The effects of caffeine on wound healing

The purine alkaloid caffeine is a major component of many beverages such as coffee and tea. Caffeine and its metabolites theobromine and xanthine have been shown to have antioxidant properties. Caffeine can also act as adenosine‐receptor antagonist. Although it has been shown that adenosine and antioxidants promote wound healing, the effect of caffeine on wound healing is currently unknown. To investigate the effects of caffeine on processes involved in epithelialisation, we used primary human keratinocytes, HaCaT cell line and ex vivo model of human skin. First, we tested the effects of caffeine on cell proliferation, differentiation, adhesion and migration, processes essential for normal wound epithelialisation and closure. We used 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) proliferation assay to test the effects of seven different caffeine doses ranging from 0·1 to 5 mM. We found that caffeine restricted cell proliferation of keratinocytes in a dose‐dependent manner. Furthermore, scratch wound assays performed on keratinocyte monolayers indicated dose‐dependent delays in cell migration. Interestingly, adhesion and differentiation remained unaffected in monolayer cultures treated with various doses of caffeine. Using a human ex vivo wound healing model, we tested topical application of caffeine and found that it impedes epithelialisation, confirming in vitro data. We conclude that caffeine, which is known to have antioxidant properties, impedes keratinocyte proliferation and migration, suggesting that it may have an inhibitory effect on wound healing and epithelialisation. Therefore, our findings are more in support of a role for caffeine as adenosine‐receptor antagonist that would negate the effect of adenosine in promoting wound healing.     

Current concepts regarding the effect of wound microbial ecology and biofilms on wound healing

Biofilms are a collection of microbes that adhere to surfaces by manufacturing a matrix that shields them from environmental elements. Wound biofilms are difficult to evaluate clinically, and standard culture methods are inadequate for capturing the true bioburden present in the biofilm. New molecular techniques provide the means for rapid detection and evaluation of wound biofilms, and may prove to be useful in the clinical setting. Studies have shown that many commercial topical agents and wound dressings in use are ineffective against the biofilm matrix. At this stage, mechanical debridement appears to be essential in the eradication of a wound biofilm. Topical antimicrobial agents and antibiotics may be effective in the treatment of the wound bed after debridement in the prevention of biofilm reformation.     

Assessing the effect of an antimicrobial wound dressing on biofilms

To date the effect of silver-containing wound dressings on biofilms, known to be present in chronic wounds, has not been determined or documented. In this current study, we aimed to determine the antimicrobial effect of a silver-containing dressing on biofilms grown in a chambered slide model. Before the addition of a wound dressing onto a 24-hour biofilm, composed of either Pseudomonas aeruginosa , Enterobacter cloacae , Staphylococcus aureus , or a mixed bacterial community, a fluorescent dye was applied. This enabled the viability of sessile bacteria to be monitored in real-time, using a rapid form of confocal laser scanning microscopy over a contact time period of 48 hours. By analyzing all the three-dimensional data generated from the confocal time-lapse sequences, 90% of all sessile bacteria within the biofilm were observed to progressively turn red (i.e., died) within 24 hours. Total bacterial kill in the biofilm was achieved after 48 hours. This research has shown that the dressing was effective in killing the tested bacteria evident in both the tested mono and polymicrobial biofilms, which provides valuable evidence that this dressing may have an effect on biofilms found in recalcitrant chronic wounds.     

The effects of calcium alginate on wound healing

A non-woven alginate dressing has been used on experimental, full and partial thickness wound models for periods up to 14 days, to assess its effects on wound healing. Histological evaluation has shown that it is an effective haemostat, generally well tolerated by body tissues. Good epidermal healing was seen on all wounds although cellular reactions could be provoked in full thickness wounds without occlusion, if there was an insufficient volume of wound exudate to completely wet the alginate fibres.     

The effects of ultraviolet radiation on wound healing

The effects of prior ultraviolet light exposure on wound tensile strength and skin histology were evaluated in the hairless guinea pig model. Hairless guinea pigs (strain IAF/HA-HO) were irradiated with either UVA (80 J/cm2) or UVB (0.46 J/cm2) every other day for 16 weeks. Following cessation of treatment, a standard dorsal wound was made in each animal, allowed to heal, and mechanically tested to failure at 21 days. Serial 4 mm punch biopsies were obtained prior to the initial exposure and at 2, 4, 8, 12 and 16 weeks. Histological examination with haematoxylin and eosin, trichrome and elastin stains was performed. In comparison to the unexposed control group, wound tensile strength was significantly less in the UVA- and UVB-irradiated animals. Histological examination revealed a marked endothelial swelling and eosinophilic infiltration in the irradiated groups. These results indicate that repeated exposure to even moderate doses of non-ionising radiation alters normal skin structure and adversely affects subsequent wound tensile strength in this model.     

两种银敷料对慢性伤口愈合及渗液酸碱度影响的比较

目的比较两种银敷料辅助治疗慢性感染伤口的效果及对伤口渗液酸碱度的影响,以指导银敷料在慢性伤口治疗中的合理使用。方法将糖尿病足溃疡、压疮、下肢静脉溃疡、创伤性溃疡、烧伤残余创面5类慢性伤口患者104例随机分为A、B两组,每组52例。两组患者均按照统一方法评估、清洗和清创后,A组使用银离子藻酸盐敷料、B组使用纳米银敷料,分别接受30d的伤口局部辅助治疗。观察比较两组伤口治疗前及治疗后不同时间段的伤口愈合评分及渗液pH值。结果随着治疗时间的延长,两组伤口愈合计分和渗液pH值均较治疗前下降,A组患者伤口愈合计分显著优于B组(P0.01);两组伤口渗液pH值比较,差异无统计学意义(P0.05)。结论两种银敷料辅助治疗慢性感染伤口均能促进伤口愈合,但银离子藻酸盐敷料的效果更优;两种银敷料均能降低伤口渗液pH值且作用相当。     

The effects of perioperative fluorouracil administration on convalescence and wound healing

Administration of chemotherapy is delayed by most clinicians until complete recovery from surgery because it is generally feared that cytotoxic drugs impair wound healing, reduce resistance against infection, and may hinder the recovery process. However, clinical experience is lacking. This clinical study examines the effect of perioperative administration of fluorouracil on the healing of wounds and intestinal anastomoses and the recovery process in general. Forty patients with advanced gastrointestinal tract cancers entered the study. Intravenous bolus administration of 0.5 g of fluorouracil was started during surgery. The patients underwent a variety of abdominal operations for palliation or cure. A total of 22 gastric and enteric anastomoses were performed. One half gram of fluorouracil diluted in 150 mL of 5% glucose solution was given intravenously over one hour daily for ten days postoperatively. The patients were carefully evaluated for any alteration in the postoperative recovery. Thirty-eight of the 40 patients received the full course of fluorouracil. Twenty-one patients had an uneventful postoperative course. Eighteen had mild to moderate respiratory and cardiovascular complications unrelated to fluorouracil administration. One patient died of pulmonary emboli 16 days after abdominoperineal resection. Surgical wounds healed without complications in 37 patients. One case of wound disruption occurred after sigmoidectomy. Two patients developed wound infections that healed secondarily. All 22 patients with anastomoses recovered without any evidence of leakage. Colostomies and gastrostomies functioned as anticipated. Side effects attributed to fluorouracil appeared in seven of the patients; in only two of the patients were complications life-threatening, involving bone marrow depression. All patients recovered after discontinuation of fluorouracil therapy and with supportive treatment. On the whole, the course of recovery of this group was no different than expected from patients with advanced malignant neoplasms who were undergoing extensive surgery. Based on this study, it seems that fluorouracil administration during and immediately after surgery has no deleterious effect on wound healing and recovery.     

The effects of age-related skin changes on wound healing rates

The evidence that wound healing is adversely affected by age-related changes is inconclusive. Some studies report that ageing skin loses its ability to regenerate, whereas others have found that ageing processes can have beneficial effects.     

The effects of single-dose dexamethasone on wound healing in rats

Dexamethasone effectively decreases the incidence of nausea and vomiting among pediatric and adult patients. In this study, we evaluated the effects of single-dose dexamethasone on wound healing in a prospective, randomized, experimental animal model. Anesthesia was induced with thiopental 100 mg/kg intraperitoneally. Dexamethasone 1 mg/kg was administered intraperitoneally in a dexamethasone group, and physiological saline was administered in a control group. Collagenization, epithelization, and fibroblast content were significantly less in the dexamethasone group compared with the control group (P values of 0.002, 0.041, and 0.023, respectively). The vascularity and the degree of inflammatory cells were more intense in the dexamethasone group compared with the control group (P values of 0.023 and 0.002, respectively). The white blood cell count was similar in the control (7.84 +/- 2.09) and dexamethasone (6.98 +/- 2.12) groups. The mean hydroxyproline level was 0.72 +/- 0.13 mg/g in the dexamethasone and 1.03 +/- 0.19 mg/g in the control group. Hydroxyproline levels were significantly less in the dexamethasone group (P = 0.001). We conclude that dexamethasone at 1 mg/kg may have negative effects on wound healing. IMPLICATIONS: We evaluated the effects of dexamethasone on wound healing in a prospective, randomized, experimental animal model. Our results show that dexamethasone at 1 mg/kg may have negative effects on wound healing.     

Staphylococcal biofilms impair wound healing by delaying reepithelialization in a murine cutaneous wound model

Bacterial biofilms have gained increasing visibility in recent years as a ubiquitous form of survival for microorganisms in myriad environments. A number of in vivo models exist for the study of biofilms in the setting of medically relevant implanted foreign bodies. Growing evidence has demonstrated the presence of bacterial biofilms in the setting of a number of chronic wound states including pressure sores, diabetic foot ulcers, and venous stasis ulcers. Here we present a novel murine cutaneous wound system that directly demonstrates delayed reepithelialization caused by the presence of a bacterial biofilm. We established biofilms using either Staphylococcus aureus or Staphylococcus epidermidis in splinted cutaneous punch wounds created on the backs of normal C57Bl6/J mice. Wound reepithelialization was significantly delayed by bacterial biofilms. This effect was specifically dependent on the ability of the bacteria to form biofilms as demonstrated by exogenous administration of biofilm inhibiting peptides and the use of mutant Staphylococcus spp. deficient in biofilm formation. This represents the first direct evidence for the effect of bacterial biofilms on cutaneous wound healing.     

Oxygen therapies and their effects on wound healing

Oxygen is an important factor for wound healing. Although several different therapies investigated the use of oxygen to aid wound healing, the results of these studies are not unequivocal. This systematic review summarizes the clinical and experimental studies regarding different oxygen therapies for promoting wound healing, and evaluates the outcomes according the methodological details. A systematic literature search was conducted using Embase, Medline, Web of Science, Cochrane, PubMed publisher, and Google Scholar libraries. Clinical and experimental studies investigating oxygen for wound healing were selected. Included articles were categorized according to the kind of therapy, study design, and wound type. The methodological details were extracted and analyzed. Sixty‐five articles were identified and divided in three different oxygen therapies: Local oxygen therapy, hyperbaric oxygen therapy, and supplemental inspired oxygen therapy. More than half of the included local oxygen and hyperbaric oxygen studies had one or more significant positive outcomes, 77 and 63%, respectively. Supplemental inspired oxygen therapy during gastrointestinal and vascular surgery was more likely to have a positive result than during other surgical interventions reducing surgical site infections. These many positive outcomes promote the use of oxygen treatment in the stimulation of wound healing. However, the lack of clinical studies and vast methodological diversity made it impossible to perform a proper comparison within and between the different therapies. Further randomized clinical studies are warranted to examine the value of these therapies, especially studies that investigate the more patient‐friendly oxygen dressings and topical wound oxygen therapies. Also, to achieve more solid and consistent data, studies should use more standardized methods and subjects.     

Lignocaine: its effects on wound healing

In the light of clinical observations that local anaesthetic impairs wound healing, the effect of lignocaine at various concentrations, with and without adrenaline, on the tensile strength of skin wounds in rats 3, 5 and 7 days after operation was studied. Lignocaine had an adverse effect on wound healing at 5 and 7 days, perhaps due partly to the destructive effect of the intra- and subcutaneous injection, but certainly due also to the lignocaine itself. Adrenaline potentiated this effect. It was concluded that it is better to use dilute solutions of lignocaine, preferably without adrenaline, for local anaesthesia.     

Potential of Curcumin nanoemulsion as antimicrobial and wound healing agent in burn wound infection

The review article concentrates on the potential uses of curcumin nanoemulsion in treatment and management of burn wound. Poor solubility and low bioavailability of curcumin limits the efficient and effective use of curcumin in management of bacterial infection related to burn wound. Nano particle based drug delivery system can be of great aid to solve this problem. Among this nanoemulsion is most favourable system due to its simplicity and low manufacturing cost. Nanoemulsion also enhances the skin permeation ability of curcumin and thus enhances its pharmacological efficacy specially as a potential antimicrobial agent, which can have applicability as a topical therapeutic agent in burn wound infection.     

The effects of Beeswax,Olive oil and Butter impregnated bandage on burn wound healing

BackgroundBeeswax, Olive oil and Butter (BOB) are nutritive products that could support wound healing by adsorption to bandage. This study demonstrated the therapeutic effects of BOB on second degree burn.MethodsSecond degree burn model was created in rats. Experimental groups were assigned to Healthy, Burn, Silver Sulfadiazine (SS) and BOB. The effects of BOB were evaluated on skin regeneration, vesicles and bullae and fibroblast activity by histopathological analyses and wound contraction percent were determined. Transforming Growth Factor-Beta1 (TGF-β1) and Vascular Endothelial Growth Factor-alpha (VEGF-α) mRNA expressions were analyzed with Real Time-Polymerase Chain Reaction. All parameters analyzed at 3rd, 7th, 14th days.ResultsThe BOB treatment increased TGF-β1 and VEGF-α expressions compared to Burn group. The histopathological analyses showed that epidermis and dermis layers injured due to burn. BOB treatment augmented the regeneration of these layers and increased fibroblast activity and keratinization which are play important role on the new blood vessels production. Also with the BOB treatment we showed wound contraction levels were higher than Burn and SS treatment.ConclusionThis study demonstrated that beeswax–olive oil–butter mixture impregnated bandage treatment in a second-degree burn rat model improved burn wound healing and encouraged skin renewal via modulating tissue TGF-β1 and VEGF-α.     

The effects of intradermal and topical mitomycin C on wound healing.

OBJECTIVE: To determine the effect of intradermal and topical mitomycin C (MMC) on skin wound healing. STUDY DESIGN/SETTING: A prospective, controlled study in a rat wound model performed in an academic medical center. RESULTS: Intradermal and topical MMC application decreased wound integrity when compared with saline-treated animals at 1 week, 2 weeks, 1 month, and 6 months. Skin necrosis occurred in animals that received intradermal MMC. Hemotoxylin and eosin and immunohistochemical staining showed no consistent difference between treatment arms. Fibrosis and collagen deposition were reduced in MMC-treated wounds on trichrome staining. CONCLUSIONS: MMC-treated wounds showed decreased wound strength compared with controls. Intradermal MMC can cause skin necrosis. Histologic findings did not always correspond with clinical data. SIGNIFICANCE: The data suggest cautious use of MMC in clinical situations when wound breaking strength is critical.     

The effects of education and training on clinical practice in wound healing

This article considers the effects of two different types of educational programme on community nurse clinical practice in venous ulceration. One group of nurses (the experimental group) attended an educational programme designed to take account of training needs and learning styles. A second group of nurses (the control group) attended a standardised educational programme. A multiple‐choice question examination and Objective Structured Clinical Examination were used to measure knowledge and skills. Kolb’s Learning Styles Inventory was used to measure learning styles. Findings were that experimental nurses failed to show improved post‐intervention clinical practice compared with the control group.     

The effects of chemotherapy on murine wound healing and orocutaneous fistula closure

The effects of cisplatin and 5-fluorouracil on wound breaking strength and the rate of closure of an orocutaneous fistula were studied in 80 male rodents. Treatment rats received a total of 4.6 mg/kg cisplatin and 62 mg/kg 5-fluorouracil in six doses/12 days; control rats received 0.9 per cent saline. After treatment, 30 treatment and 30 control rats received a dorsal skin incision which was closed primarily. Wound breaking strength were tested at one, three and five weeks in ten rats from each group. An 8-mm orocutaneous fistula was made in the remaining ten treatment and ten control rats; the rate of closure was noted weekly. Cisplatin and 5-fluorouracil did not significantly impair wound breaking strength at one, three, or five weeks. The rate of closure of the orocutaneous fistula was not effected by cisplatin/5-fluorouracil. The chemotherapy caused severe facial cellulitis and death in four orocutaneous fistula rats. Combined chemotherapy with cisplatin and 5-fluorouracil should not interfere with planned surgical care of head and neck tumors. Concomitant antibiotic coverage, however, is advocated.     

The impact of topical agents and dressing on pH and temperature on wound healing: A systematic,narrative review

To assess the impact of topical agents and dressings on surface wound pH, temperature, and subsequent wound healing. This was a systematic, narrative review of the literature, following the PRISMA (2020) guidelines. The databases searched were Medline PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Library, Embase, Web of Science, and Scopus. Data synthesis and analysis were conducted using a structured narrative synthesis. The quality of the included clinical studies was appraised using the Evidence‐Based Literature (EBL) Critical Appraisal Tool. A total of six clinical studies were assessed as eligible for inclusion, A total of six dressings/topical agents were assessed and the types of wounds included non‐healing chronic wounds. Of the studies, five explored pH and one explored temperature. The EBL validity of the clinical studies was low (mean quality score was 51.3%). The five clinical studies that explored pH investigated different dressings and topical agents reporting an associated reduction in pH and improved wound outcomes. One clinical study investigated the impact of topical sodium nitrite on temperature and found that sodium nitrite increased peri‐wound skin temperature and improved wound outcomes with a reduction in leg ulcer size. Given the low certainty of the evidence, we cannot confidently recommend the use of any particular topical agent or dressing to manipulate pH, or temperature to improve wound outcomes. Thus, there is a need for further research to develop a greater understanding of this topic. Irish Research Council, Enterprise Partnership Scheme.