Cytopathology & Histopathology

Biography

Biography: Gjumrakch Aliev

Abstract

It is widely accepted that during neuronal energy crisis, cerebral hypometabolism and vascular hypoperfusion are major and potentially treatable contributors to the loss of function in patients with stroke as well as Alzheimer disease (AD). We have determined the cellular and subcellular features of vascular lesions and mitochondria in brain vascular wall cells as well as neurons from human AD brain biopsies, human short postmortem brain tissues, rat model of 2 vessel occlusion (2-VO), yeast artificial chromosome (YAC), and C57B6/SJL transgenic positive (Tg+) mice overexpressing amyloid beta precursor protein (AßPP). We expand our models towards the E4 isoform of apolipoprotein E (ApoE) which is involved in cardiovascular and cerebrovascular disorders and is the most prevalent risk factor for late onset of sporadic AD. In situ hybridization, using mitochondrial DNA (mtDNA) probes for human wild type, 5kb deleted and mouse mtDNA, was performed in conjunction with immunocytochemistry using antibodies against AßPP, 8-hydroxyguanosine, all three isoforms of nitric oxide synthase (neuronal, inducible and endothelial NOSs), GRK-2 and cytochrome c oxidase. We have also measured age-dependent effects of the human ApoE4 on cerebral blood flow (CBF) using ApoE4 transgenic mice compared to age-matched wild-type (WT) mice by use of [¹⁴C] iodoantipyrene autoradiography. Spatial memory and temporal memory tests were also employed to determine the potential protective effects of ALCAR+LA as a selective mitochondrial antioxidants treatment. Our animal study applies the vascular dementia paradigm to ApoE4 Tg+ mice in order to analyze the effects of the selective mitochondrial antioxidants ALCAR+LA on cerebral blood flow (CBF), neuropathology, brain and vessel ultrastructural abnormalities and behavior. A significant higher degree of mitochondrial damage was found in neurons and cerebrovascular cell walls in AD and in animal models used when compared to age-matched controls and non-treated subjects. These abnormalities coexist with the over expression of GRK-2, AßPP and inducible NOS immunoreactivity in these cells, and closely related to amyloid deposition in the same regions. They were also characterized by the presence of large, lipid-laden vacuoles in the cell body of severely damaged neurons and cytoplasmic matrix of the vascular endothelium. In situ hybridization revealed deleted mtDNA positive signals in the damaged mitochondria of neurons, vascular endothelium and perivascular cells. Moreover, brain microvessels with atherosclerotic lesions revealed endothelium and perivascular cells, which stained positively and in clusters when probed with wild and deleted mtDNA probes. These mtDNA deletions were associated with increased amounts of immunoreactive GRK-2, AßPP, 8OHG, and COX in the same cellular and subcellular compartments. Moreover, GRK overexpression appeared to be a selective hallmark for mitochondrial damage at the earlier but not late stages of neuronal and other brain cellular compartment lesions. ApoE4 associated factors reduced the CBF gradually and created brain hypoperfusion when compared to the WT and the differences in CBF were greatest as animals aged from 6 weeks to 12 months. Transmission electron microscopy (TEM) with colloidal gold immunocytochemistry and in situ hybridization using human and mouse DNA probes showed structural damage and mitochondrial DNA overproliferation and/or deletion in the young and aged microvessels endothelium of ApoE4 animals, extending to the cytoplasm of perivascular cells, perivascular nerve terminals, hippocampal neurons, and glial cells. These blood flow changes associates with severe structural lesions in young and aged microvessels endothelium of ApoE4 animals extended to the cytoplasmic matrix of perivascular cells, perivascular nerve terminals and hippocampal neurons and glial cells in the damaged regions of the brain. The mitochondrial structural alterations coexist with mitochondrial DNA overproliferation and/or deletion in all brain cellular compartments. Most likely, further development of these alterations can lead to blood brain barrier (BBB) failure and breakage during the development of AD. In contrary to this observation, the animals that received selective mitochondrial antioxidants (ALCAR+LA) treatment showed an absence of any cellular or subcellular abnormality in brain cellular compartments. Spatial and temporal memory tests showed a trend in improving cognitive function in ApoE4 Tg+ mice that were fed with the selective mitochondrial antioxidants (ALCAR+LA).

  Our conclusion is that for the first time we were able to demonstrate the potential pharmacologic modulation of brain hypometabolism and therefore the cognitive improvements by using combination of selective mitochondrial antioxidants/metabolites, a gene expression modification substance (A10) and supplement for brain aging (BLF) with diet changes and brain exercise training. This represents a completely new and more effective strategy to treat stroke, Alzheimer and/or other types of dementia. Moreover, further increase in the examination of the ultrastructural degeneration caused by aging, especially under cardio- and cerebrovascular disease complications, is likely to contribute to our understanding of neurodegenerative etiology and will indicate a new avenue for the development of novel prophylactic and treatment strategies by offering selective mitochondrial antioxidants like ALCAR+LA and gene expression modification substrate (A10) and brain aging supplement (BLF) to the stroke, AD and/or other demented patients.