Stem Cells: An Overview
Stem cells are primitive undifferentiated cells that have the ability to self-replicate and/or adopt a specific cell type in the body (e.g. skin cells, connective tissue, cartilage, etc.). Stem cells are defined by their potency and depending on the source of stem cells, the potency may vary. For instance, stem cells harvested from the umbilical cord blood would be considered pluripotent and therefore be of a higher order than multipotent stem cells from other sources. A topic that has led to controversy in the media is the distinction (or lack thereof) between embryonic stem cells and adult stem cells. Research into embryonic stem cells would in the past have been associated with the need to sacrifice an embryo ‒ a natural source of moral conflict in many countries. But adult stem cells ‒ the type used in regenerative medicine ‒ are taken from sources such as the umbilical cord blood, bone marrow, or from adipose tissue. Adult stem cells can either be donated (allogeneic) or be derived from the individual him- or her-self (autologous). Haematopoietic stem cells have been used in medicine for decades for the reconstruction of the blood cells that make up the immune system. However, when referring to regenerative medicine, it is the mesenchymal stem cell type that is implied. Mesenchymal stem cells (or MSCs) have four properties that are believed to contribute to their therapeutic potential:
- MSCs can give rise to a number of different cell lineages (differentiation)
- MSCs can proliferate (self-replication)
- MSCs are immunomodulatory
- MSCs can act via the paracrine signalling mechanism (a 2nd aspect involved in regeneration)
A misconception that seems to permeate the general public is that stem cell therapy is still only at the research stage. Adult stem cell therapy is already available today in the clinic ‒ with some regions of the world ahead of others: particularly, Asia has taken the lead when it comes to offering the most advanced treatment protocols. At the moment, the medical industry is seeing a wave of clinical trials being undertaken in order to demonstrate efficacy for the use of stem cells in relation to a number of diseases. As these clinical trials progress through phases I to III, more and more clarity will emerge in terms of the efficacy of stem cells as well as knowledge gathered in relation to evidence-based treatment protocols (e.g. the number of stem cells needed to reach a therapeutic threshold, administration methods, window-of-opportunity, and so forth).
Stem Cell Therapy: The Patient Perspective
A stem cell treatment usually lasts one to three weeks. Treatments of shorter duration are also possible but are typically associated with cosmetic procedures or rejuvenation therapy. Regardless, the actual process behind a stem cell treatment begins with the patient contacting a (series of) clinic(s) to inquire about the medical conditions they treat, the procedure, the expected outcome, as well as the pricing, and length of stay. This can all be done via e-mail but it is not uncommon to also schedule a video session. While the consultation is free-of-charge, stem cell clinics/hospitals will typically require the patient to pay a deposit once he/she has made a decision to go for treatment at that specific clinic. The deposit serves as a reservation of the hospital facilities for the entire treatment duration. For overseas treatments, the fee usually also covers things such as airport pick-up, assistance during the stay, and accommodation/meals. However, the exact items included can vary ‒ so do check that carefully.
Once the patient has arrived at the location, it is time to either check in at a hotel (out-patient) or at the hospital itself (in-patient). As with any other medical procedure, the patient will have a consultation with a doctor (possibly several) where the patient's medical history and medical records are evaluated thoroughly (although these will usually have been submitted in advance). Blood work will then be carried out and the first day of actual treatment will be scheduled. Stem cells are typically transplanted either intravenously or via lumbar puncture. Sometimes transplantation is done locally (e.g. injections into the joint). For intravenous procedures, be aware that it is a two-hour process through a medical drip bag (and not a vaccination type of injection done in less than a minute). Steroids are also administered to avoid rejection of the transplanted cells. The process of receiving stem cells is then repeated some 3-5 times in the following days/weeks. The quantity of stem cells varies but usually ranges from around 100 to 500 million. For donated stem cells, sources are often the cord tissue or the cord blood. For autologous stem cell procedures, the cells are usually harvested from the belly fat through a liposuction procedure.
Going through a stem cell treatment is often fairly uncomplicated and can be quite inspiring. Results from the stem cell procedure may vary depending on the medical condition and how far a disease has progressed by the time of treatment. Changes in a person's medical condition may begin to show after 2-4 weeks and further improvements can be expected to continue to occur for up to 8-12 weeks after the end of the treatment cycle. For certain medical conditions, the physicians may recommend repeat treatments at regular intervals (e.g. MS-patients).
Making The Headlines
The field of regenerative medicine is contributing to the media headlines almost on a daily basis. A lot has changed since I underwent my own treatments back in 2013. At the moment, a number of clinical trials employing stem cells are attempting to establish safety and efficacy for a whole range of medical conditions. Below are a few of the many stories that were featured in the news.
Both acute- and chronic-stage stroke disability are two of the medical conditions for which stem cells are being explored as a potential treatment. In 2017, the Pharmacological Journal provided an in-depth article on the various ongoing studies, their current status, and results. Specifically, the article reviews the results from two clinical trials that used an intracerebral administration of stem cells (for chronic stroke disability) and one that used a simple IV-transplantation (for acute-stage stroke). Stem cells are believed to exert their beneficial effects in different ways depending on the chronicity of the stroke injury. In the study sponsored by Athersys, IV-injected stem cells are believed to dampen the inflammation produced by the immune system in the slipstream of an ischemic stroke and which further contributes to the existing injury of the brain. Entities such as ReNeuron and Stanford University are exploring treatments for chronic stroke disability. In such cases, stem cells need to be administered near the original site of injury. The ongoing clinical research is showing initial encouraging results. [Media Link]
Articles concerning patients who underwent stem cell therapy for the treatment of MS are not uncommon in the media. BBC journalist Caroline Wyatt likely one of the more noteworthy accounts and her story was featured via her employer's media channel. A few other reports that made the headlines were the those of Mr. Eric Thomson and Ms. Malia Litman. But also clinical trial updates such as this one have made the headlines. In terms of basic research, new insights into the mechanisms that lead the immune system to attack the myelin sheath of nerve cells were presented in a publication in early 2018. The same research article proposes that it is the immunomodulatory properties of stem cells which can help dampen the immune system in MS patients – a step that could help reverse the damage. [Media Link]
Spinal Cord Injury
Two pharmaceuticals are currently in the process of advancing their respective clinical trials through phases I to III. Asterias Biotherapeutics is investigating stem cell therapy for acute-stage injury via the SCiStar study. Neuralstem is in the early stages of carrying out phase-I safety studies for the treatment of chronic SCI injuries. Also, patient testimonials who underwent treatment at their own expense have made the headlines. One of these featured Andy Bell who was left in a wheelchair after crashing his motorbike. Approximately 17,000 people suffer a spinal cord injury in the United States every year [Media Link]
A publication on a first-of-its-kind study that used stem cells for the treatment of eczema made the headlines in 2016. Participants in the study were divided into two treatment arms. Those participants who received the larger dose of stem cells saw a significant improvement in the reduction of their eczema severity – an improvement that lasted throughout the follow-up evaluation period. The trial used donated umbilical cord stem cells which were administered subcutaneously in a single treatment round. Further large-scale studies are planned. [Media Link]
Since several years, a clinical trial investigating stem cells for the treatment of hearing loss has been underway at the Florida Hospital For Children. This is a first-of-its-kind study to examine if intravenously administered stem cells have the capability to induce restoration of sensorineural hearing loss in young children. Despite the small size of the trial – which counts just 10 participants – it has taken roughly five years to complete enrollment and follow-up evaluations. Given the low risk of injury involved in IV-administration of stem cells (as compared to procedures that involve the cochlea directly), should encouraging results emerge from the trial, the findings would help pave the way for bringing a viable treatment forward that addresses an unmet need within the field of otology. According to a source affiliated with the investigation, publication of results were expected towards the end of 2017, but have so far not been published. [Media Link]
Encouraging findings from a phase-I/IIa dose-escalation trial for the treatment of ALS were reported in early 2016. The investigation – which was sponsored by BrainStorm Cell Therapeutics – used the patients' own bone-marrow-derived stem cells. Prior to transplantation, the stem cells were modified using a patented procedure called NurOwn. The enhanced mesenchymal stem cells (called MSC-NTF) secrete neurotrophic factors which have the potential to restore function in damaged nerve cells. The participants of the trial were divided into different treatment cohorts which accounted for some of the differences in response to treatment. Further studies are planned. [Media Link]
Last revision date: 7th of March, 2018