Comparative In Vivo Study of Solid-Type Pure Hyaluronic Acid in Thread Form: Safety and Efficacy Compared to Hyaluronic Acid Filler and Polydioxanone Threads

INTRODUCTION

Although various products are commonly used for skin rejuvenation, solid-type hyaluronic acid (HA) as an injectable form has not been researched or utilized. This study aimed to demonstrate the safety and efficacy of solid-type HA in thread form, which differs from the conventional gel-type HA commonly used.

METHOD

Solid-type HA threads, conventional HA fillers, and polydioxanone (PDO) threads were inserted into the dorsal subcutaneous layer of mice. Photographs were taken on days 0, 1, 3, and 7, and on day 7, the samples were harvested for histological analysis. Inflammatory reactions and detection of collagen were confirmed through tissue staining, and real-time PCR was conducted to quantify collagen synthesis.

RESULTS

In the histological analysis, the PDO threads exhibited a greater inflammatory response compared to the HA threads. Masson's trichrome staining revealed a higher degree of collagen synthesis in the HA thread group compared to the HA filler group. While collagen type 1 expression was significantly higher in the PDO thread group than in the HA thread group, the HA thread group showed higher expression levels of collagen type 3. Furthermore, the PDO thread group demonstrated a statistically significant increase in TGF-β1 compared to the HA group.

CONCLUSION

This in vivo study demonstrated the stable application of solid-type pure HA threads and their potential for inducing collagen production, while also yielding a low inflammatory response. The findings highlight the promising applications of solid-type HA in the field of cosmetic dermatology.

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Experimental Investigation on the Tissue Response Induced by Face-Lifting Mesh Suspension Thread in Rats

Background

Face-lifting procedures are often performed to hide the effects of aging. Thread-lifting, a minimally invasive technique for the correction of facial aging, has become increasingly popular, and various materials for the procedure have been developed.

Objective

This study compared tissue responses to two types of threading sutures placed under rat skin: polypropylene (PP) monofilament mesh suspension thread (a novel face-lifting material) and polydioxanone (PDO) barbed thread.

Methods

Eight rats each were assigned to the PP monofilament mesh suspension, PDO barbed thread, and control groups. Tissue reactions were evaluated 28 days after subcutaneous loading of the materials.

Results

Significant increases in tensile strength and the mean area occupied by collagen fibers were evident in skin loaded with PDO barbed thread and PP monofilament mesh suspension thread compared to control skin (p<0.05). Compared to sites loaded with PDO barbed thread, those loaded with PP monofilament mesh suspension thread showed a significant increase in the number of collagen fibers and a lower grade of inflammation (p<0.05).

Conclusion

PP monofilament mesh suspension thread has skin-rejuvenating effects comparable to those of PDO barbed thread, but induces a less severe inflammatory response. This indicates that it is a safe and effective material for use in thread-lifting procedures on aging skin.