Targeting Endothelin in Alzheimer's Disease: A Promising Therapeutic Approach

Gene therapy: an alternative to treat Alzheimer's disease

Alzheimer's disease (AD), a neuro-degenerative disease that primarily affects the elderly, is a worldwide phenomenon. Loss of memory, cognitive decline, behavioural changes, and many other signs are used to classify it. Various hypotheses that may contribute to Alzheimer's disease have been found during decades of survey, including tau theory, the amyloid theory, the cholinergic hypothesis, and the oxidative stress hypothesis. According to some theories, the two leading causes of AD are the accumulation of amyloid beta plaque and development of NFTs in the brain. The hippocampus and cerebral cortex are the primary sites where amyloid beta plaques gather in the body. NFT formation in the brain impairs the brain's neurons' potential of signalling. According to the age at which it manifests in a person, there are two subtypes of AD: 'LOAD (Late Onset Alzheimer's Disease)' and 'EOAD (Early Onset Alzheimer's Disease)'. Long-term research into AD treatment has resulted in the introduction of some medications that provided symptomatic relief to patients but did not alter the disease's pathophysiology, like cholinesterase inhibitors, inhibitors of tau aggregation, and monoclonal antibodies to Aβ aggregation. Even though the medications did not halt the progression of AD, researchers did not discontinue their work, which lead to the introduction of gene therapy - a recently created cutting-edge method of delivering genes to target sites where they can express the intended functionalities. Viral or non-viral vectors could be used to deliver the gene, each with advantages and limitations of their own. Gene therapy is proven to be a potential disease-modifying treatment for AD. This article discusses about gene therapy, its merits and demerits and the various ways of gene delivery. Additionally, it focuses on AD as the target for treatment through gene therapy, the pathophysiology of AD, and the multiple targets for gene therapy in the treatment of AD.

To evaluate the effect of endothelin receptor agonist IRL-1620 alone and in combination with donepezil in modulating neurodegeneration elicited by amyloid-β in rats

BACKGROUND

The development of efficient therapies for Alzheimer''s disease is essential since it is a serious public health problem. This investigation sought to ascertain any potential synergistic benefits of treating Alzheimer's disease with IRL-1620 monotherapy in addition to Donepezil. Additionally, the effect of IRL-1620 was evaluated using different doses (5 μg/kg,7 μg/kg, and 9 μg/kg). The study further assessed neurobehavioral, biochemical, molecular, and histopathological parameters to evaluate the efficacy of both IRL1620 by its own and in association with Donepezil. Fifty-eight adult male Wistar rats were allocated to eight experimental groups. A dose-ranging study of IRL-1620 was conducted using different doses administered via intravenous injection. Alzheimer's disease was induced by Aβ administration, and treatment arms included disease Control (Sham), Donepezil monotherapy, and combination treatment with IRL-1620 5 μg/kg (Dose selected from the dose-ranging study). The treatment using IRL-1620 (9 μg/kg) intravenously and Donepezil (1 mg/kg orally) both on its own and in addition substantially enhanced memory in comparison with the control group (p < 0.05). Dose of IRL-1620 (9 μg/kg) intravenously, escape latency decreased and the time spent in the target quadrant was considerably increased, and they further benefited from combination therapy. Moreover, IRL-1620 (9 μg/kg) intravenously and combination treatment reduced lipid peroxidation and acetylcholinesterase levels while increasing antioxidant enzyme levels. Immunohistochemistry and molecular analysis revealed enhanced expression of neurotrophic factors with combination treatment. The combination of IRL-1620 and Donepezil showed significant improvements in memory and neurobehavioral parameters (p < 0.05). Alzheimer's disease in male Wistar rats. These results indicate to the probable therapeutic advantages of IRL-1620 and Donepezil in the management of Alzheimer's disease. The combination treatment exhibited enhanced effects compared to monotherapy, highlighting its potential promising therapeutic approach. Additional research is required to understand the mechanisms behind these synergistic benefits and to establish the ideal dosage and duration of therapy for therapeutic applications.

Evolving therapeutic interventions for the management and treatment of Alzheimer's disease

Alzheimer's Disease (AD) patients experience diverse symptoms, including memory loss, cognitive impairment, behavioral abnormalities, mood changes, and mental issues. The fundamental objective of this review is to discuss novel therapeutic approaches, with special emphasis on recently approved marketed formulations for the treatment of AD, especially Aducanumab, the first FDA approved moiety that surpasses the blood-brain barrier (BBB) and reduces amyloid plaques in the brain, thereby reducing associated cognitive decline. However, it is still in the phase IV trial and is to be completed by 2030. Other drugs such as lecanemab are also under clinical trial and has recently been approved by the FDA and is also discussed here. In this review, we also focus on active and passive immunotherapy for AD as well as several vaccines, such as amyloid-beta epitope-based vaccines, amyloid-beta DNA vaccines, and stem cell therapy for AD, which are in clinical trials. Furthermore, ongoing pre-clinical trials associated with AD and other novel strategies such as curcumin-loaded nanoparticles, Crispr/ cas9, precision medicine, as well as some emerging therapies like anti-sense therapy are also highlighted. Additionally, we discuss some off-labeled drugs like non-steroidal anti-inflammatory drugs (NSAID), anti-diabetic drugs, and lithium, which can manage symptoms of AD and different non-pharmacological approaches are also covered which can help to manage AD. In summary, we have tried to cover all the therapeutic interventions which are available for the treatment and management of AD under sections approved, clinical phase, pre-clinical phase or futuristic interventions, off-labelled drugs, and non-pharmacological interventions for AD, offering positive findings and well as challenges that remain.

New Pathways Identify Novel Drug Targets for the Prevention and Treatment of Alzheimer’s Disease

Alzheimer’s disease (AD) is an incurable, progressive neurodegenerative disorder. AD is a complex and multifactorial disease that is responsible for 60–80% of dementia cases. Aging, genetic factors, and epigenetic changes are the main risk factors for AD. Two aggregation-prone proteins play a decisive role in AD pathogenesis: β-amyloid (Aβ) and hyperphosphorylated tau (pTau). Both of them form deposits and diffusible toxic aggregates in the brain. These proteins are the biomarkers of AD. Different hypotheses have tried to explain AD pathogenesis and served as platforms for AD drug research. Experiments demonstrated that both Aβ and pTau might start neurodegenerative processes and are necessary for cognitive decline. The two pathologies act in synergy. Inhibition of the formation of toxic Aβ and pTau aggregates has been an old drug target. Recently, successful Aβ clearance by monoclonal antibodies has raised new hopes for AD treatments if the disease is detected at early stages. More recently, novel targets, e.g., improvements in amyloid clearance from the brain, application of small heat shock proteins (Hsps), modulation of chronic neuroinflammation by different receptor ligands, modulation of microglial phagocytosis, and increase in myelination have been revealed in AD research.

Targeting Microglia in Alzheimer’s Disease: From Molecular Mechanisms to Potential Therapeutic Targets for Small Molecules

Alzheimer’s disease (AD) is a common, progressive, and devastating neurodegenerative disorder that mainly affects the elderly. Microglial dysregulation, amyloid-beta (Aβ) plaques, and intracellular neurofibrillary tangles play crucial roles in the pathogenesis of AD. In the brain, microglia play roles as immune cells to provide protection against virus injuries and diseases. They have significant contributions in the development of the brain, cognition, homeostasis of the brain, and plasticity. Multiple studies have confirmed that uncontrolled microglial function can result in impaired microglial mitophagy, induced Aβ accumulation and tau pathology, and a chronic neuroinflammatory environment. In the brain, most of the genes that are associated with AD risk are highly expressed by microglia. Although it was initially regarded that microglia reaction is incidental and induced by dystrophic neurites and Aβ plaques. Nonetheless, it has been reported by genome-wide association studies that most of the risk loci for AD are located in genes that are occasionally uniquely and highly expressed in microglia. This finding further suggests that microglia play significant roles in early AD stages and they be targeted for the development of novel therapeutics. In this review, we have summarized the molecular pathogenesis of AD, microglial activities in the adult brain, the role of microglia in the aging brain, and the role of microglia in AD. We have also particularly focused on the significance of targeting microglia for the treatment of AD.

Exploring the multifaceted role of TGF-β signaling in diabetic complications

Diabetes is one of the most comprehensive metabolic disorders and is spread across the globe. The data from IDF Diabetes Atlas and National Diabetes Statistics mentions that the number of patients with diabetes is increasing at an exponential rate which is challenging the current therapeutics used for the management of diabetes. However, current therapies used for the treatment may provide symptomatic relief but lack in preventing the progression of the disease and thereby limiting the treatment of diabetes-associated complications. A thorough review and analysis were conducted using various databases including EMBASE, MEDLINE, and Google Scholar to extract the available information on challenges faced by current therapies which have triggered the development of novel molecules or drugs. From the analysis, it was analyzed that transforming growth factor βs (TGF-βs) have been shown to exhibit pleiotropic activity and are responsible for maintaining homeostasis and its overexpression is convoluted in the pathogenesis of various disorders. Therefore, developing drugs that block TGF-β signaling may provide therapeutic benefits. This extensive review concluded that drugs targeting TGF-β signaling pathway and its subsequent blockade have shown promising results and hold the potential to become drugs of choice in the management of diabetes and associated complications.

The Emerging Role of Metabolism in Brain-Heart Axis: New Challenge for the Therapy and Prevention of Alzheimer Disease. May Thioredoxin Interacting Protein (TXNIP) Play a Role?

Alzheimer disease (AD) is the most frequent cause of dementia and up to now there is not an effective therapy to cure AD. In addition, AD onset occurs decades before the diagnosis, affecting the possibility to set up appropriate therapeutic strategies. For this reason, it is necessary to investigate the effects of risk factors, such as cardiovascular diseases, in promoting AD. AD shows not only brain dysfunction, but also alterations in peripheral tissues/organs. Indeed, it exists a reciprocal connection between brain and heart, where cardiovascular alterations participate to AD as well as AD seem to promote cardiovascular dysfunction. In addition, metabolic dysfunction promotes both cardiovascular diseases and AD. In this review, we summarize the pathways involved in the regulation of the brain-heart axis and the effect of metabolism on these pathways. We also present the studies showing the role of the gut microbiota on the brain-heart axis. Herein, we propose recent evidences of the function of Thioredoxin Interacting protein (TXNIP) in mediating the role of metabolism on the brain-heart axis. TXNIP is a key regulator of metabolism at both cellular and body level and it exerts also a pathological function in several cardiovascular diseases as well as in AD.