J AM ACAD DERMATOL
Isolagen, available in the United Kingdom and Australia, is an autologous isolation of fibroblasts obtained by a punch biopsy specimen from the patient. The tissue is sent to a laboratory where the company cultures the fibroblasts and then places them in an injectable suspension. That product is returned to the clinician for use within 1 day of receipt. There are few side effects because it is autologous, however, the company does still suggest skin testing for this product. This is another substance that loses volume initially so more than one injection with overcorrection is usually standard.
An available bovine collagen in 3.5% or 6.5% solution is Resoplast. Because of its derivation, a skin test is required before use. Endoplast-50 consists of solubilized elastin peptides in bovine collagen. Fascian was introduced in 1998 as allogenic human cadaver collagen from fascia lata or gastrocnemius fascia. There are 5 particle sizes: 0.1, 0.25, 0.5, 1.0, and 2.0 mm. Neocollagenesis from the ingrowth of fibroblasts occurs after injection of the product.60 Cosmoderm was created in 2003 as a human-derived collagen produced under laboratory conditions with extensive safety testing. On completion, it is mixed into a solution of lidocaine for injection. No skin testing is required and 3 to 7 months of benefit can be expected. Cosmoplast is yet another laboratorycreated human-derived collagen. It is also put into a lidocaine solution for use and does not require skin tests. This product, however, is cross-linked with glutaraldehyde to resist degradation and hopefully prolong effect.61 A newer, porcine-derived product is Evolence. It contains ribose moieties that are cross-linked to the collagen. No skin testing is necessary and refrigeration of the injectable is not needed. There may be up to 1 year of effect after placement.62
Autologous fat is another alternative for augmentation, first noted in 1893, to improve acne scars. These cells are obtained from the patient’s own body so must be harvested by liposuction or other methods. Injection is into the subcutaneous area, although some suggest dermal application is acceptable as well. It is good for contour defects but overcorrection must be done because a percentage of the injected material is initially or permanently nonviable. The reabsorption rate varies by location, amount injected, technique, or other factors. Variable reports of 6 to 18 months’ duration may be seen. One study of autologous fat transplantation included 43 patients (24 women, 19 men; age 22-69 years, mean 34.5 years), 23 specifically with acne scars, with 3- to 48-month (mean 26 months) followup to evaluate graft survival. It found that the greatest resorption was in areas of fibrotic acne scars and 65% remained at 3 months, 50% at 6 months, 40% at 9 months, and 30% at 12 months. The authors suggested that this was possibly because of decreased vascularity and, thus, viability.63 It has also been reported that including adipose-derived stem cells with the injected fat improves results. At 6 months, fat with the stem cells weighed 2.5 times more than the fat-only group and demonstrated a greater volume. In addition, the stem cellefree grafts appeared more fibrous at 6 months as compared with the adipocytes richeappearing grafts.64 This finding may improve long-term results or lead to other valuable research. The benefit is direct augmentation from the adipocytes if they are vascularized and can function normally or, some propose, from their contribution to fibrosis and physical enhancement of the area. As stated, several sessions are required and bruising, erythema, or mild inflammation may occur with a report of unilateral blindness as a result of intravascular injection even noted. Excess fat may be frozen for later use and there are no immunologic concerns because it comes from the patient.
‘‘Silicone,’’ a term consisting of polymers in the family of the element silicon, most commonly polydimethylsiloxane (silicon, oxygen, methane), is a permanent injectable. It is safe, nonmutagenic, noncarcinogenic, and nonteratogenic despite scattered case reports of adverse events. The mechanism of action is from physical filling of connective tissue defects and possible production of fibrotic collagen that encapsulates the injected material (a foreign body) preventing migration. Final results could take months while the collagen is deposited and remodels. In addition, it is not altered, metabolized, or destroyed by the human body. Considering all of these facts, undercorrection is often prudent initially. Side effects, including injection pain, mild inflammation, edema, hyperpigmentation or hypopigmentation, and poor placement, are possible but can be reduced with meticulous detail. Silicone is not a growth media for bacteria or other organisms and no true allergies have been reported, so skin tests are not required before use.
Acne Scarring Tissue Augmentation page 3
Acne Scarring A review and current treatment modalities BACKGROUND and ACNE SCARS ACNE SCARS page 2 ACNE SCAR TREATMENT and MEDICAL MANAGEMENT SURGICAL MANAGEMENT PROCEDURAL MANAGEMENT PROCEDURAL MANAGEMENT page 2 TISSUE AUGMENTATION TISSUE AUGMENTATION page 2 TISSUE AUGMENTATION page 3 TISSUE AUGMENTATION page 4 Light, laser, and energy therapy Light, laser, and energy therapy page 2 Light, laser, and energy therapy page 3 Light, laser, and energy therapy page 4 Conclusion and REFERENCES Manufacturers of brand name drugs mentioned in this article