Curcumin accelerates cutaneous wound healing via multiple biological actions: The involvement of TNF‐α, MMP‐9, α‐SMA,and collagen

Curcumin, a constituent of the turmeric plant, has antitumor, anti‐inflammatory, and antioxidative effects, but its effects on wound healing are unclear. We created back wounds in 72 mice and treated them with or without topical curcumin (0.2 mg/mL) in Pluronic F127 gel (20%) daily for 3, 5, 7, 9, and 12 days. Healing in wounds was evaluated from gross appearance, microscopically by haematoxylin and eosin staining, by immunohistochemistry for tumour necrosis factor alpha and alpha smooth muscle actin, and by polymerase chain reaction amplification of mRNA expression levels. Treatment caused fast wound closure with well‐formed granulation tissue dominated by collagen deposition and regenerating epithelium. Curcumin increased the levels of tumour necrosis factor alpha mRNA and protein in the early phase of healing, which then decreased significantly. However, these levels remained high in controls. Levels of collagen were significantly higher in curcumin‐treated wounds. Immunohistochemical staining for alpha smooth muscle actin was increased in curcumin‐treated mice on days 7 and 12. Curcumin treatment significantly suppressed matrix metallopeptidase‐9 and stimulated alpha smooth muscle levels in tumour necrosis factor alpha‐treated fibroblasts via nuclear factor kappa B signalling. Thus, topical curcumin accelerated wound healing in mice by regulating the levels of various cytokines.     

17β‐Estradiol administration promotes delayed cutaneous wound healing in 40‐week ovariectomised female mice

This study investigated the effect of 17β‐estradiol on wound healing in 40‐week ovariectomised female mice. Thirty‐six‐week‐old female mice were divided into three groups: medication with 17β‐estradiol after ovariectomy (OVX + 17β‐estradiol), ovariectomy (OVX) and sham (SHAM). The mice received two full‐thickness wounds, and the OVX + 17β‐estradiol group was administered 17β‐estradiol at 0·01 g/day until healing. In the OVX + 17β‐estradiol group, the ratio of wound area was significantly smaller than those of the OVX and SHAM groups on days 1–3, 5, 6, 8–12 and 9–12, respectively, the numbers of neutrophils and macrophages were significantly smaller than those on days 3 and 7, the ratio of re‐epithelialisation was significantly higher than those on days 3 and 11, the ratio of myofibroblasts was significantly higher than those on day 11 and smaller on day 14, and the ratio of collagen fibres was significantly larger than that of the OVX group on days 7–14. We found that 17β‐estradiol administration promotes cutaneous wound healing in 40‐week female mice by reducing wound area, shortening inflammatory response, and promoting re‐epithelialisation, collagen deposition and wound contraction. Our results suggest that cutaneous wound healing that is delayed because of ageing is promoted by exogenous and continuous 17β‐estradiol administration.     

Comparison of the effects of once‐weekly and once‐daily rhPTH (1–34) injections on promoting fracture healing in rodents

To compare the efficacy of once‐weekly and once‐daily subcutaneous injections of teriparatide (recombinant human parathyroid hormone 1–34) on fracture healing, 50 adult male Sprague–Dawley rats were subjected to a unilateral tibia fracture and received internal fixation with a Kirschner needle. Based on the injection dose and frequency, the rats were randomly divided into five groups (n = 10 each): subcutaneous injections of saline or 10 µg/kg/w, 20 µg/kg/w, 10 µg/kg/d, and 20 µg/kg/d teriparatide. Four weeks later, the rats were euthanatized, and the fractured tibiae were assessed using X‐rays, dual‐energy X‐ray absorptiometry, micro‐computed tomography, the three‐point bending biomechanics test, and histology. Compared to the saline control group, either daily or weekly subcutaneous injections of teriparatide significantly increased bone mass, improved the bone microarchitecture, and promoted fracture healing (p < 0.05). There were no significant differences in bone mineral density (BMD), bone microstructure or bone strength between the 20 µg/kg/w and 10 µg/kg/d groups (p > 0.05). Teriparatide 20 µg weekly injections promoted bone fracture healing to the same extent as teriparatide 10 µg daily injections, which can dramatically decrease the cumulative dosage of teriparatide injections. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1145–1152, 2018.

     

Pro‐healing effects of bilirubin in open excision wound model in rats

Bilirubin, a by‐product of heme degradation, has an important role in cellular protection. Therefore, we speculated that bilirubin could be of potential therapeutic value in wound healing. To validate the hypothesis, we used a full‐thickness cutaneous wound model in rats. Bilirubin (30 mg/kg) was administered intraperitoneally every day for 9 days. The surface area of the wound was measured on days 0, 2, 4, 7 and 10 after the creation of the wound. The granulation tissue was collected on day 10 post‐wounding for analysing various parameters of wound healing. Bilirubin treatment accelerated wound contraction and increased hydroxyproline and glucosamine contents. mRNA expression of pro‐inflammatory factors such as intercellular cell adhesion molecule‐1 (ICAM‐1) and tumour necrosis factor‐α (TNF‐α) were down‐regulated and that of anti‐inflammatory cytokine interleukin‐10 (IL‐10) was up‐regulated. The findings suggest that bilirubin could be a new agent for enhancing cutaneous wound healing.     

Favourable effect of β‐glucan treatment against cisplatin‐induced reproductive system damage in male rats

The aim of this study was to investigate the potential beneficial effects of β‐glucan treatment against oxidative, histological and spermatological damage caused by cisplatin on the male reproductive system. Twenty‐eight Sprague Dawley male rats were used in the study. The rats were randomly divided into four equal‐sized groups: a control group, cisplatin group (7 mg/kg in a single‐dose cisplatin administered intraperitoneally), β‐glucan group (β‐glucan given at a dose of 50 mg kg^?1 d^?1 for 14 day) and a cisplatin plus β‐glucan group (cisplatin and β‐glucan administered together at the same dose). Cisplatin administration induced an increase in the level of thiobarbituric acid‐reactive substances, a lipid peroxidation indicator. It induced a decrease in enzymatic (superoxide dismutase, catalase and glutathione peroxidase) activities and nonenzymatic (reduced glutathione) antioxidant levels. In addition, cisplatin caused both histological and spermatological damage, as shown by a decrease in sperm motility and epididymal sperm concentrations and an increase in abnormal sperm rates. The β‐glucan treatment improved cisplatin‐induced oxidative, histological and spermatological damage. This study revealed that β‐glucan treatment provided prevention against male reproductive system damage caused by cisplatin. These preventative effects were likely due to its antioxidant properties.     

Local release of pioglitazone (a peroxisome proliferator‐activated receptor γ agonist) accelerates proliferation and remodeling phases of wound healing

Peroxisome proliferator‐activated receptor γ (PPARγ) is a member of the nuclear receptor superfamily known for its anti‐inflammatory and macrophage differentiation effects, as well as its ability to promote fat cell differentiation and reduce insulin resistance. Pioglitazone (Pio) is a PPARγ agonist used clinically as an anti‐diabetic agent for improving insulin sensitivity in patients with diabetes. The objective of this study was to develop a drug delivery system (DDS) for the local release of Pio to promote wound healing. Pio of low aqueous solubility was water‐solubilized by micelles formed from gelatin grafted with L‐lactic acid oligomers, and incorporated into a biodegradable gelatin hydrogel. An 8‐mm punch biopsy tool was used to prepare two skin wounds on either side of the midline of 8‐week‐old mice. Wounds were treated by the hydrogels with (Pio‐hydrogel group) or without (control group) Pio, and the wound area were observed 1, 4, 7, and 14 days after treatment. In addition, a protein assay and immunohistological stain were performed to determine the effects of the Pio‐hydrogel on inflammation and macrophage differentiation. The Pio‐hydrogels promote wound healing. Moreover, Western blotting analysis demonstrated that treatment with Pio‐hydrogels resulted in decreased levels of the cytokines MIP‐2 and TGF‐β, and increased levels of glucose‐regulating adiponectin. It is concluded that Pio‐incorporated hydrogels promote the proliferation and remodeling phases of wound healing, and may prove to be effective as wound dressings.     

Utility of a human–mouse xenograft model and in vivo near‐infrared fluorescent imaging for studying wound healing

To study the complex cellular interactions involved in wound healing, it is essential to have an animal model that adequately mimics the human wound microenvironment. Currently available murine models are limited because wound contraction introduces bias into wound surface area measurements. The purpose of this study was to demonstrate utility of a human–mouse xenograft model for studying human wound healing. Normal human skin was harvested from elective abdominoplasty surgery, xenografted onto athymic nude (nu/nu) mice, and allowed to engraft for 3 months. The graft was then wounded using a 2‐mm punch biopsy. Wounds were harvested on sequential days to allow tissue‐based markers of wound healing to be followed sequentially. On the day of wound harvest, mice were injected with XenoLight RediJect cyclooxygenase‐2 (COX‐2) probe and imaged according to package instructions. Immunohistochemistry confirms that this human–mouse xenograft model is effective for studying human wound healing in vivo. Additionally, in vivo fluorescent imaging for inducible COX‐2 demonstrated upregulation from baseline to day 4 (P = 0·03) with return to baseline levels by day 10, paralleling the reepithelialisation of the wound. This human–mouse xenograft model, combined with in vivo fluorescent imaging provides a useful mechanism for studying molecular pathways of human wound healing.     

Combined effects of TNF‐α, IL‐1β, and HIF‐1α on MMP‐2 production in ACL fibroblasts under mechanical stretch: An in vitro study

The dynamics between inflammatory factors, mechanical stress, and healing factors, in an intra‐articular joint, are very complex after injury. Injury to intra‐articular tissue [anterior cruciate ligament (ACL), synovium] results in hypoxia, accumulation of various pro‐inflammatory factors, cytokines, and metalloproteases. Although the presence of increased amounts of matrix‐metalloproteinases (MMP) in the joint fluid after knee injury is considered the key factor for ACL poor healing ability; however, the exact role of collective participants of the joint fluid on MMP‐2 activity and production has not been fully studied yet. To investigate the combined effects of mechanical injury, inflammation and hypoxia induced factor‐1α (HIF‐1α) on induction of MMP‐2; we mimicked the microenvironment of joint cavity after ACL injury. The results show that TNF‐α and IL‐1β elevate the activity of MMP‐2 in a dose‐ and time‐dependent manner. In addition, mechanical stretch further enhances the MMP‐2 protein levels with TNF‐α, IL‐1β, and their mixture. CoCl₂‐induced HIF‐1α (100 and 500 µM) also increases the levels and activity of MMP‐2. Mechanical stretch has a strong additional effect on MMP‐2 production with HIF‐1α. Our results conclude that mechanical injury, HIF‐1α and inflammatory factors collectively induce increased MMP‐2 production in ACL fibroblasts, which was inhibited by NF‐κB pathway inhibitor (Bay‐11‐7082). © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1008–1014, 2011     

Health economic assessment of negative pressure wound therapy use in the management of subcutaneous abdominal wound healing impairment (SAWHI) in the out‐of‐hospital setting

Development of subcutaneous abdominal wound healing impairment (SAWHI) can greatly affect patient care. Complications from SAWHI include delayed healing, increased risk of infection, and fascial dehiscence resulting in increased patient care and associated costs. Treatment options include conventional wound treatment or negative pressure wound therapy, both of which can be used in the out‐of‐hospital setting. However, limited published evidence on cost‐effectiveness exists. A conservative health economic model was created to assess the cost–benefit of negative pressure wound therapy in the out‐of‐hospital setting for the management of SAWHI. Study data from a published multicentre randomised controlled trial were used and represented 221 patients that received care in the out‐of‐hospital setting. The mean per‐patient total cost within 42 days was slightly higher in the negative pressure wound therapy group (2034.98 € versus 1918.91 €); however, when wound closure rates were considered, a cost savings of 4155.98 € per closed wound was observed with the use of negative pressure wound therapy (4324.34 € versus 8480.32 €). A cost‐effectiveness analysis was constructed, and negative pressure wound therapy was observed to have a lower cost of care and a higher incremental closure rate.     

Severe postoperative wound healing disturbance in a patient with alpha‐1‐antitrypsin deficiency: the impact of augmentation therapy

Wound healing disturbance is a common complication following surgery, but the underlying cause sometimes remains elusive. A 50‐year‐old Caucasian male developed an initially misunderstood severe wound healing disturbance following colon and abdominal wall surgery. An untreated alpha‐1‐antitrypsin (AAT) deficiency in the patient's medical history, known since 20 years and clinically apparent as a mild to moderate chronic obstructive pulmonary disease, was eventually found to be at its origin. Further clinical work‐up showed AAT serum levels below 30% of the lower reference value; phenotype testing showed a ZZ phenotype and a biopsy taken from the wound area showed the characteristic, disease‐related histological pattern of necrotising panniculitits. Augmentation therapy with plasma AAT was initiated and within a few weeks, rapid and adequate would healing was observed. AAT deficiency is an uncommon but clinically significant, possible cause of wound healing disturbances. An augmentation therapy ought to be considered in affected patients during the perioperative period.     

Activation of mTORC1 in B Lymphocytes Promotes Osteoclast Formation via Regulation of β‐Catenin and RANKL/OPG

The cytokine receptor activator of nuclear factor‐κB ligand (RANKL) induces osteoclast formation from monocyte/macrophage lineage cells. However, the mechanisms by which RANKL expression is controlled in cells that support osteoclast differentiation are still unclear. We show that deletion of TSC1 (tuberous sclerosis complex 1) in murine B cells causes constitutive activation of mechanistic target of rapamycin complex 1 (mTORC1) and stimulates RANKL but represses osteoprotegerin (OPG) expression and subsequently promotes osteoclast formation and causes osteoporosis in mice. Furthermore, the regulation of RANKL/OPG and stimulation of osteoclastogenesis by mTORC1 was confirmed in a variety of RANKL‐expressing cells and in vivo. Mechanistically, mTORC1 controls RANKL/OPG expression through negative feedback inactivation of Akt, destabilization of β‐catenin mRNA, and downregulation of β‐catenin. Our findings demonstrate that mTORC1 activation‐stimulated RANKL expression in B cells is sufficient to induce bone loss and osteoporosis. The study also established a link between mTORC1 and the RANKL/OPG axis via negative regulation of β‐catenin. © 2016 American Society for Bone and Mineral Research.