Phosphorylase Kinase Inhibition Therapy in Burns and Scalds
Severe burns and scalds almost always result in unsightly hypertrophic scarring. Among the important processes involved in scarring are fibroblast formation and transformation of fibroblasts into myofibroblasts. Myofibroblasts contain α-smooth muscle actin which has contractile properties and can lead to wound contraction and hypertrophic scarring.
Phosphorylase kinase (PhK), expressed within 5 mins of injury, is among the earliest
enzymes released after tissue damage. It is responsible for activation of NF-kB, which in turn activates over 200 different genes related to inflammation, fibroblastic proliferation, myofibroblast conversion, and eventual scar tissue formation. The sequence and approximate timing of events following injury include the following: activation of PhK (5 mins), followed by appearance of neutrophils (30 mins), macrophages (hours to days), fibroblasts (1 week) and myofibroblasts (2 weeks).
Cytokines and growth factors secreted by macrophages include fibroblast growth factor (FGF) and transforming growth factors α and β (TGFα and TGFβ). Fibroblast growth factor is responsible for fibroblastic proliferation, and TGFβ1 for conversion of fibroblasts into myofibroblasts. After thermal injury, the use of topical curcumin, a non-competitive, selective PhK inhibitor that blocks PhK activity upstream of NF-kB activation, was found to be associated with more rapid and improved skin healing, as well as less severe or absent scarring.
Wound healing in adult skin: aiming for perfect regeneration
Wound healing in adult skin, a complex process involving many cell types and processes such as epidermal, fibroblastic, and endothelial cell proliferation, cell migration, matrix synthesis, and wound contraction, almost invariably results in scar tissue formation and wound induration. Unlike in adult skin, wound healing in embryos involves repair processes that result in the essentially perfect regeneration of damaged tissue. This paper discusses key mechanisms that lead to scar tissue formation in adult human skin and treatment modalities, including curcumin gel, that may result in essentially perfect skin regeneration following surgical procedures.
Acute and chronic injury: burns and photodamaged skin
Phosphorylase kinase (PhK) is a unique enzyme in which the spatial arrangements of the specificity determinants can be manipulated to allow the enzyme to recognize substrates of different specificities. In this way, PhK is capable of transferring high energy phosphate bonds from ATP to serine/threonine and tyrosine moieties in serine/threonine kinases and tyrosine kinases, thus playing a key role in the activation of multiple signaling pathways.
Phosphorylase kinase is released within five minutes following injury and is responsible for activating inflammatory pathways in injury-activated scarring following burns. In photodamaged skin, PhK plays an important role in promoting photocarcinogenesis throughactivation of NF-kB-dependent signaling pathways with inhibition of apoptosis of photodamaged cells, thus promoting the survival of precancerous cells and allowing for subsequent tumor transformation. Curcumin, the active ingredient in the spice, turmeric, is a selective and non-competitive PhK inhibitor. By inhibition of PhK, curcumin targets multiple PhK-dependent pathways, with salutary effects on a number of skin diseases induced by injury. In this paper, we show that curcumin gel produces rapid healing of burns, with little or no residual scarring. Curcumin gel is also beneficial in the repair of photo-damaged skin, including pigmentary changes, solar elastosis, thinning of the skin with telangiectasia (actinic poikiloderma), and premalignant lesions such as actinic keratoses, dysplastic nevi, and advanced solar lentigines, but the repair process takes many months.
Anti-Photoaging and Anti-Carcinogenic Therapy
Photocarcinogenesis is caused by DNA damage from solar radiation in the ultraviolet
range, resulting in the development of both melanoma and non-melanoma skin cancers.Although the ultraviolet B (UVB) spectrum has previously been considered the more carcinogenic of the two, recent evidence suggests that ultraviolet A (UVA) irradiation may have damaging effects that are not generally appreciated.
Furthermore, it is becoming apparent that although sunscreens have been in use for many years, they are relatively ineffective in protecting against UVA-induced photoaging and UVA-induced skin cancers. More recently,attention has been directed on certain dietary phytochemicals, in particular curcumin, in the attempt to repair photodamaged skin as a means of preventing degeneration into solar induced skin cancers. Curcumin has been shown to protect against the deleterious effects
of injury by attenuating oxidative stress and suppressing inflammation. In this review, the curcumin-targeted signaling pathways directed against solar-induced injury are reviewed. The ability of curcumin to block multiple targets on these pathways serve as a basis for the potential use of this phytochemical in photoaging skin and photocarcinogenesis.
Psoriasis: A Proof of Concept Study
Background: Phosphorylase kinase (PhK) activity is induced by injurious stimuli, which is known to precipitate psoriasis.We had previously reported that elevated PhK activity in psoriatic epidermis correlated with increased psoriatic activity, and that suppression of PhK activity by its inhibitor, curcumin gel, correlated with disease resolution.
Objective: We evaluated the efficacy of a strategy of combining PhK inhibition by topical curcumin with elimination ofPhK-generating precipitating factors from various injurious stimuli in producing improvement of psoriatic activity, aiming at complete resolution. Patients and Methods: We studied a cohort of 647 consecutive patients with mild to severe psoriasis in a single center. Our therapeutic regimen consisted of curcumin gel, topical steroids, strict avoidance of contact allergens, avoidance of dairy products in lactose-intolerant patients, and treatment of infections to eliminate bacterial superantigens. Results: PASI scores at 0 wk was 24.7 +/– 17.1 (SD), n = 647. PASI scores improved significantly at 4 weeks to 11.5 +/– 8.1 (n = 638; p < 0.0001), at 8 weeks to 4.5 +/– 4.2 (n = 636, p < 0.0001), and at 16 weeks to 0.9 +/– 2.5 (n = 641, p < 0.0001). At 16 weeks, 72.2% of patients were completely clear of psoriatic activity (PASI = 0). Conclusion: Our results indicate that a regimen of PhK inhibition by topical curcumin with elimination of PhK-generating factors is effective in producing significant reduction of psoriatic activity at 16 weeks, with complete clearance of psoriasis in 72.2% of patients.
A Disruptive Treatment to Prevent Amputation
Background:
Chronic wounds are a growing problem internationally, termed a silent epidemic. To combat this epidemic, it is not sufficient to rely on traditional wound care treatments alone, but to look to innovative and alternative therapies. The indispensable role of oxygen in wound healing is well-discussed in the literature, and in the past two decades the topical application of oxygen has shown promising results in the healing of chronic wounds. However, the toxic effects of oxygen are usually not appreciated and can often lead to wound necrosis and gangrene in wounds with compromised blood supply. While wounds with adequate blood supply contain free radical quenchers (catalases, superoxide dismutase and reduced glutathione) which neutralize the free radicals (reactive oxygen species) released as a by-product of the Krebs cycle, wounds with deficient blood supply are deficient in free radical quenchers and are further damaged by exposure to oxygen as a result of reperfusion injury/oxygen toxicity. Topical hyperbaric oxygen (THOT®) uses low oxygen tensions in the hyperbaric range to stimulate angiogenesis, while preventing excessive oxygen toxicity. The result is the induction of marked angiogenesis, with increasing capacity for quenching reactive oxygen species, resulting in wound healing of ischemic wounds.
Case Presentation:
This case report describes a 95-year-old Caucasian female who presented with a stage IV chronic necrotic ulcer on her lower left leg. Surgical pathology results revealed calcifying vasculopathy, which is thought to be responsible for deficient blood supply to the leg, leading to a necrotic, chronic leg ulcer of her left leg. After traditional wound therapies were unsuccessful, she was considered for leg amputation. The introduction of adjunctive treatment with topical hyperbaric oxygen therapy saw complete healing of the wound within 15 weeks. The wound remained closed, without the presence of scar tissue, with no signs of wound breakdown at three-month and six-month follow-ups.
Conclusions:
Chronic hypoxic wounds with vascular insufficiency are considered “unlikely to heal” and tend to lead to limb amputation. The use of THOT® technology, with low hyperbaric oxygen tensions to neutralize free radicals released by the Krebs cycle when oxygen contacts the wound, prevents oxygen toxicity and results in angiogenesis necessary for wound healing. In this way, THOT® treatment was able to convert the hypoxic “unlikely to heal” wound considered for limb amputation into one which healed, with limb salvage. The results of this case report demonstrate the potential for complete healing of chronic hypoxic wounds even in complex cases with multiple confounding factors preventing wound healing, using a cost-effective treatment that is easily accessible to patients.
Enhanced Healing/Cost-Savings of Low–Pressure Oxygen Therapy
Recent advances in topical hyperbaric oxygen technology identified the use of low- pressure topical hyperbaric oxygen therapy in enhancing wound healing. This study prospectively examined the feasibility of technology transfer from university to Health Maintenance Organization personnel, using topical hyperbaric oxygen therapy to heal necrotic wounds.
Fifteen patients with 24 gangrenous and/or necrotic wounds that did not improve or worsened after at least 6 weeks of standard wound care were treated with topical hyperbaric oxygen therapy by trained HMO personnel. Four patients underwent digital amputation for osteomyelitis and/or gangrene followed by topical hyperbaric oxygen therapy. Assessment parameters included wound healing and cost of wound care before and after topical hyperbaric oxygen therapy. Six of the six Level 2 wounds healed within 2 to 4 weeks, nine of the ten Level 3 wounds healed within 4 to 10 weeks, and seven of the eight Level 4 wounds healed within 4 to 12 weeks. The ulcers improved by a mean of 0.829 cm2 per day. T test (SSPS 7.5) showed significant improvement per day after topical hyperbaric oxygen therapy, t = 5.217, df = 24, P < 0.0001 (95% CI = 1.13 – 0.49). Wound healing with topical hyperbaric oxygen therapy was associated with decreased costs. The results of this support the feasibility of transfer of new wound healing technology from research to HMO personnel.
Angiogenesis in Necrotic Ulcers Treated with HBO Therapy
Necrotic/gangrenous wounds lack adequate blood supply and develop further vascular damage from either reperfusion injury or oxygen toxicity when exposed to oxygen at the wrong pressures. A prospective randomized study was performed to confirm the efficacy of topical hyperbaric oxygen at 1.004 to 1.013 atmospheres (THOT) in stimulating angiogenesis and healing of necrotic/gangrenous wounds. Participants included 40 inpatients (79 ulcers) recruited over 12 months who were assigned to treatment by either THOT or standard wound care (SWC). The results showed that 90% of the wounds healed in the THOT group compared to 22% in the SWC controls.
Repeated measures ANOVA on log (ulcer size at 4 weeks) showed a significant group by time interaction, F(1,55) = 68.2, P < 0.0001. The size of ulcers (at 4 weeks) was significantly smaller with THOT, but larger with SWC. Capillary density/hpf (high power field) was significantly higher in THOT wounds than in SWC wounds (P < 0.001). It was concluded that THOT is effective in stimulating angiogenesis with enhanced healing of necrotic wounds.
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