Implications for cumulative and prolonged clinical improvement induced by cross-linked hyaluronic acid: An in vivo biochemical/microscopic study in humans.
Exp Dermatol
; 33(1): e14998, 2024 Jan.
Article
en En
| MEDLINE
| ID: mdl-38284186
ABSTRACT
In photoaged human skin, type I collagen fragmentation impairs dermal extracellular matrix (ECM) integrity, resulting in collapsed/contracted fibroblasts with reduced type I procollagen synthesis. Injections of cross-linked hyaluronic acid (CL-HA) reverse these deleterious changes. To investigate the time course and effects of biochemical changes induced by injected CL-HA, particularly whether fibroblast activation leads to accumulation/deposition of dermal collagen, we injected CL-HA into photoaged skin of human participants over 60 years-old and performed biochemical/microscopic analyses of skin samples. Beginning 1 week post-injection and lasting 6-9 months, fibroblasts exhibited activation, including increased immunostaining and gene expression of markers of type I collagen synthesis, such as heat shock protein 47 and components of the transforming growth factor-ß pathway. At 1 week post-injection, multiphoton microscopy revealed elongation/stretching of fibroblasts, indicating enhanced dermal mechanical support. At 4 weeks, second-harmonic generation microscopy revealed thick collagen bundles densely packed around pools of injected CL-HA. At 12 months, accumulation of thick collagen bundles was observed and injected CL-HA remained present in substantial amounts. Thus, by occupying space in the dermal ECM, injected CL-HA rapidly and durably enhances mechanical support, stimulating fibroblast elongation and activation, which results in thick, densely packed type I collagen bundles accumulating as early as 4 weeks post-injection and continuing for at least a year. These observations indicate that early and prolonged clinical improvement following CL-HA injection results from space-filling and collagen deposition. As type I collagen has an estimated half-life of 15 years, our data provide the foundations for optimizing the timing/frequency of repeat CL-HA injections.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Colágeno Tipo I
/
Ácido Hialurónico
Límite:
Humans
/
Middle aged
Idioma:
En
Revista:
Exp Dermatol
Asunto de la revista:
DERMATOLOGIA
Año:
2024
Tipo del documento:
Article
País de afiliación:
Estados Unidos