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Letter: Safety and Feasibility of Autologous Mesenchymal Stem Cell Transplantation in Chronic Stroke in Indian patients. A four-year follow up

Letter to the Editor
Davis O1

Author Names in full: Oliver Davis1

1Brighton and Sussex Medical school, University of Sussex, Falmer

Citation: Davis O. Letter: Safety and Feasibility of Autologous Mesenchymal Stem Cell Transplantation in Chronic Stroke in Indian patients. A four-year follow up. J Stem Cells Regen Med 2018 Feb. [Epub ahead of print]


Keywords: Autologous mesenchymal stem cells; Stroke cell therapy; Stem cell regeneration; Older patients

I thank Bhasin et al., [1] for their fascinating study examining the long-term effects of therapeutic mesenchymal stem transplants in stroke patients. Their results importantly suggest that at four years of follow up no significant side effects, such as the formation of tumours, occur with this treatment. In addition, they found a statistically significant improvement in the independence of experimentally-treated patients over time (measured with the modified Barthel Index Score), as well as improvements in upper limb motor recovery (measured with Fugl Meyer scale).

Interestingly, no significant improvement was seen in terms of overall muscle power and tone (using Muscle Power and modified Ashworth scales). It seems unusual that patients would be more independent with stem cell therapy, but that this would not be due to an improvement in muscle power or stiffness. It is theoretically interesting to try and reconcile these different patterns of recovery. For example, could this suggest anything about the regenerative effects of mesenchymal stem cells?

On the other hand, a difference may not have been detected due to a low sample number, which was not enough to detect a statistically significant improvement. In line with this the authors highlight that a weakness of this study is the limited sample number (n=6 in each of experimental and control patient groups). This was due to ethical considerations. Therefore, the information in this study could be used as pilot data for a larger study. More specifically, it could be used in a sample number calculation to suggest an appropriate sample number to assess for any statistically significant differences in muscle power and tone, should any exist [2]. In turn, this, and the proof that no significant side effects are related to the treatment, would help to ethically justify a study with a larger, statistically appropriate number.

Within such a larger study, there would also be an opportunity to recruit older patients, as those used in this study were relatively young (mean age 42.8); this would be well placed to fit  the  demographics  of  stroke,  which,  for example, a third of occur in the people over 85 years old [3].

Such results would be of more general and direct interest to mainstream clinical practice.

One might protest at this point to argue regenerative abilities decrease as one ages. In the context of stroke, aged brains contain less proliferative neural progenitor cells, and initiate recovery at a later stage than a younger brain [4,5]. Nevertheless, the aged brain remains able to regenerate, which invites cell therapeutic approaches, including mesenchymal stem cells, induced pluripotent stem cells, and others[6]. Furthermore, animal experiments support the approach of trialling this therapy in older patients: studies in rats suggest mesenchymal stem cells are just as effective a treatment in older individuals as younger ones [7].

Finding therapies for younger patients who suffer from stroke is crucial to their long-term future well-being. In an age when life expectancy is continuously rising, this is also becoming true of older people, and so extending the exciting work of this study to a larger on, incorporating older patients, offers a truly exciting opportunity to improve clinical treatments and the lives of many people.

Potential Conflicts of Interests



  1. Bhasin A, Kumaran SS, Bhatia R, Mohanty S, Srivastava MVP. Safety and Feasibility of Autologous Mesenchymal Stem Cell Transplantation in Chronic Stroke in Indian patients. A four-year follow up. J Stem Cells Regen Med 2017; 13(1) :14-19
  2. Altman DG. Practical Statistics for Medical Research. Chapman & Hall/CRC Texts in Statistical Science.  Hardcover Nov 1990.
  3. Roger VL, Go AS, Lloyd-Jones DM, Benjamin EJ, Berry JD, Borden WB, Bravata DM, Dai S, Ford ES, Fox CS, Fullerton HJ, Gillespie C, Hailpern SM, Heit JA, Howard VJ, Kissela BM, Kittner SJ, Lackland DT, Lichtman JH, Lisabeth LD, Makuc DM, Marcus GM, Marelli A, Matchar DB, Moy CS, Mozaffarian D, Mussolino ME, Nichol G,  Paynter NP, Soliman EZ, Sorlie PD, Sotoodehnia N, Turan TN, Virani SS, Wong ND, Woo D, Turner MB; American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics--2012 update: a report from the American Heart Association. Circulation. 2012;125(1):e2-e220.
  4. Zhang L, Yi L, Chopp M, Kramer BC, Romanko M, Gosiewska A, Hong K. Intravenous administration of human umbilical tissue-derived cells improves neurological function in aged rats after embolic stroke. Cell Transplant. 2013;22(9):1569-76.
  5. Balseanu AT, Buga AM, Catalin B, Wagner DC, Boltze J, Zagrean AM, Reymann K, Schaebitz W, Popa-Wagner A. Multimodal Approaches for Regenerative Stroke Therapies: Combination of Granulocyte Colony-Stimulating Factor with Bone Marrow Mesenchymal Stem Cells is Not Superior to G-CSF Alone. Front Aging Neurosci. 2014 ;6:130.
  6. Sandu RE, Balseanu AT, Bogdan C, Slevin M, Petcu E, Popa-Wagner A. Stem cell therapies in preclinical models of stroke. Is the aged brain microenvironment refractory to cell therapy? Exp Gerontol. 2017;94:73-77.
  7. Brenneman M, Sharma S, Harting M, Strong R, Cox CS Jr, Aronowski J, Grotta JC, Savitz SI. Autologous bone marrow mononuclear cells enhance recovery after acute  ischemic stroke in young and middle-aged rats. J Cereb Blood Flow Metab. 2010;30(1):140-9

Corresponding Author

Oliver Davis, Brighton and Sussex Medical School, University of Sussex, Brighton, BN1 9PX, United Kingdom; Email: