Bhupesh Sharma

Modulation of celecoxib- and streptozotocin-induced experimental dementia of Alzheimer's disease by pitavastatin and donepezil

Present study was designed to investigate modulation of experimental dementia by Pitavastatin and donepezil. Learning and memory of the swiss albino mice were studied on Morris water-maze. Celecoxib orally (p.o.)/Streptozotocin (STZ) intracerebroventricular administrations were used to induce experimental dementia. Brain acetyl cholinesterase activity was measured by EllManns method to assess cholinergic activity of the brain. Brain thio barbituric acid reactive species (TBARS) levels and reduced glutathione (GSH) levels were measured by Ohokawas and Beutlers method respectively, to assess total oxidative stress in brain. Total serum cholesterol level was measured by Allains method. Celecoxib/STZ treatments produced a significant loss of learning and memory. Pitavastatin/Donepezil successfully attenuated this Celecoxib/STZ induced dementia. Higher levels of brain acetyl-cholinesterase (AChE) activity, TBARS and lower level of GSH were observed in Celecoxib/STZ treated animals, which were significantly attenuated by Donepezil. Pitavastatin also attenuated the Celecoxib/STZ induced high levels of TBARS & low levels of GSH without effecting AChE activity and total serum cholesterol levels. Celecoxib induced dementia noted in the present study may be attributed to its stimulatory effect on amyloid beta-42, brain AChE activity, and oxidative stress. Sub-diabetogenic STZ induced memory deficits closely related to Alzheimers disease. Reversal of Celecoxib/STZ induced memory deficits by Pitavastatin may be due to its antioxidative, anti beta amyloid aggregatory property, and by Donepezil, due to its anticholinesterase and neuroprotective actions.

Ameliorative role of Atorvastatin and Pitavastatin in L-Methionine induced vascular dementia in rats

BackgroundStatins, HMG-CoA reductase inhibitors, are widely prescribed drugs for dyslipidemias. Recent studies have indicated number of cholesterol independent actions of statins including their beneficial effects on vascular endothelial dysfunction and memory deficits associated with dementia of Alzheimers type. However the potential of statins in dementia of vascular origin still remains to be explored. Therefore, the present study has been designed to investigate the effect of Atorvastatin & Pitavastatin on vascular endothelial dysfunction associated memory deficits in rats. In this study L-Methionine induced vascular dementia was assessed by Morris water-maze (MWM) test. Biochemical analysis was also performed to unfold possible mechanism of statins mediated modulation of vascular dementia.ResultsL-Methionine produced endothelial dysfunction as reflected by significant decrease in serum nitrite concentration. L-Methionine treated rats performed poorly on MWM indicating impairment of memory as well. These rats also showed a significant rise in brain oxidative stress, acetylcholinesterase (AChE) activity and serum total cholesterol levels. Both Atorvastatin as well as Pitavastatin attenuated L-Methionine induced endothelial dysfunction associated memory deficits. Statins also reversed L-Methionine induced rise in brain oxidative stress, AChE activity and serum cholesterol.ConclusionThe beneficial effects of statins may be attributed to their multiple effects and the study highlights the potential of these drugs in vascular dementia.

Attenuating effect of lisinopril and telmisartan in intracerebroventricular streptozotocin induced experimental dementia of Alzheimer’s disease type: possible involvement of PPAR-γ agonistic property

This study investigates the beneficial role of lisinopril, an angiotensin converting enzyme inhibitor (ACEI) and telmisartan, an angiotensin receptor blocker (ARB), in intracerebroventricular (i.c.v.) streptozotocin (STZ) induced dementia of Alzheimer’s disease (AD) type in mice. This study also aimed to explore the role of PPAR-γ in lisinopril and telmisartan mediated effects in i.c.v. STZ mice. Donepezil served as the positive control in the study. Mice underwent i.c.v. injection of STZ. The Morris water maze (MWM) test was employed for assessment of learning and memory. Various biochemical estimations, namely brain acetylcholinesterase (AChE) activity, myeloperoxidase (MPO) activity, nitrite/nitrate and thiobarbituric acid reactive species (TBARS) levels and reduced glutathione (GSH) levels, were also performed. The study showed that i.c.v. STZ significantly impaired learning and memory of the animals along with a significant enhancement in brain AChE, MPO, TBARS, nitrite/nitrate levels and reduction in brain GSH levels. Treatments of lisinopril/telmisartan/donepezil significantly attenuated STZ induced behavioral and biochemical changes. Pre-treatment with bisphenol-A-diglycidyl ether (BADGE), a selective PPAR-γ antagonist, significantly abolished the beneficial effect of lisinopril/telmisartan in i.c.v. STZ treated animals. The results of this investigation document a potential role of PPAR-γ in the beneficial effects of lisinopril and telmisartan in i.c.v. STZ dementia of AD type.

Exploitation of HIV protease inhibitor Indinavir as a memory restorative agent in experimental dementia

The present study was undertaken to investigate the beneficial effect of HIV protease inhibitor Indinavir on memory deficits associated with experimental dementia of Alzheimer diseases (AD) type. Dementia was induced in Swiss albino mice by administration of Celecoxib (100 mg kg(-1) orally, daily for 9 days) or Streptozotocin (3 mg kg(-1) administered intracerebroventricularly on 1st and 3rd day) and the cognitive behaviors of Swiss albino mice were assessed using Morris water maze test. Brain acetyl cholinesterase (AChE) activity was measured by Ell Manns method. Brain thiobarbituric acid reactive species (TBARS) levels and reduced glutathione (GSH) levels were measured by Ohokawas and Beutlers method respectively to assess total oxidative stress. Donepezil (0.1 mg kg(-1) i.p.) served as positive control in the present investigation. Celecoxib as well as Streptozotocin (STZ) produced a significant loss of learning and memory. Indinavir (100 and 200 mg kg(-1) orally) successfully attenuated Celecoxib as well as STZ induced cognitive deficits. Higher levels of brain AChE activity, TBARS and lower levels of GSH were observed in Celecoxib as well as STZ treated animals, which were significantly attenuated by Donepezil and Indinavir. Study highlights the potential of Indinavir in memory dysfunctions associated with dementia of AD.

Behavioral and biochemical investigations to explore pharmacological potential of PPAR-gamma agonists in vascular dementia of diabetic rats

Vascular dementia (VaD) is the second most common dementing illness. We have recently reported that diabetes induces VaD in rats. The present study has been designed to investigate the potential of peroxisome-proliferator-activated receptors-gamma (PPAR-γ) agonists in diabetes induced VaD of Wistar Albino rats. The rats were administered, single dose of streptozotocin (STZ) for the induction of diabetes. Morris water-maze (MWM) test was employed for testing learning and memory. Serum glucose, bodyweight, vascular endothelial function, serum nitrite/nitrate levels, aortic and brain oxidative stress levels (viz. aortic superoxide anion levels, brain thiobarbituric acid reactive species and brain glutathione levels) and brain acetylcholinesterase activity were also tested. STZ treated animals performed poorly on MWM hence reflecting impairment of learning and memory behavior with a significant reduction in body weight, impairment of vascular endothelial function, and decrease in serum nitrite/nitrate levels, increase in serum glucose, aortic and brain oxidative stress levels and brain acetylcholinesterase activity. Treatment of PPAR-γ agonists, pioglitazone as well as rosiglitazone significantly reversed, diabetes induced impairment of learning and memory behavior, endothelial function, and changes in various biochemical parameters. It is concluded that PPAR-γ modulators pioglitazone and rosiglitazone may be considered as potential pharmacological agents for the management of diabetes induced VaD.

Experimental hypertension induced vascular dementia: pharmacological, biochemical and behavioral recuperation by angiotensin receptor blocker and acetylcholinesterase inhibitor.

Involvement of vascular pathology has been suggested in hypertension as well as vascular dementia (VaD), which also have a very high degree of co-occurrence in ageing population. We have recently reported that experimental diabetes as well as hyperhomocystenemia induces VaD. In the present research work, for the first time we are reporting the genesis of VaD by deoxycorticosterone acetate (DOCA)-salt induced experimental hypertension. Furthermore, we have also investigated the beneficial effect of telmisartan, an angiotensin II type 1 receptor blocker (ARB) and donepezil, an acetylcholinesterase inhibitor (AChEI), on DOCA-salt hypertension induced VaD in rats. DOCA-salt hypertensive rats performed poorly on Morris water maze, reflecting impairment in their learning and memory. Furthermore, DOCA-salt treatment has shown a significant impairment of vascular endothelial function (DOCA attenuated acetylcholine induced endothelium dependent relaxation), with a significant reduction in serum nitrite/nitrate levels, along with increased aortic, serum and brain oxidative stress levels (aortic superoxide anion, serum and brain thiobarbituric acid reactive species, brain glutathione) and brain acetylcholinesterase activity. Treatments of telmisartan as well as donepezil significantly attenuated DOCA-salt hypertension induced learning and memory deficits, endothelial dysfunction, and changes in various biochemical parameters. It may be concluded that DOCA-salt hypertension induces VaD in rats. ARBs and AChEIs may be considered as potential pharmacological agents for the management of hypertension induced VaD.

Salutary effect of NFκB inhibitor and folacin in hyperhomocysteinemia–hyperlipidemia induced vascular dementia

Dementia of vascular origin or vascular dementia (VaD) is considered as the second commonest form of dementia after Alzheimers disease (AD). In the last ten years various researchers have reported a strong association of hyperhomocysteinemia (HHcy), hyperlipidemia (HL) and dementia. This study investigates the salutary effect of natrium diethyl dithio carbamate trihydrate (NDDCT), a nuclear factor-kappaB (NF-κB) inhibitor as well as folacin (Vitamin-B(9)) in HHcy-HL induced VaD. l-methionone was used to induce HHcy-HL and associated VaD. Morris water-maze (MWM) was used for testing learning and memory. Vascular system assessment was done by testing endothelial function. Biochemical estimations were performed to assess HHcy (serum homocysteine), HL (serum cholesterol), oxidative stress (aortic superoxide anion, serum and brain thiobarbituric acid reactive species and brain glutathione), nitric oxide levels (serum nitrite/nitrate) and cholinergic activity (brain acetyl cholinesterase activity). L-methionine treated animals have shown HHcy-HL, endothelial dysfunction, impairment of learning, memory, reduction in serum nitrite/nitrate levels and brain glutathione (GSH) along with increase in serum and brain thiobarbituric acid reactive species (TBARS), and brain acetylcholinesterase activity. NDDCT, folacin and donepezil (positive control) significantly improved HHcy-HL induced impairment of learning, memory, endothelial dysfunction, and changes in various biochemical parameters. l-methionine induced HHcy-HL has caused VaD development in rats. NFκ-B inhibitors and folacin may be considered as potential agents for the management of HHcy-HL induced VaD.

Defensive effect of natrium diethyldithiocarbamate trihydrate (NDDCT) and lisinopril in DOCA–salt hypertension-induced vascular dementia in rats

RationaleVascular dementia and hypertension are increasing day by day, with a high degree of co-occurrence. Tremendous amount of research work is required so that new pharmacological agents may be identified for their appropriate therapeutic utility to combat different dementing disorders.ObjectivesThis study investigates the effect of natrium diethyldithiocarbamate trihydrate (NDDCT), a nuclear factor kappa-B (NF-κB) inhibitor, as well as lisinopril, an angiotensin converting enzyme (ACE) inhibitor, on deoxycorticosterone acetate (DOCA) hypertension-induced vascular dementia in rats.MethodsDOCA was used to induce hypertension and associated vascular dementia. Morris water maze (MWM) was used for testing learning and memory. Endothelial function was assessed by acetylcholine-induced endothelium-dependent relaxation of aortic strips. Different biochemical estimations were used to assess oxidative stress (aortic superoxide anion, serum and brain thiobarbituric acid reactive species, and brain glutathione), nitric oxide levels (serum nitrite/nitrate), and cholinergic activity (brain acetyl cholinesterase activity).ResultsDOCA treatment significantly raised the mean arterial blood pressure of rats, and these hypertensive rats performed poorly on MWM, reflecting impairment of learning and memory. DOCA treatment also impaired vascular endothelial function and different biochemical parameters. Treatments of NDDCT as well as lisinopril significantly attenuated DOCA hypertension-induced impairment of learning and memory, endothelial dysfunction, and changes in various biochemical levels.ConclusionsDOCA–salt hypertension induces vascular dementia in rats. NF-κB as well as ACE inhibitors may be considered as potential pharmacological agents for the management of hypertension-induced vascular dementia.

Modulation of Transient Receptor Potential Vanilloid Subtype 1 (TRPV 1 ) and Norepinephrine Transporters (NET) Protect Against Oxidative Stress, Cellular Injury, and Vascular Dementia

Chronic cerebral hypoperfusion (CCH) is a risk factor for the development of vascular dementia (VaD). CCH participates in a negative role in cognitive impairments. Transient receptor potential vanilloid subtype 1 (TRPV1) participates in cognition, ischemic damage and neuroprotection. Selective norepinephrine transporter (NET) inhibitors have a role in cognitive dysfunction and oxidative stress. The role of TRPV1 and NET in CCH induced VaD is still unknown. The present study has been structured to investigate the role of vanillin; a selective agonist of TRPV1 as well as atomoxetine; a selective NET inhibitor in CCH induced VaD in mice. Permanent bilateral common carotid arteries ligation or two vessel occlusion (2VO) technique was used to induce a stage of chronic cerebral hypoperfusion in mice. 2VO animals have shown significant impairment of locomotion (Actophotometer), motor coordination (Rota rod), learning and memory (Morris water maze). 2VO animals have shown significant reduction in brain catalase, glutathione, and superoxide dismutase, with significant increase in brain infarct size (TTC staining), malondialdehyde and acetyl cholinesterase-AChE activity. Whereas, administration of vanillin as well as atomoxetine has significantly attenuated 2VO induced impaired locomotion, motor coordination, learning and memory, brain damage, brain oxidative stress and higher AChE activity. It may be concluded that 2VO induced CCH has elicited VaD, which was attenuated by vanillin and atomoxetine. Thus, modulators of vanilloid receptors and norepinephrine transporter may be explored further for their benefits in CCH induced VaD.

Selective modulator of cannabinoid receptor type 2 reduces memory impairment and infarct size during cerebral hypoperfusion and vascular dementia.

Vascular dementia is the highly devastating neurodegenerative disorder after Alzheimers disease (AD) and mainly found in aged people but the effectual therapeutic target is still not there. Chronic cerebral hypoperfusion (CCH) has been broadly found in vascular dementia (VaD) patients. CCH is thought to link with neurodegenerative disorders and their subsequent cognitive deteriorate on. This study has been framed to examine the role of a selective agonist of cannabinoid receptor type 2(CB2); 1-phenylisatin in CCH induced VaD. Permanent bilateral common carotid arteries ligation or two vessels occlusion (2VO) technique was used to induce CCH in rats. 2VO animals have shown significant impairment in learning-memory (Morris water maze) and in executive functioning (Attentional set-shifting test). These animals have shown a considerable reduction in brain oxidative stress (thiobarbituric reactive acid substance-TBARS; glutathione-GSH; catalase-CAT and superoxide dismutase-SOD), mitochondrial dysfunction (complexes I, II, IV) with a significant enhancement in cholinergic activity- AChE and brain infarct size2,3,5-triphenylterazolium chloride staining (TTC staining). Animals treated with 2VO have also demonstrated a considerable augmentation in brain edema (water content). Oral administration of 1-phenylisatin has significantly recuperated 2VO induced impairment in learning-memory, an increase in TBARS, GSH, CAT, SOD, mitochondrial activity with a significant reduction in AChE activity and brain damage. Administration of 1- phenylisatin has also reported recovering brain edema in these animals. These results indicate that 2VO induced CCH in rats, which was attenuated with the treatment of 1-phenylisatin. Hence, it may be suggested that modulation of cannabinoid receptor may provide benefits in CCH as cognitive impairment and VaD. Therefore, selective agonists of CB2 receptors may be a potential research target for the alleviation of VaD.