Explore the Healing Potential of Adipose-Derived Stem Cells

Adipose-derived stem cells (ASCs) are unspecialized cells that can be found in various organs including the adipose tissue
(1). They are derived from mesodermal progenitor cells that can self-renew and differentiate into more specific cell types
(1). In addition, ASCs can be modified to express certain growth factors that promote healing and tissue regeneration
(2). There are two types of ASCs: autologous and allogeneic. Autologous ASCs are ASCs obtained from the individual to be treated
(3). Autologous ASCs are often used in the treatment of degenerative diseases of the musculoskeletal system
(4). Due to the ease of harvesting, autologous ASCs can be applied to individuals of any age. Allogeneic ASCs are ASCs obtained from the tissues of a different individual
(5). Allogeneic ASCs are often utilized in bone healing and joint regeneration due to their high proliferation rate and ability to differentiate into bone and cartilage cells
(5). Allogeneic ASCs are usually harvested from the adipose tissue of an individual who will not receive the injected stem cells
(6).The use of ASCs in regenerative medicine has become more prevalent in recent years due to their ease of access and ability to differentiate into other cell types
(7). As a result, ASCs have been investigated and utilized in a variety of different fields including sports medicine, dentistry, and orthopedics
(8). In this article, we will explore how ASCs are used in regenerative medicine specifically concerning orthopedic applications.

TECHNIQUE
A popular technique for separating ASC from white adipose tissue was created by Zuk et al

(9). Collagenase type II is used to enzymatically break down minced adipose tissues
(10). The pellet that results from centrifugation is known as the stroma vascular fraction (SVF). One milliliter of lipoaspirate can yield between 2 and 6 million cells in SVF. About 3.5 to 1.6*106 ASCs can be produced from 1 gram of aspirated fat tissue, compared to just 1*105 ASCs from 1 gram of bone marrow
(11).Figure retrieved from: https://www.sciencedirect.com/science/article/pii/S2452199X2100027X

ASCs are isolated from the SVF after plating because they adhere to tissue culture-treated flask surfaces very quickly
(12). The normal doubling time of grown ASCs ranges from 2 to 5 days, depending on the number of passes and the culture medium, and they can be easily cultivated in culture and multiplied in vitro
(13). ASC proliferation or differentiation is unaffected by cryopreservation. Cells can be increased in culture for tissue-engineered cell therapies, recombined with a tissue scaffold (such as cell-enriched fat grafts), or immediately re-injected as a mesotherapeutic agent
(14).

RESULTS

Stem cells have been used in regenerative medicine to treat a variety of orthopedic conditions including arthritis, bone injuries, and osteoarthritis
(15). Regenerative medicine with stem cells is a promising field with applications in sports medicine, orthopedics, and dentistry. The use of adipose-derived stem cells in regenerative medicine is expected to increase as the ease of harvesting and ability to differentiate into other cell types is further explored
(16).

ARTHRITIS

Arthritis is a degenerative disease of the joints characterized by inflammation, pain, and limited mobility
(17). ASCs have been investigated as a possible treatment for arthritis due to their anti-inflammatory and immunomodulatory properties.

BONE INJURIES

Bone injuries such as bone fractures and post-traumatic bone defects can be treated with ASCs
(18). ASCs have been shown to promote bone repair through a variety of different mechanisms including direct differentiation into bone cells and secretion of growth factors
(19).

OSTEOARTHRITIS

Osteoarthritis is a degenerative joint disease characterized by the breakdown of cartilage in the joints
(20). ASCs can be applied to treat osteoarthritis due to their ability to differentiate into chondrocytes and release cartilage growth factors.

LIMB LENGTHENING USING ASCS

Limb lengthening is a surgical procedure in which a section of bone is surgically broken and then allowed to heal in a shortened position followed by a regimen of daily bone growth-stimulating injections
(21). ASCs have been investigated as a regenerative agent in limb lengthening due to their high proliferation rate and differentiation capability into bone cells
(21). In limb lengthening, ASCs are injected into the shortened bone to induce new bone growth that will ultimately facilitate the lengthening of the limb
(22). The injected ASCs will differentiate into bone cells that will contribute to the lengthening of the bone by creating a new bone matrix.

UTILIZATION OF ASCS FOR BONE REGENERATION

ASCs have been investigated as a possible treatment for patients with osteoporosis due to the ability of autologous ASCs to differentiate into bone cells
(23). Studies have shown that ASCs can be genetically modified to produce large amounts of the cytokine, bone morphogenetic protein-2 (BMP-2), which promotes bone growth
(23). These genetically modified ASCs are an attractive option for the treatment of osteoporosis as they are autologous and can be easily harvested from the patient.

RECOVERY

About 10-15% of people report recovery within a few weeks of the use of ASC, but the majority have some reduction in pain, edema, and inflammation within six weeks
(24). The development of reparative tissue can require 4-6 months. ASCs allow us to resume our normal activities afterward with far less recovery time than anticipated from common cartilage, joint, or spinal operations
(25).