Inhibitory Role of L-theanine, a Structural Analogue of Glutamate, Against GluR5 Kainate Receptor and its Prospective Utility Against Excitotoxicity.

BACKGROUND: Overactivation of receptors that respond to excitatory neurotransmitters can result in various harmful outcomes, such as the inability to properly modulate calcium levels, generation of free radicals, initiation of the mitochondrial permeability transition, and subsequent secondary damage caused by excitotoxicity. A non-proteinogenic amino acid of tea, L-theanine, is structurally related to glutamate, the major stimulatory neurotransmitter in the brain. Previous reports have emphasised its ability to bind with glutamate receptors. OBJECTIVE: An in-depth understanding of the binding compatibility between ionotropic glutamate receptors and L-theanine is a compelling necessity. METHODS: In this molecular docking study, the antagonistic effect of L-theanine and its possible therapeutic benefit in GluR5 kainate receptor inhibition has been evaluated and compared to the familiar AMPA and kainite receptor antagonists, cyanoquinoxaline (CNQX) and dinitroquinoxaline (DNQX), using Molegro Virtual Docker 7.0.0. RESULTS: The capacity of L-theanine to cohere with the GluR5 receptor was revealed to be higher than that of glutamate, although it could not surpass the high binding tendency of competitive antagonists CNQX and DNQX. Nonetheless, the drug-likeness score and the blood-brain barrier traversing potential of L-theanine were higher than CNQX and DNQX. CONCLUSION: The study provides an inference to the advantage of L-theanine, which can be a safe and effective alternative natural therapy for rescuing neuronal death due to excitotoxicity.

Clinical Course and Outcomes of COVID-19 in Kidney Transplant Recipients.

Introduction: Kidney transplant recipients (KTR) are at increased risk of morbidity and mortality due to coronavirus disease 2019 (COVID-19). This study aimed to explore the clinical characteristics and outcomes of COVID-19 in KTR. Methods: We reviewed the clinical profile, outcomes, and immunological responses of recipients admitted with COVID-19. We determined the risk factors for mortality and severe COVID-19. Results: Out of 452 recipients on follow-up, 60 were admitted with COVID-19. Prevalent comorbidities were hypertension (71%), diabetes (40%), lung disease (17%). About 27% had tuberculosis. The median Sequential Organ Failure Assessment score at presentation was 3 (interquartile range [IQR] 1-5). There was a high incidence of diarrhea (52%) and anemia (82%). Treatment strategies included antimetabolite withdrawal (85%), calcineurin inhibitor decrease or withdrawal (64%), increased steroids (53%), hydroxychloroquine (21%), remdesivir (28.3%), and tocilizumab (3.3%). Severe COVID-19 occurred in 34 (56.4%) patients. During a median follow-up of 42.5 days (IQR 21-81 days), 83% developed acute kidney injury (AKI) and eight (13%) died. Mortality was associated with the baseline graft dysfunction, hypoxia at admission, lower hemoglobin and platelets, higher transaminases, higher C reactive protein, diffuse radiological lung involvement, hypotension requiring inotropes, and Kidney Diseases Improving Global Outcomes (KDIGO) stage 3 AKI (univariate analysis). Around 57% of patients remained RT-PCR positive at the time of discharge. By the last follow-up, 66.6% of patients developed IgM (immunoglobulin M) antibodies and 82.3% of patients developed IgG antibodies. Conclusion: COVID-19 in kidney transplant recipients is associated with a high risk of AKI and significant mortality.

Cardiovascular Complications in Kidney Transplant Recipients with COVID-19: A Case Series.

Kidney transplant recipients (KTRs) are at a higher risk for developing severe COVID-19 which can be associated with cardiovascular complications. We studied five KTRs recipients infected with COVID-19 who developed severe cardiovascular complications. Two patients presented with ST segment myocardial infarction and two with clinically suspected myocarditis. One patient presented with atrial fibrillation. Two of these patients developed cardiogenic shock. Inflammatory markers were at peak during the event in four of these who had presented with severe COVID-19. Coronary angiography done in two patients with STEMI did not reveal any evidence of atherosclerotic coronary artery disease. Also, based on the cardiovascular (CV) risk estimation by Framingham score, four patients had low CV risk and one patient had intermediate CV risk. All five patients survived. Even with low CV risk, KTRs can develop myocardial injury and arrhythmias solely because of severe COVID-19.

High dependency renal unit for the management of COVID-19 in patients with severe acute or chronic kidney disease.

Coronavirus disease 2019 (COVID-19) in patients with severe impairment of kidney function is associated with high mortality. We evaluated the effect of high dependency renal unit (HDRU), with nephrologists as primary care physicians, as a quality improvement initiative for the management of these patients. This was a quasi-experimental observational study conducted at a tertiary care hospital in western India. Patients hospitalized for COVID-19 with pre-existing end-stage-renal-disease and those with severe AKI requiring dialysis (AKI-D) were included. For the first 2 months, these patients were cared for in medical wards designated for COVID-19, after which HDRU was set up for their management. With nephrologists as primary care providers, the 4 key components of care in HDRU included: care bundles focusing on key nephrology and COVID-19 related issues, checklist-based clinical monitoring, integration of multi-specialty care, and training of nurses and doctors. Primary outcome of the study was in-hospital mortality before and after institution of the HDRU care. Secondary outcomes were dialysis dependence in AKI-D and predictors of death. A total of 238 out of 4254 (5.59%) patients with COVID-19, admitted from 28th March to 30th September 2020, had severe renal impairment (116 AKI-D and 122 end-stage-renal-disease). 145 (62%) had severe COVID-19. From 28th May to 31st August 2020, these patients were managed in HDRU. Kaplan-Meier analysis showed significant improvement in survival during HDRU care [19 of 52 (36.5%) in pre-HDRU versus 35 of 160 (21.9%) in HDRU died, P ≤ .01]. 44 (67.7%) AKI-D survivors were dialysis dependent at discharge. Breathlessness and altered mental status at presentation, development of shock during hospital stay, and leukocytosis predicted mortality. HDRU managed by nephrologists is a feasible and potentially effective approach to improve the outcomes of patients with COVID-19 and severe renal impairment.

Garcinol blocks motor behavioural deficits by providing dopaminergic neuroprotection in MPTP mouse model of Parkinson's disease: involvement of anti-inflammatory response.

Although the etiology of Parkinson's disease (PD) is poorly understood, studies in animal models revealed loss of dopamine and the dopaminergic neurons harbouring the neurotransmitter to be the principal cause behind this neuro-motor disorder. Neuroinflammation with glial cell activation is suggested to play a significant role in dopaminergic neurodegeneration. Several biomolecules have been reported to confer dopaminergic neuroprotection in different animal models of PD, owing to their anti-inflammatory potentials. Garcinol is a tri-isoprenylated benzophenone isolated from Garcinia sp. and accumulating evidences suggest that this molecule could provide neuroprotection by modulating oxidative stress and inflammation. However, direct evidence of dopaminergic neuroprotection by garcinol in the pre-clinical model of PD is not yet reported. The present study aims to investigate whether administration of garcinol in the MPTP mouse model of PD may ameliorate the cardinal motor behavioural deficits and prevent the loss of dopaminergic neurons. As expected, garcinol blocked the parkinsonian motor behavioural deficits which include akinesia, catalepsy, and rearing anomalies in the mice model. Most importantly, the degeneration of dopaminergic cell bodies in the substantia nigra region was significantly prevented by garcinol. Furthermore, garcinol reduced the inflammatory marker, glial fibrillary acidic protein, in the substantia nigra region. Since glial hyperactivation-mediated inflammation is inevitably associated with the loss of dopaminergic neurons, our study suggests the anti-inflammatory role of garcinol in facilitating dopaminergic neuroprotection in PD mice. Hence, in the light of the present study, it is suggested that garcinol is an effective anti-parkinsonian agent to block motor behavioural deficits and dopaminergic neurodegeneration in PD.

Recovery of kidney function after AKI because of COVID-19 in kidney transplant recipients.

Evidence on the evolution of graft function in kidney transplant recipients recovering from coronavirus disease-2019 (COVID-19) is lacking. This multicenter observational study evaluated the short-term clinical outcomes in recipients with acute kidney injury (AKI) secondary to COVID-19. Out of 452 recipients following up at five centers, 50 had AKI secondary to COVID-19. 42 recipients with at least 3-month follow-up were included. Median follow-up was 5.23 months [IQR 4.09-6.99]. Severe COVID-19 was seen in 21 (50%), and 12 (28.6%) had KDIGO stage 3 AKI. Complete recovery of graft function at 3 months was seen in 17 (40.5%) patients. Worsening of proteinuria was seen in 15 (37.5%) patients, and 4 (9.5%) patients had new onset proteinuria. Graft failure was seen in 6 (14.3%) patients. Kidney biopsy revealed acute tubular injury (9/11 patients), thrombotic microangiopathy (2/11), acute cellular rejection (2/11), and chronic active antibody-mediated rejection (3/11). Patients with incomplete recovery were likely to have lower eGFR and proteinuria at baseline, historical allograft rejection, higher admission SOFA score, orthostatic hypotension, and KDIGO stage 3 AKI. Baseline proteinuria and the presence of orthostatic hypotension independently predicted incomplete graft recovery. This shows that graft recovery may remain incomplete after AKI secondary to COVID-19.

Lycopene - A pleiotropic neuroprotective nutraceutical: Deciphering its therapeutic potentials in broad spectrum neurological disorders.

Lycopene is a naturally occurring carotenoid found abundantly in red fruits and vegetables. Myriads of literature documented potential health benefits of lycopene, owing to its sublime capacity of suppressing oxidative stress, inflammation, and modulation of various cell survival pathways. Due to its lipophilic nature, lycopene can reach brain adequately by traversing the blood-brain barrier thereby extending it's promising therapeutic benefits in neurological disorders. Lycopene efficiently assists in restoring the characteristic behavioural and pathophysiological changes associated with neurodegenerative disorders, epileptic conditions, aging, subarachnoid hemorrhage, spinal cord injury, and neuropathy. The detrimental impacts of environmental neurotoxins on brain and neuropathological consequences of consumption of high-lipid diet can also be mitigated by lycopene. Apart from its high antioxidant potency, lycopene confers neuroprotection by preventing proteinopathies, neuroinflammation, apoptosis, cerebral edema, and synaptic dysfunction. This review provides a lucid idea on the potential multi-faceted benefits of lycopene in disorders of the central nervous system and elucidates the molecular mechanisms and pathways of its action.

Natural Products and Their Therapeutic Effect on Autism Spectrum Disorder.

Autism is a complex neurodevelopmental disorder that is evident in early childhood and can persist throughout the entire life. The disease is basically characterized by hurdles in social interaction where the individuals demonstrate repetitive and stereotyped interests or patterns of behavior. A wide number of neuroanatomical studies with autistic patients revealed alterations in brain development which lead to diverse cellular and anatomical processes including atypical neurogenesis, neuronal migration, maturation, differentiation, and degeneration. Special education programs, speech and language therapy, have been employed for the amelioration of behavioral deficits in autism. Although commonly prescribed antidepressants, antipsychotics, anticonvulsants, and stimulants have revealed satisfactory responses in autistic individuals, adverse side effects and increased risk of several other complications including obesity, dyslipidemia, diabetes mellitus, thyroid disorders, etc. have compelled the researchers to turn their attention toward herbal remedies. Alternative approaches with natural compounds are on continuous clinical trial to confirm their efficacy and to understand their potential in autism treatment. This chapter aims to cover the major plant-based natural products which hold promising outcomes in the field of reliable therapeutic interventions for autism.

Neuroprotective attributes of L-theanine, a bioactive amino acid of tea, and its potential role in Parkinson's disease therapeutics.

Meta-analyses of tea consumption and reduced risk of Parkinson's disease have thrown light in the pathway of exploring beneficial properties of tea components. On the basis of dry mass, a typical black or green tea beverage contains approximately 6% of free amino acids, which impart high quality, taste and distinctive aroma to the tea infusion. L-theanine (chemically known as γ-glutamylethylamide) is a non-proteinogenic amino acid of tea that takes part in the biosynthesis of its polyphenols. Recently discovered neuroprotective effects of L-theanine can be attributed to its structural analogy with glutamate, the principal excitatory neurotransmitter in brain. This unique amino acid also bears a potential to ameliorate the pathophysiological changes associated with Parkinson's disease as it displays antioxidant and anti-inflammatory properties, improves motor behavioral abnormalities, increases dopamine availability and may cause a favorable downshift in neurodegeneration due to glutamate excitotoxicity. To gain an explicit understanding of the role of L-theanine, this review article is the first one to focus on its mechanism of neuromodulatory action and to critically evaluate the possibilities of employing this bioactive amide in the forage of anti-Parkinsonian medication. We also hypothesize the idea of L-theanine being a potent natural agent against L-DOPA induced dyskinesia, since long-term reliance on dopamine replacement therapy is linked with elevation in glutamate receptor activity.

Garcinol, a multifaceted sword for the treatment of Parkinson's disease.

Garcinol, the principal phytoconstituent of plants belonging to the genus Garcinia, is known for its anti-oxidant as well as anti-inflammatory properties, which can be extended to its possible neuroprotective role. Recent reports disseminate the capacity of garcinol to influence neuronal growth and survival, alter the neurochemical status in brain, as well as regulate memory and cognition. The concomitant neuro-rescue property of garcinol may render it as an effective compound in Parkinson's disease (PD) therapeutics since it is capable of ameliorating the related pathophysiological changes. Emerging pieces of evidence linking histone acetylation defects to the progression of neurodegenerative diseases provide an effective basis for targeting PD. Hyperacetylation of histones has been reported in Parkinsonian brain, which demands the use of pharmacological inhibitors of histone acetyltransferases (HAT). Garcinol serves as a potent natural HAT inhibitor and has unveiled promising results in molecular interaction studies against Monoamine oxidase B (MAO-B) and Catechol-O-Methyltransferase (COMT), as well as in L-DOPA induced dyskinesia. This review highlights the prospective implications of garcinol as a novel anti-Parkinsonian agent, and establishes a bridge between histone acetylation defects and the pathological aspects of PD.

Clinical Proteomics and Cytokine Profiling for Dengue Fever Disease Severity Biomarkers.

Dengue fever (DF) is a major global health burden with a pathophysiology that is still incompletely understood. Biomarkers that predict and explain susceptibility to DF and its progression to its more severe hemorrhagic form are much needed. DF is endemic in tropical and subtropical regions of the world, with a rapidly increasing incidence of disease severity. We conducted a clinical biomarker discovery study using both a case-control and longitudinal study design. Plasma proteome alterations in patients with DF (n = 12) and dengue hemorrhagic fever (DHF, n = 24) were analyzed in comparison to healthy controls (HCs, n = 16), using the isobaric tags for relative and absolute quantification (iTRAQ)-based quantitative proteomics methodology (false discovery rate of 1%, ≥2 peptides). Several proteins such as the alpha-2 macroglobulin, angiotensinogen, apolipoprotein B-100, serotransferrin, and ceruloplasmin were upregulated (fold change >1.2) in all DHF cases, and downregulated in DF (fold change <0.83), compared with HCs. Plasma cytokine profiling (8 DF, 8 DHF, and 8 HC) on two consecutive time points, at day 0 (day of admission) and days 5-7, found significant elevation in IL-1RA, IL-7, TNF-α, MCP1-MCAF, and MIP-1ß levels, but only in the DHF cases, which is the severe disease, and not in DF, compared with HCs (p < 0.05). These new observations on changes in the plasma proteome and cytokine profiles in patients with dengue infection identify several putative molecular leads for future biomarker development and precision medicine in relation to forecasting DF disease severity.