Reproducible Large-Scale Isolation of Exosomes from Adipose Tissue-Derived Mesenchymal Stem/Stromal Cells and Their Application in Acute Kidney Injury.

Acute kidney injury (AKI) is a fatal medical episode caused by sudden kidney damage or failure, leading to the death of patients within a few hours or days. Previous studies demonstrated that exosomes derived from various mesenchymal stem/stromal cells (MSC-exosomes) have positive effects on renal injuries in multiple experimental animal models of kidney diseases including AKI. However, the mass production of exosomes is a challenge not only in preclinical studies with large animals but also for successful clinical applications. In this respect, tangential flow filtration (TFF) is suitable for good manufacturing practice (GMP)-compliant large-scale production of high-quality exosomes. Until now, no studies have been reported on the use of TFF, but rather ultracentrifugation has been almost exclusively used, to isolate exosomes for AKI therapeutic application in preclinical studies. Here, we demonstrated the reproducible large-scale production of exosomes derived from adipose tissue-derived MSC (ASC-exosomes) using TFF and the lifesaving effect of the ASC-exosomes in a lethal model of cisplatin-induced rat AKI. Our results suggest the possibility of large-scale stable production of ASC-exosomes without loss of function and their successful application in life-threatening diseases.

Intraoperative Strategies for Minimal Manipulation of Autologous Adipose Tissue for Cell- and Tissue-Based Therapies: Concise Review.

The stromal vascular fraction (SVF) is a heterogeneous population of stem/stromal cells isolated from perivascular and extracellular matrix (ECM) of adipose tissue complex (ATC). Administration of SVF holds a strong therapeutic potential for regenerative and wound healing medicine applications aimed at functional restoration of tissues damaged by injuries or chronic diseases. SVF is commonly divided into cellular stromal vascular fraction (cSVF) and tissue stromal vascular fraction (tSVF). Cellular SVF is obtained from ATC by collagenase digestion, incubation/isolation, and pelletized by centrifugation. Enzymatic disaggregation may alter the relevant biological characteristics of adipose tissue, while providing release of complex, multiattachment of cell-to-cell and cell-to-matrix, effectively eliminating the bioactive ECM and periadventitial attachments. In many countries, the isolation of cellular elements is considered as a "more than minimal" manipulation, and is most often limited to controlled clinical trials and subject to regulatory review. Several alternative, nonenzymatic methods of adipose tissue processing have been developed to obtain via minimal mechanical manipulation an autologous tSVF product intended for delivery, reducing the procedure duration, lowering production costs, decreasing regulatory burden, and shortening the translation into the clinical setting. Ideally, these procedures might allow for the integration of harvesting and processing of adipose tissue for ease of injection, in a single procedure utilizing a nonexpanded cellular product at the point of care, while permitting intraoperative autologous cellular and tissue-based therapies. Here, we review and discuss the options, advantages, and limitations of the major strategies alternative to enzymatic processing currently developed for minimal manipulation of adipose tissue. Stem Cells Translational Medicine 2019;8:1265&1271.

Microvascular breast reconstruction in the diabetic patient.

BACKGROUND: The free transverse rectus abdominis musculocutaneous (TRAM) flap is frequently advocated for autogenous breast reconstruction following mastectomy. The success rate and complications associated with free TRAM flap breast reconstruction are well documented. Risk factors such as cigarette smoking and obesity have been studied. Because of abnormalities in endothelial and red cell function, platelet function, altered blood viscosity, and abnormal intimal repair, diabetes mellitus is generally considered to be a risk factor for free TRAM flap breast reconstruction. The success rate of microvascular TRAM flap breast reconstruction in patients with diabetes mellitus has not been clearly defined. METHODS: A retrospective review of 893 free TRAM flaps used for breast reconstruction in 763 patients at a single institution was performed. All flaps were performed at M. D. Anderson Cancer Center after January 1, 1985, and before December 31, 1997. Patients were classified as insulin-dependent (type 1) diabetic, non-insulin-dependent (type 2) diabetic, and nondiabetic. Flap and donor-site complications were compared among the three groups. Multivariate statistical analysis was used to examine demographic characteristics, body mass index, comorbid conditions, preoperative radiation therapy, immediate versus delayed reconstruction, and smoking history in patients with type 1 diabetes mellitus, type 2 diabetes mellitus, and nondiabetic patients. RESULTS: The incidence of flap complications did not differ significantly between type 1 diabetics, type 2 diabetics, and nondiabetic patients. The incidence of donor-site complications did not differ significantly between type 1 diabetics, type 2 diabetics, and nondiabetic patients. CONCLUSION: The present data indicate that type 1 diabetes mellitus and type 2 diabetes mellitus are not relative or absolute contraindications to microvascular TRAM flap breast reconstruction.