Human Histology and Persistence of Various Injectable Filler Substances for Soft Tissue Augmentation

Abstract

An increasing number of soft tissue filler substances have been introduced to the beauty market outside the U.S. which lack experimental and clinical data in support of their claim. Ten commercially available filler substances were examined for biocompatibility and durability: 0.1 cc of each substance was injected deep intradermally into the volar forearm of one of the authors and observed for clinical reaction and permanence. At 1, 3, 6, and 9 months the test sites were excised, histologically examined, and graded according to foreign body reactions classification. Collagen (Zyplast) was phagocytosed at 6 months and hyaluronic acid (Restylane) at 9 months. PMMA microspheres (Artecoll) had encapsulated with connective tissue, macrophages, and sporadic giant cells. Silicone oil (PMS 350) was clinically inconspicuous but dissipated into the tissue, causing a chronic foreign body reaction. Polylactic acid microspheres (New-Fill) induced a mild inflammatory response and had disappeared clinically at 4 months. Dextran microspheres (Reviderm intra) induced a pronounced foreign body reaction and had disappeared at 6 months. Polymethylacrylate particles (Dermalive) induced the lowest cellular reaction but had disappeared clinically at 6 months. Polyacrylamide (Aquamid) was well tolerated and remained palpable to a lessening degree over the entire testing period. Histologically, it dissipated more slowly and was kept in place through fine fibrous capsules. Polyvinylhydroxide microspheres suspended in acrylamide (Evolu-tion) were well tolerated, slowly diminishing over 9 months. Calcium hydroxylapatite microspheres (Radiance FN) induced almost no foreign body reaction but were absorbed by the skin at 12 months.Host defense mechanisms react differently to the various filler materials, but all substances-resorbable or nonresorbable-appeared to be clinically and histologically safe, although all exhibit undesirable side effects. Since the mechanism of late inflammation or granuloma formation is still unknown, early histological findings are not useful in predicting possible late reactions to filler substances.

Poly-L-Lactic Acid Increases Collagen Gene Expression and Synthesis in Cultured Dermal Fibroblast (Hs68) Through the p38 MAPK Pathway

“…At the sites where the PLLA was administered, a weak inflammatory reaction, infiltration of foreign body giant cells, and elongated fibroblasts were observed, which are presumed to be the central mechanistic features 4 . Type I collagen statistically and significantly increased from baseline to 6 months after PLLA injection in human skin 7,8 . Moreover, the clinically volume-augmenting effect of PLLA could be confirmed even within one month after injection, which is much faster than the rate reported in an- other study 8 .…”

Biochemical and biomechanical comparisions of decellularized scaffolds derived from porcine subcutaneous and visceral adipose tissue

“…Although hyaluronic acid and collagen-based gels are available soft-tissue filler for filling subcutaneous voids in clinics, these materials fail to stimulate adipose regeneration and often suffer from limited longevity due to rapid resorption in vivo. 66,67 Our results suggested that future soft-tissue filler materials could incorporate DAT elements in order to restore the adipose deficits instead of simply filling them with static materials. Since the present study demonstrated that SDAT and VDAT have different mechanical stiffness, they could serve as available substitutes for filling soft-tissue defects that require various stiffness.…”

Facial Soft Tissue Augmentation With Bellafill: A Review of 4 Years of Clinical Experience in 212 Patients

“…However, the problem of granuloma formation needs to be solved. Bellafill, being a third generation PMMA filler following Artefill and Artecol, was developed to avert the complication of granuloma formation, with 3 major improvements, namely (i) uniform microspheres sized above 20 microns, thereby preventing them from being phagocytosed by macrophages, [5][6][7][8] (ii) lack of irregular surfaces mitigates inflammatory foreign body reaction, (iii) clumping of microspheres is prevented by fixation in a suspension of viscous collagen, allowing for even collagenesis. A 5-year study on the safety of Bellafill in nasolabial fold augmentation showed a 1.7% incidence of granuloma formation.…”

“…[5][6][7] Aggregation of microspheres is prevented by fixation in a suspension of viscous collagen, allowing for even collagenesis around the microspheres. 5,8 Bellafill provides an immediate volumizing effect due to the bovine collagen which will be absorbed over a month. This is followed by permanent volumization through collagenesis induced by the PMMA microspheres.…”