Historical Overview of Stem Cell Biology and Fat Grafting

Remission Strategies with Fat Grafting to Prevent Recurrence of Pedal Ulcerations and Pain: A Case Series

Background

Foot deformities and gait abnormalities can result in locally elevated peak pedal pressures or atypical pedal biomechanics. Combined with underlying comorbidities such as neuropathy, stroke, atrophic fat padding and history of ulcerations, this can lead to recurrent ulcerations and pain. Pedal fat grafting (PFG) is a treatment modality that has been shown to reduce peak pressures and accelerate wound healing. This study aimed to investigate the utility of PFG to treat and prevent ulcerations.

Methods

We retrospectively analyzed medical history, demographics, wound volume at time of procedure, volume of fat injected, surgical outcomes, and presence of new wounds in 15 patients who underwent PFG at Keck Hospital between 2018 and 2023.

Results

Seventeen feet from 15 patients (63 ± 12 years old, body mass index 30.9 ± 3.1) received PFG with an average volume of fat injected of 10.7 mL and procedure time of 84.6 minutes. At the time of PFG, nine wounds were present on nine feet with an average wound volume of 1.6 ± 2.7 cm3. Average follow-up was 6.9 months (range 1-36 months), with no complications or recurrent ulcerations since the procedure.

Conclusions

PFG is a promising treatment option for reducing peak pedal pressure and preventing ulcer recurrence in patients with various conditions. Further study is warranted for long-term follow-up.

Recent clinical trials with stem cells to slow or reverse normal aging processes

Aging is associated with a decline in the regenerative potential of stem cells. In recent years, several clinical trials have been launched in order to evaluate the efficacy of mesenchymal stem cell interventions to slow or reverse normal aging processes (aging conditions). Information concerning those clinical trials was extracted from national and international databases (United States, EU, China, Japan, and World Health Organization). Mesenchymal stem cell preparations were in development for two main aging conditions: physical frailty and facial skin aging. With regard to physical frailty, positive results have been obtained in phase II studies with intravenous Lomecel-B (an allogeneic bone marrow stem cell preparation), and a phase I/II study with an allogeneic preparation of umbilical cord-derived stem cells was recently completed. With regard to facial skin aging, positive results have been obtained with an autologous preparation of adipose-derived stem cells. A further sixteen clinical trials for physical frailty and facial skin aging are currently underway. Reducing physical frailty with intravenous mesenchymal stem cell administration can increase healthy life expectancy and decrease costs to the public health system. However, intravenous administration runs the risk of entrapment of the stem cells in the lungs (and could raise safety concerns). In addition to aesthetic purposes, clinical research on facial skin aging allows direct evaluation of tissue regeneration using sophisticated and precise methods. Therefore, research on both conditions is complementary, which facilitates a global vision.

SVF-GEL Cryopreserved for Different Times Exhibits Varied Preservation and Regeneration Potential After Transplantation in a Mouse Model

BACKGROUND

Matrix vascular component (SVF) gels derived from fat preserve tissue integrity and cell viability under cryopreserved conditions, making them easy to inject again for later use. Here, we compared the preservation power and regeneration potential of SVF-gel under different cryopreservation times.

METHODS

The SVF-gel stored under - 20 °C, without cryoprotectant cryopreservation for 5, 15, and 45 days, with fresh SVF-gel as control. We evaluated the rate of volume retention after thawing the SVF-gel and the apoptosis rate of adipose-derived stem cells. Next, we analyzed retention rated, adipogenesis, angiogenesis, and connective tissue hyperplasia of the grafts, one month after subcutaneously transplanting the specimen into immunodeficient mice.

RESULTS

SVF-gel cryopreserved for 5 and 15 days exhibited no significant different in apoptosis rates relative to the control group. Extending the cryopreservation time to 45 days resulted in significantly increased and decreased apoptosis and volume retention rates of SVF-gel, respectively. SVF-gel grafts cryopreserved for 5 and 15 days exhibited no significant differences from those in the control group, although their weights and volumes still fluctuated. Extending the cryopreservation time to 45 days resulted in significantly decreased retention rates of the grafts. Histologically, extending freezing time resulted in a gradual decline in the graft's health adipose tissue, as well as decreased angiogenesis, and connective tissue hyperplasia.

CONCLUSION

Simple freezing of SVF-gel at - 20 °C conferred them with sufficient cell viability. Notably, short-term cryopreservation did not significantly increase the apoptosis rate, and it still had a certain regeneration after transplantation. However, prolonging freezing time to 45 days resulted in increased apoptosis rate and worsened transplantation effect.

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