Table 2 Summary of clinical studies on the effect of conditioned medium of mesenchymal stem cells on scars

Park et al., 2019 [25]

Evaluation of the effects of conditioned media of stem cells (HSCM) following fractional CO₂ laser in patients with atrophic acne scars and skin pores

Fifteen patients, aged 19 to 65, received treatment for atrophic scar sites, initially using an energy of 20–30 mJ at a density of 400 per 120, followed by treatment of the entire cheeks with an energy of 20 mJ at a density of 200 per 400 μm of stain. Subsequently, 100% HSCM was randomly applied to one resurfacing site (T), while normal saline was used as the control (C) on the other site. For the following six days, a solution containing 80% HSCM and hyaluronic acid (HA) was applied to the treated side (T), and HA alone was used on the control side (C).

Assessment of scar volume and erythema index using Antera 3D^® CS

23.5% reduction in scar volume in group T versus 15% reduction in group C after two months

37.6% decrease in skin pore volume in T vs. 15.9% in C

2.8% increase in erythema (T) vs. 3.1% (C)

At least 15% improvement in atrophic scars and skin pores in the area treated by HSCM after one treatment session compared to the control side.

Improvement of the therapeutic effects of fractional CO₂ laser after using HSCM

Abdel-Maguid et al., 2019 [27]

Assessment of the effectiveness of stem cell-conditioned medium compared to platelet-rich plasma after fractional CO₂ laser (FCL) treatment for atrophic post-acne scars

Thirty-three patients participated in the study. Group 1 (n = 17) received FCL treatment with topical SC-CM applied to one side of the face and FCL with normal saline on the other side. Group 2 (n = 16) received FCL treatment with either topical PRP or SC-CM. All patients underwent three treatment sessions per month.

Assessment of results using the Echelle d’Evaluation Clinique des Cicatrices d’Acne (ECCA) scale.

There was no significant difference in the clinical improvement of acne scars between the FCL/SC-CM and FCL sides of the face. However, faster and more noticeable recovery was observed on the FCL/PRP-treated side compared to the FCL/SC-CM-treated side. No significant differences in side effects were found between the two treatment sides in both groups. Both FCL/PRP and FCL/SC-CM treatments led to increased skin collagen and upregulation of the type I procollagen gene compared to FCL treatment alone. While the use of SC-CM enhanced the effect of FCL, PRP may be a more effective option.

Joo, 2022 [28]

To investigate the effects of combining non-ablative laser treatment with human stem cell-conditioned medium (HSCM) on hypertrophic scars (HTSs).

The study included 14 patients who underwent three non-ablative laser treatment sessions at four-week intervals. HSCM was applied to experimental scars, while saline was applied to control scars for comparison.

Assessment of erythema, trans-epidermal water loss (TEWL), skin elasticity, and scar thickness.

Both groups showed significant improvements in erythema (P < 0.001), TEWL (P < 0.001), and skin elasticity (P < 0.05). However, experimental scars demonstrated superior thickness reduction (-0.003 ± 0.09) compared to control scars (0.04 ± 0.12; P = 0.01), suggesting that HSCM enhances short-term outcomes when combined with laser treatment for HTSs.