[A comparative clinical study of the treatment of hypertrophic scars with either intralaesional steroid or silicone gel sheeting]

Natural products for the treatment of hypertrophic scars: Preclinical and clinical studies

Hypertrophic scarring (HS) is a complication of wound healing that causes physiological and psychological distress in patients. However, the possible mechanism underlying HS is not fully understood, and there is no gold standard for its treatment. Natural products are more effective, economical, convenient, and safe than existing drugs, and they have a wide application prospect. However, there is a lack of literature on this topic, so we reviewed in vivo, in vitro, and clinical studies and screened natural products showing beneficial effects on HS that can become potential therapeutic agents for HS to fill in the gaps in the field. In addition, we discussed the drug delivery systems related to these natural products and their mechanisms in the treatment of HS. Generally speaking, natural products inhibit inflammation, myofibroblast activation, angiogenesis, and collagen accumulation by targeting interleukins, tumor necrosis factor-α, vascular endothelial growth factors, platelet-derived growth factors, and matrix metalloproteinases, so as to play an anti-HS effects of natural products are attributed to their anti-inflammatory, anti-proliferative, anti-angiogenesis, and pro-apoptotic (enhancing apoptosis and autophagy) roles, thus treating HS. We also screened the potential therapeutic targets of these natural compounds for HS through network pharmacology and constructed a protein-protein interaction (PPI) network, which may provide clues for the pharmacological mechanism of natural products in treating this disease and the development and application of drugs.

Biological approaches for hypertrophic scars

Scar formation is usually the pathological consequence of skin trauma. And hypertrophic scars (HSs) frequently occur in people after being injured deeply. HSs are unusually considered as the result of tissue contraction and excessive extracellular matrix component deposition. Myofibroblasts, as the effector cells, mainly differentiated from fibroblasts, play the crucial role in the pathophysiology of HSs. A number of growth factors, inflammatory cytokines involved in the process of HS occurrence. Currently, with in-depth exploration and clinical research of HSs, various creative and effective treatments budded. In here, we summarize the progress in the molecular mechanism of HSs, and review the available biotherapeutic methods for their pathophysiological characteristics. Additionally, we further prospected that the comprehensive therapy may be more suitable for HS treatment.

Silicone gel sheeting for preventing and treating hypertrophic and keloid scars

BACKGROUND

Keloid and hypertrophic scars are common and are caused by a proliferation of dermal tissue following skin injury. They cause functional and psychological problems for patients, and their management can be difficult. The use of silicone gel sheeting to prevent and treat hypertrophic scarring is still relatively new and started in 1981 with treatment of burn scars.

OBJECTIVES

To determine the effectiveness of silicone gel sheeting for:(1) prevention of hypertrophic or keloid scarring in people with newly healed wounds (e.g. post surgery);(2) treatment of established scarring in people with existing keloid or hypertrophic scars.

SEARCH METHODS

In May 2013 we searched the Cochrane Wounds Group Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL for this second update.

SELECTION CRITERIA

Any randomised or quasi-randomised controlled trials, or controlled clinical trials, comparing silicone gel sheeting for prevention or treatment of hypertrophic or keloid scars with any other non surgical treatment, no treatment or placebo.

DATA COLLECTION AND ANALYSIS

We assessed all relevant trials for methodological quality. Three review authors extracted data independently using a standardised form and cross-checked the results. We assessed all trials meeting the selection criteria for methodological quality.

MAIN RESULTS

We included 20 trials involving 873 people, ranging in age from 1.5 to 81 years. The trials compared adhesive silicone gel sheeting with no treatment; non silicone dressing; other silicone products; laser therapy; triamcinolone acetonide injection; topical onion extract and pressure therapy. In the prevention studies, when compared with a no treatment option, whilst silicone gel sheeting reduced the incidence of hypertrophic scarring in people prone to scarring (risk ratio (RR) 0.46, 95% confidence interval (CI) 0.21 to 0.98) these studies were highly susceptible to bias. In treatment studies, silicone gel sheeting produced a statistically significant reduction in scar thickness (mean difference (MD) -2.00, 95% CI -2.14 to -1.85) and colour amelioration (RR 3.49, 95% CI 1.97 to 6.15) but again these studies were highly susceptible to bias.

AUTHORS' CONCLUSIONS

There is weak evidence of a benefit of silicone gel sheeting as a prevention for abnormal scarring in high-risk individuals but the poor quality of research means a great deal of uncertainty prevails. Trials evaluating silicone gel sheeting as a treatment for hypertrophic and keloid scarring showed improvements in scar thickness and scar colour but are of poor quality and highly susceptible to bias.