{"title":"Impact of light on inner workings of neuronal functions.","authors":"Jose Martinez-Hernandez, Alain Buisson","doi":"10.1016/bs.irn.2026.01.012","DOIUrl":"https://doi.org/10.1016/bs.irn.2026.01.012","url":null,"abstract":"<p><p>The aim of this chapter is to review the molecular mechanisms that underlie the effect of red and near-infrared light --collectively referred to as photobiomodulation (PBM)-- on brain tissue. We discuss the therapeutic potential of PBM in the brain, considering both systemic actions and cell-type-specific responses. The prevailing hypothesis is that PBM enhances mitochondrial activity, leading to increased cellular energy production. While this mechanism may benefit many cell types, the central nervous system (CNS) appears particularly responsive to PBM due to either cell- specific signalling pathways that are highly energy-dependent or the existence of several mechanisms of action for PBM, some of them could be specific to CNS cells. In this chapter, we highlighted studies demonstrating PBM's functional impact on different CNS cell populations in order to identify the molecular and cellular mediators of its effects.</p>","PeriodicalId":94058,"journal":{"name":"International review of neurobiology","volume":"189 ","pages":"237-259"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148803561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Circulating biochemical signatures of neurodegeneration in Alzheimer's disease.","authors":"Greata Rubavathi Eliazer, Mahesh Kandasamy","doi":"10.1016/bs.irn.2026.06.004","DOIUrl":"https://doi.org/10.1016/bs.irn.2026.06.004","url":null,"abstract":"<p><p>Alzheimer's Disease (AD), a major cause of progressive memory loss, is pathogenically associated with the accumulation of amyloid-beta (Aβ) plaques, tau-mediated neurofibrillary tangles, neuroinflammation, and neurodegeneration. The molecular, biochemical and cellular malformation apears to occur before the onset of behavioural symptoms and intensifies as the disease progresses, highlighting the importance of early diagnostic approaches. The routine neuroimaging-based techniques, such as magnetic resonance imaging and positron emission tomography, are highly valuable to monitor the emergence of symptoms but are limited by high cost and accessibility. The cerebrospinal fluid-based methods provide valuable insight into the state of disease, however the procedure associated with sample collection is highly invasive. Eventually, the blood-based biomarkers have emerged as a promising and minimally invasive alternative procedure for the detection and monitoring of AD. The circulating biomarkers such as Aβ , phosphorylated tau isoforms, and associated abnormal biochemical signatures are correlated with pathological processes in AD. Assessing these blood biomarkers is not only crucial for diagnostics but also important for monitoring the changes associated with treatment in AD. As most current treatment options provide only symptomatic relief, advanced diagnostic approaches are essential for early detection and therapeutic intervention. The blood-based biomarkers represent a transformative step toward early diagnosis, large-scale screening, and precision medicine in AD, with significant potential for the development of disease-modifying therapies. Thus, this book chapter provides an overview of blood-based biomarker panels and discusses recent advances in bioanalytical technologies in AD.</p>","PeriodicalId":94058,"journal":{"name":"International review of neurobiology","volume":"191 ","pages":"91-111"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149042833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohammad Muzaffar Mir, Gulzar Muzaffar Mir, Abdul Majid, Muffarah Hamid Alharthi, Abdullah M Alshahrani
{"title":"The clinical utility of blood-based biomarkers of Alzheimer's disease: Triumphs and pitfalls.","authors":"Mohammad Muzaffar Mir, Gulzar Muzaffar Mir, Abdul Majid, Muffarah Hamid Alharthi, Abdullah M Alshahrani","doi":"10.1016/bs.irn.2026.05.008","DOIUrl":"https://doi.org/10.1016/bs.irn.2026.05.008","url":null,"abstract":"<p><p>Alzheimer's disease is increasingly understood as a biological continuum characterized by amyloid deposition, tau pathology, neurodegeneration, and neuroinflammatory processes. Blood-based biomarkers have emerged as accessible tools for detecting these processes in peripheral circulation, offering an alternative to cerebrospinal fluid and imaging-based diagnostics. This chapter examines the clinical utility of key blood-based biomarkers, including phosphorylated tau, amyloid-β ratios, neurofilament light chain, and glial fibrillary acidic protein, within the context of current diagnostic frameworks. Phosphorylated tau, particularly p-tau217, demonstrates strong performance in identifying Alzheimer's disease-related pathology, while amyloid biomarkers contribute to early detection and risk stratification. Neurofilament light chain reflects the extent of neurodegeneration, and glial fibrillary acidic protein provides insight into astrocytic activation and inflammatory responses. The integration of these markers into combined models supports stage-specific interpretation across the disease continuum and improves diagnostic efficiency. Despite these advances, important limitations remain, including variability across analytical platforms, influence of systemic factors, and differences in performance across clinical settings. Biomarker results are inherently probabilistic and require interpretation within structured clinical pathways. Blood-based biomarkers have the potential to improve access to biological assessment and support clinical decision-making. Their effective implementation depends on continued standardization, validation across diverse populations, and integration into patient-centered care.</p>","PeriodicalId":94058,"journal":{"name":"International review of neurobiology","volume":"191 ","pages":"403-446"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149043066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Redefining Alzheimer's disease diagnostics in the age of blood-based biomarkers.","authors":"Pradeep Uc Yadav, Anurag Tk Baidya, Rajnish Kumar","doi":"10.1016/bs.irn.2026.05.006","DOIUrl":"https://doi.org/10.1016/bs.irn.2026.05.006","url":null,"abstract":"<p><p>Alzheimer's disease (AD) is the primary cause of dementia and represents an increasing medical and socioeconomic burden in aging populations worldwide. The disease is characterized by progressive pathological changes, including amyloid-β deposition, tau hyperphosphorylation, synaptic dysfunction, and widespread neurodegeneration, which develop long before clinical symptoms become evident. While cerebrospinal fluid biomarkers and positron emission tomography imaging have significantly improved biological diagnosis and disease staging, their invasive nature, high cost, and limited accessibility constrain routine clinical application. As a result, blood-based biomarkers have gained attention as minimally invasive and scalable alternatives. This chapter summarizes the evolution and current landscape of blood-derived biomarkers for AD, covering amyloid-related measures, phosphorylated tau species, neurofilament light chain as an indicator of neurodegeneration, and emerging markers of neuroinflammation and synaptic dysfunction. Recent advances in ultrasensitive assays and analytical standardization have improved their clinical reliability, positioning blood-based biomarkers as valuable tools for early detection, disease monitoring, and therapeutic decision-making.</p>","PeriodicalId":94058,"journal":{"name":"International review of neurobiology","volume":"191 ","pages":"61-89"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149043073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tushar Matta, Mahendra Bishnoi, Kanwaljit Chopra, Kanthi Kiran Kondepudi
{"title":"The microbiota-gut-brain axis in epilepsy: Mechanistic insights and emerging probiotic-based therapeutics.","authors":"Tushar Matta, Mahendra Bishnoi, Kanwaljit Chopra, Kanthi Kiran Kondepudi","doi":"10.1016/bs.irn.2026.05.007","DOIUrl":"https://doi.org/10.1016/bs.irn.2026.05.007","url":null,"abstract":"<p><p>Epilepsy is a chronic neurological disorder affecting more than 50 million people globally. Over one-third of patients remain pharmacoresistant to conventional antiepileptic therapy, creating a substantial healthcare and societal burden. Recently, the gut-brain axis has emerged as a novel and pivotal route in the pathophysiology and progression of epilepsy. The gut microbiota regulates brain function by influencing immune responses, neurotransmitter levels, and the integrity of the gut-brain barrier. Studies increasingly show that epilepsy is linked to gut dysbiosis, reflected by reduced abundance of beneficial genera such as Lactobacillus, Bifidobacterium, and Faecalibacterium, and an increased abundance of Ruminococcus, Bacteroides and Enterococcus. These microbial shifts disrupt the homeostatic production of short-chain fatty acids and GABA, and elevate systemic inflammation, thereby contributing to epileptogenesis. Furthermore, mental stress and neuroinflammation may indirectly trigger gut disturbances, disrupting the bidirectional gut-brain homeostasis. Considering the crucial role of the microbiota-gut-brain axis (MGBA) in epilepsy, research attention has increasingly focused on therapeutic interventions that can positively modulate the MGBA to prevent disease progression and severity. Various preclinical studies using PTZ-kindling, pilocarpine, and kainic acid models demonstrate that selected probiotic strains can significantly reduce seizure severity, restore antioxidant balance, dampen hippocampal inflammation, improve SCFA levels, strengthen gut barrier integrity, and preserve dendritic spine density. This chapter provides an integrative overview of the evolving role of the MGBA in the pathogenesis and management of epilepsy, emphasizing the mechanisms of gut-brain communication and how biotics, particularly GABA-producing probiotics, may beneficially modulate these pathways to offer promising adjunctive therapeutic opportunities.</p>","PeriodicalId":94058,"journal":{"name":"International review of neurobiology","volume":"191 ","pages":"537-569"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149043034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Neurovascular coupling and energy substrate delivery in Alzheimer's disease.","authors":"Shivam Malviya, Debasmita Saha, Anagha Kamble, Divya Ramesh Singh, Sivaraj Mohana Sundaram, Vasudharani Devanathan","doi":"10.1016/bs.irn.2026.05.001","DOIUrl":"10.1016/bs.irn.2026.05.001","url":null,"abstract":"<p><p>The brain has exceptionally high metabolic demands and depends on a continuous supply of oxygen and glucose to maintain neuronal activity and cognitive function. Despite accounting for only about 2 % of body weight, it consumes more than 20 % of the body's energy. This demand is met through tightly regulated cerebral blood flow mediated by neurovascular coupling (NVC), a process that links neuronal activity with local vascular responses. The cellular components responsible for this regulation including neurons, astrocytes, endothelial cells, pericytes, and vascular smooth muscle cells form the neurovascular unit (NVU), which maintains blood brain barrier (BBB) integrity, metabolic homeostasis, and efficient substrate delivery. Increasing evidence suggests that disruption of neurovascular and metabolic regulation is an early and critical contributor to Alzheimer's disease (AD). Impairment of NVU function leads to reduced cerebral blood flow, endothelial dysfunction, pericyte loss, and breakdown of the BBB. These vascular changes compromise the delivery of oxygen and glucose, resulting in cerebral hypometabolism that often precedes classical pathological hallmarks such as amyloid-β plaques and tau neurofibrillary tangles. Alterations in glucose transport across the BBB, particularly reduced expression of the GLUT1 transporter, further exacerbate neuronal energy deficits. Disturbances in lactate metabolism and mitochondrial dysfunction also contribute to oxidative stress and progressive neurodegeneration. Understanding the interaction between neurovascular dysfunction, impaired brain metabolism, and AD pathology provides important insight into disease progression. Therapeutic strategies aimed at restoring vascular function, improving metabolic substrate delivery, and enhancing neuronal energy metabolism may offer promising avenues for early intervention in AD.</p>","PeriodicalId":94058,"journal":{"name":"International review of neurobiology","volume":"186 ","pages":"317-338"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148229862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mercy Priyadharshini Babu Deva Irakkam, Mahesh Kandasamy
{"title":"Astroglial dysregulation and gliotransmitter imbalance in schizophrenia.","authors":"Mercy Priyadharshini Babu Deva Irakkam, Mahesh Kandasamy","doi":"10.1016/bs.irn.2026.05.013","DOIUrl":"https://doi.org/10.1016/bs.irn.2026.05.013","url":null,"abstract":"<p><p>Schizophrenia is a neuropsychiatric illness characterized by progressive deterioration of thought processes and marked behavioral abnormalities arising from an unknown pathogenesis underlying the false perceptions, primarily hallucinations and delusions. The clinical symptoms of schizophrenia also include apathy, communication disorders and suicidal thoughts. Although the etiopathogenesis of schizophrenia remains not fully elucidated, the development of schizophrenia has been linked to adverse pregnancy, obstetric complications, neurodevelopmental disorders, neurotransmission imbalance and aberrant neurogenic events. Astrocytes are the most predominant glial cell type in the central nervous system (CNS), where they provide metabolic support, regulate neuroimmune mechanisms, facilitate neurotransmitter reuptake, and sustain synaptic homeostasis. Abnormal neural transmission is considered central to the pathogenesis of schizophrenia. Recent studies have highlighted that malformations in glial cells, particularly dysfunctional or reactive astrocytes, play a crucial role in the pathophysiology. Astrocytic dysregulation in schizophrenia is likely to result in synaptic dysfunction due to altered levels of key gliotransmitters such as glutamate, gamma-aminobutyric acid (GABA) and D-serine leading to altered neurobehavioral outcomes. Thus, insight into the scientific concepts that interrelate the pathophysiology of schizophrenia with astroglia dysregulation at the level of gliotransmitter imbalance could provide innovative hints for developing therapeutic strategies for the treatment of schizophrenia. This chapter describes the key roles of astrocytes and emphasizes imbalances in gliotransmitters as main contributors to the pathophysiology of schizophrenia.</p>","PeriodicalId":94058,"journal":{"name":"International review of neurobiology","volume":"188 ","pages":"91-112"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148703048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nitin Yadav, Jyotirmoy Banerjee, Manisha Tiwari, Aparna Dixit
{"title":"Brain lipid dysregulation as a driver of energy metabolism failure in Alzheimer's disease.","authors":"Nitin Yadav, Jyotirmoy Banerjee, Manisha Tiwari, Aparna Dixit","doi":"10.1016/bs.irn.2026.02.004","DOIUrl":"https://doi.org/10.1016/bs.irn.2026.02.004","url":null,"abstract":"<p><p>Alzheimer's Disease (AD) is becoming more widely recognized as a condition of brain energy metabolism, wherein lipid dysregulation plays a crucial, although unrecognized, role. In addition to functioning as structural elements of neuronal membranes, lipids such as phospholipids, sphingolipids, and cholesterol play a crucial role in regulating mitochondrial bioenergetics, synaptic activity, and membrane-associated signaling pathways. In AD, modifications in lipid composition, distribution, and turnover compromise membrane fluidity, disturb mitochondrial dynamics, and obstruct lipid-mediated transport of energy substrates. These alterations intensify oxidative stress, impair glucose and ketone utilization, and stimulate neuroinflammatory pathways that further diminish metabolic capacity. Progress in lipidomics has uncovered disease-specific lipid signatures, providing a fresh understanding of the relationship between lipid homeostasis and neuronal energy loss. Despite extensive focus on amyloid and tau, lipid-mediated bioenergetic failure remains underrepresented in integrative AD models; this chapter addresses this gap and consolidates existing information connecting lipid modifications to metabolic dysfunction in AD, emphasizing molecular pathways and prospective treatment strategies aimed at lipid metabolism to re-establish bioenergetic equilibrium.</p>","PeriodicalId":94058,"journal":{"name":"International review of neurobiology","volume":"188 ","pages":"363-396"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148703064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Diagnostic potential of exosomes in the neurodegenerative disorders and cancer.","authors":"Naveen Soni, Shweta Dongre, Bhawana Bissa","doi":"10.1016/bs.irn.2026.07.001","DOIUrl":"https://doi.org/10.1016/bs.irn.2026.07.001","url":null,"abstract":"<p><p>Neurodegenerative disorders are the progressive loss of function of the nervous system, in which the brain or CNS gradually die. The study related to neurodegeneration has several limitations, including the difficulty of obtaining brain tissue for pathophysiological analysis and the lack of prominent biomarkers. Similarly, the blood-brain barrier makes it more difficult to treat brain-related disorders by limiting the effectiveness of the drugs. Exosomes, a key intercellular signalling nanovesicle, transmit crucial genetic information between cells. Moreover, its ability to cross the blood-brain barrier makes it a more prominent biomarker and can even be used as a therapeutic carrier in the CNS. Exosomes also serve as excellent biomarkers for different cancer types by carrying tumor specific molecules, and might enable quick and efficient detection for a broad range of cancers. Exosomes are also involved in promoting metastasis, drug resistance, and manipulation of the immune system to facilitate tumor growth. In this study, we highlight recent studies that have demonstrated the utility of exosome-based biomarkers for the diagnosis of neurodegenerative disorders (Alzheimer's Disease, Parkinson's Disease, and Huntington's Disease) and different types of cancers (Breast Cancer, Lung Cancer, and Brain Cancer).</p>","PeriodicalId":94058,"journal":{"name":"International review of neurobiology","volume":"191 ","pages":"509-536"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149042867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Blood-based emerging biomarkers in early detection and diagnosis of Alzheimer's disease.","authors":"Trishna Anand, Awanish Kumar","doi":"10.1016/bs.irn.2026.01.002","DOIUrl":"https://doi.org/10.1016/bs.irn.2026.01.002","url":null,"abstract":"<p><p>In the medical field, such as oncology and cardiovascular diseases, biomarker discovery and development for clinical research, diagnostics, and therapy monitoring in clinical trials have advanced quickly. This has facilitated the development of biomarker-guided, precision-medicine-based targeted therapies and helped in quick and early detection. Cerebrospinal fluid and PET indicators of tau and amyloid-β proteins are among the biomarker discovery and validation advances in Alzheimer's disease (AD). They have shown remarkable accuracy in identifying the presence of pathophysiological and neuropathological alterations linked to AD. However, these assays' high cost, lack of accessibility, and/or invasiveness restrict their applicability as practical first-line methods for identifying pathophysiological patterns. However, the concentrations of brain-derived chemicals in blood are significantly lower than those in CSF, which presents an analytical problem. Blood, as a biofluid to evaluate biomarkers for diseases of the central nervous system, has further problems. However, there has been a significant advancement in recent years. The current status of research on blood biomarkers for AD and associated neurodegenerative dementias is updated in this chapter.</p>","PeriodicalId":94058,"journal":{"name":"International review of neurobiology","volume":"191 ","pages":"145-174"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149042902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}