Clinical and experimental embryology, developmental anatomy, teratogenic studies, histopathology, renal and neural development, anatomical variations, applied anatomy, and medical education research.

Dr. Amit Kumar Srivastava is an accomplished anatomist and medical educator with over 14 years of teaching and academic experience in human anatomy. He holds a PhD in Medical Anatomy (2024) with a Gold Medal, along with an M.Sc. in Medical Anatomy, and has been actively involved in undergraduate and postgraduate medical education since 2010. His teaching expertise spans gross anatomy, neuroanatomy, embryology, histology, osteology, and cadaveric dissection, with a strong commitment to competency-based medical education in line with National Medical Commission (NMC) guidelines. He has played a key role in establishing anatomy departments, setting up histology research laboratories, and managing dissection halls, embalming procedures, museum development, and body donation programs in government medical colleges. Dr. Srivastava has an extensive research portfolio with 25+ publications in PubMed-indexed, Scopus-indexed, and international peer-reviewed journals. His research interests include experimental embryology, histopathology, teratogenic studies, renal and neural development, anatomical variations, and applied medical anatomy. He has also contributed book chapters to internationally published academic volumes and received formal appreciation for his contribution to the renowned textbook Inderbir Singh’s Human Embryology (13th Edition). He serves as an Editor and Reviewer for several international journals, including Scopus and PubMed-indexed publications, and is a frequent oral presenter at national and international conferences. His professional excellence has been recognized with multiple honors, including the Excellence in Service Award, Best Researcher Award, and Corona Warrior Award for his contributions during the COVID-19 pandemic. Dr. Srivastava is a life member of leading professional bodies such as the Anatomical Society of India, Society of Medical Anatomists, and the Electron Microscopic Society of India. Beyond academics, he actively contributes to institutional administration, examination systems, IT coordination, and medico-legal responsibilities within government medical education. Reference: The Glymphatic System: A Comprehensive Framework for Understanding Brain Waste Clearance Introduction: The brain, despite comprising only 2% of body mass, accounts for approximately 20% of total energy consumption, generating substantial metabolic waste that requires efficient removal mechanisms. Unlike peripheral organs that utilize lymphatic vessels for waste clearance, the brain lacks a conventional lymphatic system, presenting a unique challenge for metabolite removal. Recent discoveries have revealed the glymphatic system, a specialized brain-wide paravascular pathway that facilitates the clearance of interstitial solutes and metabolic waste products. This system represents a paradigm shift in understanding central nervous system fluid dynamics and has profound implications for neurological health and disease. Anatomical Perspective: The glymphatic system comprises a network of perivascular spaces surrounding cerebral blood vessels, specifically the Virchow-Robin spaces that encircle penetrating arteries and veins. Cerebrospinal fluid (CSF) enters the brain parenchyma along periarterial spaces, driven by arterial pulsation and facilitated by aquaporin-4 (AQP4) water channels localized on astrocytic endfeet. These polarized AQP4 channels enable rapid fluid exchange between the CSF-filled perivascular spaces and the brain interstitium. Interstitial fluid (ISF) containing metabolic waste products is then directed toward perivenous spaces for drainage into cervical lymphatic vessels. The anatomical organization of astrocytic endfeet and their strategic positioning at the interface between blood vessels and brain tissue is critical for maintaining the directional flow necessary for efficient waste clearance. Present Application: Current researches have established the glymphatic system's crucial role in clearing potentially neurotoxic proteins, including amyloid-beta and tau, which accumulate in Alzheimer's disease. Imaging studies utilizing contrast-enhanced magnetic resonance imaging (MRI) have demonstrated that glymphatic function is significantly enhanced during sleep, with interstitial space volume increasing by approximately 60% compared to waking states. This sleep-dependent clearance mechanism provides a physiological explanation for the restorative functions of sleep and the association between sleep disorders and neurodegenerative diseases. Clinical investigations have revealed impaired glymphatic clearance in conditions including traumatic brain injury, stroke, and normal pressure hydrocephalus, suggesting that glymphatic dysfunction contributes to disease pathogenesis. Therapeutic strategies aimed at enhancing glymphatic function, such as optimizing sleep quality, body positioning during sleep, and maintaining cardiovascular health, are being explored as potential interventions for preventing or slowing neurodegenerative disease progression. Conclusion and Future Scope: The discovery of the glymphatic system has fundamentally transformed our understanding of brain homeostasis and waste management. This pathway represents a critical mechanism for maintaining cerebral proteostasis and preventing the accumulation of neurotoxic substances. Future research directions include developing non-invasive biomarkers for assessing glymphatic function in clinical populations, elucidating the molecular mechanisms regulating AQP4 polarization and glymphatic efficiency, and investigating pharmacological interventions that could enhance clearance capacity. Advanced imaging techniques, including dynamic contrast-enhanced MRI and positron emission tomography, promise to enable real time monitoring of glymphatic activity in humans. Understanding age-related changes in glymphatic function and identifying modifiable risk factors that influence clearance efficiency may provide novel therapeutic targets for neurodegenerative diseases. The integration of glymphatic system research with studies of sleep physiology, cardiovascular function, and neuroinflammation will likely yield comprehensive strategies for promoting brain health across the lifespan and developing disease-modifying treatments for conditions characterized by protein aggregation and impaired waste clearance. Keywords: Glymphatic system, Waste clearance, Aquaporin-4, Perivascular pathways, Neurodegenerative diseases, Sleep physiology, Brain homeostasis, Cerebrospinal fluid dynamics