mechanical-micronization-of-lipoaspirates-for-regenerative-therapy

Mechanical Micronization of Lipoaspirates for Regenerative Therapy

Stromal vascular fraction (SVF) has become a regenerative tool for various diseases; however, legislation strictly regulates the clinical application of ...

Southern Medical University

Fat grafting experiences a regeneration process from free lipoaspirate to intact adipose tissue. The adipose extracellular matrixes (ECM) provide the structure and biochemical support for surrounding cells; inflammatory cells, like macrophages, regulate the process. Our hypothesis states that transferred fat undergoes ECM remodeling after fat grafting and this process is regulated by macrophage infiltration.

Macrophage infiltration regulates the adipose ECM reconstruction and the fibrosis process after fat grafting.

Hematopoietic stem cells (HSCs) promote fat graft survival by modulating its revascularization. The authors hypothesize that mobilization of HSCs by G-CSF will improve fat graft survival. Hence, we evaluated the effect of different doses of G-CSF on fat grafting.

Low-dose G-CSF improves fat graft retention by mobilizing endogenous stem cells and inducing angiogenesis, whereas high-dose G-CSF inhibits adipogenesis with prolonged inflammation and severe fibrosis.

Fat grafting is a popular soft-tissue filler method; however, its results are variable and technique-dependent. Macrophages are present in fat grafts and closely associated with tissue regeneration. The authors hypothesized that activation/depletion of early macrophages in transferred fat improves/impairs fat graft survival.

Early Macrophage Infiltration Improves Fat Graft Survival by Inducing Angiogenesis and Hematopoietic Stem Cell Recruitment.

Flap necrosis due to insufficient blood supply is a common postoperative complication in random pattern flaps. Stem cell therapies have emerged as promising biologics for tissue ischemia. A novel fat derived product, stromal vascular fraction gel (SVF-gel), can be prepared with lipoaspirate through simple mechanical processing, removing only the lipid content. SVF-gel enriches adipose-derived stem cells and potentially beneficial for flap necrosis.

Ischemic flap survival improvement by composition-selective fat grafting with novel adipose tissue derived product - stromal vascular fraction gel.

Fat grafting has become an important tool for breast reconstruction in breast cancer patients. Tamoxifen, the hormone therapy agent most frequently used for breast cancer, can affect adipose metabolism and cause browning of adipose tissue. This study hypothesized that tamoxifen could increase fat graft survival by altering adipose metabolism.

Tamoxifen-Prefabricated Beige Adipose Tissue Improves Fat Graft Survival in Mice.

External volume expansion devices are effective for adipose tissue regeneration. However, the detailed mechanisms by which external volume expansion devices induce adipose tissue regeneration remain unclear.

External Volume Expansion Up-Regulates CXCL12 Expression and Enhances Mesenchymal Stromal Cell Recruitment toward Expanded Prefabricated Adipose Tissue in Rats.

The apoptosis of mature adipocytes after fat grafting can result in chronic inflammation, absorption, and fibrosis, leading to unpredictable outcomes. Selective elimination of mature adipocytes may result in better outcomes and a different underlying retention mode. The authors previously developed a mature adipocyte-free product, stromal vascular fraction gel, derived from lipoaspirate, which eliminates adipocytes and preserves the stromal vascular fraction. This study investigated the retention and regeneration mode of stromal vascular fraction gel grafting.

Improved Long-Term Volume Retention of Stromal Vascular Fraction Gel Grafting with Enhanced Angiogenesis and Adipogenesis.

Fat grafting is a commonly used procedure; however, the mechanisms that regulate graft outcomes are not clear. Estrogen has been associated with vascularization, inflammation and fat metabolism, yet its role in fat grafting is unclear.

Decreased serum estrogen improves fat graft retention by enhancing early macrophage infiltration and inducing adipocyte hypertrophy.

The clinical outcomes of fat grafting vary and are technique-dependent. Stromal vascular fraction (SVF) gel is a novel, mechanically processed fat product with high concentrations of adipose tissue-derived stem cells and other SVF cells. This study evaluated the volumization and rejuvenation effects of SVF-gel.

Adipose Stromal Vascular Fraction Gel Grafting: A New Method for Tissue Volumization and Rejuvenation.

Soft tissue generation, especially in large tissue, is a major challenge in reconstructive surgery to treat congenital deformities, posttraumatic repair, and cancer rehabilitation. The concern is along with the donor site morbidity, donor tissue shortage, and flap necrosis. Here, we report a dissection-free adipose tissue chamber-based novel guided adipose tissue regeneration strategy in a bioreactor of elastic gelatin cryogel and polydopamine-assisted platelet immobilization intended to improve angiogenesis and generate large adipose tissue in situ. In order to have matched tissue mechanics, we used 5% gelatin cryogel as growth substrate of bioreactor. Platelets from the platelet-rich plasma were then immobilized onto the gelatin cryogel with the aid of polydopamine to form a biomimetic bioreactor (polydopamine/gelatin cryogel/platelet). Platelets on the substrate led to a sustained high release in both platelet-derived growth factor and vascular endothelial growth factor compared with non-polydopamine-assisted group. The formed bioreactor was then transferred to a tissue engineering chamber and then inserted above inguinal fat pad of rats without flap dissection. This integrate strategy significantly boomed the vessel density, stimulated cellular proliferation, and upregulated macrophage infiltration. There was a noticeable rise in the expression of dual-angiogenic growth factors (platelet-derived growth factor and vascular endothelial growth factor) in chamber fluid; host cell migration and host fibrous protein secretion coordinated with gelatin cryogel degradation. The regenerated adipose tissue volume gained threefold larger than control group (p < 0.05) with less fibrosis tissue. These results indicate that a big well-vascularized three-dimensional mature adipose tissue can be regenerated using elastic gel, polydopamine, platelets, and small fat tissue.

Large adipose tissue generation in a mussel-inspired bioreactor of elastic-mimetic cryogel and platelets.

Fat grafting is a popular soft-tissue filler method; however, the mechanism of its survival and regeneration is still not fully understood. Neutrophils are the frontier inflammatory cells and closely associated with tissue regeneration. To understand the role of neutrophils in fat graft retention, we adopted neutrophil depletion and up-regulation models.

The Disturbed Function of Neutrophils at the Early Stage of Fat Grafting Impairs Long-Term Fat Graft Retention.

Hypertrophic scars cause cosmetic and functional problems for patients, and their treatment remains challenging. Mechanical micronization of adipose tissue can remove adipocytes and concentrate functional cells. Stromal vascular fraction (SVF)-gel is obtained by a series of simple mechanical processes, including shifting between syringes and centrifugation. This study aimed to assess the therapeutic effect of SVF-gel on hypertrophic scars.

Junrong Cai

Department of Plastic and Cosmetic Surgery,
Nanfang Hospital,
Department of Plastic and Cosmetic Surgery, Nanfang Hospital

Southern Medical University

Mechanical Micronization of Lipoaspirates for Regenerative Therapy

Junrong Cai

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Plastic and Cosmetic Surgery,Nanfang Hospital,Department of Plastic and Cosmetic Surgery, Nanfang Hospital

Southern Medical University

Mechanical Micronization of Lipoaspirates for Regenerative Therapy

Department of Plastic and Cosmetic Surgery,
Nanfang Hospital,
Department of Plastic and Cosmetic Surgery, Nanfang Hospital