Claire M Rice

Adult bone marrow is a rich source of human mesenchymal ‘stem’ cells but umbilical cord and mobilized adult blood are not

Summary. In postnatal life, mesenchymal stem cells (MSC) self‐replicate, proliferate and differentiate into mesenchymal tissues, including bone, fat, tendon, muscle and bone marrow (BM) stroma. Possible clinical applications for MSC in stem cell transplantation have been proposed. We have evaluated the frequency, phenotype and differentiation potential of MSC in adult BM, cord blood (CB) and peripheral blood stem cell collections (PBSC). During culture, BM MSC proliferated to confluence in 10–14 d, maintaining a stable non‐haemopoietic phenotype, HLA class‐1+, CD29+, CD44+, CD90+, CD45–, CD34– and CD14 through subsequent passages. Using the colony forming unit fibroblasts assay, the estimated frequency of MSC in the BM nucleated cell population was 1 in 3·4 × 104 cells. Both adipogenic and osteogenic differentiation of BM MSC was demonstrated. In contrast, CB and PBSC mononuclear cells cultured in MSC conditions for two passages produced a population of adherent, non‐confluent fibroblast‐like cells with a haemopoietic phenotype, CD45+, CD14+, CD34–, CD44–, CD90– and CD29–. In paired experiments, cultured BM MSC and mature BM stroma were seeded with CB cells enriched for CD34+. Similar numbers of colony‐forming units of granulocytes–macrophages were produced by MSC‐based and standard stroma cultures over 10 weeks. We conclude that adult BM is a reliable source of functional cultured MSC, but CB and PBSC are not.

Neural progenitor cells from postmortem adult human retina

Background: Given the presence of neural progenitor cells (NPC) in the retina of other species capable of differentiating into multiple neural components, the authors report the presence of NPC in the adult human retina. A resident population of NPC suggests that the retina may constitutively replace neurons, photoreceptors, and glia. Methods: Adult human postmortem retinal explants and cell suspensions were used to generate cells in tissue culture that display the features of NPC. The phenotype of cells and differentiation into neurons was determined by immunocytochemistry. Dividing cells were labelled with 5-bromo-2-deoxyuridine (BrdU) and neurospheres were generated and passaged. Results: Cells labelled with nestin, neurofilament M (NFM), rhodopsin, or glial fibrillary acidic protein (GFAP) grew out from explant cultures. BrdU labelling of these cells occurred only with basic fibroblast growth factor (FGF-2). Dissociated retina and pars plana generated primary neurospheres. From primary neurospheres, NPC were passaged to generate secondary neurospheres, neurons, photoreceptors, and glia. BrdU labelling identified dividing cells from neurospheres that differentiated to express NFM and rhodopsin. Conclusion: The adult human retina contains NPC and may have the potential to replace neurons and photoreceptors. This has implications for the pathogenesis and treatment of retinal disorders and degenerations, including glaucoma, and those disorders associated with retinal scarring.

Adult stem cells--reprogramming neurological repair?

Much excitement has surrounded recent breakthroughs in embryonic stem-cell research. Of lower profile, but no less exciting, are the advances in the field of adult stem-cell research, and their implications for cell therapy. Clinical experience from use of adult haemopoietic stem cells in haematology will facilitate and hasten transition from laboratory to clinic--indeed, clinical trials using adult human stem cells are already in progress in some disease states, including myocardial ischaemia. Here, with particular reference to neurology, we review processes that might underlie apparent changes in adult cell phenotype. We discuss implications these processes might have for the development of new therapeutic strategies using adult stem cells.

Safety and feasibility of autologous bone marrow cellular therapy in relapsing-progressive multiple sclerosis.

In this phase I study, we assessed the safety and feasibility of intravenous, autologous bone marrow (BM) cell therapy, without immunosuppressive preconditioning, in six patients with clinically definite, relapsing‐progressive multiple sclerosis (MS). Assessment of efficacy was a secondary objective and employed clinical disability rating scales, multimodal evoked potential (MMEP) recordings, and magnetic resonance imaging (MRI) scans. Cells were harvested, filtered and infused intravenously in a day‐case procedure that was well tolerated by patients and was not associated with any serious adverse events (AEs). Over a period of 12 months after the therapy, clinical disability scores showed either no change (Extended Disability Status Score, EDSS) or improvement (MS impact scale‐29, MSIS‐29), and MMEPs showed neurophysiological improvement. MRI scans did not show any significant changes over a post‐therapy period of 3 months. The lack of serious adverse effects and the suggestion of a beneficial effect in this small sample of patients with progressive disease justify conducting a larger phase II/III study to make a fuller assessment of the efficacy of mobilization of autologous BM in patients with MS.

Treatment effectiveness of alemtuzumab compared with natalizumab, fingolimod, and interferon beta in relapsing-remitting multiple sclerosis: a cohort study

BACKGROUND Alemtuzumab, an anti-CD52 antibody, is proven to be more efficacious than interferon beta-1a in the treatment of relapsing-remitting multiple sclerosis, but its efficacy relative to more potent immunotherapies is unknown. We compared the effectiveness of alemtuzumab with natalizumab, fingolimod, and interferon beta in patients with relapsing-remitting multiple sclerosis treated for up to 5 years. METHODS In this international cohort study, we used data from propensity-matched patients with relapsing-remitting multiple sclerosis from the MSBase and six other cohorts. Longitudinal clinical data were obtained from 71 MSBase centres in 21 countries and from six non-MSBase centres in the UK and Germany between Nov 1, 2015, and June 30, 2016. Key inclusion criteria were a diagnosis of definite relapsing-remitting multiple sclerosis, exposure to one of the study therapies (alemtuzumab, interferon beta, fingolimod, or natalizumab), age 65 years or younger, Expanded Disability Status Scale (EDSS) score 6·5 or lower, and no more than 10 years since the first multiple sclerosis symptom. The primary endpoint was annualised relapse rate. The secondary endpoints were cumulative hazards of relapses, disability accumulation, and disability improvement events. We compared relapse rates with negative binomial models, and estimated cumulative hazards with conditional proportional hazards models. FINDINGS Patients were treated between Aug 1, 1994, and June 30, 2016. The cohorts consisted of 189 patients given alemtuzumab, 2155 patients given interferon beta, 828 patients given fingolimod, and 1160 patients given natalizumab. Alemtuzumab was associated with a lower annualised relapse rate than interferon beta (0·19 [95% CI 0·14-0·23] vs 0·53 [0·46-0·61], p<0·0001) and fingolimod (0·15 [0·10-0·20] vs 0·34 [0·26-0·41], p<0·0001), and was associated with a similar annualised relapse rate as natalizumab (0·20 [0·14-0·26] vs 0·19 [0·15-0·23], p=0·78). For the disability outcomes, alemtuzumab was associated with similar probabilities of disability accumulation as interferon beta (hazard ratio [HR] 0·66 [95% CI 0·36-1·22], p=0·37), fingolimod (1·27 [0·60-2·70], p=0·67), and natalizumab (0·81 [0·47-1·39], p=0·60). Alemtuzumab was associated with similar probabilities of disability improvement as interferon beta (0·98 [0·65-1·49], p=0·93) and fingolimod (0·50 [0·25-1·01], p=0·18), and a lower probability of disability improvement than natalizumab (0·35 [0·20-0·59], p=0·0006). INTERPRETATION Alemtuzumab and natalizumab seem to have similar effects on annualised relapse rates in relapsing-remitting multiple sclerosis. Alemtuzumab seems superior to fingolimod and interferon beta in mitigating relapse activity. Natalizumab seems superior to alemtuzumab in enabling recovery from disability. Both natalizumab and alemtuzumab seem highly effective and viable immunotherapies for multiple sclerosis. Treatment decisions between alemtuzumab and natalizumab should be primarily governed by their safety profiles. FUNDING National Health and Medical Research Council, and the University of Melbourne.

Autologous bone marrow stem cells — properties and advantages

The properties of self-renewal and multi-lineage differentiation make stem cells attractive candidates for use in cellular reparative therapy, particularly in neurological diseases where there is a paucity of treatment options. However, clinical trials using foetal material in Parkinsons disease have been disappointing and highlighted problems associated with the use of embryonic stem cells, including ethical issues and practical concerns regarding teratoma formation. Understandably, this has led investigators to explore alternative sources of stem cells for transplantation. The expression of neuroectodermal markers by cells of bone marrow origin focused attention on these adult stem cells. Although early enthusiasm has been tempered by dispute regarding the validity of reports of in vitro (trans)differentiation, the demonstration of functional benefit in animal models of neurological disease is encouraging. Here we will review some of the required properties of stem cells for use in transplantation therapy with specific reference to the development of bone marrow-derived cells as a source of cells for repair in demyelination.

Cell therapy for multiple sclerosis: an evolving concept with implications for other neurodegenerative diseases

Multiple sclerosis is a major cause of neurological disability, and particularly occurs in young adults. It is characterised by conspicuous patches of damage throughout the brain and spinal cord, with loss of myelin and myelinating cells (oligodendrocytes), and damage to neurons and axons. Multiple sclerosis is incurable, but stem-cell therapy might offer valuable therapeutic potential. Efforts to develop stem-cell therapies for multiple sclerosis have been conventionally built on the principle of direct implantation of cells to replace oligodendrocytes, and therefore to regenerate myelin. Recent progress in understanding of disease processes in multiple sclerosis include observations that spontaneous myelin repair is far more widespread and successful than was previously believed, that loss of axons and neurons is more closely associated with progressive disability than is myelin loss, and that damage occurs diffusely throughout the CNS in grey and white matter, not just in discrete, isolated patches or lesions. These findings have introduced new and serious challenges that stem-cell therapy needs to overcome; the practical challenges to achieve cell replacement alone are difficult enough, but, to be useful, cell therapy for multiple sclerosis must achieve substantially more than the replacement of lost oligodendrocytes. However, parallel advances in understanding of the reparative properties of stem cells--including their distinct immunomodulatory and neuroprotective properties, interactions with resident or tissue-based stem cells, cell fusion, and neurotrophin elaboration--offer renewed hope for development of cell-based therapies. Additionally, these advances suggest avenues for translation of this approach not only for multiple sclerosis, but also for other common neurological and neurodegenerative diseases.

Adult human mesenchymal cells proliferate and migrate in response to chemokines expressed in demyelination.

Systemic delivery of multipotent mesenchymal stem cells (MSC) may be of benefit in the treatment of neurological diseases, including multiple sclerosis (MS). Certainly, animal studies have demonstrated functional benefits following MSC transplantation, although the mechanisms by which MSCs migrate to lesions and stimulate repair remain unknown. Chemokines stimulate migration in other settings. In this study, we systematically explore the migratory and proliferative responses of human MSCs (hMSC) to chemokines expressed in MS lesions. We demonstrate that these chemokines trigger hMSC migration. In addition, we show that RANTES and IP-10 promote hMSC proliferation.

Primary progressive multiple sclerosis: progress and challenges

Primary progressive multiple sclerosis (MS) has long been recognised as presenting great difficulties to our management of what is increasingly a treatable neurological disease. Here we review some basic and clinical aspects of primary progressive MS, and describe how the disorder in fact offers powerful insights and opportunities for better understanding multiple sclerosis, and from a practical perspective an invaluable clinical substrate for studying and treating progressive disability in MS. Difficult hurdles remain, however, and these too are reviewed.

Purkinje Cell Pathology and Loss in Multiple Sclerosis Cerebellum.

Cerebellar ataxia commonly occurs in multiple sclerosis, particularly in chronic progressive disease. Previous reports have highlighted both white matter and grey matter pathological changes within the cerebellum; and demyelination and inflammatory cell infiltrates appear commonly. As Purkinje cell axons are the sole output of the cerebellar cortex, understanding pathologic processes within these cells is crucial to develop strategies to prevent their loss and thus reduce ataxia. We studied pathologic changes occurring within Purkinje cells of the cerebellum. Using immunohistochemic techniques, we found changes in neurofilament phosphorylation states within Purkinje cells, including loss of dephosphorylated neurofilament and increased phosphorylated and hyperphosphorylated neurofilament. We also found Purkinje axonal spheroids and Purkinje cell loss, both of which occurred predominantly within areas of leucocortical demyelination within the cerebellar cortex. These changes have important implications for the study of cerebellar involvement in multiple sclerosis and may help design therapies to reduce the burden of ataxia in the condition.