Allogeneic and autologous mode of stem cell transplantation in regenerative medicine: Which way to go? Murali Krishna Mamidi a , Susmita Dutta b , Ramesh Bhonde a , Anjan Kumar Das c,⇑ , Rajarshi Pal a,⇑ a School of Regenerative Medicine, Manipal University, Bangalore, India b Department of Anesthesiology, Taylor’s University Clinical School, Sungai Buloh Hospital, Selangor, Malaysia c Department of Surgery, Taylor’s University Clinical School, Sungai Buloh Hospital, Selangor, Malaysia article info Article history: Received 1 August 2014 Accepted 14 October 2014 abstract Stem cell transplantation is a generic term covering different techniques. However there is argument over the pros and cons of autologous and allogeneic transplants of mesenchymal stem cells (MSCs) for regenerative therapy. Given that the MSCs have already been proven to be safe in patients, we hypoth- esize that allogeneic transplantation could be more effective and cost-effective as compared to autolo- gous transplantation specifically in older subjects who are the likely victims of degenerative diseases. This analysis is based on the scientific logic that allogeneic stem cells extracted in large numbers from young and healthy donors could be physiologically, metabolically and genetically more stable. Therefore stem cells from young donors may be expected to exhibit higher vigor in secreting trophic factors leading to activation of host tissue-specific stem cells and also be more efficient in remodeling the micro- environmental niche of damaged tissue. Ó 2014 Elsevier Ltd. All rights reserved. Introduction In recent years, there has been an increasing interest in possible clinical use of non-hematopoietic multipotent progenitor cells that are found in the bone marrow. Mesenchymal stem cells (MSCs) are the first non-hematopoietic progenitors to be isolated from the bone marrow and extensively characterized. The term MSC refers to adult mesenchymal progenitor cells with the capacity to pro- duce progeny that can differentiate into various connective tissue lineages. Traditionally, MSCs are thought to form progenitor cells for bone formation during bone remodeling or repair, cartilage for- mation, vascular maintenance, haematopoietic support and act as progenitors for adipocytes [1–4]. Apart from these MSCs have been shown to exhibit immune regulatory or modulatory properties [5]. Recent studies have demonstrated that MSCs can stimulate the existing stem cell niche of host tissue through paracrine effect mediated by the trophic factors [6]. Based on these unique proper- ties, researchers proposed that the MSCs can be offered as a suit- able tool for clinical applications in near future. Although MSCs are capable of rapidly proliferating ex vivo and differentiating into various mesenchymal lineages; scientists have shown age-related loss of proliferation, differentiation potential with subsequent increase in senescent cell numbers [7]. These types of studies have addressed the effects of aging on MSCs to some extent, but whether the number of human MSCs decline with age or not still remains obscure. In such a conflicting scenario, this review sum- marizes background information about allogeneic stem-cell trans- plantation and discusses the current role of the procedure. Hypothesis We hypothesize that the allografts of MSCs isolated from young donors could be more effective and powerful as cellular therapy as compared to autologous transplantation particularly in older indi- viduals since one of the key factor that may affect the results of MSC-based therapy is the age of donors. We further back our con- ception with logical scientific reasoning and at the same time high- light the clinical and commercial values of this upcoming treatment modality. Bone marrow-derived MSCs (BM-MSCs) are considered as the gold standard for autologous stem cell therapy; nevertheless we have expanded the following section wherein we have included description of other stem cells both from prenatal as well as post- natal sources. In vitro studies Self-renewal and differentiation potential BM-MSC is a type of somatic stem cell and can sustain a maxi- mum of 30–40 population doublings in vitro [8]. Hence a decline in http://dx.doi.org/10.1016/j.mehy.2014.10.010 0306-9877/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding authors. E-mail addresses: akdcts@yahoo.com (A.K. Das), rajarshi.pal@manipal.edu (R. Pal). Medical Hypotheses 83 (2014) 787–791 Contents lists available at ScienceDirect Medical Hypotheses journal homepage: www.elsevier.com/locate/mehy