Pre-Treatment with Metformin in Comparison with Post-Treatment Reduces Cerebral Ischemia Reperfusion Induced Injuries in Rats

MPO and its role in cancer, cardiovascular and neurological disorders: An update

Myeloperoxidase (MPO) is an enzyme that contains a heme group, found mostly in neutrophils and in small amounts in monocytes and plays a major role in their anti-microbial activity. However, excessive levels of MPO have been linked to various disorders and identified as a major cause of tissue destruction. Inhibiting its activity can reduce the severity and extent of tissue damage. Over activity of MPO during chronic inflammation has been shown to be involved in tumorigenesis by inducing a hyper-mutagenic environment through oxidant interaction with DNA, causing DNA modification. Vascular endothelium is one of the most important targets of MPO and high levels have been associated with increased rates of cardiomyopathy, ischemic stroke, heart failure, myocardial infarction, and atrial fibrillation. Therefore, it may be considered a therapeutic target in the treatment of cardiovascular disorders. MPO also participates in the pathogenesis of neurodegenerative diseases. For example, an increase in MPO levels has been observed in the brain tissue of patients with Alzheimer's, Multiple sclerosis (MS), and Parkinson's diseases. In Alzheimer's disease, active MPO is mostly found in the location of beta amyloids and microglia. Therefore, targeting MPO may be a potential treatment and prevention strategy for neurological disorders. This review will discuss MPO's physiological and pathological role in cancer, cardiovascular, and neurological disorders.

Neuroprotective Effects of Metformin in Stroke Patients: A Systematic Review and Meta-analysis of Cohort Studies

OBJECTIVES

People with diabetes are 1.5 times more likely to experience stroke than those without diabetes, underlining the urgent need to address this issue. Metformin is often the initial medication chosen to manage diabetes mellitus (DM). The purpose of our systematic review and meta-analysis is to explore the potential neuroprotective effects of metformin in individuals who have received it prior to stroke.

METHOD

Our study encompassed cohort studies that drew a comparison between the severity and diverse outcomes of stroke among individuals with DM who were administered metformin prior to the stroke event and those with DM who did not receive the treatment.

RESULTS

Ten studies met the eligibility criteria. Prestroke metformin use was associated with a significantly lower National Institutes of Health Stroke Scale score (mean difference = -1.29, 95% confidence interval: -2.11 to -0.47) in ischemic stroke. Metformin pretreatment in ischemic stroke was associated with increased odds of favorable outcome (mRS < 2) at 90 days (odds ratio [OR] = 1.45, 95% confidence interval [CI]: 1.06 to 1.99), but it was not significant at discharge. Metformin was found to be associated with reduced mortality (OR = 0.52, 95% CI: 0.42 to 0.64) in ischemic stroke. In hemorrhagic stroke, the results showed a significantly lower intracranial hemorrhage volume in prestroke metformin use (mean difference = -4.77, 95% CI: -6.56 to -2.98).

CONCLUSIONS

We found that prestroke metformin use in diabetic patients yielded neuroprotective effects. In ischemic strokes, metformin reduces stroke severity and 90-day mortality; it also improves 90-day functional outcomes. In hemorrhagic strokes, prestroke metformin use can also cause less intracranial hemorrhage volume. Further clinical trials are needed to confirm its efficacy and verify its benefits in stroke management.

Repurposing metformin: A potential off-label indication for ischaemic stroke?

The term 'clinical cemetery' is frequently used to characterize ischaemic stroke, one of the leading causes of mortality and long-term morbidity globally. Over the past two decades, a number of novel therapies have been investigated for ischaemic stroke. However, aside from mechanical thrombectomy, the only FDA-approved prescription for treating ischaemic stroke is tissue plasminogen activator, which has a limited therapeutic period. Although post-stroke rehabilitation therapies are helpful in improving functional recovery, their benefits cannot be yielded promptly. Nowadays, drug repurposing might be an appealing approach to expanding therapeutic options for ischaemic stroke. During the last decade, metformin has been extensively researched as a potential repurposing medicine for ischaemic stroke, with a focus on both preventive and therapeutic approaches. With regard to the idea of repurposing metformin in ischaemic stroke, this review aims to compile the available data from pre-clinical and clinical trials, address and clarify any discrepancies, and offer solutions.

SGLT-2 Inhibitors' and GLP-1 Receptor Agonists' Influence on Neuronal and Glial Damage in Experimental Stroke

Background: SGLT-2 inhibitors (SGLT-2i) and GLP-1 receptor agonists (GLP-1RA) have demonstrated nephro- and cardioprotective effects, but their neuroprotective properties, especially concerning stroke severity, and mechanisms are not unambiguous. We aimed to study the influence of SGLT-2i with different selectivity and GLP-1RA on brain damage volume and neurological status in non-diabetic and diabetic rats and to investigate the underlying mechanisms. Methods: Non-diabetic Wistar rats were divided into five groups (n = 10 each) and received empagliflozin, canagliflozin, or dulaglutide as study drugs and metformin as comparison drug. Control animals were administered 0.9% NaCl for 7 days before stroke. At 48 h after stroke, we assessed neurological deficit, neuronal and astroglial damage markers, and brain damage volume. We also modeled type 2 DM in Wistar rats using the high-fat diet+nicotinamide/streptozotocin method and established similar treatment groups. After 8 weeks, rats were subjected to stroke with further neurological deficit, neuroglial damage markers, and brain necrosis volume measurement. Results: In non-diabetic rats, all the drugs showed an infarct-limiting effect; SGLT-2i and dulaglutide were more effective than metformin. DULA improved neurological status compared with MET and SGLT-2i treatment. All the drugs decreased neurofilament light chains (NLCs) level and neuronal damage markers, but none of them decreased the glial damage marker S100BB. In DM, similarly, all the drugs had infarct-limiting effects. Neurological deficit was most pronounced in the untreated diabetic rats and was reduced by all study drugs. All the drugs reduced NLC level; dulaglutide and empagliflozin, but not canagliflozin, also decreased S100BB. None of the drugs affected neuron-specific enolase. Conclusions: SGLT-2i and GLP-1RA are neuroprotective in experimental stroke. GLP-1RA might be more effective than SGLT-2i as in non-diabetic conditions it influences both brain damage volume and neurological status. All study drugs decrease neuronal damage, while GLP-1RA and highly selective SGLT-2i EMPA, but not low-selective CANA, also have an impact on neuroglia in diabetic conditions.

Comparative study of the neuroprotective potential of semaglutide injectable preparations in experimental ischemic stroke

Introduction. Stroke remains one of the major causes of death in type diabetes mellitus (DM). Injectable form of glucagon-like peptide-1 receptor agonist semaglutide, Ozempic® decreases the stroke risk. In Russia there appeared a biosimilar Semavic® but its effects on the brain are not yet studied.

Aim. To compare neuroprotective properties of Semavic® and Ozempic® while used before ischemic stroke in rats without DM.

Materials and methods. The study was conducted in male Wistar rats that were divided into the following groups: “Control” (n = 10) – 0.9% NaCl, “MET” (n = 9) – metformin 200 mg/kg once daily per os, “Ozempic” (n = 10) – Ozempic® 0.012 mg/kg s.c. once daily, “Semavic” (n = 9) – Semavic® 0.012 mg/kg s.c. once daily. After 7 days ischemic stroke was modelled, after 48 hour of reperfusion neurological deficit and brain damage volume were evaluated. Glycemia was measured on the 3rd, 7th days as well as during and after ischemia.

Results. None of the study drugs caused hypoglycemia including in poststroke period. Neurological deficit in “MET” group did not differ from that in the “Control” (11.00 [6.50; 12.50] and 10.0 [6.25; 12.00] scores). Both semaglutide drugs caused comparable improvement in neurological status (14.00 [12.00; 18.00] and 14.00 [11.00; 18.00] scores in “Ozempic” and “Semavic” groups). Brain necrosis volume in “Control” group was 16.60 [13.40; 28.58] %. All the study drugs had infarct-limiting effect but brain damage volume in “Ozempic” (6.00 [4.32; 8.44] %) and “Semavic” (7.69 [2.99; 11.33] %) was smaller than in “MET” group (13.07 [8.67; 29.94] %). There were no differences between semaglutide drugs.

Conclusions. Biosimilar Semavic® and original Ozempic® demonstrate comparable neuroprotective effect while used in animals without DM prior to ischemic stroke modelling. This protective effect is not due to the drugs’ influence on glycemic profile.

Promising use of metformin in treating neurological disorders: biomarker-guided therapies

Neurological disorders are a diverse group of conditions that affect the nervous system and include neurodegenerative diseases (Alzheimer's disease, multiple sclerosis, Parkinson's disease, Huntington's disease), cerebrovascular conditions (stroke), and neurodevelopmental disorders (autism spectrum disorder). Although they affect millions of individuals around the world, only a limited number of effective treatment options are available today. Since most neurological disorders express mitochondria-related metabolic perturbations, metformin, a biguanide type II antidiabetic drug, has attracted a lot of attention to be repurposed to treat neurological disorders by correcting their perturbed energy metabolism. However, controversial research emerges regarding the beneficial/detrimental effects of metformin on these neurological disorders. Given that most neurological disorders have complex etiology in their pathophysiology and are influenced by various risk factors such as aging, lifestyle, genetics, and environment, it is important to identify perturbed molecular functions that can be targeted by metformin in these neurological disorders. These molecules can then be used as biomarkers to stratify subpopulations of patients who show distinct molecular/pathological properties and can respond to metformin treatment, ultimately developing targeted therapy. In this review, we will discuss mitochondria-related metabolic perturbations and impaired molecular pathways in these neurological disorders and how these can be used as biomarkers to guide metformin-responsive treatment for the targeted therapy to treat neurological disorders.

Neuroprotective effects of ivermectin against transient cerebral ischemia-reperfusion in rats

Stroke is a leading cause of disability and death worldwide. Ivermectin is a broad-spectrum anti-parasitic agent with potential anti-bacterial, anti-viral, and anti-cancer effects. However, the effects of ivermectin on the brain are poorly described. This study examined the effects of ivermectin on cerebral ischemia-reperfusion (IR) in rats. A rat model of transient global IR was induced by bilateral carotid artery occlusion for 20 min. Rats received ivermectin (2 mg/kg/day, ip) one hour after inducing cerebral IR for three consecutive days at 24-h intervals. Next, we examined the effects of ivermectin on brain infarction, histopathology, malondialdehyde levels, myeloperoxidase activity, spatial learning and memory, and phospho-AMPK protein levels. The results showed that ivermectin reduced brain infarct size (P < 0.001) and histopathological changes such as cerebral leukocyte accumulation and edema (P < 0.05) compared to untreated rats with IR. Treatment with ivermectin also decreased myeloperoxidase activity (P < 0.01) and malondialdehyde levels (P < 0.05) while increasing AMPK activity (P < 0.001), memory, and learning compared to the untreated IR group. Overall, we show for the first time that ivermectin conferred neuroprotective effects in a rat model of cerebral IR. Our results indicate that three days of treatment with ivermectin reduced brain infarct size, lipid peroxidation, and myeloperoxidase activity and improved memory and learning in rats with cerebral IR. These effects likely occurred via AMPK-dependent mechanisms.

Neuroprotective effects of glucose-lowering drugs in rat focal brain ischemia-reperfusion model

Background.Ischemic stroke is one of the leading causes of death in patients with type 2 diabetes mellitus (DM). According to the results of clinical and experimental studies, the ability of glucagon-like peptide-1 receptor agonists (GLP-1RA) to reduce the risk and severity of stroke in DM has been proven; data on the sodium-glucose cotransporter-2 inhibitors (SGLT-2i) effect are scarce. There has been no direct comparative study of the GLP-1RA and SGLT-2i neuroprotective effect.

Objective.To evaluate and to compare the effect of GLP-1RA of varying duration of action and SGLT-2i of varying selectivity on the neurological deficit severity and the brain damage volume in a transient focal brain ischemia model in rats without DM.

Design and methods.Male Wistar rats were divided into groups (n = 10 each) depending on the therapy received: “EMPA” (empagliflozin per os 2 mg/kg once daily), “CANA” (canagliflozin per os 25 mg/kg once daily), “LIRA” (liraglutide 1 mg/kg s. c. once daily), “DULA” (dulaglutide 0,12 mg/kg s. c. every 72 hours), “SEMA” (semaglutide 0,012 mg /kg s. c. once daily), “MET” (metformin per os 200 mg/kg once daily — comparison group), “Control” (administration of 0,9 % NaCl solution s. c. once daily). After 7 days, all groups underwent transient focal 30-minute filament middle cerebral artery occlusion. After 48 hours of reperfusion, neurological deficit was assessed using the Garcia scale, then the brain was collected and sections were stained with 1 % triphenyltetrazolium chloride solution to calculate the damage volume.

Results.Neurological deficit severity in the “LIRA” (14,50 (12,25; 15,25) points) and “SEMA” (14,00 (13,50; 18,00) points) groups was significantly less than in the “Control” group (11.00 (6,75; 12,00) points). The use of both SGLT-2i, as well as metformin, had no effect on the neurological status. At the same time, therapy with all study drugs had an infarct-limiting effect, compared with the “Control” group (damage volume 24,50 (14,69; 30,12) % of the total brain volume). At the same time, the brain damage volume in the “MET” group (12,93 (6,65, 26,66) %) was greater than that in the “EMPA” (6,08 (2,97, 7,63) %), “CANA” (5,11 (3,96; 8,34) %), “LIRA” (3,40 (2,09; 8,08) %), “DULA” (4,37 (2,72; 5,40) %), “SEMA” (5,19 (4,11; 7,83) %) groups.

Conclusions.SGLT-2i of varying selectivity and GLP-1RA of varying duration of action have a similar infarct-limiting effect in acute experimental brain ischemia. At the same time, GLP-1RA neuroprotective potential is higher, as it is characterized by an additional positive effect on the neurological status.

Metformin treatment and acute ischemic stroke outcomes in patients with type 2 diabetes: a retrospective cohort study

BACKGROUND AND PURPOSE

Preclinical studies have shown that metformin has neuroprotective actions in stroke. However, the optimal treatment timing and duration remain unknown. Herein, we examined the efficacy of metformin treatment on prognosis in acute ischemic stroke (AIS) patients, and assessed the optimal treatment timing and duration.

METHODS

AIS patients with type 2 diabetes mellitus were retrospectively enrolled. Patients were grouped into those who never received metformin (MET - group), those who received metformin continuously before stroke and after admission (pre-stroke + /post-stroke + group), those who only received metformin before stroke onset (pre-stroke + /post-stroke - group), and those who only received metformin after admission (pre-stroke - /post-stroke + group). The all MET + group represents the sum of the three metformin treatment groups. The efficacy outcome was the 90-day modified Rankin Scale (mRS) score.

RESULTS

In total, 309 eligible patients were included (MET - [N = 130], pre-stroke + /post-stroke + [N = 94], pre-stroke + /post-stroke - [N = 30], pre-stroke - /post-stroke + [N = 55]; all MET + [N = 179]). The all MET + group had a trend toward a lower 90-day mRS score compared with that in the MET - group (1 [0-2] vs 1 [0-3], unadjusted odds ratio [OR] = 0.652, P = 0.041; adjusted OR = 0.752, P = 0.218). In the three metformin treatment groups, only the pre-stroke + /post-stroke + group had a significantly lower 90-day mRS score (1 [0-1] vs 1 [0-3], adjusted OR = 0.497, 95%CI = 0.289-0.854; P = 0.011) and higher proportion of mRS score 0-1 (78.7% vs. 61.5%, adjusted OR = 2.278, 95%CI = 1.108-4.680; P = 0.025) than the MET - group.

CONCLUSION

AIS patients with type 2 diabetes mellitus who receive continuous metformin treatment before stroke onset and after admission have improved functional outcome at 90 days.

Pre-Ischemic Oxytocin Treatment Alleviated Neuronal Injury via Suppressing NF-κB, MMP-9, and Apoptosis Regulator Proteins in A Mice Model of Stroke

OBJECTIVE

This study was designed to determine the effects of pre-ischemic administration of oxytocin (OXT) on neuronal injury and possible molecular mechanisms in a mice model of stroke.

MATERIALS AND METHODS

In this experimental study, stroke was induced in the mice by middle cerebral artery occlusion (MCAO) for 60 minutes and 24 hours of reperfusion. OXT was given as intranasal daily for 7 consecutive days before ischemic stroke. Neuronal damage, spatial memory, and the expression levels of nuclear factor-kappa B (NF-κB), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9), brain-derived neurotrophic factor (BDNF) and apoptosis were assessed 24 hours after stroke.

RESULTS

Pre-ischemic treatment with OXT significantly reduced the infarct size (P<0.01); but did not recover the neurological and spatial memory dysfunction (P>0.05). Moreover, OXT treatment considerably decreased the expressions of NF-κB, TNF-α, IL-1β, and MMP-9 (P<0.001) and enhanced the level of BDNF protein. OXT treatment also significantly downregulated Bax expression and overexpressed Bcl-2 proteins.

CONCLUSION

The finding of this study indicated that administration of OXT before ischemia could limit brain injury by inhibiting MMP-9 expression, apoptosis, inflammatory signaling pathways, and an increase in the BDNF protein level. We suggested that OXT may be potentially useful in the prevention and/or reducing the risk of the cerebral stroke attack, and could be offered as a new prevention option in the clinics.

Post-treatment with metformin improves random skin flap survival through promoting angiogenesis in rats

Skin flap necrosis has been remained as an unsolved problem in plastic and reconstructive surgeries. Here, we explored the effects of metformin post-treatment on random skin flap survival in rats. An 8.00 × 2.00 cm dorsal skin flap was created in 24 rats and they were then divided into three groups (n = 8) including Control, metformin (Met) 50.00 mg kg^-1 and Met 100 mg kg^-1. All animals were administrated orally until seven days after flap surgery. Flap survival, the number of blood vessels and mast cells in the flap tissues were analyzed. Vascular endothelial growth factor (VEGF) expression levels in flap tissues was also determined using immunohistochemical methods. The percentage of survival area in Met 50.00 mg kg^-1 and Met 100 mg kg^-1 groups were significantly higher compared to control. The blood vessel density and the VEGF positive cells in the viable areas of flaps showed a significant increase in Met 50.00 mg kg^-1 group compared to control group. The results of this study suggested that treatment with metformin, especially with low dose following skin flap surgery was effective in improving the flap survival and increasing the neovascularization in the flaps tissues of rats.

The Protective Effect of miR-27-3p on Ischemia-Reperfusion-Induced Myocardial Injury Depends on HIF-1α and Galectin-3

Cardiac ischemia-reperfusion injury usually results in acute myocardial infarction (AMI). MiRNAs have been identified as key regulators of AMI. This study was carried out to investigate the effect of miR-27-3p on cardiomyocyte injury in AMI. CCK-8 and flow cytometry assays were used to evaluate cell viability and apoptosis. The expression levels of miR-27-3p, galectin-3, and hypoxia-inducible factor-1α were measured by qRT-PCR. The relationship among miR-27-3p, galectin-3, and HIF-1α was assessed by bioinformatics analysis and luciferase assay. The effects of miR-27-3p and/or galectin-3 and HIF-1α on the inhibition of cell viability and apoptosis induced by H/R were explored. The expression levels of apoptosis-related proteins were determined by Western blot analysis. The expression levels of miR-27-3p were reduced in both ischemia-reperfusion myocardium and HL-1 cells during hypoxia. Overexpression of miR-27-3p reduced I/R-induced myocardial injury, and HIF-1α can reduce this effect. H/R reduced the expression levels of miR-27-3p in HL-1 cardiomyocytes, and HIF1-α reduced this effect, indicating that HIF1-α could regulate the expression of miR-27-3p, and galectin-3 was a target of miR-27-3p. Finally, overexpression of galectin-3 reduced the protective effect of miR-27-3p on cardiomyocyte injury. The expression levels of HIF1-α were increased, and miR-27-3p was downregulated after AMI. HIF-1α promoted myocardial protection by upregulating miR-27-3p, and downregulation of miR-27-3p promoted myocardium cell injury by targeting galectin-3.

Neuroprotective effect of green and roasted coffee bean extracts on cerebral ischemia-induced injury in rats

Stroke is a lethal event with a high incidence in Egypt. Quick early intervention can be lifesaving. Transient global ischemia (TGI), a type of ischemic stroke, is mainly instigated by cardiac arrest. Ischemia followed by reperfusion causes further neuronal cell damage. In this study, we aimed to evaluate the potential apoptotic, anti-inflammatory, and neuroprotective effects of green (GCBE) and roasted (RCBE) coffee bean water extract against transient global ischemia-induced via a bilateral common carotid artery occlusion (CAO) in rats. Before CAO, 1.5 ml/kg body weight/day of GCBE or RCBE was administered for 14 days by oral gavage. Ischemia/reperfusion (I/R) and sham groups were treated with a vehicle. Oxidative stress biomarkers and antioxidant enzyme activities, such as MDA, NO, GSH, SOD, CAT, GR, GPx, inflammatory markers TNF-α, IL-1β, and NF-κB, and BDNF were investigated. Quantitative real-time PCR analysis of mitogen-activated protein kinase pathways, in addition to heme oxygenase 1, and nuclear factor erythroid 2-related factor 2 were determined. Apoptotic markers, including Bcl-2, Bax, and caspase 3, in addition to the vascular endothelial growth factor-a, were investigated, followed by an examination of hippocampal histopathology. Pre-administration of GCBE and RCBE improved neurological function and neuronal survival, suppressed the spread of oxidative stress, inflammation, and apoptosis, and reversed most of the pathological changes. However, green coffee bean extract was more effective than roasted coffee bean extract, perhaps due to the roasting process, which may affect active compounds. In conclusion, GCBE and RCBE represent a potential clinical strategy for pre-ischemic conditioning.

Renal Delivery of Pharmacologic Agents During Machine Perfusion to Prevent Ischaemia-Reperfusion Injury: From Murine Model to Clinical Trials

Donor organ shortage still remains a serious obstacle for the access of wait-list patients to kidney transplantation, the best treatment for End-Stage Kidney Disease (ESKD). To expand the number of transplants, the use of lower quality organs from older ECD or DCD donors has become an established routine but at the price of increased incidence of Primary Non-Function, Delay Graft Function and lower-long term graft survival. In the last years, several improvements have been made in the field of renal transplantation from surgical procedure to preservation strategies. To improve renal outcomes, research has focused on development of innovative and dynamic preservation techniques, in order to assess graft function and promote regeneration by pharmacological intervention before transplantation. This review provides an overview of the current knowledge of these new preservation strategies by machine perfusions and pharmacological interventions at different timing possibilities: in the organ donor, ex-vivo during perfusion machine reconditioning or after implementation in the recipient. We will report therapies as anti-oxidant and anti-inflammatory agents, senolytics agents, complement inhibitors, HDL, siRNA and H2S supplementation. Renal delivery of pharmacologic agents during preservation state provides a window of opportunity to treat the organ in an isolated manner and a crucial route of administration. Even if few studies have been reported of transplantation after ex-vivo drugs administration, targeting the biological pathway associated to kidney failure (i.e. oxidative stress, complement system, fibrosis) might be a promising therapeutic strategy to improve the quality of various donor organs and expand organ availability.

Repurposing metformin to treat age-related neurodegenerative disorders and ischemic stroke

Aging is a risk factor for major central nervous system (CNS) disorders. More specifically, aging can be inked to neurodegenerative diseases (NDs) because of its deteriorating impact on neurovascular unit (NVU). Metformin, a first line FDA-approved anti-diabetic drug, has gained increasing interest among researchers for its role in improving aging-related neurodegenerative disorders. Additionally, numerous studies have illustrated metformin's role in ischemic stroke, a cerebrovascular disorder in which the NVU becomes dysfunctional which can lead to permanent life-threatening disabilities. Considering metformin's beneficial preclinical actions on various disorders, and the drug's role in alleviating severity of these conditions through involvement in commonly characterized cellular pathways, we discuss the potential of metformin as a suitable drug candidate for repurposing in CNS disorders.

Pretreatment with bisoprolol and vitamin E alone or in combination provides neuroprotection against cerebral ischemia/reperfusion injury in rats

Global cerebral ischemia/reperfusion (I/R) induces selective neuronal injury in the hippocampus, leading to severe impairment in behavior, learning, and memory functions. This study aimed to evaluate the neuroprotective effects of bisoprolol (biso) and vitamin E (vit E) treatment alone or in combination on cerebral ischemia/reperfusion (I/R) injury. A total of 30 male rats were divided randomly into five groups (n = 6), sham, I/R, I/R + biso, I/R + vit E, and I/R + biso+vit E. Cerebral I/R group underwent global ischemia by bilateral common carotid artery occlusion for 20 min. Treatment groups received drugs once daily intraperitoneally for 7 days before the I/R induction. Locomotive and cognitive behaviors were utilized by open-field and Morris water maze tests. After behavioral testing, the brain was removed and processed to evaluate cerebral infarct size, histopathologic changes, myeloperoxidase (MPO) activity, and malondialdehyde (MDA) level. In I/R group tissue MDA and MPO levels and cerebral infarct size were significantly increased in comparison with the sham group. Furthermore, significant deficits were observed in locomotion and spatial memory after I/R. The areas of cerebral infarction, MPO, and MDA levels in biso, vit E, and combination group were significantly reduced compared with I/R group. Histopathological analysis demonstrated a significant reduction in leukocyte infiltration in all treated groups with the most profound reduction in the combination group. According to the behavioral tests, administration of biso and/or vit E protected locomotive ability and improved spatial memory after cerebral I/R. Our findings show that biso and vit E have beneficial effects against the I/R injury and due to their synergistic effects when administered in combination, may have a more pronounced protective effect on the cerebral I/R injury.

Metformin: A Novel Weapon Against Inflammation

It has become widely accepted that inflammation is a driving force behind a variety of chronic diseases, such as cardiovascular disease, diabetes, kidney disease, cancer, neurodegenerative disorders, etc. However, the existing nonsteroidal anti-inflammatory drugs show a limited utility in clinical patients. Therefore, the novel agents with different inflammation-inhibitory mechanisms are worth pursuing. Metformin, a synthetic derivative of guanidine, has a history of more than 50 years of clinical experience in treating patients with type 2 diabetes. Intense research efforts have been dedicated to proving metformin’s inflammation-inhibitory effects in cells, animal models, patient records, and randomized clinical trials. The emerging evidence also indicates its therapeutic potential in clinical domains other than type 2 diabetes. Herein, this article appraises current pre-clinical and clinical findings, emphasizing metformin’s anti-inflammatory properties under individual pathophysiological scenarios. In summary, the anti-inflammatory effects of metformin are evident in pre-clinical models. By comparison, there are still clinical perplexities to be addressed in repurposing metformin to inflammation-driven chronic diseases. Future randomized controlled trials, incorporating better stratification/targeting, would establish metformin’s utility in this clinical setting.

Metformin Preconditioning and Postconditioning to Reduce Ischemia Reperfusion Injury in an Isolated Ex Vivo Rat and Porcine Kidney Normothermic Machine Perfusion Model

Metformin may act renoprotective prior to kidney transplantation by reducing ischemia-reperfusion injury (IRI). This study examined whether metformin preconditioning and postconditioning during ex vivo normothermic machine perfusion (NMP) of rat and porcine kidneys affect IRI. In the rat study, saline or 300 mg/kg metformin was administered orally twice on the day before nephrectomy. After 15 minutes of warm ischemia, kidneys were preserved with static cold storage for 24 hours. Thereafter, 90 minutes of NMP was performed with the addition of saline or metformin (30 or 300 mg/L). In the porcine study, after 30 minutes of warm ischemia, kidneys were preserved for 3 hours with oxygenated hypothermic machine perfusion. Subsequently, increasing doses of metformin were added during 4 hours of NMP. Metformin preconditioning of rat kidneys led to decreased injury perfusate biomarkers and reduced proteinuria. Postconditioning of rat kidneys resulted, dose-dependently, in less tubular cell necrosis and vacuolation. Heat shock protein 70 expression was increased in metformin-treated porcine kidneys. In all studies, creatinine clearance was not affected. In conclusion, both metformin preconditioning and postconditioning can be done safely and improved rat and porcine kidney quality. Because the effects are minor, it is unknown which strategy might result in improved organ quality after transplantation.

Potential Neuroprotective Treatment of Stroke: Targeting Excitotoxicity, Oxidative Stress, and Inflammation

Stroke is a major cause of death and adult disability. However, therapeutic options remain limited. Numerous pathways underlie acute responses of brain tissue to stroke. Early events following ischemic damage include reactive oxygen species (ROS)-mediated oxidative stress and glutamate-induced excitotoxicity, both of which contribute to rapid cell death within the infarct core. A subsequent cascade of inflammatory events escalates damage progression. This review explores potential neuroprotective strategies for targeting key steps in the cascade of ischemia–reperfusion (I/R) injury. NADPH oxidase (NOX) inhibitors and several drugs currently approved by the U.S. Food and Drug Administration including glucose-lowering agents, antibiotics, and immunomodulators, have shown promise in the treatment of stroke in both animal experiments and clinical trials. Ischemic conditioning, a phenomenon by which one or more cycles of a short period of sublethal ischemia to an organ or tissue protects against subsequent ischemic events in another organ, may be another potential neuroprotective strategy for the treatment of stroke by targeting key steps in the I/R injury cascade.

Inflammatory Consequences of Maternal Diabetes on the Offspring Brain: a Hippocampal Organotypic Culture Study

Gestational diabetes is a disorder associated with abnormal chronic inflammation that poses a risk to the developing fetus. We investigated the effects of experimentally induced diabetes (streptozotocin model) in Wistar female rats on the inflammatory status of the hippocampi of their offspring. Additionally, the impact of antidiabetic drugs (metformin and glyburide) on inflammatory processes was evaluated. Organotypic hippocampal cultures (OHCs) were prepared from the brains of the 7-day-old rat offspring of control and diabetic mother rats. On the 7th day in vitro, the cultures were pretreated with metformin (3 μM) or glyburide (1 μM) and then stimulated for 24 h with lipopolysaccharide (LPS, 1 μg/ml). The OHCs obtained from the offspring of diabetic mothers were characterized by the increased mortality of cells and an enhanced susceptibility to damage caused by LPS. Although we showed that LPS stimulated the secretion of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) in the control and diabetic cultures, the levels of IL-1β and IL-6 in the OHC medium obtained from the offspring of diabetic mothers were more pronounced. In the diabetic cultures, enhanced levels of TLR-4 and the overactivation of the NLRP3 inflammasome were demonstrated. Metformin and glyburide pretreatment normalized the LPS-induced IL-1β secretion in the control and diabetic cultures. Furthermore, glyburide diminished both: LPS-induced IL-6 and TNF-α secretion in the control and diabetic cultures and increased NF-κB p65 subunit phosphorylation. Glyburide also diminished the levels of the NLRP3 subunit and caspase-1, but only in the diabetic cultures. The results showed that maternal diabetes affected inflammatory processes in the offspring brain and increased hippocampal sensitivity to the LPS-induced inflammatory response. The use of antidiabetic agents, especially glyburide, had a beneficial impact on the changes caused by maternal diabetes.

The beneficial roles of metformin on the brain with cerebral ischaemia/reperfusion injury

Cerebral ischaemia/reperfusion (I/R) injury is the transient loss, followed by rapid return, of blood flow to the brain. This condition is often caused by strokes and heart attacks. The underlying mechanisms resulting in brain damage during cerebral I/R injury include mitochondrial dysregulation, increased oxidative stress/reactive oxygen species, blood-brain-barrier breakdown, inflammation of the brain, and increased neuronal apoptosis. Metformin is the first-line antidiabetic drug which has recently been shown to be capable of acting through the aforementioned pathways to improve recovery following cerebral I/R injury. However, some studies have suggested that metformin therapy may have no effect or even worsen recovery following cerebral I/R injury. The present review will compile and examine the available in vivo, in vitro, and clinical data concerning the neuroprotective effects of metformin following cerebral I/R injury. Any contradictory evidence will also be assessed and presented to determine the actual effectiveness of metformin treatment in stroke recovery.