Amelioration of cognitive ability in senescence-accelerated mouse prone 8 (SAMP8) by intra-bone marrow-bone marrow transplantation

Intrathecal umbilical cord mesenchymal stem cells injection alleviates neuroinflammation and oxidative stress in the cyclophosphamide-induced interstitial cystitis rats through the Sirt1/Nrf2/HO-1 pathway

AIMS

Neuroinflammation in the spinal dorsal horn (SDH) region plays an important role in the pathogenesis of interstitial cystitis (IC)/bladder pain syndrome (BPS). Oxidative stress is an important etiological factor for inflammatory diseases. This study aimed to investigate the therapeutic effects of umbilical cord mesenchymal stem cells UMSCs on neuroinflammation and oxidative stress in IC and the underlying mechanisms.

MATERIALS AND METHODS

Rats were intraperitoneally injected with cyclophosphamide (50 mg/kg bodyweight) to establish the IC animal model. Additionally, rats were intrathecally injected with a Sirt1-specific agonist (SRT1720; 8 μg/rat) or inhibitor (EX527; 8 μg/rat). Furthermore, rats were intrathecally injected with human UMSCs (hUMSCS; 8 × 105 cells/rat). Rat behavior was examined using the mechanical allodynia test, novel object recognition test, sucrose preference test, and urodynamics analysis. Neuroinflammation and oxidative stress the SDH region were examined using western blotting, immunofluorescence, enzyme-linked immunosorbent assay, and commercial kits.

KEY FINDINGS

The Sirt1/Nrf2/HO-1 pathway was downregulated in IC rats. Sirt1 activation and inhibition differentially affected the behavior of IC rats. hUMSCs effectively mitigated the upregulation of oxidative stress, proinflammatory cytokines, and glial activation in the SDH region. Additionally, hUMSCs suppressed mechanical allodynia, dysregulated urodynamics, memory deficits, and depressive-like behavior in IC rats. hUMSCs exerted therapeutic effects through the Sirt1/Nrf2/HO-1 pathway.

SIGNIFICANCE

intrathecal hUMSCs injection alleviated behavioral deficits of IC rats by mitigating neuroinflammation and oxidative stress through the Sirt1/Nrf2/HO-1 pathway and can be potentially an effective therapeutic strategy for IC.

Mesenchymal Stem Cell Therapy and Alzheimer's Disease: Current Status and Future Perspectives

Alzheimer's disease (AD) is the most common progressive neurodegenerative disease worldwide, but its cause remains unclear. Although a few drugs can provide temporary and partial relief of symptoms in some patients, no curative treatment is available. Therefore, attention has been focused on research using stem cells to treat AD. Among stem cells, mesenchymal stem cells (MSCs) have been used to treat the related pathologies in animal models of AD, and other neurodegenerative disease. This review describes latest research trends on the use of MSC-based therapies in AD and its action of mechanism. MSCs have several beneficial effects. They would be specified as the reduction of neuroinflammation, the elimination of amyloid-β, neurofibrillary tangles, and abnormal protein degradation, the promotion of autophagy-associated and blood-brain barrier recoveries, the upregulation of acetylcholine levels, improved cognition, and the recovery of mitochondrial transport. Therefore, this review describes the latest research trends in MSC-based therapy for AD by demonstrating the importance of MSC-based therapy and understanding of its mechanisms in AD and discusses the limitations and perspectives of stem cell therapy in AD.

Alzheimer's Disease: Mechanism and Approach to Cell Therapy

Alzheimer’s disease (AD) is the most common form of dementia. The risk of AD increases with age. Although two of the main pathological features of AD, amyloid plaques and neurofibrillary tangles, were already recognized by Alois Alzheimer at the beginning of the 20th century, the pathogenesis of the disease remains unsettled. Therapeutic approaches targeting plaques or tangles have not yet resulted in satisfactory improvements in AD treatment. This may, in part, be due to early-onset and late-onset AD pathogenesis being underpinned by different mechanisms. Most animal models of AD are generated from gene mutations involved in early onset familial AD, accounting for only 1% of all cases, which may consequently complicate our understanding of AD mechanisms. In this article, the authors discuss the pathogenesis of AD according to the two main neuropathologies, including senescence-related mechanisms and possible treatments using stem cells, namely mesenchymal and neural stem cells.

Increased recruitment of bone marrow-derived cells into the brain associated with altered brain cytokine profile in senescence-accelerated mice

Bone marrow-derived cells enter the brain in a non-inflammatory condition through the attachments of choroid plexus and differentiate into ramified myeloid cells. Neurodegenerative conditions may be associated with altered immune-brain interaction. The senescence-accelerated mouse prone 10 (SAMP10) undergoes earlier onset neurodegeneration than C57BL/6 (B6) strain. We hypothesized that the dynamics of immune cells migrating from the bone marrow to the brain is perturbed in SAMP10 mice. We created 4 groups of radiation chimeras by intra-bone marrow-bone marrow transplantation using 2-month-old (2 mo) and 10 mo SAMP10 and B6 mice as recipients with GFP transgenic B6 mice as donors, and analyzed histologically 4 months later. In the [B6 → 10 mo SAMP10] chimeras, more ramified marrow-derived cells populated a larger number of discrete brain regions than the other chimeras, especially in the diencephalon. Multiplex cytokine assays of the diencephalon prepared from non-treated 3 mo and 12 mo SAMP10 and B6 mice revealed that 12 mo SAMP10 mice exhibited higher tissue concentrations of CXCL1, CCL11, G-CSF, CXCL10 and IL-6 than the other groups. Immunohistologically, choroid plexus epithelium and ependyma produced CXCL1, while astrocytic processes in the attachments of choroid plexus expressed CCL11 and G-CSF. The median eminence produced CXCL10, hypothalamic neurons G-CSF and tanycytes CCL11 and G-CSF. These brain cytokine profile changes in 12 mo SAMP10 mice were likely to contribute to acceleration of the dynamics of marrow-derived cells to the diencephalon. Further studies on the functions of ramified marrow-derived myeloid cells would enhance our understanding of the brain-bone marrow interaction.

Stem cell treatment for Alzheimer's disease

Alzheimer’s disease (AD) is a progressive and neurodegenerative disorder that induces dementia in older people. It was first reported in 1907 by Alois Alzheimer, who characterized the disease as causing memory loss and cognitive impairment. Pathologic characteristics of AD are β-amyloid plaques, neurofibrillary tangles and neurodegeneration. Current therapies only target the relief of symptoms using various drugs, and do not cure the disease. Recently, stem cell therapy has been shown to be a potential approach to various diseases, including neurodegenerative disorders, and in this review, we focus on stem cell therapies for AD.

Intractable diseases treated with intra-bone marrow-bone marrow transplantation

Bone marrow transplantation (BMT) is used to treat hematological disorders, autoimmune diseases (ADs) and lymphoid cancers. Intra bone marrow-BMT (IBM-BMT) has been proven to be a powerful strategy for allogeneic BMT due to the rapid hematopoietic recovery and the complete restoration of T cell functions. IBM-BMT not only replaces hematopoietic stem cells (HSCs) but also mesenchymal stromal cells (MSCs). MSCs are multi-potent stem cells that can be isolated from bone marrow (BM), umbilical cord blood (UCB), and adipose tissue. MSCs play an important role in the support of hematopoiesis, and modify and influence the innate and adaptive immune systems. MSCs also differentiate into mesodermal, endodermal and ectodermal lineage cells to repair tissues. This review aims to summarize the functions of BM-derived-MSCs, and the treatment of intractable diseases such as rheumatoid arthritis (RA) and malignant tumors with IBM-BMT.

Stem cell transplantation improves aging-related diseases

Aging is a complex process of damage accumulation, and has been viewed as experimentally and medically intractable. The number of patients with age-associated diseases such as type 2 diabetes mellitus (T2DM), osteoporosis, Alzheimer's disease (AD), Parkinson's disease, atherosclerosis, and cancer has increased recently. Aging-related diseases are related to a deficiency of the immune system, which results from an aged thymus and bone marrow cells. Intra bone marrow-bone marrow transplantation (IBM-BMT) is a useful method to treat intractable diseases. This review summarizes findings that IBM-BMT can improve and treat aging-related diseases, including T2DM, osteoporosis and AD, in animal models.

Neuroprotective effects of the amylin analogue pramlintide on Alzheimer's disease pathogenesis and cognition

Amylin is a metabolic peptide hormone that is co-secreted with insulin from beta cells in the pancreas and activates many of the downstream targets of insulin. To investigate the relationship between this hormone and Alzheimer's disease (AD), we measured plasma human amylin levels in 206 subjects with AD, 64 subjects with mild cognitive impairment, and 111 subjects with no cognitive impairment and found significantly lower amylin levels among subjects with AD and mild cognitive impairment compared with the cognitively intact subjects. To investigate mechanisms underlying amylin's effects in the brain, we administered chronic infusions of the amylin analog pramlintide in the senescence-accelerated prone mouse, a mouse model of sporadic AD. Pramlintide administration improved performance in the novel object recognition task, a validated test of memory and cognition. The pramlintide-treated mice had increased expression of the synaptic marker synapsin I and the kinase cyclin-dependent kinase-5 in the hippocampus, as well as decreased oxidative stress and inflammatory markers in the hippocampus. A dose-dependent increase in cyclin-dependent kinase-5 and activation of extracellular-signal-regulated-kinases 1/2 by pramlintide treatment in vitro was also present indicating functionality of the amylin receptor in neurons. Together these results suggest that amylin analogs have neuroprotective properties and might be of therapeutic benefit in AD.

Selective localization of bone marrow-derived ramified cells in the brain adjacent to the attachments of choroid plexus

Although the immune system modulates higher functions of the brain under non-inflammatory conditions, how immune cells interact with brain parenchymal cells remains to be determined. Using bone marrow chimeric mice in which the recipients' immune system was reconstituted by marrow cells derived from GFP-transgenic mice by syngeneic intra-bone marrow-bone marrow transplantation (IBM-BMT) and by intravenous (IV)-BMT, we examined the distribution, density and differentiation of donor-derived marrow cells in the brain parenchyma 2 weeks and 1, 4 and 8 months after BMT. Marrow-derived cells started to populate discrete brain regions from 1 to 4 months after BMT, exhibited ramified morphology and expressed Iba-1. The ramified marrow-derived cells were distributed in more brain regions and for a longer time after IBM-BMT than IV-BMT. Most of these discrete regions were adjacent to the attachments of choroid plexus that comprised thinned brain parenchyma consisting of astroglial processes in the narrow channel between the ependyma and pia. These specific portions of astroglial processes expressed fractalkine. In the choroid plexus stroma, not only Iba-1+ myeloid cells but also non-myeloid CXCL12-expressing cells were of bone marrow-origin. Transcripts of fractalkine, CXCL12 and their related molecules such as CX3CR1, ADAM10 and CXCR4 were detected in the tissue consisting of the choroid plexus, the attachments and adjacent brain parenchyma. Thus, bone marrow cells selectively enter the discrete brain regions adjacent to the attachments of choroid plexus and differentiate into ramified myeloid cells. Fractalkine in the attachments of choroid plexus and CXCL12 in the choroid plexus stroma may be involved in these brain-immune interactions.

A novel BMT technique for treatment of various currently intractable diseases

A recently-developed BMT method combines a "Perfusion Method" (PM) for collecting bone marrow cells (BMCs) with the Intra-Bone Marrow (IBM) injection of BMCs (IBM-BMT). As distinct from the conventional aspiration method (AM), the PM allows rapid (within 1 h) collection of BMCs without T cell contamination (T cells < 10%). Therefore, no GvHD occurs. Moreover, the burden on donors, such as back pain, bleeding and infection, can be reduced. Full chimerism can be achieved even with only mild conditioning regimens if IBM-BMT is carried out, since IBM-BMT replaces not only the recipient's hemopoietic stem cells (HSCs) but also mesenchymal stem cells (MSCs) with donor-derived HSCs and MSCs. Using this method, we show that most currently intractable diseases are HSC or MSC disorders, and that this novel strategy (PM + IBM-BMT) can be used to treat various otherwise intractable diseases (including autoimmune diseases and age-associated diseases). We believe that the development of this technique will herald a revolution in the field of BMT, regeneration medicine and also organ transplantation.