in six participants only in the DM group, and no relationship was found between the suppression of DSC1 degradation and decreased skin hydration in the DM group. There was no significant difference in skin hydration values between the DM and non-DM groups. CONCLUSION: DSC1 degradation was suppressed in the DM group. There was no relationship between the suppression of DSC1 degradation and decreased skin hydration in the DM group. Current external force callus care would not be sufficient. This study highlights the need to develop novel callus care to enhance the degradation of DSC1.

Topically injected adrenocorticotropic hormone induces mechanical hypersensitivity on a full-thickness cutaneous wound model in rats.

Cutaneous wound pain causes physical and psychological stress for patients with wounds. Previous studies reported that stress induces hyperalgesia and deteriorates wound healing. However, the effect of the stress response such as in hypothalamic-pituitary-adrenal (HPA) axis on local wound area is unclear. We aimed to investigate the effects of a stress response on the mechanical withdrawal threshold in the local wound area and describe the identification of a wound pain exacerbation. We topically injected adrenocorticotropic hormone (ACTH) into the granulation tissue of full-thickness cutaneous wound model rats on the fifth day postwounding and measured the mechanical withdrawal thresholds, cytochrome P450 2Bs levels and concentration of 5,6-epoxyeicosatrienoic acid in wound exudate. We found that ACTH induced mechanical hypersensitivity at 4 and 6 hours after injection (P = .004 and .021, respectively), and increased gene expression of cytochrome P450 2B12 expression (P = .046). Concentration of 5,6-EET in the wound exudate was moderately correlated with the mechanical withdrawal threshold (r = -.630). Finally, the mechanical withdrawal threshold in the 5,6-EET group was significantly lower than that in the control group at 2 hours after the injection (P = .015). We propose that 5,6-EET is one of the most promising contributors to the wound pain exacerbation. These findings could guide clinical wound and pain management.