Sirtuins as therapeutic targets for improving delayed wound healing in diabetes.

Sirtuins are a vast family of histone deacetylases, which are NAD+ dependent enzymes, consisting of seven members, namely SIRT 1, SIRT 6 and SIRT 7 located within the nucleus, SIRT 2 in the cytoplasm and SIRT 3, SIRT 4 and SIRT 5 in the mitochondria. They have vital roles in regulating various biological functions such as age-related metabolic disorders, inflammation, stress response, cardiovascular and neuronal functions. Delayed wound healing is one of the complication of diabetes, which can lead to lower limb amputation if not treated timely. SIRT 1, 3 and 6 are potent targets for diabetic wound healing. SIRT 1 deficiency reduces recruitment of fibroblasts, macrophages, mast cells, neutrophils to wound site and delays wound healing; negatively expressing MMP-9. The SIRT 1 mediated signalling pathway in diabetic wound healing is the SIRT 1-FOXO-c-Myc pathway. On the contrary, SIRT 3 deficiency impairs proliferation and migration of fibroblasts and SIRT 6 deficiency impairs wound closure rate and interrupts the vascular remodelling. This review focuses on the role of sirtuins in improving delayed wound healing in diabetes and its natural modulators with their specific functions towards healing diabetic wounds.

Beta-Caryophyllene, a CB2R Selective Agonist, Protects Against Cognitive Impairment Caused by Neuro-inflammation and Not in Dementia Due to Ageing Induced by Mitochondrial Dysfunction.

BACKGROUND: Dementia is a neurodegenerative disorder majorly evidenced by cognitive impairment. Although there are many types of dementia, the common underlying etiological factors in all the types are neuro-inflammation or aging induced apoptosis. ß-caryophyllene, a cannabinoid type-2 receptor agonist, has been reported to have promising neuroprotective effects in cerebral ischemia and neuro-inflammation. OBJECTIVE: In the present study, we evaluated the effects of ß-caryophyllene against animal models of dementia whose etiology mimicked neuro-inflammation and aging. METHODS: Two doses (50 and 100 mg/kg of body weight) of ß-caryophyllene given orally were tested against AlCl3-induced dementia in male Sprague Dawley (SD) rats using the Morris water maze test. Subsequently, the effect of the drug was assessed for episodic memory in female SD rats using novel object recognition task in doxorubicin-induced neuro-inflammation and chemobrain model. Moreover, its effects were evaluated in D-galactose-induced mitochondrial dysfunction leading to dementia. RESULTS: ß-caryophyllene, at both doses, showed significant improvement in memory when assessed using parameters like target quadrant entries, escape latency and path efficiency in the Morris water maze test for spatial memory. In the doxorubicin-induced chemobrain model, ß-caryophyllene at 100 mg/kg significantly elevated acetylcholinesterase and catalase levels and lowered lipid peroxidation compared to the disease control. In the novel object recognition task, ß-caryophyllene at 100 mg/kg significantly improved recognition index and discrimination index in the treated animals compared to the disease control, with a significant increase in catalase and a decrease in lipid peroxidation in both hippocampus and frontal cortex. However, in the D-galactose-induced mitochondrial dysfunction model, ß-caryophyllene failed to show positive effects when spatial memory was assessed. It also failed to improve D-galactose-induced diminished mitochondrial complex I and II activities. CONCLUSION: Hence, we conclude that ß-caryophyllene at 100 mg/kg protects against dementia induced by neuro-inflammation with no effect on neuronal aging induced by mitochondrial dysfunction.

Sesamol-Loaded PLGA Nanosuspension for Accelerating Wound Healing in Diabetic Foot Ulcer in Rats.

BACKGROUND: Diabetic foot ulcer is an intractable complication of diabetes, characterized by the disturbed inflammatory and proliferative phases of wound healing. Sesamol, a phenolic compound, has been known for its powerful antioxidant, anti-inflammatory, anti-hyperglycaemic and wound healing properties. The aim of the present study was to develop a sesamol nano formulation and to study its effect on the various phases of the wound healing process in diabetic foot condition. METHODS: Sesamol-PLGA (SM-PLGA) nanosuspension was developed  using nanoprecipitation method. TEM, in vitro drug release assay and in vivo pharmacokinetic studies were performed for the optimised formulation. Diabetic foot ulcer (DFU) in high fat diet (HFD)-fed streptozotocin-induced type-II diabetic animal model was used to assess the SM-PLGA nanosuspension efficacy. SM-PLGA nanosuspension was administered by oral route. TNF-α levels were estimated using ELISA and Western blot analysis was performed to assess the effect on the expression of HSP-27, ERK, PDGF-B and VEGF in wound tissue. Wound re-epithelization, fibroblast migration, collagen deposition and inflammatory cell infiltration were assessed by H&E and Masson's trichrome staining. Effect on angiogenesis was assessed by CD-31 IHC staining in wound sections. RESULTS: The optimized SM-PLGA nanosuspension had an average particle size of <300 nm, PDI<0.200 with spherical shaped particles. Approximately 80% of the drug was released over a period of 60 h in in vitro assay. Half-life of the formulation was found to be 13.947 ± 0.596 h. SM-PLGA nanosuspension treatment decreased TNF-α levels in wound tissue and accelerated the collagen deposition. Whereas, HSP-27, ERK, PDGF-B and VEGF expression increased and improved new blood vessels' development. Rapid re-epithelization, fibroblast migration, collagen deposition and reduced inflammatory cell infiltration at the wound site were also observed. CONCLUSION: Results indicate that sesamol-PLGA nanosuspension significantly promotes the acceleration of wound healing in diabetic foot ulcers by restoring the altered wound healing process in diabetic condition.

Erratum: Catechin ameliorates depressive symptoms in Sprague Dawley rats subjected to chronic unpredictable mild stress by decreasing oxidative stress.

[This corrects the article DOI: 10.3892/br.2019.1226.].

Catechin ameliorates depressive symptoms in Sprague Dawley rats subjected to chronic unpredictable mild stress by decreasing oxidative stress.

Catechin is an active ingredient of green tea. It is reported to inhibit corticosteroid-induced anxiety and depression-like symptoms. Considering the complex nature of depression, effects of catechin need to be studied in a clinically relevant depression model. The present study was designed to explore the antidepressant effect of catechin in Sprague Dawley rats subjected to chronic unpredictable mild stress (CUMS). Animals were subjected to CUMS and treated with (+)-catechin (50 mg/kg) or escitalopram (10 mg/kg) orally; a CUMS control and a vehicle control that was not exposed to CUMS were also established. Various stressors were applied daily in an unpredictable manner for 8 weeks achieve CUMS. Sucrose preference test were performed after 4 and 8 weeks and forced swim tests (FSTs) were conducted at weeks 4, 6 and 8. At the end of week 8, animals were sacrificed and the brain homogenate was studied for antioxidant parameters. Compared with the vehicle control, animals of the CUMS control group showed a significant decrease in sucrose intake. Catechin and escitalopram treatment significantly improved the sucrose intake compared with the CUMS control. A similar trend was observed in the FSTs, where catechin and escitalopram treatment significantly reduced the immobility time, and antioxidant parameters, including catalase, glutathione and superoxide dismutase levels were recovered in treated animals compared with the CUMS control. Thus, it was concluded that catechin reverses CUMS-induced depression in rats by ameliorating oxidative stress, which may help to develop a novel treatment for major depressive disorder.

Targeting glucose-dependent insulinotropic polypeptide receptor for neurodegenerative disorders.

INTRODUCTION: Incretin hormones, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide-1 (GLP-1) exert pleiotropic effects on endocrine pancreas and nervous system. Expression of GIP and GIP receptor (GIPR) in neurons, their roles in neurogenesis, synaptic plasticity, neurotransmission, and neuromodulation uniquely position GIPR for therapeutic applications in neurodegenerative disorders. GIP analogs acting as GIPR agonists attenuate neurobehavioral and neuropathological sequelae of neurodegenerative disorders in preclinical models, e.g. Alzheimer's disease (AD), Parkinson's disease (PD), and cerebrovascular disorders. Modulation of GIPR signaling offers an unprecedented approach for disease modification by arresting neuronal viability decline, enabling neuronal regeneration, and reducing neuroinflammation. Growth-promoting effects of GIP signaling and broad-based neuroprotection highlight the therapeutic potential of GIPR agonists. Areas covered: This review focuses on the role of GIPR-mediated signaling in the central nervous system in neurophysiological and neuropathological conditions. In context of neurodegeneration, the article summarizes potential of targeting GIPR signaling for neurodegenerative conditions such as AD, PD, traumatic brain injury, and cerebrovascular disorders. Expert opinion: GIPR represents a validated therapeutic target for neurodegenerative disorders. GIPR agonists impart symptomatic improvements, slowed neurodegeneration, and enhanced neuronal regenerative capacity in preclinical models. Modulation of GIPR signaling is potentially a viable therapeutic approach for disease modification in neurodegenerative disorders.

Long circulating PEGylated-chitosan nanoparticles of rosuvastatin calcium: Development and in vitro and in vivo evaluations.

The aim of this study was to improve the pharmacokinetics and pharmacodynamics profile of rosuvastatin calcium by formulating long-circulating PEGylated chitosan nanoparticles (NPs). Chitosan was PEGylated by a carbodiimide mediated reaction, using a carboxylic acid derivative of PEG (polyethylene glycol). The NPs were optimised for particle size, polydispersity index, zeta potential and drug entrapment efficiency. In vitro drug release, pharmacokinetic and pharmacodynamics studies of the optimized nanoparticles were performed. PEGylation of chitosan was confirmed by FTIR analysis. Drug-excipient compatibility was studied by differential scanning calorimetry and FTIR analyses. Two batches of nanoparticles were optimized with particle size of <200nm and entrapment efficiency of ≈14%. In vitro drug release studies revealed cumulative release of 14.07±0.57% and 22.02±0.81% of rosuvastatin over the period of 120h, indicating appreciable sustained release of drug. TEM analysis showed the spherical structure of nanoparticles. Pharmacokinetic studies indicated that optimized NPs showed prolonged drug release over a period of 72h. Pharmacodynamics studies in hyperlipidemic rat model demonstrated greater lipid-lowering capability of rosuvastatin nanoparticles in comparison with plain rosuvastatin. The nanoparticles demonstrated substantial prolonged delivery of the drug in vivo along with better therapeutic action, which could be potential drug delivery modality for 'statins'.

Insulin Combined with Glucose Improves Spatial Learning and Memory in Aluminum Chloride-Induced Dementia in Rats.

Therapeutic intervention using drugs against Alzheimer disease is curative clinically. At present, there are no reports on the curative role of insulin in chronic models of dementia. We evaluated the curative role of insulin and its combination with glucose in dementia. We also investigated the impact of treatments on blood glucose to correlate with cognitive deficit. Further, we analyzed the interaction of treatments with the cholinergic system and oxidative stress in memory centers (i.e., hippocampus and frontal cortex). The antidementia activity of insulin was assessed against aluminum chloride (AlCl3)-induced dementia in rats. Behavioral parameters (Morris water maze test) along with biochemical parameters (Hippocampus and frontal cortex) such as acetylcholinesterase (AChE), catalase, and glutathione (GSH) levels were assessed to correlate cognitive function with cholinergic transmission and oxidative stress. Rats administered insulin and glucose showed improved cognitive function in the Morris water maze test. The combination corrected the diminished level of antioxidant enzymes such as catalase and GSH in the hippocampus and frontal cortex.Combined administration of insulin and glucose to aluminum-treated rats did not inhibit the aluminum action on the acetylcholinesterase enzyme. No significant changes were observed in blood glucose levels between the treatment groups.

Effect of insulin on spatial memory in aluminum chloride-induced dementia in rats.

Latest reports suggest the involvement of insulin in modulating memory. A few published in-vitro studies favor the antidementia effect of insulin. Thus, the present study aimed to evaluate the prophylactic role of insulin and its combination with glucose and its possible mechanism(s) in an aluminum chloride (AlCl3)-induced cognitive dysfunction model in rodents, with a special focus on memory centers namely, the hippocampus and the frontal cortex. Male Wistar rats were exposed to AlCl3 (175 mg/kg orally) for 60 days. Insulin (0.5 IU/kg), Insulin (0.5 IU/kg) in combination with glucose (200 mg/kg), and rivastigmine (1 mg/kg) were administered intraperitoneally 45 min before the administration of AlCl3 for 60 days. Spatial memory was assessed using the Morris water-maze test. After 60 days of treatment, animals were killed, and the hippocampus and frontal cortex were collected and analyzed for acetylcholinesterase activity and antioxidant enzyme level. Blood glucose levels were also analyzed. Treatment with the standard drug, rivastigmine (1 mg/kg), produced a significant reduction in escape latency and increased the time spent in the target quadrant compared with the AlCl3-treated group. Insulin and its combination with glucose could not inhibit the behavioral impairments in aluminum-exposed rats. Treatment with insulin alone and its combination with glucose reversed the increased glucose levels. Insulin alone and its combination with glucose could not inhibit aluminum-induced oxidative stress and impaired cholinergic transmission in the hippocampus and frontal cortex regions. The study suggests the inability of prophylactic insulin administration against cognitive dysfunction induced by environmental toxin (AlCl3) in the hippocampus and the frontal cortex.

Rutin protects against neuronal damage in vitro and ameliorates doxorubicin-induced memory deficits in vivo in Wistar rats.

Doxorubicin (DOX) is the most widely used broad-spectrum anticancer agent, either alone or in combination, for most cancers including breast cancer. Long-term use of chemotherapeutic agents to treat breast cancer patients results in cognitive complications with a negative impact on survivors' quality of life. The study objective was to evaluate rutin (RUT) for its neuroprotective effect against DOX in human neuroblastoma (IMR32) cells in vitro and study its potential to ameliorate DOX-induced cognitive dysfunction in Wistar rats. Cell viability assay (3-[4,5 dimethyl thiazol-2-yl]-2,5-diphenyl tetrazolium bromide), neurite growth assay, detection of apoptosis by (acridine orange/ethidium bromide) staining, intracellular reactive oxygen species (ROS) assay, and flowcytometric analysis were carried out to assess neuroprotective potential against DOX. An in vivo study was conducted for assessing protective effect of RUT against memory deficit associated with DOX-induced chemobrain using object recognition task (ORT). Locomotion was assessed using open field test. Serum biochemistry, acetylcholinesterase, oxidative stress markers in hippocampus, and frontal cortex were assessed. Histopathological analysis of major organ systems was also carried out. Prior exposure to RUT at 100 µM protected IMR32 cells from DOX (1 µM) neurotoxicity. DOX exposure resulted in increased cellular death, apoptosis, and intracellular ROS generation with inhibition of neurite growth in differentiated IMR32 cells, which was significantly ameliorated by RUT. Cognitive dysfunction was induced in Wistar rats by administering ten cycles of DOX (2.5 mg/kg, intra-peritoneal, once in 5 days), as we observed significant impairment of episodic memory in ORT. Coadministration with RUT (50 mg/kg, per os) significantly prevented memory deficits in vivo without any confounding influence on locomotor activity. RUT also offered protection against DOX-induced myelosuppression, cardiotoxicity, and nephrotoxicity. In conclusion, RUT may be a possible adjuvant therapeutic intervention to alleviate cognitive and other complications associated with DOX chemotherapy.

Atypical Antidepressant Activity of 3,4-Bis(3,4-Dimethoxyphenyl) Furan-2,5-Dione Isolated from Heart Wood of Cedrus deodara, in Rodents

Cedrus deodara (Pinaceae) has been used traditionally in Ayurveda for the treatment of central nervous system disorders. 3,4-bis(3,4-dimethoxyphenyl)furan-2,5-dione (BDFD) was isolated from heart wood of Cedrus deodara and was shown to have antiepileptic and anxiolytic activity. Thus, the present study was aimed to explore its anti-depressant effect and to correlate the effect with serotonin and nor adrenaline levels of brain. Albino mice were used as experimental animal. Animals were divided in to three groups; vehicle control, imipramine (30 mg/kg i.p.), BDFD (100 mg/kg i.p.). Tail suspension test (TST) and forced swim test (FST) was performed to evaluate antidepressant effect of BDFD. BDFD (100 mg/kg, i.p.) showed a significant decrease in immobility time when subjected to FST whereas immobility time was not significantly altered in TST. BDFD treatment increased serotonin and noradrenaline levels in the brain which is indicative of BDFD having possible atypical antidepressant action.

Impact of caffeic acid on aluminium chloride-induced dementia in rats.

OBJECTIVE: Literature favours the in vitro neuroprotective role of caffeic acid, a naturally derived polyphenolic compound. This study was aimed to investigate the role of caffeic acid in experimental model of Alzheimer's disease. METHODS: Firstly, caffeic acid was tested for in vitro anticholinesterase potential using rat brain homogenate. Later, in vivo antidementia activity of caffeic acid was assessed against aluminium chloride (AlCl3 )-induced dementia in rats. Behavioural (Morris water maze test) and brain biochemical parameters (acetylcholinesterase (AChE), catalase, glutathione-S-transferase (GST) activity, glutathione (GSH) and nitrite levels) were assessed to correlate the cognitive function with cholinergic transmission and oxidative stress. KEY FINDINGS: Rats administered with caffeic acid showed improved cognitive function in Morris water maze test. The antidementia activity of caffeic acid was confirmed by the reduction in brain AChE activity and nitrite levels. Further, caffeic acid corrected the diminished level of antioxidant enzymes such as catalase, GSH and GST in brain. CONCLUSION: These findings suggest the antidementia activity of caffeic acid against AlCl3 -induced dementia in rats. The outcome of present study offers a wider scope to screen caffeic acid against neurodegeneration associated disorders.

Synthesis and antihistaminic activity of 3H-benzo [4,5] thieno [2,3-d][1,2,3] triazin-4-ones.

In the present study the antihistaminic activity of tricyclic benzothieno 1,2,3-triazine derivatives namely CP-3 (3-(phenyl)-5,6,7,8-tetrahydro,3H-benzo[4,5] thieno [2,3-d][1,2,3] triazin-4-one), CP-5 (3-(3-methyl phenyl)-5,6,7,8-tetrahydro,3H-benzo[4,5] thieno [2,3-d][1,2,3] triazin-4-one) and CP-8 (3-(4-chloro phenyl)-5,6,7,8-tetrahydro,3H-benzo[4,5] thieno [2,3-d][1,2,3] triazin-4-one) were evaluated using in vitro (isolated guinea pig ileum) and in vivo (bronchodilator activity in guinea pigs) models and the sedative potential of the test compounds were evaluated using actophotometer in mice. In in vitro antihistaminic study, the CP-3, CP-5, CP-8 and chlorpheniramine maleate (CPM) have shown a rightward shift in concentration response curve (CRC) of histamine with a change in EC50 values of histamine in all the four tissue preparations. The slope obtained in the schild plot indicated that CP-5, CP-8 and CPM were competitive in nature for H1-receptors. However, CP-3 has shown non-competitive antagonism. In in vivo antihistaminic study, the CP-3, CP-5, CP-8 and CPM have shown mean increase in exposition time against histamine challenge compared to control group (p < 0.001). All the test drugs (10 mg/kg) and CPM (2 mg/kg) have offered a significant (p < 0.001) protection against preconvulsive dyspnoea (PCD) compared to control. In conclusion, all the test drugs have shown very good antihistaminic activity and the test drugs have very little sedative action compared to CPM.

Antidiarrheal effect of fractions from stem bark of Thespesia populnea in rodents: Possible antimotility and antisecretory mechanisms.

OBJECTIVE: To evaluate antidiarrheal activity of the fractions of aqueous extract from stem barks of Thespesia populnea (Malvaceae). METHODS: From the aqueous extract three fractions namely ethyl acetate fraction (EAF), methanolic fraction (MF) and residue fraction (RF) were made and studied for antidiarrheal activity. Antidiarrheal activity of the fractions were evaluated in castor oil induced diarrhea, prostaglandin E(2) (PG-E(2)) induced diarrhea and charcoal meal test as in vivo models and the most potent fraction was further evaluated with in vitro models to determine the possible antimotility effect. RESULTS: In castor oil induced diarrhea model, the RF (10, 25, 50 and 100 mg/kg, po.) and MF (100 mg/kg, po.) has significantly reduced the cumulative wet faecal mass, where as the EAF have not shown any significant antidiarrheal activity, RF was found to be more potent than MF. Based on these results and percentage yield, only RF was evaluated in PG-E(2) induced enteropooling and charcoal meal test. RF (10, 25 and 50 mg/kg) had shown significant inhibition of PG-E(2) induced secretions (antisecretory) and decreased the movement of charcoal in charcoal meal test indicating its antimotility activity. Furthermore, RF has showed significant inhibition of acetylcholine, histamine and BaCl(2) induced contractions on rat colon, guinea pig ileum and rabbit jejunum with EC(50) values of 241.7, 303.1 and 286.1 µg/mL, respectively indicating the antimotility effect of RF. The phytochemical analysis of RF showed presence of gums and mucilages and the possible mechanism may be the combination inhibition of elevated prostaglandin biosynthesis and reduced propulsive movement of the intestine. CONCLUSIONS: RF possesses good antidiarrheal activity comparing with other two fractions and the possible mechanism thought to be associated with combination of antisecretory and antimolity.