Efficacy and safety of CO2 laser in the treatment of chronic wounds: A Retrospective Matched Cohort Trial.

OBJECTIVES: Treating chronic cutaneous wounds is challenging, and debridement is a central concept in treating them. Studies have shown that CO2 laser debridement can control local infection and promote the wound healing process. The present study aimed to investigate the efficacy and safety of fully ablative CO2 laser debridement compared to routine surgical debridement in the treatment of chronic wounds. METHODS: The retrospective cohort study was conducted on patients with chronic (>1 month) cutaneous wounds (≥1 cm2 ) between December 1, 2017, and December 1, 2020, in the Wound Healing Center at Shanghai Ruijin Hospital, China. Patients treated with CO2 laser debridement with a DEKA SmartXide2 C80 (DEKA) (the CO2 laser group) were compared with matched control patients with similar baseline characteristics who had undergone routine surgical debridement (the routine group). The primary outcome was time-to-heal (days) for chronic wounds in two groups, and secondary outcomes included the wound area and BWAT (Bates-Jensen wound assessment tool) score before treatment, and at 1, 2, 3, and 4 weeks after treatment. RESULTS: The study included 164 patients (82 in the CO2 laser group and 82 matched in the routine group). The time-to-heal for patients in the CO2 laser group (41.30 ± 17.11) was significantly shorter than that of the patients in the routine group (48.51 ± 24.32) (p = 0.015). At 3 and 4 weeks after treatment, the absolute wound area of the CO2 laser group was significantly smaller than that of the routine group. Also, the CO2 laser group exhibited a significantly lower relative area at 2, 3, and 4 weeks after treatment. The CO2 laser group yielded significantly lower BWAT scores at 2, 3, and 4 weeks after treatment. Additionally, the relative BWAT score was significantly lower in the CO2 laser group than the relative scores in the routine group at 2, 3, and 4 weeks after treatment. No adverse events related to the treatments were observed in either group during the study period. CONCLUSIONS: The present study has shown that fully ablative CO2 laser debridement has several advantages over routine sharp surgical debridement. It is superior at ameliorating wound status and reducing wound area, and it also significantly reduces the time-to-heal for chronic wounds, without causing any adverse events.

Prevalence and prognosis of hard-to-heal wounds with comorbidities in China.

OBJECTIVE: Regular retrospective analysis is necessary for potential improvement in clinical practice for the treatment of hard-to-heal wounds. Comorbidities and outcomes have demonstrated spatial and temporal diversity, emphasising the importance of updates in epidemiology. The complexity of healing hard-to-heal wounds has long been known, and so we sought evidence-based improvement on the current principles of treatment. METHOD: Demographic and clinical information of patients from the WoundCareLog database was collected. Patients who met the inclusion criteria and completed follow-up after treatment were included. Comorbidities were diagnosed and classified into eight categories based on ICD-10. We compared the demographic and aetiological characteristics between patients with and without comorbidities by t-test and Chi-squared test. The impact of comorbidities on wound healing were evaluated with a multivariate Cox model. RESULTS: A total of 2163 patients met the inclusion criteria and were enrolled, of whom 37.0% were aged 61-80 years, 36.0% were aged 41-60 years and 60.8% were male. The lower extremities and buttocks were the most commonly affected areas with hard-to-heal wounds. Non-traumatic wounds accounted for 66.6% of cases, and infection, pressure and diabetes were the most common causes. Paralysis and diabetes were the most important factors which led to a prolonged healing process and inferior clinical outcomes. CONCLUSION: Comorbidities of hard-to-heal wounds were treated as separate contributors and their weighted effect on outcome was calculated through correlation analysis. Paralysis and diabetes were the most unfavourable comorbidities affecting the treatment of non-traumatic hard-to-heal wounds. Our study highlighted the priority of comorbidity treatment through data-driven approaches. It provides potential value in developing better public health strategies and preventive medicine.

Pyridoxamine ameliorates methylglyoxal-induced macrophage dysfunction to facilitate tissue repair in diabetic wounds.

Methylglyoxal (MGO) is a highly reactive dicarbonyl compound formed during hyperglycaemia. MGO combines with proteins to form advanced glycation end products (AGEs), leading to cellular dysfunction and organ damage. In type 2 diabetes mellitus (T2DM), the higher the plasma MGO concentration, the higher the lower extremity amputation rate. Here, we aimed to identify the mechanisms of MGO-induced dysfunction. We observed that the accumulation of MGO-derived AGEs in human diabetic wounds increased, whereas the expression of glyoxalase 1 (GLO1), a key metabolic enzyme of MGO, decreased. We show for the first time that topical application of pyridoxamine (PM), a natural vitamin B6 analogue, reduced the accumulation of MGO-derived AGEs in the wound tissue of type-2 diabetic mice, promoted the influx of macrophages in the early stage of tissue repair, improved the dysfunctional inflammatory response, and accelerated wound healing. In vitro, MGO damaged the phagocytic functions of M1-like macrophages induced by lipopolysaccharide (LPS), but not those of M0-like macrophages induced by PMA or of M2-like macrophages induced by interleukins 4 (IL-4) and 13 (IL-13); the impaired phagocytosis of M1-like macrophages was rescued by PM administration. These findings suggest that the increase in MGO metabolism in vivo might contribute to macrophage dysfunction, thereby affecting wound healing. Our results indicate that PM may be a novel therapeutic approach for treating diabetic wounds. MGO forms protein adducts that cause macrophage dysfunction. These adducts cause cell and organ dysfunction that is common in diabetes. Pyridoxamine scavenges MGO to ameliorate this dysfunction, promoting wound healing. Pyridoxamine could be used therapeutically to treat non-healing diabetic wounds.

Fractal analysis of rat dermal tissue in the different injury states.

Scar formation and chronic ulcers can develop following a skin injury. They are the result of the over- or underproduction of collagen. It is very important to evaluate the quality and quantity of the collagen that is produced during wound healing, especially with respect to its structure, as these factors are very important to a complicated outcome. However, there is no standard way to quantitatively analyse dermal collagen. As prior work characterised some potentially fractal properties of collagen, it was hypothesised that collagen structure could be evaluated with fractal dimension analysis. Small-angle X-ray scattering technology (SAXS) was used to evaluate the dermis of rats exposed to graft harvest, burn, and diabetic pathologic states. It was found that almost all collagen structures could be quantitatively measured with fractal dimension analysis. Further, there were significant differences in the three-dimensional (3-D) structure of normal collagen versus that measured in pathologic tissues. There was a significant difference in the 3-D structure of collagen at different stages of healing. The findings of this work suggest that fractal analysis is a good tool for wound healing analysis, and that quantitative collagen analysis is very useful for assessing the structure of dermal collagen.

Exploring nanoscale structure change of dermal tissues suffering injury by small angle X-ray scattering and transmission electron microscopy.

Scar formation and wound non-healing often occur during wound repair after skin injury, which are still unresolved. Clinic indicated that the structure played an important role in the wound repair. Our previous research showed that the wound over-healed (scar formation) when the integrity and continuity of dermal tissues was destroyed by injury. Other evidences showed that wound healing was impaired in diabetes because the underlying alternation in their skin tissues occurred caused by advanced glycation end products (AGES) aggregation. In order to explore the changes of the structure of skin at nanoscale, the small angle X-ray scattering (SAXS), compared with transmission electron microscopy (TEM), was applied to observe the skin in different pathological status. The results showed that there were some regular patterns in the structure of dermal tissue. The patterns were changed by different pathological status, which would result in wound healing disorder. These will be beneficial for clarifying the pathological mechanisms of wound healing.

Hydrogen Peroxide: A Potential Wound Therapeutic Target?

Hydrogen peroxide (H2O2) is a topical antiseptic used in wound cleaning which kills pathogens through oxidation burst and local oxygen production. H2O2 has been reported to be a reactive biochemical molecule synthesized by various cells that influences biological behavior through multiple mechanisms: alterations of membrane potential, generation of new molecules, and changing intracellular redox balance, which results in activation or inactivation of different signaling transduction pathways. Contrary to the traditional viewpoint that H2O2 probably impairs tissue through its high oxidative property, a proper level of H2O2 is considered an important requirement for normal wound healing. Although the present clinical use of H2O2 is still limited to the elimination of microbial contamination and sometimes hemostasis, better understanding towards the sterilization ability and cell behavior regulatory function of H2O2 within wounds will enhance the potential to exogenously augment and manipulate healing.

Dose inhibin B or anti-Müllerian hormone relate to precocious puberty in girls? result of a systematic review and meta-analysis.

BACKGROUNDS: Existing studies have investigated the relationship between the levels of serum inhibin B (INHB), anti-müllerian hormone (AMH) and precocious puberty in girls, but the results are inconsistent. OBJECTIVE: The aim of this meta-analysis was to assess whether the INHB and AMH levels changed in girls with precocious puberty relative to healthy controls. METHODS: PubMed, Embase, Cochrane Library and Web of Science were searched through June 2022. We included observational clinical studies reporting the serum levels INHB and AMH in girls with precocious puberty. Conference articles and observational study abstracts were included if they contained enough information regarding study design and outcome data. Case series and reports were excluded. An overall standard mean difference (SMD) between precocious puberty and healthy controls was estimated using a DerSimonian-Laird random-effects model. RESULTS: A total of 11 studies featuring 552 girls with precocious puberty and 405 healthy girls were selected for analysis. The meta-analysis showed that the INHB level of precocious puberty [including central precocious puberty (CPP) and premature the larche (PT)] were significantly increased. While there was no significant association between precocious puberty [including CPP, PT, premature pubarche (PP) and premature adrenarche (PA)] and the level of serum AMH. CONCLUSION: Scientific evidence suggested that the INHB level, but not the AMH level, altered in girls with precocious puberty compared with healthy controls. Through our results we think that INHB level might be a marker for the auxiliary diagnosis of precocious puberty (especially CPP and PT). Therefore, it is important to evaluate and thoroughly investigate the clinical indicators (e.g., INHB) in order to ensure early diagnosis and medical intervention, and the risk of physical, psychological and social disorders in immature girls with precocious puberty is minimized.

Single-cell analysis reveals melanocytes may promote inflammation in chronic wounds through cathepsin G.

During acute wound (AW) healing, a series of proper communications will occur between different epidermal cells at precise temporal stages to restore the integrity of the skin. However, it is still unclear what variation happened in epidermal cell interaction in the chronic wound environment. To provide new insights into chronic wound healing, we reconstructed the variations in the epidermal cell-cell communication network that occur in chronic wound healing via single-cell RNA-seq (scRNA-seq) data analysis. We found that the intricate cellular and molecular interactions increased in pressure ulcer (PU) compared to AW, especially the PARs signaling pathways were significantly upregulated. It shows that the PARs signaling pathways' main source was melanocytes and the CTSG-F2RL1 ligand-receptor pairs were its main contributor. Cathepsin G (CatG or CTSG) is a serine protease mainly with trypsin- and chymotrypsin-like specificity. It is synthesized and secreted by some immune or non-immune cells. Whereas, it has not been reported that melanocytes can synthesize and secrete the CTSG. F2R Like Trypsin Receptor 1 (F2RL1) is a member of proteinase-activated receptors (PARs) that are irreversibly activated by proteolytic cleavage and its stimulation can promote inflammation and inflammatory cell infiltration. In this study, we found that melanocytes increased in pressure ulcers, melanocytes can synthesize and secrete the CTSG and may promote inflammation in chronic wounds through CTSG-F2RL1 pairs, which may be a novel potential target and a therapeutic strategy in the treatment of chronic wounds.

Diabetes-impaired wound healing and altered macrophage activation: a possible pathophysiologic correlation.

Macrophages play a critical role in wound healing and can be activated to two distinctive phenotypes in vitro: classical macrophage activation (caM) and alternative macrophage activation (aaM). This study investigated whether the impaired cutaneous repair observed in streptozotocin-induced diabetic rats was associated with altered macrophage activation. Our results show that macrophage activation phenotypes could be observed in wound healing through double immunostaining. The caM macrophages appeared in the initial stage of wound healing, followed by aaM macrophages, which predominated in normal wounds. However, through examining markers associated with activation by immunoblotting and real-time polymerase chain reaction (PCR), diabetic wounds demonstrated insufficient caM in the early stage but excessive aaM in the later proliferative phase. Moreover, the macrophage activation markers were correlated with the instructive T helper cell type 1 (Th1)/Th2 cytokines in both groups. It was indicated that changed macrophage activation might contribute to impaired healing in diabetes wounds, and that strategies for reverting this abnormal activation could be useful for enhancing the wound healing process.

Distribution and Antibiotic Resistance Patterns of Pathogenic Bacteria in Patients With Chronic Cutaneous Wounds in China.

Background: To determine the distribution and antimicrobial susceptibility pattern of pathogenic bacteria in patients with chronic cutaneous wounds on a national scale. Methods: A retrospective study was conducted using the data recorded between January 1, 2018 and January1, 2020 in 195 hospitals across China. After screening the data, 815 patients with chronic wounds were finally analyzed. The data collected included information about the patients' general condition and local cutaneous wound assessments, especially microbial culture and antibiotic susceptibility tests. The analyses were performed using SPSS Version 26. Results: The study included 815 patients (290 [35.6%] females; 63 [50-74] years). The most common causes of chronic cutaneous wounds were diabetes (183, 22.5%), infection (178, 21.8%), and pressure (140, 17.2%). Among these, 521(63.9%) samples tested yielded microbial growth, including 70 (13.4%) polymicrobial infection and 451 (86.6%) monomicrobial infection. The positive rate of microbial culture was highest in wound tissue of ulcers caused by infection (87.6%), followed by pressure (77.1%), diabetes (68.3%), and venous diseases (67.7%). Bates-Jensen wound assessment tool (BWAT) scores >25 and wounds that lasted for more than 3 months had a higher positive rate of microbial culture. BWAT scores >25 and wounds in the rump, perineum, and feet were more likely to exhibit polymicrobial infection. A total of 600 strains were isolated, of which 46.2% (277 strains) were Gram-positive bacteria, 51.3% (308 strains) were Gram-negative bacteria, and 2.5% (15 strains) were fungi. The most common bacterial isolates were Staphylococcus aureus (29.2%), Escherichia coli (11.5%), Pseudomonas aeruginosa (11.0%), Proteus mirabilis (8.0%), and Klebsiella pneumoniae (5.8%). The susceptibility tests showed that 116 cultured bacteria were Multidrug resistant (MDR) strains. The resistance rates of S. aureus were 92.0% (161/175) to penicillin, 58.3% (102/175) to erythromycin, and 50.9% (89/175) to clindamycin. Vancomycin was the most effective antibiotic (0% resistance rate) against all Gram-positive bacteria. Besides, the resistance rates of E. coli were 68.1% (47/69) to ampicillin, 68.1% (47/69) to ciprofloxacin, 60.9% (42/69) to levofloxacin. However, all the isolated Gram-negative bacteria showed low resistance rates to tigecycline (3.9%) and amikacin (3.6%). Conclusions: The distribution of bacteria isolated from chronic cutaneous wounds varies with the BWAT scores, causes, duration, and the location of wounds. Multidrug resistance is a serious health issue, and therefore antibiotics used in chronic wounds must be under strict regulation. Our findings may help clinicians in making informed decisions regarding antibiotic therapy.

Successful Postoperative Nephrocutaneous Fistula Treatment With Omental Flap Grafting: A Case Report.

Nephrocutaneous fistula (NCF) is a rare and severe complication of renal disease and surgical procedures. Treatments for NCF are based on the renal function, and can include nephrectomy, heminephrectomy, nephroureterectomy, endourological maneuvers or antibiotic therapy alone. Here we report a case of a chronic NCF which occurred 5 years after partial nephrectomy. In this report, we describe a new surgical approach for the management of a patient with postoperative NCF. In the present case, in addition to removing the fistulous tract, we also performed an omental flap grafting to tightly cover the kidney. In addition to limiting and controlling the local inflammation, the omental flap prevents contact between the kidney and the flank muscle on its posterior rim. No recurrence or complications occurred throughout 10 months of follow-up. The NCF was successfully treated with completely removal of the sinus tract and omental flap grafting, without nephrectomy. This case adds new aspects to the treatment of NCF.

Exploring the collagen nanostructure of dermal tissues after injury.

Scar often occurred during wound repair. It was known that there were differences in collagen structure in dermal tissues at millimeter scale and micron scale, however, it was not known whether there were differences in collagen structure in dermal tissues at nanoscale during wound repair. In order to compare the difference at nanoscale, skin samples from patients were selected, the control groups were the normal skin from the same patients. These samples were tested by the small angle X-ray scattering techniques (SAXS) and wide angle X-ray scattering (WAXS) techniques. The transmission electron microscopy (TEM) was used as a comparison. The results showed that there were not only significantly differences between the normal tissue and scar tissue, but also between the center and the margin of the scar tissue at nanoscale by SAXS and WAXS, which was not demonstrated by other studies. These findings demonstrated that the SAXS and WAXS were excellent tools to detect the collagen structure at nanoscale and the orientation of the collagen alignment, which was beneficial for skin tissue engineering and skin regenerative medicine.

Hypocoagulation induced by broad-spectrum antibiotics in extensive burn patients.

BACKGROUND: Patients with extensive burns usually develop pro-coagulation soon after the injury if there is no sepsis occurred. We describe the case of an extensive burn adult suffering from hypocoagulation not related to sepsis, but secondary to antibiotic treatment. CASE PRESENTATION: Here, we report a case of an adult male patient suffering from flame burns of 45% total body surface area (40% full thickness) combined with inhalation injury. Hypocoagulopathy with soaring prolonged activated partial thromboplastin time value occurred on third week post-burn while systemic infection had been under control by application of broad-spectrum antibiotics. Investigations showed that not the infection but vitamin K-related coagulation factor deficiency were responsible for unexpected bleeding. However, supplemental vitamin K was not the key as we expected, which prompted us trying to decode the underlying cause of coagulation disturbance in this patient and pick out the most effective treatment for live-saving. After the withdrawal of highly suspected broad-spectrum antibiotic, Meropenem®, disturbed vitamin K related coagulation factors gradually restored to their optimal levels so as to maintain normal coagulation status. Therefore, surgical procedures without further risk of bleeding could be carried out in time for wound recovery. The patient was discharged on post-burn day 67 and transferred to a secondary hospital for his rehabilitation. CONCLUSION: Hypocoagulopathy may be devoted to different reasons other than sepsis in extensive burns. Early recognition of the cause for coagulation disturbance is critical to make appropriate treatment and save patients' lives. This case illustrated the importance of unveiling the mist cause for coagulation disturbance occurred in extensive burn patient, which paved the way for optimal life-saving treatments. And we also recommend burn surgeons to be alerted to antibiotic-induced vitamin K deficiency-related coagulopathy among critical burn patients.

Effects of extracellular matrix glycosylation on proliferation and apoptosis of human dermal fibroblasts via the receptor for advanced glycosylated end products.

The balance between proliferation and apoptosis of skin cells is responsible for skin turnover and the success of the wound healing process. Recent reports have shown that advanced glycosylation end product (AGE) formation participates in dermatologic problems in diabetes. However, the effect on proliferation and apoptosis of dermal fibroblasts remains unclear. The aim of this study was to investigate the effects of dermal microenvironment glycosylation on the balance of cellular proliferation and apoptosis. Histology and immunohistochemical staining were performed on type II diabetic and nondiabetic skin tissue specimens to determine the distributions of proliferating cell nuclear antigen, apoptotic cells, AGEs, and receptors for AGEs (RAGEs). Matrix secreted by cultured human fibroblasts was glycosylated by 0.5 M D-ribose. RAGE-blocking antibodies were applied to inhibit the interaction of RAGE and AGEs in this system and then cell viability, cell cycle phase distribution, and apoptosis were measured. Diabetic skin has degenerative, loosely arranged collagen and increased apoptotic cells compared with normal skin. Expression of AGE and RAGE in diabetic skin tissue increased. Glycosylated matrix induced cell cycle arrest and apoptosis of cultured dermal fibroblasts, whereas application of RAGE-blocking antibodies redressed these changes. The accumulation of glycosylated extracellular matrix in diabetic skin tissue is a critical mediator of cellular function. Mediation of RAGE affects the balance of cellular proliferation and apoptosis, which confirms that diabetic wounds possess atypical origin in the repair process.

Village-Scale Livelihood Change and the Response of Rural Settlement Land Use: Sihe Village of Tongwei County in Mid-Gansu Loess Hilly Region as an Example.

Rural livelihood change has great influence on the scale, structure, and morphology of rural settlement land use, thus bringing new challenges to rural revitalization and settlement reconstruction. Sihe village of Tongwei County in mid-Gansu loess hilly region (China) was taken as an example here. Based on participatory rural appraisal data, we analyzed the structure and allocation of rural households' livelihood assets as well as their livelihood diversity by using ecological asset, livelihood diversification index, and landscape pattern index models. We aimed to find a response mechanism between rural livelihood change and rural settlement land use change. The results might provide useful information for the selection of new village sites, reconstruction of rural settlements, and creation of livable rural environment. Results indicate that: (1) The total value of the average livelihood assets per household in the Sihe village increased significantly from 0.48 in 1988 to 1.288 in 2016. The four types of livelihood assets including natural, material, manpower, and financial assets changed with time. In 1988, the manpower asset was the most important type of livelihood assets, with value accounting for 76.67% of the total value of livelihood assets. With the extension of time, the proportions of the four types of assets in total livelihood assets became closer to each other. The livelihood diversification index of the Sihe village increased from 2.01 in 1988 to 3 in 2016, indicating the rural livelihoods became diverse; (2) Because of the dual influence of external environmental factors and the rural development policies of the country and the region, the livelihoods changed towards agricultural sector from 1988 to 2008, and the agricultural livelihoods tended to be diverse. The following trend of livelihood strategy change was observed: from diverse non-agricultural production group (IV) to agricultural and non-agricultural production group (III), then to diverse agricultural production group (II) and finally to agricultural production group (I). After 2008, the livelihoods changed towards non-agricultural sector, and the non-agricultural livelihoods tended to be diverse. This trend of livelihood change is opposite to that before 2008; (3) 2008 is the key year of livelihood change. Livelihood change caused changes in the scale, structure, and morphology of rural settlement land use, which eventually led to the change of rural residential land use.

[Study on the biological function of dermal fibroblasts in the wounds of diabetic and non-diabetic rats with deep burns].

OBJECTIVE: To explore the changes of the biological function of dermal fibroblasts (FBs) in the wounds of diabetic and non-diabetic burned rats and the pathogenesis of impaired wound healing in diabetes. METHODS: 80 Sprague-Dawley (SD) rats weighing 220 g were randomly divided into control and STZ-induced diabetic groups, and then deep partial thickness scald involving 10% TBSA was reproduced in the two groups. The diabetic groups were randomized into pre-scalding, post-scalding day (PSD 3), PSD 7, PSD 14 and PSD 21 groups, with 6 rats in each group. Controls were also randomized into 5 groups. Skin specimens from the wound were harvested at each time point. Cell cycles of FBs were analyzed with flow cytometry. The amount of hydroxyproline in the skin tissue was assessed on 0, 3, 7, 14, and PSD 21. The type I and III collagens were determined by ELISA. The expression of alpha-SMA in the dermal fibroblasts of each group was assessed by immunohistochemistry method. Transmission electron microscopy was used to observe the ultrastructure changes of FBs. RESULTS: Compared with that in the normal rats, the percentage of the cells in G(0)/G(1) phase in the DM group was evidently lower on PSD 0 (65.79 +/- 5.24 vs 82.43 +/- 9.68, P < 0.01). After the scalding, the percentage of the cells in G(0)/G(1) phase in DM group was significantly higher (70.00 +/- 4.27 vs 42.04 +/- 12.96, on PSD 3, P < 0.01), meanwhile the percentage of S phase was remarkably lower than those in C group on 3, 7, 14, 21PSD (P < 0.05, P < 0.01). The amount of hydroxyproline in the diabetic skin tissue was obviously lower than those of the responding control groups before (0.72 +/- 0.06 vs 1.42 +/- 0.28, P < 0.01) and after burn injury (P < 0.01). Furthermore, the rate of I/III collagen on 7, 14 and PSD 21 was much higher in DM group than that in C group (P < 0.01). The expression of alpha-SMA in DM groups on PSDS 3, 7, 14 and PSD 21 was evidently lower than those of the controls (levels 10.28 +/- 3.99, C group 28.42 +/- 2.73, on PSD 14, P < 0.01), although that inclined to be heightened after burn injury. Ultrastructure changes of FBs in the wounds of diabetic rats could be observed, such as the outstretched endoplasmic reticulum, un development of Golgi's body, lackness of microtubule and microfilament, a sharp increase of cytolysosomes, and so on. CONCLUSION: The FB proliferation in the diabetic skin is abnormal, the synthetical ability of collagen is weakened, the expression of alpha-SMA is insufficient, the microtubule and microfilament is lack, and the number of cytolysosomes increases. The pathogenesis of impaired-wound healing in diabetics might be related with the above mentioned factors.

Blocking AGE-RAGE Signaling Improved Functional Disorders of Macrophages in Diabetic Wound.

Advanced glycosylation end products (AGEs) accumulate in diabetic wounds. Interactions between AGEs and their receptor (RAGE) leads to dermatologic problems in diabetes. Macrophage, which plays important roles in wound healing, highly expresses RAGE. Therefore, we investigated whether RAGE-expressing macrophages might be responsible for impaired wound healing on diabetes. We used anti-RAGE antibody applied topically on diabetic wounds. After confirming that wound healing was improved in anti-RAGE antibody group compared with normal mice, our results showed that macrophages appeared insufficient in the early stage and fading away slowly in the later proliferative phase compared with the control group, which was ameliorated in anti-RAGE antibody-applied wounds. Blocking AGE-RAGE signaling also increased neutrophils phagocytized by macrophages and promoted the phenotypic switch of macrophages from proinflammatory to prohealing activities. In vitro, phagocytosis of THP-1 (M0) and lipopolysaccharide- (LPS-) induced (M1) macrophages was impaired by treatment with AGEs, while IL-4- and IL-13-induced (M2) macrophages was not. Finally, AGEs increased the proinflammatory response of M1 macrophages, while inhibiting the polarization and anti-inflammatory functions of M2 macrophages. In conclusion, inhibition of AGE-RAGE signaling improved functional disorders of macrophages in the early inflammatory phase, which promoted the healing of wounds in diabetic mice.

Aminoguanidine cream ameliorates skin tissue microenvironment in diabetic rats.

INTRODUCTION: The aim of the study was to explore the effect of aminoguanidine cream on the skin tissue microenvironment in diabetic rats. MATERIAL AND METHODS: A total of 51 healthy male Sprague Dawley (SD) rats were randomly divided into three groups: the diabetes group (n = 18), the aminoguanidine group (n = 18) and the control group (n = 15). Rats in the diabetes group and aminoguanidine group were injected with 65 mg/kg streptozotocin to induce the diabetes model, and in the control group with citrate buffer. After successful induction of diabetes, the back hair of all rats was stripped by barium sulfide, and the aminoguanidine group was treated with aminoguanidine cream using disinfected cotton swabs twice every day for 40 days, while the diabetes and control groups were treated with the cream matrix. The pathological changes of skin were observed by HE staining, while the content of inflammatory cytokines (TNF-α, IL-8, ICAM and IL-1α) and the antioxidant indexes (T-AOC, GSH-PX, MPO MDA H2O2) were examined using commercial kits. RESULTS: After 40 days of treatment, the diabetes group manifested tissue lesions, whereas the aminoguanidine group seemed normal. Compared with the diabetes group, the content of inflammatory cytokines TNF-α, IL-8, ICAM and IL-1α was dramatically lower in the aminoguanidine group. T-AOC in all groups underwent dramatic changes and returned to normal finally. The activities of GSH-PX and MPO and content of H2O2 in the diabetes group were all higher than those in the aminoguanidine group. CONCLUSIONS: Aminoguanidine may have a good systemic effect on alleviating the pathological changes of skin tissue in diabetic rats, which may be attributed to the regulation of GSH-PX, TNF-α, IL-8, ICAM and IL-1α.

The Relationship Between Inflammation and Impaired Wound Healing in a Diabetic Rat Burn Model.

Inflammation, initiated by polymorphonuclear neutrophil (PMNs) infiltration, is the first step in wound healing. The aim of this study is to investigate the function of neutrophils in a diabetes-impaired wound healing model and to explore the underlying mechanisms leading to neutrophil dysfunction. Superficial second-degree burns were created in the streptozotocin (STZ)-induced diabetic rat model, and the changes in the levels of advanced glycation end products (AGE), receptor of AGE (RAGE), inflammatory cytokines and oxidative markers, as well as cell apoptosis were determined. The effects of AGE on isolated PMNs were also determined in vitro. We found that deposition of AGE in diabetic rat skin activated the neutrophils before injury. However, the dense inflammatory band failed to form in the diabetic rats after injury. Compared with the controls, enhanced expression of RAGE and accelerated cell apoptosis were observed in the burned skin of diabetic rats. The altered expression pattern of inflammatory cytokines (tumor necrosis factor-alpha and interleukin-8) and oxidative markers (glutathione peroxidase, myeloperoxidase, hydrogen peroxide, and malondialdehyde) between burned skin of diabetic and control rats revealed delayed neutrophil chemotaxis and respiratory burst. Furthermore, the results in vitro showed that exposure to AGE inhibited the viability of PMNs, promoted RAGE production and cell apoptosis, and prevented the migration of PMNs, consistent with the findings in vivo. Besides, AGE-treated neutrophils showed increased secretion of inflammatory cytokines and increased oxidative stress. Combined, our results suggest that an interaction between AGE and its receptors inhibits neutrophil viability and function in the diabetic rat burn model.

[Infiltration of macrophages and their phenotype in the healing process of full-thickness wound in rat].

OBJECTIVE: To study the infiltration of macrophages and their phenotype in the healing process of full-thickness wound in rat. METHODS: Thirty healthy SD rats were divided into control group (n = 6) and injury group (n = 24) according to the random number table. Two round full-thickness skin defects (11 mm diameter) were created on both sides of dorsal spine of rats in injury group with surgical scissors and homemade trephine. After injury, wound area was measured immediately. The wounds were disinfected with iodophor every day. Rats in control group received anesthesia and hair removal only. On post injury day (PID) 1, 3, 7, and 13, respectively, 6 rats of injury group were sacrificed after the measurement of wound area (wound healing rate was calculated). Wound samples were obtained by excision down to healthy fascia along wound edge. Histological study was done with HE staining. The expression of CD68 (the surface marker of macrophage) in the wound tissue was observed with immunohistochemical staining. The double positive expressions of induced nitric oxide synthase (iNOS) plus CD68 (type I macrophage) and arginase 1 (Arg-1) plus CD68 (type II macrophage) were observed with immunofluorescence staining. The levels of interferon-γ (IFN-γ), TNF-α, IL-4, IL-13, IL-10, and IL-12 in wound tissue were assayed by double-antibody sandwich ELISA, and the ratio of IL-10/IL-12 was calculated. Full-thickness skin tissues (11 mm diameter) in rats of control group were excised at the same site as rats in injury group, and the histological observation and cytokines assay were performed as well. Data were processed with one-way analysis of variance or LSD- t test. RESULTS: Wound area of rats in injury group was gradually reduced after injury, and the overall difference of the wound healing rate on each PID was statistically significant (F = 358.55, P < 0.01). No abnormal appearance of skin tissue was observed in rats of control group. In injury group, inflammatory cell infiltration was obvious in wound tissue on PID 1 and 3; vascular structure and fresh collagen were observed in wound tissue on PID 7 and 13. Numbers of CD68 positive cells in skin tissue of rats in control group and wound tissue of rats in injury group on PID 1, 3, 7, and 13 were respectively (2.7 ± 1.5), (31.8 ± 3.5), (40.8 ± 4.7), (20.8 ± 2.8), (3.2 ± 2.4) per 200 times visual field (F = 180.55, P < 0.01). Compared with that in control group, the number of CD68 positive cells of rats in injury group was increased on PID 1, 3, and 7 (with t values respectively 18.81, 18.79, 14.05, P values below 0.01). No double positive expression of iNOS plus CD68 or Arg-1 plus CD68 was observed in normal tissue of rats in control group. In injury group, proportions of iNOS plus CD68 double positive cells on PID 1, 3, 7, and 13 were respectively (12.2 ± 2.8)%, (16.5 ± 2.9)%, (4.2 ± 2.3)%, (0.7 ± 0.8)% (F = 72.50, P < 0.01); proportions of Arg-1 plus CD68 double positive cells on PID 1, 3, 7, and 13 were respectively 0, (8.2 ± 1.9)%, (21.5 ± 3.4)%, (4.7 ± 2.0)% (F = 120.93, P < 0.01). In injury group, proportion of iNOS plus CD68 double positive cells on PID 3 was significantly higher than that on other PID (with t values respectively 2.65, 8.17, 12.95, P values below 0.05); proportion of Arg-1 plus CD68 double positive cells on PID 7 was higher than that on other PID (with t values respectively 15.27, 8.25, 10.38, P values below 0.01). Compared with that of Arg-1 plus CD68 double positive cells, proportion of iNOS plus CD68 double positive cells was higher on PID 1 and 3 (with t values respectively 10.71 and 5.88, P values below 0.01) and lower on PID 7 and 13 (with t values respectively 10.24 and 4.60, P values below 0.01). The overall differences of IFN-γ, TNF-α, IL-4, IL-13, and IL-10/IL-12 ratio in skin tissue of rats in control group and wound tissue of rats in injury group on every PID were statistically significant (with F values from 14.08 to 631.03, P values below 0.01). Compared with those in control group, levels of IFN-γ, TNF-α, IL-4, and IL-13 in wound tissue of rats in injury group were significantly higher on every PID (with t values from 4.58 to 9.17, P values below 0.05), while IL-10/IL-12 ratio was significantly higher on PID 1, 3, and 7 (with t values respectively 27.70, 30.51, 9.49, P values below 0.05) . In injury group, IFN-γ level on PID 1 [(61 ± 5) pg/mL] and IL-10/IL-12 ratio on PID 3 (1.647 ± 0.098) were significantly higher than those of control group and those on other PID in injury group [with IFN-γ level respectively (32 ± 4), (54 ± 6), (46 ± 7), (47 ± 4) pg/mL and IL-10/IL-12 ratio respectively 0.328 ± 0.045, 0.960 ± 0.034, 0.530 ± 0.028, 0.289 ± 0.040, with t values respectively from 3.19 to 8.20 and from 16.59 to 31.84, P values below 0.05]. CONCLUSIONS: Macrophage infiltration increases in the healing process of full-thickness wound in rat with different phenotypes, among which type I macrophage appears in the inflammatory stage, and type II macrophage predominates in the proliferative stage.