The hematopoietic growth factor "erythropoietin" enhances the therapeutic effect of mesenchymal stem cells in Alzheimer's disease

Unravelling the potential neuroprotective facets of erythropoietin for the treatment of Alzheimer's disease

During the last three decades, recombinant DNA technology has produced a wide range of hematopoietic and neurotrophic growth factors, including erythropoietin (EPO), which has emerged as a promising protein drug in the treatment of several diseases. Cumulative studies have recently indicated the neuroprotective role of EPO in preclinical models of acute and chronic neurodegenerative disorders, including Alzheimer's disease (AD). AD is one of the most prevalent neurodegenerative illnesses in the elderly, characterized by the accumulation of extracellular amyloid-ß (Aß) plaques and intracellular neurofibrillary tangles (NFTs), which serve as the disease's two hallmarks. Unfortunately, AD lacks a successful treatment strategy due to its multifaceted and complex pathology. Various clinical studies, both in vitro and in vivo, have been conducted to identify the various mechanisms by which erythropoietin exerts its neuroprotective effects. The results of clinical trials in patients with AD are also promising. Herein, it is summarized and reviews all such studies demonstrating erythropoietin's potential therapeutic benefits as a pleiotropic neuroprotective agent in the treatment of Alzheimer's disease.

Therapeutic effects of erythropoietin expressed in mesenchymal stem cells for dilated cardiomyopathy in rat

Dilated cardiomyopathy (DCM) is considered as the final common response of myocardium to diverse genetic and environmental insults and characterized mainly by left ventricular systolic dysfunction. The current therapies for the treatment of DCM are costly high and outcomes are often unsatisfactory. To date, mesenchymal stem cells (MSCs) have been thought to be an ideal stem cell to repair damaged myocardium but was still within relatively small scales and few cases have been conducted in clinical trials. The use of erythropoietin (EPO), a growth factor produced in the kidneys have been found prevent cardiomyocyte apoptosis. This study was aimed to transplant MSCs into DCM rat bone marrow to express EPO in vivo and investigate the regulation of EPO on cell signaling pathways after transfection. The results found that transplantation of MSCs carrying EPO could significantly relief the cardiac dysfunctions of the DCM rat. This underylying mechanism involved with inhibiting p-NF-κB and p-P38, regulateing and promoting the anti-inflammatory balance, thereby alleviating tissue injury in DCM rats and exhibiting a protective role. Meanwhile, the MSCs + EPO treatment in DCM rat also activated the p-Akt pathway and thus protecting the myocardium from apoptosis in DCM rats. The study revealed an potential therapeutic effect of MSCs and EPO in clinical and provided a molecular mechanism of action for treating DCM.

Pharmacological modulation of cell functional activity with valproic acid and erythropoietin

Introduction: Valproic acid (VA) is carboxylic acid with a branched chain, which is used as an antiepileptic drug.

Valproic acid influence on cells in vivo: VA, which is an antiepileptic drug, is also a teratogen, which causes defects of a neural tube and an axial skeleton, although the mechanisms are not yet fully clear.

Valproic acid influence on mesenchymal stem cells (MSC) in vitro: It is shown that valproic acid reduces the intracellular level of oxygen active forms.

Valproic acid effect on tumor cells: VA inhibits tumor growth through several mechanisms, including the cell cycle stop, differentiation induction and inhibition of growth of tumor vessels.

Valproic acid influence on enzymes: It affects mainly GSK-3.

Valproic acid influence on animals’ cells: It is shown that VA can significantly improve an ability to develop in vitro and improve nuclear reprogramming of embryos.

Erythropoietin (EPO): Is an hypoxia-induced hormone and a cytokine, which is necessary for normal erythropoiesis. EPO is widely used in in vitro experiments.

Conclusion: Thus, the influence of VA and EPO on cells can be used in cell technologies.

The Effect of Thymoquinone, α7 Receptor Agonist and α7 Receptor Allosteric Modulator on the Cerebral Cortex in Experimentally Induced Alzheimer's Disease in Relation to MSCs Activation

Background and Objectives

Alzheimer's disease (AD) is the most common form of dementia among older persons. Thymoquinone (TQ) has anti-inflammatory, anticonvulsant and antioxidant activity. A novel α7 nicotinic acetyl choline receptor (α7 nAChR ) agonist (PNU- 282987) have been identified to enhance the cognitive performance. An alternative treatment strategy via compounds known as nicotinic "positive allosteric modulators" (PAMs) has been reported. This study was designed to investigate the combination of PAM of α7 nAChRs with PNU- 282987 or with TQ as a possible treatment for AD in rat.

Methods

48 male albino rats were divided into 4 groups. Group І (Control), Group II received lipopolysaccharide, 0.8 mg/kg by intraperitoneal injection (IPI) once, Group III received TQ 10 mg/kg by IPI, Group IV received PNU-120596 1 mg/kg by IPI, in addition to PNU-282987 1 mg/kg by IPI in subgroup IVa and TQ in subgroup b. All treatment drugs were given for 5 days.

Results

Acidophilic masses, deformed neurons, Congo red +ve masses and reduced Phospho-CREB immunoexpression were seen in group II. All changes regressed by treatment. Some CD44 +ve cells were noticed in group II and few +ve cells in subgroup IVa, that became multiple in group III and subgroup IVb. The histological, histochemical and immunohistochemical changes were confirmed statistically and significant differences were recorded.

Conclusions

TQ or α7 nAChR agonist combined with PAM can have an important role in treatment of AD that is superior to thymoquinone alone. Exceptionally, TQ single or combined with PAM proved activation of MSC.

Comparative Histological Study on the Therapeutic Effect of Green Tea and Stem Cells in Alzheimer's Disease Complicating Experimentally Induced Diabetes

BACKGROUND AND OBJECTIVES

Alzheimer's disease (AD) is a devastating neurodegenerative disorder. Increasing evidence implicates diabetes mellitus (DM) as a risk factor for AD. Green tea (GT) has several beneficial effects attributed to its anti-oxidant phenolic compounds. Adipose tissue is a rich source of adipose-derived mesenchymal stem cells (ADSCs). This study was designed to evaluate and compare the possible therapeutic effect of green tea extract (GTE) and ADSCs on AD complicating induced DM in male rat.

METHODS

31 adult male albino rats were divided into 5 groups. Group I (Control), Group II received GTE, 50 mg/kg daily orally for 4 weeks, Group III received a single intraperitoneal injection of Streptozotocin (STZ), 50 mg/kg, Group IV: received STZ followed by GTE and Group V: received STZ followed by human ADSCs (hADSCs) intravenously.

RESULTS

Multiple acidophilic masses, deformed neurons, Congo red +ve masses and Caspase 3 +ve neurons were seen in group III, became few in group IV and occasional in group V. Multiple Prussian blue +ve cells were detected in group V. Some CD44 +ve cells were noticed in group III, became multiple in groups IV and V. The mean area of neurons exhibiting acidophilic cytoplasm, mean area of amyloid plaques and mean area % of Caspase 3 +ve cells indicated a significant increase in group III. The mean area % of CD44 +ve cells recorded a significant increase in group IV.

CONCLUSIONS

hADSCs exerted a more marked therapeutic effect on the neurodegenerative changes complicating DM and corresponding to AD.

Downstream modulation of extrinsic apoptotic pathway in streptozotocin-induced Alzheimer's dementia in rats: Erythropoietin versus curcumin

Erythropoietin and curcumin showed promising neuroprotective effects in various models of Alzheimer's dementia. This study was designed to compare the beneficial effects of erythropoietin and/or curcumin in intracerebro-ventricular (ICV) streptozotocin-induced Alzheimer's like disease in rats. Rats received ICV injection of either saline (control, n=8 rats), or streptozotocin. Three weeks following surgery, streptozotocin-injected rats were assigned into 4 groups (8 rats each); vehicle, curcumin (80mg/kg/day, orally), erythropoietin (500 IU/kg every other day, intraperitoneally) and combined (curcumin and erythropoietin)-treated groups. After 3 months of treatment, rats were subjected to neurobehavioral testing, and then killed for biochemical and histological assessment of hippocampus. Fas ligand protein and caspase-8 activity as mediators of extrinsic apoptotic pathway, oxidative stress markers (malondialdehyde and reduced glutathione) and β-amyloid (1-40 and 1-42) peptides were measured. The results showed that administration of erythropoietin suppressed extrinsic apoptosis better than curcumin, while curcumin was more effective in combating oxidative stress in ICV-streptozotocin injected rats. Both erythropoietin and curcumin treatments (individually or combined) equally reduced the hippocampal β-amyloid accumulation and improved cognitive impairment in Morris water maze and passive avoidance tasks. The combined treatment was the most effective in ameliorating apoptosis and oxidative stress rather than behavioral responses or β-amyloid burden. In conclusion, ICV-streptozotocin-induced Alzheimer's dementia activates hippocampal Fas ligand-mediated apoptosis, which could be reduced by erythropoietin and/or curcumin treatment. Curcumin supplementation alone could ameliorate cognitive deficits and reverse biochemical alterations in ICV-streptozotocin Alzheimer's rat model without the hazardous polycythemic effect of long-term erythropoietin injection.