17 Apr Adipose Stem Cell Therapy
Stem cells have made a lot of headlines in past several years, most of them touting them as the next big thing in medicine, but few staying grounded in scientific facts. This hyperbolic buzz can be dangerous, and may become hard to separate the wheat from chaff. Let’s try to make sense of it all.
There are four basic kinds of stem cells: (a) embryonic; (b) fetal; (c) adult and (d) induced pluripotent. Human embryonic stem cells (ES cells) are derived from the inner layer of the blastocyst and are pluripotent. Human fetal mesenchymal stem cells (hfMSCs) are harvested from the amniotic fluid or the umbilical cord, and are multipotent. There are ethical issues with harvesting them resulting in extremely limited availability. The induced pluripotent stem cells (iPSCs) do not any related ethical issues with harvesting, but it is expensive and logistically laborious to carry out their induction and production. It is for these reasons that adult stem cells are best suited for clinical practice and research.
Adipose tissue-derived stem cells (ADSCs) are mesenchymal cells, which can self-renew and be differentiated into several lineages, including adipocytes, chondrocytes, myocytes, osteoblasts and neurocytes. They have been used in trials related to diabetes mellitus, liver disease, corneal lesions, articular and cutaneous lesions, etc. Their biggest advantage is their greater ease of access (through lipoaspiration) and harvesting. They have widely studied for efficacy in various regenerative medicine approaches and for safety. They also release a wide variety of chemicals, such as adipocytokines, cytokines, transcriptional and growth factors, that play a key role in tissue repair and regeneration.
The process starts with liposuction, a procedure by which a small portion of the fat is taken out of a certain part of the body (lipoaspiration). The next step is to extract the stromal vascular fraction (SVF) from the lipoaspirate. ADSCs are then separated from SVF by washing, enzymatic digestion and centrifugation of the samples. The mesenchymal cell lines are grown in cultures that could retain a stable phenotype could be induced to differentiate into a specific cell lineage/tissue as needed, such as ADSCs. The key to a high yield lies in the making sure that there is abundant presence of cells, harvesting is done through minimally invasive procedures, there is regulation of the differentiation of cell lineages, and that they can be used as an autograft.
ADSCs have potential uses in osteoporosis, Duchenne muscular dystrophy, autoimmune thyroiditis, rheumatoid arthritis, diabetes mellitus, myocardial infarction, etc. Furthermore, they have antitumor actions on models of melanomas, pancreatic cancer and prostate cancer, etc.
Anti-tumor ADSCs can be encapsulated or genetically modified to protect them from immune reaction and so that they can that they can serve as vectors for antineoplastic drugs. In experimental murine models, positive results have been shown in gliomas, Kaposi’s sarcoma, melanoma and lung cancer. But their role in human diseases is still incompletely understood. Research is underway to evaluate if similar success can be replicated in humans, and safely so. Furthermore, long-term outcomes studies are necessary to satisfy any concerns about their own tumorigenicity. While there is tremendous promise, one has to be patient and cautiously optimistic about stem cell therapy becoming commonplace. We still have same ways to go before we usher into the era of regenerative medicine.