The Renin Angiotensin System as a Therapeutic Target in Traumatic Brain Injury.

Traumatic brain injury (TBI) is a major public health problem, with limited pharmacological options available beyond symptomatic relief. The renin angiotensin system (RAS) is primarily known as a systemic endocrine regulatory system, with major roles controlling blood pressure and fluid homeostasis. Drugs that target the RAS are used to treat hypertension, heart failure and kidney disorders. They have now been used chronically by millions of people and have a favorable safety profile. In addition to the systemic RAS, it is now appreciated that many different organ systems, including the brain, have their own local RAS. The major ligand of the classic RAS, Angiotensin II (Ang II) acts predominantly through the Ang II Type 1 receptor (AT1R), leading to vasoconstriction, inflammation, and heightened oxidative stress. These processes can exacerbate brain injuries. Ang II receptor blockers (ARBs) are AT1R antagonists. They have been shown in several preclinical studies to enhance recovery from TBI in rodents through improvements in molecular, cellular and behavioral correlates of injury. ARBs are now under consideration for clinical trials in TBI. Several different RAS peptides that signal through receptors distinct from the AT1R, are also potential therapeutic targets for TBI. The counter regulatory RAS pathway has actions that oppose those stimulated by AT1R signaling. This alternative pathway has many beneficial effects on cells in the central nervous system, bringing about vasodilation, and having anti-inflammatory and anti-oxidative stress actions. Stimulation of this pathway also has potential therapeutic value for the treatment of TBI. This comprehensive review will provide an overview of the various components of the RAS, with a focus on their direct relevance to TBI pathology. It will explore different therapeutic agents that modulate this system and assess their potential efficacy in treating TBI patients.

Perception of Alcohol Use and Alcohol Use Disorder among Persons Involved in Road Accidents at an Emergency Department: A Cross-Sectional Study.

Background: Alcohol plays a significant role in road traffic accidents in Ghana. However, little is known about the perspectives of victims who suffer road traffic accidents, RTAs, and the extent to which alcohol use disorder is involved. Methodology: We conducted a three-month cross-sectional study in a teaching hospital involving 102 patients involved in a road accident and presented to the hospital's emergency. The Alcohol Use Disorder Identification Test, AUDIT, was used to assess for Alcohol Use Disorder, AUD, at a score of 8. In addition, we used open-ended questionnaires to assess their perception of alcohol use and road accidents. Results: Of the 102 respondents, 75% were males, and 60% were between 15 and 35 years old. About 69% of respondents admitted to using alcohol, while 31%, including a single female, screened positive for alcohol use disorder. A significant majority of about 90% of respondents believed in some myths of alcohol use in Ghana, and a similar percentage were aware of the risks alcohol use posed to road use. Over 30% of respondents, mainly drivers or riders, had used alcohol within 12 hours of the accident. All but three respondents knew alcohol-induced aggression and poor coordination of movements. A similar number of respondents knew alcohol made people cross roads carelessly and were hyperactive or disinhibited. Conclusion: Alcohol use and alcohol use disorder are significantly high among persons presenting with RTA to the emergency. Knowledge of the deleterious effects of alcohol is high, yet their behavior did not reflect the knowledge. Therefore, a significant reduction in RTA can be achieved by enforcing blood alcohol concentration limits for road users and intensive education to the populace.

Assessment of corn starch as substitute for agarose in DNA gel electrophoresis.

OBJECTIVE: The use of agarose in nucleic acid electrophoresis is the gold standard. However, agarose is very expensive and not readily available in resource limited developing countries like Ghana. Hence, finding a more affordable and readily available alternative to agarose will be a major boost to molecular research in developing countries. This study was aimed at investigating the use of corn starch as a potential substitute for agarose in DNA gel electrophoresis. RESULTS: Genomic deoxyribonucleic acid (DNA) extracted from Plasmodium falciparum and primers were obtained from the West African Centre for Cell Biology of Infectious Pathogens and amplified using polymerase chain reaction. The amplicon was run on agarose gel to ascertain the molecular weight (as a positive control). When visualized under both blue light and ultraviolet light, the DNA and ladder showed clear and clean bands with the expected molecular weight. Corn starch was then modified with sodium borate buffer, casted into a gel and used to run the same DNA sample. Our findings indicated that similar to agarose, the DNA sample and ladder migrated successfully through the modified starch gel but no bands were visible when visualized under blue and ultra-violet light.

A Rare Case of Thyrotoxic Periodic Paralysis After Epidural Steroid Injection: A Case Report and Literature Review.

BACKGROUND Thyrotoxic periodic paralysis (TPP) is a rare cause of acute paralysis, which if not promptly recognized and treated, can lead to significant morbidity and mortality. TPP can be precipitated by several factors, including a high carbohydrate diet and exercise. This report is of a rare case of TPP after epidural steroid injection in a young man, with a review of the literature of previous cases. CASE REPORT A 36-year-old Asian man presented to the emergency department with sudden onset of paralysis of all his limbs following epidural steroid injection for traumatic low back pain. At presentation, he was found to have severe hypokalemia of 1.8 mEq/L. Further investigations led to the diagnosis of hyperthyroidism and Graves' disease. In the process of correcting his potassium, there was an unexpected rebound hyperkalemia that was successfully corrected. He had a rapid recovery and an early discharge from hospital. CONCLUSIONS Although several factors can lead to paralysis after an epidural steroid injection, TPP should be considered in the differential diagnosis, especially in individuals who have predisposing factors of ethnicity and gender. If patients have undiagnosed hyperthyroidism on presentation, the diagnosis of TPP can be delayed or missed. In the management of patients with TPP, care should be taken when correcting potassium levels.

Microglial Activation Results in Inhibition of TGF-ß-Regulated Gene Expression.

Chronic inflammation mediated by persistent microglial activation is associated with the pathogenesis of neurodegenerative diseases. The mechanisms underlying chronic microglial activation are poorly understood. We have previously shown that anti-inflammatory TGF-ß signaling is inhibited in LPS-treated microglia. In this study, we assessed whether different disease-related microglial activators could downregulate TGF-ß induction of gene expression. We examined the effects of amyloid ß (Aß) (1-42)- or heat-killed Listeria monocytogenes (HKLM) on the TGF-ß-regulated gene expression in primary rat microglia. We found that Aß (1-42) oligomers and HKLM, in addition to LPS, suppressed TGF-ß-mediated induction of gene expression in part through reducing expression of TßR1 mRNA encoding the TGF-ß receptor 1 in primary microglia. Aß (1-42) and LPS also prevented induction of TGF-ß-induced genes in primary microglia. Additionally, Aß (1-42) rescued primary microglia from TGF-ß-mediated cell death without increasing cell proliferation. Blockage of NFκB signaling, but not the ERK or IRF3 pathways, inhibited Aß (1-42)- and LPS-mediated reduction of TßR1 mRNA. Finally, LPS and Aß (1-42) induced transient upregulation of mRNAs encoding SnoN and Bambi, inhibitors of TGF-ß signaling. Our data indicate that one mechanism through which activators may prolong microglial stimulation is through direct inhibition of anti-inflammatory signaling. A more detailed understanding of the interaction between inflammatory and anti-inflammatory pathways may reveal potential targets for ameliorating chronic inflammation and hence speed the development of therapeutics to address neurodegenerative diseases.

WWL70 attenuates PGE2 production derived from 2-arachidonoylglycerol in microglia by ABHD6-independent mechanism.

BACKGROUND: α/ß-Hydrolase domain 6 (ABHD6) is one of the major enzymes for endocannabinoid 2-arachidonoylglycerol (2-AG) hydrolysis in microglia cells. Our recent studies have shown that a selective ABHD6 inhibitor WWL70 has anti-inflammatory and neuroprotective effects in animal models of traumatic brain injury and multiple sclerosis. However, the role of ABHD6 in the neuroinflammatory response and the mechanisms by which WWL70 suppresses inflammation has not yet been elucidated in reactive microglia. METHODS: The hydrolytic activity and the levels of 2-AG in BV2 cells were measured by radioactivity assay and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The expression of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) synthases in microglia treated with lipopolysaccharide (LPS) with/without WWL70 was determined by western blot and quantitative RT-PCR. The conversion of 2-AG to PGE2 or PGE2-glyceryl ester (PGE2-G) was assessed by enzyme-linked immunoassay (EIA) or LC-MS/MS. The involvement of ABHD6 in PGE2 production was assessed using pharmacological inhibitors and small interfering RNA (siRNA). The effect of WWL70 on PGE2 biosynthesis activity in the microsome fraction from BV2 cells and experimental autoimmune encephalopathy (EAE) mouse brain was also examined. RESULTS: We found that WWL70 suppressed PGE2 production in LPS-activated microglia via cannabinoid receptor-independent mechanisms, although intracellular levels of 2-AG were elevated by WWL70 treatment. This reduction was not attributable to WWL70 inhibition of ABHD6, given the fact that downregulation of ABHD6 by siRNA or use of KT182, an alternative ABHD6 inhibitor failed to suppress PGE2 production. WWL70 attenuated the expression of COX-2 and PGES-1/2 leading to the downregulation of the biosynthetic pathways of PGE2 and PGE2-G. Moreover, PGE2 production from arachidonic acid was reduced in the microsome fraction, indicating that WWL70 also targets PGE2 biosynthetic enzymes, which are likely to contribute to the therapeutic mechanisms of WWL70 in the EAE mouse model. CONCLUSIONS: WWL70 is an anti-inflammatory therapeutic agent capable of inhibiting PGE2 and PGE2-G production, primarily due to its reduction of COX-2 and microsomal PGES-1/2 expression and their PGE2 biosynthesis activity in microglia cells, as well as in the EAE mouse brain.

Neurorestoration after traumatic brain injury through angiotensin II receptor blockage.

See Moon (doi:10.1093/awv239) for a scientific commentary on this article.Traumatic brain injury frequently leads to long-term cognitive problems and physical disability yet remains without effective therapeutics. Traumatic brain injury results in neuronal injury and death, acute and prolonged inflammation and decreased blood flow. Drugs that block angiotensin II type 1 receptors (AT1R, encoded by AGTR1) (ARBs or sartans) are strongly neuroprotective, neurorestorative and anti-inflammatory. To test whether these drugs may be effective in treating traumatic brain injury, we selected two sartans, candesartan and telmisartan, of proven therapeutic efficacy in animal models of brain inflammation, neurodegenerative disorders and stroke. Using a validated mouse model of controlled cortical impact injury, we determined effective doses for candesartan and telmisartan, their therapeutic window, mechanisms of action and effect on cognition and motor performance. Both candesartan and telmisartan ameliorated controlled cortical impact-induced injury with a therapeutic window up to 6 h at doses that did not affect blood pressure. Both drugs decreased lesion volume, neuronal injury and apoptosis, astrogliosis, microglial activation, pro-inflammatory signalling, and protected cerebral blood flow, when determined 1 to 3 days post-injury. Controlled cortical impact-induced cognitive impairment was ameliorated 30 days after injury only by candesartan. The neurorestorative effects of candesartan and telmisartan were reduced by concomitant administration of the peroxisome proliferator-activated receptor gamma (PPARγ, encoded by PPARG) antagonist T0070907, showing the importance of PPARγ activation for the neurorestorative effect of these sartans. AT1R knockout mice were less vulnerable to controlled cortical impact-induced injury suggesting that the sartan's blockade of the AT1R also contributes to their efficacy. This study strongly suggests that sartans with dual AT1R blocking and PPARγ activating properties have therapeutic potential for traumatic brain injury.

LPS antagonism of TGF-ß signaling results in prolonged survival and activation of rat primary microglia.

Accumulating evidence indicates that activated microglia contribute to the neuropathology involved in many neurodegenerative diseases and after traumatic injury to the CNS. The cytokine transforming growth factor-beta 1 (TGF-ß1), a potent deactivator of microglia, should have the potential to reduce microglial-mediated neurodegeneration. It is therefore perplexing that high levels of TGF-ß1 are found in conditions where microglia are chronically activated. We hypothesized that TGF-ß1 signaling is suppressed in activated microglia. We therefore activated primary rat microglia with lipopolysaccharide (LPS) and determined the expression of proteins important to TGF-ß1 signaling. We found that LPS treatment decreased the expression of the TGF-ß receptors, TßR1 and TßR2, and reduced protein levels of Smad2, a key mediator of TGF-ß signaling. LPS treatment also antagonized the ability of TGF-ß to suppress expression of pro-inflammatory cytokines and to induce microglial cell death. LPS treatment similarly inhibited the ability of the TGF-ß related cytokine, Activin-A, to down-regulate expression of pro-inflammatory cytokines and to induce microglial cell death. Together, these data suggest that microglial activators may oppose the actions of TGF-ß1, ensuring continued microglial activation and survival that eventually may contribute to the neurodegeneration prevalent in chronic neuroinflammatory conditions.

Prevalence of chronic kidney disease in hypertensive patients in Ghana.

Chronic kidney disease (CKD) is common in tropical Africa although there are few data on the prevalence of this disorder. Therefore we initiated a multicenter screening study to identify the prevalence and staging of CKD in 712 patients with known hypertension in four polyclinics in Accra, Ghana. We measured estimated glomerular filtration rate by the six-variable modification of diet in renal disease equation and proteinuria by the protein/creatinine ratio. All the subjects studied were Ghanaian. Of the 712 patients studied, the median age was 59 years (range 19-90 years) and 560 (78.7%) of the patients were female. The mean duration of hypertension was 4 years (range 0.1-50). The overall prevalence of CKD was 46.9% (95% CI: 43.2-50.7%); 19.1% had CKD stages 1-2 and 27.8% had CKD stages 3-5. There was no difference in age between patients with or without CKD (p = 0.12). The overall prevalence of proteinuria was 28.9% (95% CI: 25.6-32.4%); 14.7% of subjects had preexisting diabetes mellitus and their prevalence of CKD (55%; 95% CI: 42.4-62.2) did not differ from those without diabetes (46%; 95% CI: 41.9-50.0, p = 0.133). CKD is common in hypertensive patients in Ghana, with a prevalence of 46.9%. This provides justification for the inclusion of this group in CKD screening programs in Ghana.