The Rejuvenating Effect and Tolerability of an Auto-Cross-Linked Hyaluronic Acid on Décolletage: A Pilot Prospective Study

Investigation of Crosslinking Parameters and Characterization of Hyaluronic Acid Dermal Fillers: From Design to Product Performances

Despite process similarities, distinctive manufacturing technologies offer hyaluronic acid dermal fillers with different in vitro physicochemical and rheological properties due to peculiar crosslinked hydrogel networks. A better understanding of dermal filler properties could provide specific clinical indications and expectations with more accurate performance correlations. In this study, with an emphasis on the degree of modification, hyaluronic acid concentration and molecular weight, these process parameters were able to modulate dermal filler properties, especially rheology. Moreover, an extensive characterization of commercial hyaluronic acid injectables of the Hyal System line was described to present product properties and help to elucidate related clinical effects. Standardized methodologies were applied to correlate in vitro parameters with feasible clinical indications. In view of an optimized dermal filler design, the results of the extrudability measurements allowed the quantification of the effect of hydrogel composition, rheological properties and needle size on injectability. Composition, dynamic viscosity and needle size showed an impactful influence on hydrogel extrudability. Finally, the positive influence of 200 KDa hyaluronic acid in comparison to fragments of ether-crosslinked hyaluronic acid on fibroblast recognition were shown with a migration assay.

Anti-Aging and Depigmentation Effect of a Hyaluronic Acid Mechanically Stabilized Complex on Human Skin Explants

Solar radiation and environmental pollutants are factors that cause changes in the skin that trigger skin aging. The objective of the study is to evaluate the rejuvenating effects of a complex formed by hyaluronic acid supplemented with vitamins, amino acids and oligopeptides in explants of human skin. For this, surplus skin samples have been obtained from donors that have been resected and cultivated on slides with membrane inserts. The complex was administered to some skin explants and the percentage of cells with low, medium and high levels of melanin was evaluated as an indicator of the degree of pigmentation. Other skin segments were irradiated with UVA/UVB, then the product was administered on several slides and the levels of collagen, elastin, sulfated GAG and MMP1 were evaluated. The results show that the administration of the complex significantly reduces the percentage of skin cells with a high melanin content by 16%, and that in skin irradiated with UVA/UVB, there is a decrease in the content of collagen, elastin and sulfate GAGs, and the complex reverses this reduction without changing MMP1 levels. This suggests that the compound has anti-aging and depigmentation effects on the skin, giving a skin rejuvenation appearance.

Managing Pathologic Scars by Injecting Auto-Cross-linked Hyaluronic Acid: A Preliminary Prospective Clinical Study

BACKGROUND

Pathological scars are unattractive and may significantly impair the patient's quality of life. Current treatments provide inconsistent results, and none may be regarded as definitive. Recently, an auto-cross-linked hyaluronic acid (HA) formulation, IAL-SYSTEM ACP, featuring a long residence time and an enhanced safety profile, has been successfully used to prevent surgical adhesions, treat tendon lesions and rejuvenate the face and the décolletage. This study aims to preliminarily investigate whether IAL-SYSTEM ACP may also be effective in treating pathological scars resulting from burns, trauma or iatrogenic causes.

METHODS

Patients presenting one pathological scar were prospectively recruited and treated with two IAL-SYSTEM ACP injections carried out two weeks apart. Scar improvement was measured comparing the patient and observer scar assessment scale (POSAS) scores collected before treatment (T0) and 90 days after the second injection (T90) using nonparametric tests. The effect of age and scar type over score variation was investigated through quantile regression analysis.

RESULTS

Forty-one patients, 10 women and 31 men (median age, 34 years) were recruited. No patient dropped out, and no significant adverse event was observed. At T90, the median observer total score decreased by 11 units (- 77.5%) and the median patient total score decreased by 15 units (- 73.7%). The difference was significant (p < 0.001) in both cases. Traumatic injuries and young patient's age were the most significant predictors of a positive treatment outcome.

CONCLUSIONS

Treatment of pathological scars by two IAL-SYSTEM ACP injections, carried out two weeks apart, may provide significant clinical benefits. These findings should be the subject of further investigations.

LEVEL OF EVIDENCE IV

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