Regenerative medicine has much promise to repair degenerated, damaged, and injured structures, tissues, and organs. Stem cell therapy can restore
functionality by stimulating the body’s unique regenerative abilities. The field of regenerative medicine comprises several techniques and specialties, such as tissue engineering, molecular biology, and organ restoration. In addition,
various cell types are investigated for their suitability for regenerative medicine. Adipose-derived stem cells (ADSCs) are those that are obtained from fat tissue.
The observed multipotency of adipose mesenchymal stem cells (MSCs) involves their ability to differentiate into other mesenchymal cells, such as osteoblasts (bone cells), myocytes (muscle cells), adipocytes (fat cells), chondrocytes (cartilage cells and other cells).
Due to the wide availability of fat-derived stem cells, they are often used in regenerative medicine. Adipose-derived stem cells are multipotent, undifferentiated, and self-renewing. They are morphologically and phenotypically similar to other MSCs. Because obtaining adipose cells is a minimally invasive procedure, and the proliferation capacity does not decline with age, they have been proven superior to bone marrow-derived stem cells by many researchers.
Isolation and Characterization
Subcutaneous adipose (fat) tissue consists of mature adipocytes and a heterogeneous stromal vascular fraction (SVF), which includes endothelial cells, vascular smooth muscle cells, fibroblasts, pre-adipocytes, lymphocytes, monocytes, and adipose stem cells. The most used method of isolated stem cells from fat tissue relies on an enzyme digestion, which is then followed by centrifugal density gradient separation (done in the laboratory). The stem cell-specific combination surface markers on the ADSCs include CD44, CD90, CD105, CD166, and CD73. They lack the hematopoietic markers CD34 and CD45.
According to the current literature, the site of harvesting the adipose tissue does not affect the number of viable cells that are obtained. The ADSCs also showed no significant correlation between quality, proliferation capacity, and the patient’s age.
Roles of Adipose-Derived Stem Cells in Regenerative Medicine
Many regenerative medicine therapies involve ADSCs. They can differentiate into many types of cell lineages. In addition, they secrete growth factors, cytokines, and chemokines, which make them clinically attractive. ADSCs have been found to have immunomodulatory, anti-scarring, and proangiogenic effects, making them promising candidates for stem cell therapy injections.
Mesodermal Potential of Adipose-Derived Stem Cells
There have been many clinical trials investigating the use and benefits of ADSCs. These studies involve soft tissue regeneration, ischemic injuries, skeletal tissue repair, myocardial infarction, and immune disorders (Crohn’s disease, lupus, arthritis, multiple sclerosis and others). Other therapeutic uses include treatment of intervertebral disc degeneration and pulmonary disease. Due to their origin, ADSCs have mesodermal potential, which includes bone regeneration, fat reconstruction, and tissue regeneration.
Studies have shown that ADSCs have regenerative bone effects in animal subjects and humans. Regarding avascular necrosis of the femoral head (thigh bone ball), animal studies show that ADSC enhance osteogenesis (bone formation) and microstructure of the osteonecrotic tissue two months after injections. Current animal research shows very promising results for post concussion syndrome.
Fat cells also have effective anti-scarring ability. In a study where adipose cells were used after injury, they were found to attenuate the formation of hypertrophic scars by secretion of anti-fibrosis cytokines, which was show in rabbit ear scar models. The researchers injected ADSCs into a lesion and evaluated the scarring months later. Regarding cartilage regeneration, ADSCs were found to repair cartilage defects in studies. The results suggested that ADSCs and chondrocytes may have the potential to repair and regenerate cartilage in tissue engineering procedures.
Recent research performed by CSN has shown utility of ADSCS for a number of neurological disorders. For instance, over the course of two years, multiple sclerosis patients experienced a 52% reduction in MISS-29 scores over 2 years after stem cell therapy. The success rate for this disease was 73%.
In addition to multiple sclerosis, success rates have risen for disorders such as stroke (55%), Parkinson’s Disease (64.8%), Muscular Dystrophy (64.3%), and Cerebral Palsy (77.4%) thanks to ADSCS therapy.
Ectodermal and Endodermal Potential of ADSCs
Adipose stem cells have specific markers of both the neuronal nestin and glial lineages when cultivated in the presence of certain medications. This neuronal differentiation potential could benefit treatment of various neurological conditions, such as stroke, multiple sclerosis, and Parkinson’s disease. ADSCs have the ability to transform into neuron cells, which mean they could help with regeneration of endogenous neurons.
Regarding endodermal ADSC potential, researchers have shown that these stem cells can regenerate into hepatic (liver) cells and pancreatic cells. ADSCs treated with certain growth factor and chemical solutions have shown the potential to change into a hepatocyte-like cell, that expresses alpha fetoprotein. Regarding pancreatic cells, Researchers found that ADSCs expressed pancreatic markers in human subjects, and produced pancreatic hormones.
Therapeutic Effects of ADSCs
Adipose-derived stem cells are ideal for use in regenerative therapies for many reasons. These include:
They can be harvested, processed, and expanded in a minimally invasive procedure.
The use of ADSCs in stem cell procedures is straightforward and effective.
They have a high potential to differentiate into mature cells along the endodermal, ectodermal, and mesodermal lineage.
Much progress has been made in the use of ADSCs for regenerative therapy.
Progress has been made regarding the use of ADSCs as tissue-specific progenitor cells and as a paracrine-mediated signal for angiogenesis.