Neuroimaging, biochemical and cellular evidence of protection by mycophenolate mofetil on middle cerebral artery occlusion induced injury in rats

An Optimal Animal Model of Ischemic Stroke Established by Digital Subtraction Angiography-Guided Autologous Thrombi in Cynomolgus Monkeys

Objective

Ischemic stroke seriously threatens human health, characterized by the high rates of incidence, disability, and death. Developing a reliable animal model that mimics most of the features of stroke is critical for pathological studies and clinical research. In this study, we aimed to establish and examine a model of middle cerebral artery occlusion (MCAO) guided by digital subtraction angiography (DSA) in cynomolgus monkeys.

Materials and Methods

In this study, 15 adult male cynomolgus monkeys were enrolled. Under the guidance of DSA, a MCAO model was established by injecting an autologous venous clot into the middle cerebral artery (MCA) via femoral artery catheter. Thrombolytic therapy with alteplase (rt-PA) was given to eight of these monkeys at 3 h after the occlusion. Blood test and imaging examination, such as computed tomography angiography (CTA), CT perfusion (CTP), brain magnetic resonance imaging (MRI), and brain magnetic resonance angiography (MRA), were performed after the operation to identify the post-infarction changes. The behavioral performance of cynomolgus monkeys was continuously observed for 7 days after operation. The animals were eunthanized on the 8th day after operation, and then the brain tissues of monkeys were taken for triphenyltetrazolium chloride (TTC) staining.

Results

Among the 15 cynomolgus monkeys, 12 of them were successfully modeled, as confirmed by the imaging findings and staining assessment. One monkey died of brain hernia resulted from intracranial hemorrhage confirmed by necropsy. DSA, CTA, and MRA indicated the presence of an arterial occlusion. CTP and MRI showed acute focal cerebral ischemia. TTC staining revealed infarct lesions formed in the brain tissues.

Conclusion

Our study may provide an optimal non-human primate model for an in-depth study of the pathogenesis and treatment of focal cerebral ischemia.

Protective Effects of 28-O-Caffeoyl Betulin (B-CA) on the Cerebral Cortex of Ischemic Rats Revealed by a NMR-Based Metabolomics Analysis

28-O-caffeoyl betulin (B-CA) has been demonstrated to reduce the cerebral infarct volume caused by transient middle cerebral artery occlusion (MCAO) injury. B-CA is a novel derivative of naturally occurring caffeoyl triterpene with little information associated with its pharmacological target(s). To date no data is available regarding the effect of B-CA on brain metabolism. In the present study, a 1H-NMR-based metabolomics approach was applied to investigate the therapeutic effects of B-CA on brain metabolism following MCAO in rats. Global metabolic profiles of the cortex in acute period (9 h after focal ischemia onset) after MCAO were compared between the groups (sham; MCAO + vehicle; MCAO + B-CA). MCAO induced several changes in the ipsilateral cortex of ischemic rats, which consequently led to the neuronal damage featured with the downregulation of NAA, including energy metabolism dysfunctions, oxidative stress, and neurotransmitter metabolism. Treatment with B-CA showed statistically significant rescue effects on the ischemic cortex of MCAO rats. Specifically, treatment with B-CA ameliorated the energy metabolism dysfunctions (back-regulating the levels of succinate, lactate, BCAAs, and carnitine), oxidative stress (upregulating the level of glutathione), and neurotransmitter metabolism disturbances (back-regulating the levels of γ-aminobutyric acid and acetylcholine) associated with the progression of ischemic stroke. With the administration of B-CA, the levels of three phospholipid related metabolites (O-phosphocholine, O-phosphoethanolamine, sn-glycero-3-phosphocholine) and NAA improved significantly. Overall, our findings suggest that treatment with B-CA may provide neuroprotection by augmenting the metabolic changes observed in the cortex following MCAO in rats.

Upregulation of GLT-1 via PI3K/Akt Pathway Contributes to Neuroprotection Induced by Dexmedetomidine

Perioperative ischemic stroke usually leads to neurological dysfunction caused by neuron death. During the ischemic condition, excitotoxity due to extracellular glutamate accumulation is a main mechanism of neuron damage. The clearance of glutamate mainly depends on glutamate transporter-1 (GLT-1) which is expressed in astrocytes. Dexmedetomidine, an α2 adrenergic receptor agonist, is proved to induce neuroprotection. This study was set out to investigate the glutamate-related mechanism involved in the neuroprotective effect of dexmedetomidine. Middle cerebral artery occlusion (MCAO) was used as a model of ischemic stroke in our study. We determined Neurological deficit scores (NDS) and Magnetic resonance imaging (MRI) at three points (2, 6, and 24 h) after middle cerebral artery occlusion (MCAO) to evaluate the neuroprotective effect of dexmedetomidine. Besides, we performed western blot (6 and 24 h after MACO) and immunofluorescent staining (24 h after MCAO) to observe the expression of GLT-1. The effect and mechanism of dexmedetomidine on GLT-1 in primary cultured astrocytes were investigated using western blot and RT-PCR. Our results showed that pretreatment with dexmedetomidine improved NDS and reduced infarct volume as well as upregulating GLT-1 expression. Furthermore, using Atipamezole and LY294002, we found that dexmedetomidine significantly increased GLT-1 levels in astrocytes via activating α2 adrenergic receptor and PI3K/AKT pathway both in vitro and in vivo study. Overall, our present study indicated that dexmedetomidine had neuroprotective effects on ischemia stroke and upregulation of GLT-1 levels by PI3K/AKT dependent pathway might be the potential mechanism.

Comparison of PREDICTS atherosclerosis biomarker changes after initiation of new treatments in patients with SLE

Objective

Patients with SLE have an increased risk of atherosclerosis (ATH) that is not adequately explained by traditional risk factors. We previously described the Predictors of Risk for Elevated Flares, Damage Progression, and Increased Cardiovascular disease in PaTients with SLE (PREDICTS) atherosclerosis-risk panel, which includes proinflammatory HDL (piHDL), leptin, soluble tumour necrosis factor-like weak inducer of apoptosis (sTWEAK) and homocysteine, as well as age and diabetes. A high PREDICTS score confers 28-fold increased odds for future atherosclerosis in SLE. The aim of this study is to determine whether PREDICTS biomarkers are modifiable by common lupus therapies.

Methods

This prospective observational study included SLE subjects started on new lupus treatments. Leptin, sTWEAK, homocysteine and antioxidant function of HDL were measured at baseline (prior to drug initiation), 6 weeks and 12 weeks.

Results

16 subjects started mycophenolate (MMF), 18 azathioprine (AZA) and 25 hydroxychloroquine (HCQ). In MMF-treated subjects, HDL function progressively improved from 2.23 ± 1.32 at baseline to 1.37±0.81 at 6 weeks (p=0.02) and 0.93±0.54 at 12 weeks (p=0.009). sTWEAK levels also improved in MMF-treated subjects from 477.5±447.1 to 290.3±204.6 pg/mL after 12 weeks (p=0.04), but leptin and homocysteine levels were not significantly changed. In HCQ-treated subjects, only HDL function improved from 1.80±1.29 at baseline to 1.03±0.74 after 12 weeks (p=0.05). There were no changes in the AZA group. MMF treatment was still associated with significant improvements in HDL function after accounting for potential confounders such as total prednisone dose and changes in disease activity. Overall, the mean number of high-risk PREDICTS biomarkers at week 12 significantly decreased in the entire group of patients started on a new lupus therapy (2.1±0.9 to 1.8±0.9, p=0.02) and in the MMF-treated group (2.4±0.8 vs 1.8±0.9, p=0.003), but not in the AZA or HCQ groups. In multivariate analysis, the odds of having a high PREDICTS atherosclerosis risk score at 12 weeks were lower with MMF treatment (OR 0.002, 95% CI 0.000 to 0.55, p=0.03).

Conclusions

12 weeks of MMF therapy improves the overall PREDICTS atherosclerosis biomarker profile. Further studies will determine whether biomarker changes reflect decreases in future cardiovascular events.

Combination of Zizyphus jujuba and silymarin showed better neuroprotective effect as compared to single agent in MCAo-induced focal cerebral ischemia in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Traditionally, Zizyphus jujuba is used for anticonvulsant, hypnotic-sedative, anxiolytic, tranquilizer, antioxidant and anti-inflammatory properties. Likewise silymarin is popularly used for its potent antioxidant and hepatoprotective effects. Stroke being a multifactorial disease with unsatisfactory treatment outcomes, necessitates development of multimodal therapeutic interventions. Thus, we evaluated the therapeutic benefits of herbal combination of Z. jujuba and silymarin in a focal cerebral ischemia model.

AIM OF THE STUDY

To evaluate the neuroprotective potential of hydroalcoholic extract of Z. jujuba (HEZJ) fruit and silymarin alone and in combination in middle cerebral artery occlusion (MCAo) model of focal cerebral ischemia in rats.

MATERIALS AND METHODS

Male Wistar rats were pretreated with HEZJ (100, 250 and 500mg/kg, p.o.) or silymarin (250mg/kg, p.o.) for 3 days prior to induction of MCAo. Neurological deficit score, motor impairment and cerebral infarction were assessed 24h following MCAo. HEZJ (250mg/kg) co-administered with silymarin (250mg/kg) for 3 days prior to induction of MCAo was also evaluated for above parameters and oxidative stress. Malondialdehyde (MDA), nitric oxide (NO) and superoxide dismutase (SOD) levels in the cortex, striatum and hippocampal brain regions were estimated 24h post MCAo.

RESULTS

Pretreatment with HEZJ and silymarin reduced the neurological deficit score, motor impairment and cerebral infarction volume. HEZJ and silymarin pretreatment also ameliorated the oxidative stress in different brain regions, which was evident from increased SOD levels, decreased MDA and NO levels as compared to MCAo control rats. Interestingly neuroprotective efficacy was potentiated by pretreatment with HEZJ and silymarin combination.

CONCLUSION

Pretreatment with HEZJ and silymarin combination was observed to have better neuroprotection mediated via amelioration of oxidative stress in the focal cerebral ischemia model.

Mycophenolate mofetil attenuates uterine ischaemia/reperfusion injury in a rat model

This study evaluated the effect of mycophenolate mofetil (MMF) on uterine tissue preservation following ischaemia/reperfusion (I/R) injury. Uterine I/R injury was induced in rats by clamping the lower abdominal aorta and ovarian arteries for 30 min. Group I/R + V (n = 7) received vehicle alone while Group I/R + M (n = 7) received 20 mg/kg/day MMF. Control groups underwent sham surgery and received vehicle (Group C) or 20 mg/kg/day MMF (Group M) (n = 7 for both). Four hours after detorsion, uterine tissue 8-hydroxy-2'-deoxyguanosine (8-OHdG), glutathione, malondialdehyde (MDA), myeloperoxidase (MPO), superoxide dismutase (SOD) and serum ischaemia modified albumin (IMA) concentrations were measured. Histopathological analyses were performed. The I/R + M group showed significant reduction in serum IMA and uterine tissue 8-OHdG, MDA and MPO and significant increase in SOD concentrations compared with the I/R + V group, indicating a protective effect against I/R oxidative damage (P = 0.009, P = 0.006, P = 0.002, P = 0.003 and P = 0.009, respectively). Histopathological evaluation revealed MMF treatment resulted in significantly less tissue and cellular damage and apoptosis compared with the I/R + V group. These results indicate MMF is effective in attenuating uterine tissue damage and preventing apoptosis following uterine I/R injury, probably via anti-inflammatory and anti-oxidative action.

Neuroprotective effect of lercanidipine in middle cerebral artery occlusion model of stroke in rats

Oxidative stress, inflammation and apoptotic neuronal cell death are cardinal mechanisms involved in the cascade of acute ischemic stroke. Lercanidipine apart from calcium channel blocking activity possesses anti-oxidant, anti-inflammatory and anti-apoptotic properties. In the present study, we investigated neuroprotective efficacy and therapeutic time window of lercanidipine in a 2h middle cerebral artery occlusion (MCAo) model in male Wistar rats. The study design included: acute (pre-treatment and post-treatment) and sub-acute studies. In acute studies (pre-treatment) lercanidipine (0.25, 0.5 and 1mg/kg, i.p.) was administered 60min prior MCAo. The rats were assessed 24h post-MCAo for neurological deficit score (NDS), motor deficit paradigms (grip test and rota rod) and cerebral infarction via 2,3,5-triphenyltetrazolium chloride (TTC) staining. The most effective dose was found to be at 0.5mg/kg, i.p., which was considered for further studies. Regional cerebral blood flow (rCBF) was monitored till 120min post-reperfusion to assess vasodilatory property of lercanidipine (0.5mg/kg, i.p.) administered at two different time points: 60min post-MCAo and 15min post-reperfusion. In acute studies (post-treatment) lercanidipine (0.5mg/kg, i.p.) was administered 15min, 120min and 240min post-reperfusion. Based on NDS and cerebral infarction via TTC staining assessed 24h post-MCAo, effectiveness was evident upto 120min. For sub-acute studies same dose/vehicle was repeated for next 3days and magnetic resonance imaging (MRI) was performed 96h after the last dose. Biochemical markers estimated in rat brain cortex 24h post-MCAo were oxidative stress (malondialdehyde, reduced glutathione, nitric oxide, superoxide dismutase), blood brain barrier damage (matrix metalloproteinases-2 and -9) and apoptotic (caspase-3 and -9). Lercanidipine significantly reduced NDS, motor deficits and cerebral infarction volume as compared to the control group. Lercanidipine (60min post-MCAo) significantly increased rCBF (86%) as compared to vehicle treated MCAo group (64%) 120min post-reperfusion, but failed to show vasodilatation with 15min post-reperfusion group. Lercanidipine (13.78±2.78%) significantly attenuated percentage infarct volume as evident from diffusion-weighted (DWI) and T2-weighted images as compared to vehicle treated MCAo group (25.90±2.44%) investigated 96h post-MCAo. The apparent diffusion coefficient (ADC) was also significantly improved in lercanidipine group as compared to control group. Biochemical alterations were significantly ameliorated by lercanidipine till 120min post-reperfusion group and MMP-9 inhibition observed even with 240min group. Thus, lercanidipine revealed significant neuroprotective effect mediated through attenuation of oxidative stress, inflammation and apoptosis.

CNS vasculitis and stroke as a complication of DOCK8 deficiency: a case report

Background

Primary immunodeficiency disorders associated with autoimmunity are poorly understood. Central nervous system (CNS) vasculitis can complicate the courses of such entities, but it is underappreciated. Deletion of the dedicator of cytokinesis 8 (DOCK8) gene is considered to be the autosomal recessive form of hyperimmunoglobulin E syndrome which is a rare type of primary immunodeficiency disease characterized by elevated levels of IgE antibody, eczema, and recurrent staphylococcal infections. DOCK8 deletion is associated with fatal CNS vasculitis. However, descriptions of such cases and their outcomes are scarce in the literature.

Case presentation

This report describes a young female with a DOCK8 gene deletion presenting acutely with squint, fatigue and visual hallucinations. The patient was diagnosed as having neuritis of the third oculomotor nerve and encephalitis, which were thought to be related to her underlying immune deficiency, however, she subsequently was diagnosed with CNS vasculitis based on brain magnetic imaging and magnetic resonance angiography findings. We provide here a comprehensive description of the patient’s clinical outcome and outline an effective treatment approach that may be useful for similar patients and includes the use of steroids and mycophenolate mofetil (MMF). The treatment was well tolerated and enabled the patient to recover most of her neurological deficits. However, despite the initial improvement, she later developed stroke.

Conclusions

To the best of our knowledge, this is the first report in the literature of a case of primary immunodeficiency complicated by CNS vasculitis demonstrating a successful outcome. Our observations indicate that the combination of MMF and steroids is an effective treatment for CNS vasculitis associated with DOCK8 deficiency. However, lack of awareness of the neurological comorbidities associated with primary immunodeficiencies and the delay in diagnosis likely contributed to the development of acute cerebral infarction. Early treatment and aggressive control of the disease’s initial inflammation is essential for preventing catastrophic stroke.

Effects of aminoguanidine, a potent nitric oxide synthase inhibitor, on myocardial and organ structure in a rat model of hemorrhagic shock

Background:

Nitric oxide (NO) has been shown to increase following hemorrhagic shock (HS). Peroxynitrite is produced by the reaction of NO with reactive oxygen species, leads to nitrosative stress mediated organ injury. We examined the protective effects of a potent inhibitor of NO synthase, aminoguanidine (AG), on myocardial and multiple organ structure in a rat model of HS.

Materials and Methods:

Male Sprague Dawley rats (300-350 g) were assigned to 3 experimental groups (n = 6 per group): (1) Normotensive rats (N), (2) HS rats and (3) HS rats treated with AG (HS-AG). Rats were hemorrhaged over 60 min to reach a mean arterial blood pressure of 40 mmHg. Rats were treated with 1 ml of 60 mg/kg AG intra-arterially after 60 min HS. Resuscitation was performed in vivo by the reinfusion of the shed blood for 30 min to restore normo-tension. Biopsy samples were taken for light and electron microscopy.

Results:

Histological examination of hemorrhagic shocked untreated rats revealed structural damage. Less histological damage was observed in multiple organs in AG-treated rats. AG-treatment decreased the number of inflammatory cells and mitochondrial swollen in myocardial cells.

Conclusion:

AG treatment reduced microscopic damage and injury in multiple organs in a HS model in rats.