Tracking and Increasing Viability of Topically Injected Fibroblasts Suspended in Hyaluronic Acid Filler

Role of Cultured Skin Fibroblasts in Regenerative Dermatology

The skin, as the largest organ, covers the entire outer part of the body, and since this organ is directly exposed to microbial, thermal, mechanical and chemical damage, it may be destroyed by factors such as acute trauma, chronic wounds or even surgical interventions. Cell therapy is one of the most important procedures to treat skin lesions. Fibroblasts are cells that are responsible for the synthesis of collagen, elastin, and the organization of extracellular matrix (ECM) components and have many vital functions in wound healing processes. Today, cultured autologous fibroblasts are used to treat wrinkles, scars, wounds and subcutaneous atrophy. The results of many studies have shown that fibroblasts can be effective and beneficial in the treatment of skin lesions. On the other hand, skin substitutes are used as a regenerative model to improve and regenerate the skin. The use of these alternatives, restorative medicine and therapeutic cells such as fibroblasts has tremendous potential in the treatment of skin diseases and can be a new window for the treatment of diseases with no definitive treatment. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description ofthese Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Effect of bFGF and fibroblasts combined with hyaluronic acid-based hydrogels on soft tissue augmentation: an experimental study in rats

Background

Hyaluronic acid (HA) has been applied as a primary biomaterial for temporary soft tissue augmentation and as a carrier for cells and the delivery of growth factors to promote tissue regeneration. Although HA derivatives are the most versatile soft tissue fillers on the market, they are resorbed early, within 3 to 12 months. To overcome their short duration, they can be combined with cells or growth factors. The purpose of this study was to investigate the stimulating effects of human fibroblasts and basic fibroblast growth factors (bFGF) on collagen synthesis during soft tissue augmentation by HA hydrogels and to compare these with the effects of a commercial HA derivative (Restylane®).

Methods

The hydrogel group included four conditions. The first condition consisted of hydrogel (H) alone as a negative control, and the other three conditions were bFGF-containing hydrogel (HB), human fibroblast-containing hydrogel (HF), and human fibroblast/bFGF-containing hydrogel (HBF). In the Restylane® group (HGF), the hydrogel was replaced with Restylane® (R, RB, RF, RBF). The gels were implanted subdermally into the back of each nude mouse at four separate sites. Twelve nude mice were used for the hydrogel (n = 6) and Restylane® groups (n = 6). The specimens were harvested 8 weeks after implantation and assessed histomorphometrically, and collagen synthesis was evaluated by RT-PCR.

Results

The hydrogel group showed good biocompatibility with the surrounding tissues and stimulated the formation of a fibrous matrix. HBF and HF showed significantly higher soft tissue synthesis compared to H (p < 0.05), and human collagen type I was well expressed in HB, HF, and HBF; HBF showed the strongest expression. The Restylane® filler was surrounded by a fibrous capsule without any soft tissue infiltration from the neighboring tissue, and collagen synthesis within the Restylane® filler could not be observed, even though no inflammatory reactions were observed.

Conclusion

This study revealed that HA-based hydrogel alone or hydrogel combined with fibroblasts and/or bFGF can be effectively used for soft tissue augmentation.

Assessment of Long-term Outcomes of Soft-Tissue Augmentation by Injecting Fibroblasts Suspended in Hyaluronic Acid Filler

Importance

In previous studies, this group has reported that cultured human fibroblasts suspended in hyaluronic acid (HA) filler might have potential use as a long-lasting injectable soft-tissue filler. However, the data were insufficient to determine the long-term outcomes.

Objective

To evaluate the long-term outcomes of cultured human fibroblasts suspended in HA filler used for soft-tissue augmentation.

Design, Setting, and Participants

A long-term case series study was performed. Between January 2010 and December 2013, a total of 38 patients were treated with fibroblast-HA filler mixture to augment nasal dorsa, nasolabial folds, and cheek depressions. Of these 38 patients, patients with follow-up period of greater than 3 years were included in this study. A total of 22 patients met the inclusion criteria.

Main Outcomes and Measures

Subjective assessment was performed to evaluate degree and time of resorption, improvement, satisfaction, softness of injection sites, and willingness to recommend this treatment to others. Objective assessment was carried out with patients' photographs. Safety and tolerability were also evaluated for this treatment.

Results

Of the 22 patients included in this study, 19 were women; mean (SD) patient age was 43 (15) years. All 22 patients experienced improvement following the treatment. Twenty (91%) patients were satisfied with the treatment. Nineteen patients (86%) considered that the injection site was as soft as it was before treatment. Patients' mean (SD) grading of improvement, satisfaction, and softness were 4.50 (0.51) (95% CI, 4.27-4.73), 4.14 (0.71) (95% CI, 3.82-4.45), and 4.82 (0.50) (95% CI, 4.59-5.00) at the last visit, respectively. Objective assessment demonstrated postoperative improvement in all patients: a rating of "much improved" was given to 7 patients (32%) by investigator 1; 8 patients (36%) by investigator 2; and 12 patients (55%) the injecting physician. This treatment was well tolerated; no adverse event was recorded for any patient.

Conclusions and Relevance

Injection of cultured human fibroblasts suspended in HA filler might be successful for long-term soft-tissue augmentation. To our knowledge, this study represents the longest follow-up study of soft-tissue augmentation with a fibroblast-HA filler mixture to date.

Level of Evidence

4.