Inter-center comparison of good manufacturing practices-compliant stromal vascular fraction and proposal for release acceptance criteria: a review of 364 productions

Good Manufacturing Practice-Compliant Cryopreserved and Thawed Native Adipose Tissue Ready for Fat Grafting

Background: As adipose tissue-derived mesenchymal stem cells are becoming the tool of choice for many clinical applications; standardized cryopreservation protocols are necessary to deliver high-quality samples. For this purpose, the cryopreservation and thawing of native adipose tissue under GMP conditions could represent an extremely useful and powerful tool for the direct reinfusion of the tissue, and consequently, of its stromal vascular fraction. Methods: In this study, 19 samples of adipose tissue were cryopreserved and characterized before and after storage in liquid nitrogen vapors. Of these 19 samples, 14 were processed in research and 5 in a GMP-compliant environment. Storage with and without cryopreservation medium was also evaluated. After one week to three months of storage, samples were thawed, washed, enzymatically digested, and characterized with flow cytometry. Results: The results show that there is a loss of nearly 50% of total nucleated cells during the cryopreservation/thawing process. Non-GMP and GMP samples are comparable for all parameters analyzed. This study also allowed us to exclude the cryopreservation of adipose tissue without any cryopreservation medium. Conclusions: The data shown in this work are consistent with the idea that native adipose tissue, if properly processed and controlled, could be a useful source of cells for regenerative medicine, keeping in mind that there is a clear difference in the quality between fresh and thawed samples.

Therapeutic application of adipose-derived stromal vascular fraction in myocardial infarction

The insufficiency of natural regeneration processes in higher organisms, including humans, underlies myocardial infarction (MI), which is one of the main causes of disability and mortality in the population of developed countries. The solution to this problem lies in the field of revealing the mechanisms of regeneration and creating on this basis new technologies for stimulating endogenous regenerative processes or replacing lost parts of tissues and organs with transplanted cells. Of great interest is the use of the so-called stromal vascular fraction (SVF), derived from autologous adipose tissue. It is known that the main functions of SVF are angiogenetic, antiapoptotic, antifibrotic, immune regulation, anti-inflammatory, and trophic. This study presents data on the possibility of using SVF, targeted regulation of its properties and reparative potential, as well as the results of research studies on its use for the restoration of damaged ischemic tissue after MI.

Clinical, Histologic, and Transcriptomic Evaluation of Sequential Fat Grafting for Morphea: A Nonrandomized Controlled Trial

Importance

Morphea is a rare disease of unknown etiology without satisfactory treatment for skin sclerosis and soft tissue atrophy.

Objective

To provide clinical, histologic, and transcriptome evidence of the antisclerotic and regenerative effects of sequential fat grafting with fresh fat and cryopreserved stromal vascular fraction gel (SVF gel) for morphea.

Design, Setting, and Participants

This single-center, nonrandomized controlled trial was conducted between January 2022 and March 2023 in the Department of Plastic and Reconstructive Surgery of Nanfang Hospital, Southern Medical University and included adult participants with early-onset or late-onset morphea who presented with varying degrees of skin sclerosis and soft tissue defect.

Interventions

Group 1 received sequential grafting of fresh fat and cryopreserved SVF gel (at 1 and 2 months postoperation). Group 2 received single autologous fat grafting. All patients were included in a 12-month follow-up.

Main Outcome and Measures

The primary outcome included changes in the modified Localized Scleroderma Skin Severity Index (mLoSSI) and Localized Scleroderma Skin Damage Index (LoSDI) scores as evaluated by 2 independent blinded dermatologists. The histologic and transcriptome changes of morphea skin lesions were also evaluated.

Results

Of 44 patients (median [IQR] age, 26 [23-33] years; 36 women [81.8%]) enrolled, 24 (54.5%) were assigned to group 1 and 20 (45.5%) to group 2. No serious adverse events were noted. The mean (SD) mLoSSI scores at 12 months showed a 1.6 (1.50) decrease in group 1 and 0.9 (1.46) in group 2 (P = .13), whereas the mean (SD) LoSDI scores at 12 months showed a 4.3 (1.34) decrease in group 1 and 2.1 (1.07) in group 2 (P < .001), indicating that group 1 had more significant improvement in morphea skin damage but not disease activity compared with group 2. Histologic analysis showed improved skin regeneration and reduced skin sclerosis in group 1, whereas skin biopsy specimens of group 2 patients did not show significant change. Transcriptome analysis of skin biopsy specimens from group 1 patients suggested that tumor necrosis factor α signaling via NFκB might contribute to the immunosuppressive and antifibrotic effect of sequential fat grafting. A total of 15 hub genes were captured, among which many associated with morphea pathogenesis were downregulated and validated by immunohistochemistry, such as EDN1, PAI-1, and CTGF.

Conclusions and Relevance

The results of this nonrandomized trial suggest that sequential fat grafting with fresh fat and cryopreserved SVF gel was safe and its therapeutic effect was superior to that of single autologous fat grafting with improved mLoSSI and LoSDI scores. Histological and transcriptomic changes further support the effectiveness after treatment.

Trial Registration

Chinese Clinical Trial Registry identifier: ChiCTR2200058003.

Systemically delivered adipose stromal vascular fraction mitigates radiation-induced gastrointestinal syndrome by immunomodulating the inflammatory response through a CD11b+ cell-dependent mechanism

BACKGROUND

Stromal vascular fraction (SVF) treatment promoted the regeneration of the intestinal epithelium, limiting lethality in a mouse model of radiation-induced gastrointestinal syndrome (GIS). The SVF has a heterogeneous cell composition; the effects between SVF and the host intestinal immunity are still unknown. The specific role of the different cells contained in the SVF needs to be clarified. Monocytes-macrophages have a crucial role in repair and monocyte recruitment and activation are orchestrated by the chemokine receptors CX3CR1 and CCR2.

METHODS

Mice exposed to abdominal radiation (18 Gy) received a single intravenous injection of SVF (2.5 × 106 cells), obtained by enzymatic digestion of inguinal fat tissue, on the day of irradiation. Intestinal immunity and regeneration were evaluated by flow cytometry, RT-PCR and histological analyses.

RESULTS

Using flow cytometry, we showed that SVF treatment modulated intestinal monocyte differentiation at 7 days post-irradiation by very early increasing the CD11b+Ly6C+CCR2+ population in the intestine ileal mucosa and accelerating the phenotype modification to acquire CX3CR1 in order to finally restore the F4/80+CX3CR1+ macrophage population. In CX3CR1-depleted mice, SVF treatment fails to mature the Ly6C-MCHII+CX3CR1+ population, leading to a macrophage population deficit associated with proinflammatory environment maintenance and defective intestinal repair; this impaired SVF efficiency on survival. Consistent with a CD11b+ being involved in SVF-induced intestinal repair, we showed that SVF-depleted CD11b+ treatment impaired F4/80+CX3CR1+macrophage pool restoration and caused loss of anti-inflammatory properties, abrogating stem cell compartment repair and survival.

CONCLUSIONS

These data showed that SVF treatment mitigates the GIS-involving immunomodulatory effect. Cooperation between the monocyte in SVF and the host monocyte defining the therapeutic properties of the SVF is necessary to guarantee the effective action of the SVF on the GIS.

Processing Adipose Tissue Samples in a GMP Environment Standardizes the Use of SVF in Cell Therapy Treatments: Data on 302 Patients

Stromal vascular fraction (SVF) cells, together with adipose-derived mesenchymal stem cells, are becoming the tool of choice for many clinical applications. Currently, nearly 200 clinical trials are running worldwide to prove the efficacy of this cell type in treating many diseases and pathological conditions. To reach the goals of cell therapies and produce ATMPs as drugs for regenerative medicine, it is necessary to properly standardize GMP processes and, thus, collection methods, transportation strategies, extraction protocols, and characterization procedures, without forgetting that all the tissues of the human body are characterized by a wide inter-individual variability which is genetically determined and acquired during life. Here, we compare 302 samples processed under GMP rules to exclude the influence of the operator and of the anatomical site of collection. The influence of variability in the ages and genders of patients, along with laboratory parameters such as total cell number, cell viability, stem cell number, and other stromal vascular fraction cell subpopulations, has been compared. The results show that when the laboratory protocol is standardized, the variability of quantifiable cell parameters is widely statistically non-significant, meaning that we can take a further step toward standardized advanced cell therapy products.

Effects of Autologous Microfragmented Adipose Tissue on Healing of Tibial Plateau Levelling Osteotomies in Dogs: A Prospective Clinical Trial

The aim of this study was to evaluate the effects of autologous microfragmented adipose tissue (MFAT) applied after mechanical fragmentation and assess these effects radiographically in bone healing in dogs subjected to tibial plateau levelling osteotomy (TPLO). Twenty dogs with unilateral cranial cruciate ligament disease were enrolled and randomly assigned to the treatment group (MFAT) or the control group (NT). The MFAT group underwent TPLO and autologous MFAT intra-articular administration, while the NT group underwent TPLO alone. Adipose tissue was collected from the thigh region, and MFAT was obtained by mechanical fragmentation at the end of the surgery. The patients were subjected to X-ray examination preoperatively, immediately postoperatively (T0), and at 4 (T1) and 8 (T2) weeks postoperatively. Two radiographic scores that had previously been described for the evaluation of bone healing after TPLO were used. A 12-point scoring system (from 0 = no healing to 12 = complete remodelling) was used at T0, T1, and T2, while a 5-point scoring system (from 0 = no healing to 4 = 76-100% of healing) was used at T1 and T2. The median healing scores were significantly higher at T1 and T2 for the MFAT group compared with the NT group for the 12-point (p < 0.05) and 5-point (p < 0.05) scoring systems. The intra-articular injection of autologous microfragmented adipose tissue can accelerate bone healing after TPLO without complications.

A Closed-system Technology for Mechanical Isolation of High Quantities of Stromal Vascular Fraction from Fat for Immediate Clinical Use

Adipose tissue stromal vascular fraction (SVF) is increasingly used in the clinic. SVF separation from fat by enzymatic disruption is currently the gold standard for SVF isolation. However, enzymatic SVF isolation is time-consuming (~1.5 h), costly and significantly increases the regulatory burden of SVF isolation. Mechanical fat disruption is rapid, cheaper, and less regulatory challenging. However, its reported efficacy is insufficient for clinical use. The current study evaluated the efficacy of a novel rotating blades (RBs) mechanical SVF isolation system.

Methods

SVF cells were isolated from the same lipoaspirate sample (n = 30) by enzymatic isolation, massive shaking (wash), or engine-induced RBs mechanical isolation. SVF cells were counted, characterized by flow cytometry and by their ability to form adipose-derived stromal cells (ASCs).

Results

The RBs mechanical approach yielded 2 × 10⁵ SVF nucleated cells/mL fat, inferior to enzymatic isolation (4.17 × 10⁵) but superior to cells isolating from fat by the "wash" technique (0.67 × 10⁵). Importantly, RBs SVF isolation yield was similar to reported yields achieved via clinical-grade enzymatic SVF isolation. RBs-isolated SVF cells were found to contain 22.7% CD45^-CD31^-CD34⁺ stem cell progenitor cells (n = 5) yielding quantities of multipotent ASCs similar to enzymatic controls.

Conclusions

The RBs isolation technology provided for rapid (<15 min) isolation of high-quality SVF cells in quantities similar to those obtained by enzymatic digestion. Based on the RBs platform, a closed-system medical device for SVF extraction in a rapid, simple, safe, sterile, reproducible, and cost-effective manner was designed.

Micro-fragmented adipose tissue cellular composition varies by processing device and analytical method

Autologous adipose-derived biologics are of clinical interest based on accessibility of adipose tissue, a rich source of progenitor and immunomodulatory cells. Micro-fragmented adipose tissue (MFAT) preserves the cellular niche within intact extracellular matrix, potentially offering benefit over enzymatically-liberated stromal vascular fraction (SVF), however lack of standardized analyses complicate direct comparison of these products. In this study, MFAT from LipoGems® and AutoPose™ Restore systems, which utilize different washing and resizing methods, was analyzed for cellular content using different techniques. Flow cytometry was performed on SVF, with or without culture, and on the adherent cell population that naturally migrated from undigested MFAT. Cytokine release during culture was also assessed. SVF contained more diverse progenitor populations, while MFAT outgrowth contained lower cell concentrations of predominantly mesenchymal stromal cells (MSC). MSCs were significantly higher in MFAT from the AutoPose System for all analyses, with increased cytokine secretion characterized by high levels of anti-inflammatory and low to non-detectable inflammatory cytokines. These results demonstrate that cellularity depends on MFAT processing methods, and different techniques can be employed to evaluate graft cellularity. Comparisons of cell concentrations determined via these methods could be used to better interpret inter-study variability.