PDK4 facilitates fibroblast functions and diabetic wound healing through regulation of HIF-1α protein stability and gene expression.

Fibroblast activation disorder is one of the main pathogenic characteristics of diabetic wounds. Orchestrated fibroblast functions and myofibroblast differentiation are crucial for wound contracture and extracellular matrix (ECM) formation. Pyruvate dehydrogenase kinase 4 (PDK4), a key enzyme regulating energy metabolism, has been implicated in modulating fibroblast function, but its specific role in diabetic wounds remains poorly understood. In this study, we investigated the impact of PDK4 on diabetic wounds and its underlying mechanisms. To assess the effect of PDK4 on human dermal fibroblasts (HDFs), we conducted CCK-8, EdU proliferation assay, wound healing assay, transwell assay, flow cytometry, and western blot analyses. Metabolic shifts were analyzed using the Seahorse XF analyzer, while changes in metabolite expression were measured through LC-MS. Local recombinant PDK4 administration was implemented to evaluate its influence on wound healing in diabetic mice. Finally, we found that sufficient PDK4 expression is essential for a normal wound-healing process, while PDK4 is low expressed in diabetic wound tissues and fibroblasts. PDK4 promotes proliferation, migration, and myofibroblast differentiation of HDFs and accelerates wound healing in diabetic mice. Mechanistically, PDK4-induced metabolic reprogramming increases the level of succinate that inhibits PHD2 enzyme activity, thus leading to the stability of the HIF-1α protein, during which process the elevated HIF-1α mRNA by PDK4 is also indispensable. In conclusion, PDK4 promotes fibroblast functions through regulation of HIF-1α protein stability and gene expression. Local recombinant PDK4 administration accelerates wound healing in diabetic mice.

Application and effect of tension-reducing suture in surgical treatment of hypertrophic scar.

PURPOSE: To investigate the application and effectiveness of tension-reducing suture in the repair of hypertrophic scars. METHODS: A retrospective analysis of clinical data was conducted on 82 patients with hypertrophic scars treated at the Department of Burns and Plastic Surgery of Nanjing Drum Tower Hospital from September 2021 to December 2022. Patients were operated with combination of heart-shaped tension-reducing suturing technique and looped, broad, and deep buried (LBD) suturing technique or conventional suture method. Outcomes of surgical treatment were assessed before and 6 months after surgery using the Patient and Observer Scar Assessment Scale (POSAS) and the Vancouver Scar Scale (VSS). RESULTS: Improvements were achieved on scar quality compared to that preoperatively, with a reduction in scar width (1.7 ± 0.6 cm vs. 0.7 ± 0.2 cm, P < 0.001). Assessment using the POSAS and VSS scales showed significant improvements in each single parameter and total score compared to preoperative values (P < 0.05). The Combination method group achieved better score in total score of VSS scale, in color, stiffness, thickness and overall opinion of PSAS scale, and in vascularity, thickness, pliability and overall opinion of OSAS scale. CONCLUSION: The amalgamation of the heart-shaped tension-reducing suturing technique and the LBD suturing technique has shown promising outcomes, garnering notably high levels of patient satisfaction in the context of hypertrophic scar repair. Patients have exhibited favorable postoperative recoveries, underscoring the clinical merit and the prospective broader applicability of this approach in the realm of hypertrophic scar management.

PDK4 rescues high-glucose-induced senescent fibroblasts and promotes diabetic wound healing through enhancing glycolysis and regulating YAP and JNK pathway.

During the process of wound healing, fibroblasts migrate to the wound site and perform essential functions in promoting cell proliferation, as well as synthesizing and secreting the extracellular matrix (ECM). However, in diabetic wounds, senescent fibroblasts exhibit impaired proliferative capacity and fail to synthesize essential ECM components. Pyruvate dehydrogenase kinase 4 (PDK4), a key enzyme regulating energy metabolism, has been implicated in modulating cellular senescence and fibroblast function. However, its specific role in diabetic wounds remains poorly understood. In this study, we conducted a series of in vivo and in vitro experiments using STZ-induced diabetic mice and human dermal fibroblasts. We evaluated cellular senescence markers, including SA-ß-gal, P53, P16, P21, and PAI-1, as well as senescence-associated secretory phenotype (SASP) factors. Finally, we observed that PDK4 increased in normal wound healing, but its expression was insufficient in diabetic wounds. Significantly, the overexpression of PDK4 demonstrated the potential to accelerate diabetic wound healing and improve the senescence phenotype both in vivo and in vitro. Furthermore, our study elucidated the underlying mechanism by which PDK4 improved the senescent phenotype through the enhancement of glycolysis and regulation of YAP and JNK pathway. The effect was dependent on metabolic reprogramming and subsequent reduction of reactive oxygen species (ROS), which was mediated by PDK4. Overall, our findings highlight the potential of PDK4 as a promising therapeutic target for addressing diabetic wounds.

Inhibition of TAZ impairs the migration ability of melanoma cells.

Malignant melanoma (MM) is characterized by rapid growth, frequent metastasis, and high mortality. Targeted therapy for MM is still a research hotspot due to the increasing understanding of the hippo pathway. The aim of this study is to investigate the role of transcriptional coactivator with PDZ-binding motif (TAZ) in MM tumorigenesis. Based on the database analysis, we found that the median mRNA expression of TAZ (5.4) was found to be similar to that of YAP (5.5) in 473 human melanoma specimens. However, in 63 MM cell lines, the median expression of TAZ (10.8) was expressed at a higher level than that of YAP (9.5), which was then validated in A375. TAZ down-regulation by siRNA decreased the migration (72%) and invasion (74%) abilities of A375. Furthermore, the down-regulation of TAZ inhibited the proliferation of A375 without affecting apoptosis. We subsequently blocked hippo signaling with verteporfin and found that verteporfin application decreased the number of migrating (63%) and invading (69%) cells, respectively. We further found that Cyr61 declined following TAZ down-regulation. Moreover, TAZ negatively correlates with melanoma patient's overall survival. Our data proved that TAZ contributed to MM metastasis, which might be a potential therapeutic target in the future.

Mechanisms of resveratrol against diabetic wound by network pharmacology and experimental validation.

BACKGROUND: Resveratrol (RSV) that possesses anti-oxidative, anti-inflammatory, and pro-angiogenic effects is an effective drug for diabetic wound (DW), while its pharmacological mechanism remains to be elucidated. In this study, we apply network pharmacology and experimental validation approach to reveal the potential mechanism of RSV against DW. METHODS: We obtained potential targets for RSV and DW from the publicly available database. Using interaction networks and conducting GO and KEGG pathway enrichment analyses, we constructed target-pathway networks to explore the relationship between RSV and DW. To validate the pharmacological mechanism of RSV, we induced the DW model. RESULTS: Ninety overlapped targets between RSV and DW were obtained, and the hub genes of the PPI network included TNF, IL-6, CASP3, MAPK3, VEGFA, IL-1ß, AKT1, and JUN. Based on target-pathway networks, the AGE-RAGE signalling pathway was involved in the RSV treatment of DW. Furthermore, in vivo experiments revealed that RSV significantly promoted wound healing in diabetic mice and attenuated the expression of pro-inflammatory cytokines in wound tissue. Meanwhile, RSV could inhibit the AGE-RAGE signalling pathway and thus reduce the activation of NF-κB. CONCLUSION: This study initially revealed the biological mechanism of RSV for treating DW through multi-target and multi-pathway. AGE-RAGE, FoxO, MAPK, PI3K-AKT and other signalling pathways may be the main pathways of RSV in treating DW. RSV reduces the inflammatory response by inhibiting the AGE-RAGE signalling pathway, which in turn promotes DW healing.

Deep sternal wound infection and pectoralis major muscle flap reconstruction: A single-center 20-year retrospective study.

Background: One of the most drastic complications of median sternal incision is deep sternal wound infection (DSWI), as it can lead to prolonged hospitalization, increased expected costs, re-entry into the ICU and even reoperation. Since the pectoralis major muscle flap (PMMF) technique was proposed in the 1980s, it has been widely used for sternal reconstruction after debridement. Although numerous studies on DSWI have been conducted over the years, the literature on DSWI in Chinese population remains limited. The purpose of this study was to investigate the clinical characteristics of DSWI in patients and the clinical effect of the PMMF at our institution. Methods: This study retrospectively analyzed all 14,250 consecutive patients who underwent cardiac surgery in the Department of Cardiothoracic Surgery of Drum Tower Hospital from 2001 to 2020. Ultimately, 134 patients were diagnosed with DSWI.,31 of whom had recently undergone radical debridement and transposition of the PMMF in the cardiothoracic surgery or burns and plastic surgery departments because of DSWIs, while the remaining patients had undergone conservative treatment or other methods of dressing debridement. Results: In total, 9,824 patients were enrolled in the study between 2001 and 2020, of whom 134 met the DSWI criteria and 9690 served as controls. Body mass index (OR = 1.08; P = 0.02; 95% CI, 1.01∼1.16) and repeat sternotomy (OR = 5.93; P < 0.01; 95% CI, 2.88∼12.25) were important risk factors for DSWI. Of the 134 patients with DSWI, 31 underwent the PMMF technique, and the remaining 103 served as controls. There were significant differences in coronary artery bypass grafting (CABG) (P < 0.01), valve replacement (P = 0.04) and repeat sternotomy (P < 0.01) between the case group and the control group. The postoperative extubation time (P < 0.001), ICU time (P < 0.001), total hospitalization time (P < 0.001) and postoperative hospitalization time (P < 0.001) in the PMMF group were significantly lower than those in the control group. The results of multivariate regression analysis showed that PMMF surgery was an important protective factor for the postoperative survival of DSWI patients (OR = 0.12; P = 0.04; 95% CI, 0.01∼0.90). Conclusions: Staphylococcus aureus was the most common bacteria causing DSWI, which was associated with BMI and reoperation, and can be validly treated with PMMF.

Short- and long-term efficacy of negative-pressure wound therapy in split-thickness skin grafts: a retrospective study.

BACKGROUND: Graft fixation is essential for the successful survival of skin grafts. Negative-pressure wound therapy (NPWT) can be utilized for fixing a skin graft, ensuring adhesion of the graft with continuous and uniform pressure. However, the reported short- and long-term efficacy of NPWT in split-thickness skin grafts (STSGs) is inconsistent, with few studies on the long-term efficacy (scar quality). To clarify the appropriate methods of skin graft fixation, we conducted a single-center retrospective study on the shortand long-term effects of skin grafting using different fixation methods. METHODS: This study retrospectively analyzed patients who underwent STSG from December 2010 to June 2019. The patients were divided into two groups based on the skin graft-fixing method: an NPWT group and a conventional mechanical fixation group. Medical data including age, sex, underlying diseases, wound etiology, recipient site, surgical methods, surgical outcomes, postoperative complications, and follow-up data (Vancouver Scar Scale score and Patient and Observer Scar Assessment Scale score) were analyzed. RESULTS: A total of 392 cases were ultimately included in the analysis. Among them, 218 cases were fixed with NPWT for skin grafting and 174 with conventional mechanical fixation. No significant differences in baseline data were noted between the two groups. The total graft survival rate in the NPWT group was higher than that in the conventional mechanical fixation group (86.7% vs. 74.1%, P=0.002). Moreover, the infection rate in the NPWT group was lower than that in the conventional mechanical fixation group (5.5% vs. 13.2%, P=0.008). In terms of scar quality, no significant difference was observed, except for in the hand. Overall, the scar surface regularity was better in the NPWT group than in the control group. (P=0.019 for Patient Scar Assessment Scale, P=0.025 for Observer Scar Assessment Scale). CONCLUSIONS: NPWT is an effective approach for fixing skin grafts. Compared with conventional mechanical fixation, NPWT can significantly improve the survival rate and reduce the infection rate of STSG. In the long-term, NPWT can also improve scar surface regularity in the hand, with an esthetic effect that is more satisfactory to clinicians and patients.

Surgical treatment of joint burn scar contracture: a 10-year single-center experience with long-term outcome evaluation.

BACKGROUND: Burn patients often have functional problems due to joint scar contracture. Patients suffering from such contracture often experience considerable limitations in daily life. Therefore, surgical treatment is often necessary. Skin grafts, especially full-thickness skin grafts and flaps remain the most commonly used surgical methods in clinical practice. However, there are no clear guidelines stating which technique is the most effective treatment. Herein, we conducted a retrospective cohort study over 10 years of experience at a single center to investigate whether flaps or FTSGs exhibit a better long-term effect. METHODS: We performed a retrospective chart review of patients with joint burn scar contracture and collected data related to patient demographic profiles, and detailed descriptions of the scars, surgical procedures, and follow-up were collected. We performed follow-up evaluation of three aspects: adverse events (recontracture, ache, and pruritus), satisfaction scores for function and aesthetics, and scar quality (Vancouver Scar Scale score). RESULTS: Follow-up results 1 year after surgery from 88 patients were analyzed. In total, 4 (10%) patients in the flap group and 13 (27.1%) patients in the FTSG group had recontracture; the incidence of recontracture was lower in the flap group than in the FTSG group (P=0.043). The functional satisfaction score of the flap group was higher than that of the FTSG group (P=0.027). Moreover, follow-up results 5 year after surgery for 47 patients were analyzed. In total, 1 (4.8%) patient in the flap group and 7 (26.9%) patients in the FTSG group had recontracture; the incidence of recontracture was significantly lower in the flap group than in the FTSG group (P=0.044). The functional satisfaction score in the flap group was higher than that of the FTSG group (P=0.041). In this study, no significant differences in scar quality were observed between the two groups. CONCLUSIONS: If conditions permit, the application of different types of flaps may represent a better choice than FTSGs in terms of reducing the recontracture rate and improving joint function.

Sex-specific survival benefit in early skin melanoma based on 8th AJCC edition: an analysis of data from the Surveillance, Epidemiology, and End Results (SEER) database.

BACKGROUND: Females have been found to have a survival benefit over males in past studies. However, in early melanoma patients, this benefit occurred in only those aged >60 years. The 8th edition of the American Joint Committee on Cancer (AJCC) readjusted the melanoma staging system, specifically stage I. This study aims to verify whether the sex-specific benefit in females exists in different age groups according to the 8th edition of the staging system. METHODS: We collected the data of individuals diagnosed with skin melanoma between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database. Based on the 8th edition of the melanoma staging system, patients diagnosed with pathological stage T1a-T3a, N0 and M0 melanoma were enrolled. RESULTS: A total of 115,576 patients, including 62,938 male patients and 52,638 female patients, were enrolled in this study. The survival rates of males and females in each stage from IA-IIA were significantly different (P<0.001). In further analyses of each age group, it was found that the proportions of patients with stages IA, IB and IIA were significantly different in each age group. Cox analysis showed that females with stage IA in all age groups benefited significantly, but those in stage IB benefited only when they were aged >60 years. In stage IIA patients, there were significant differences between the <50 and 61-70 years age groups. CONCLUSIONS: Based on data from the SEER database, we found that according to the 8th edition of the AJCC melanoma staging system, females had a higher survival rate than males, and this difference was significant in all age groups in the stage IA group but fluctuated with age in the stage IB and IIA groups.

Skin melanoma survival is not superior in females in the new stage IIID of the 8th edition of the staging system: an analysis of data from the Surveillance, Epidemiology, and End Results (SEER) database.

BACKGROUND: In the 8th edition of the melanoma staging system, stage III was divided into stages IIIA-IIID. Previous studies have found that the long-term survival rate of females is much higher than that of males. This study was designed to explore whether this sex-specific advantage still exists in the new staging subgroups. METHODS: We obtained data from individuals diagnosed with skin melanoma between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database. A total of 8,726 patients with stage III disease were enrolled in the study (5,370 males and 3,356 females). Among these patients, 505 had stage IIID disease (370 males and 135 females). RESULTS: In the 7th edition of the staging system, there were significant sex-specific differences in overall survival (OS) and melanoma-specific survival (MSS) in each subgroup of stage III. In stages IIIA-IIIC in the 8th edition, there were also significant differences between males and females (P<0.001), but in stage IIID patients, there were no significant differences in either OS (P=0.312) or MSS (P=0.288). Cox analysis confirmed that stage IIID does not affect prognosis in males. Further research found no difference between males and females with stage IIID disease in any age subgroup. CONCLUSIONS: We compared sex-specific survival differences in patients with stage III disease according to the 8th edition of the staging system. Females with stage IIIA-IIIC disease have better survival rates than males. However, among patients with stage IIID disease, there is no significant difference in survival between males and females.