Search Results (25)

Cardiovascular–kidney–metabolic (CKM) syndrome is a systemic, interdependent disorder arising from the convergence of metabolic dysfunction, chronic kidney disease, and cardiovascular pathology. Anchored in the Developmental Origins of Health and Disease (DOHaD) framework, this review advances a “parallel hit” model, primarily based on evidence from experimental animal studies, particularly rodent models, posited that early-life environmental insults concurrently program structural and functional vulnerabilities in both renal and central nervous system hubs. These early perturbations prime susceptibility long before clinical manifestations emerge. CKM progression is conceptualized as a two-stage trajectory, with an initial phase of parallel programming affecting kidney and brain development, followed by a transition to maladaptive bidirectional crosstalk. In the later phase, heightened efferent sympathetic outflow and aberrant afferent renal signaling—potentiated by uremic toxin accumulation, neuroinflammation, and blood–brain barrier disruption—drive a self-perpetuating cycle that accelerates cardiorenal and metabolic injury. Key integrative mechanisms, including oxidative stress, chronic low-grade inflammation, mitochondrial dysfunction, and gut microbiota dysbiosis, serve as convergent pathways linking early-life exposures to adult CKM phenotypes. These pathways not only sustain disease progression but also represent actionable therapeutic targets. Importantly, this framework underscores the translational potential of early-life “reprogramming” strategies. Interventions such as precision nutrition, antioxidant supplementation, microbiota-directed therapies (including prebiotics, probiotics, and postbiotics), and mechanism-based pharmacotherapies may mitigate or reverse maladaptive programming. However, much of the current mechanistic evidence remains preclinical, and further human studies are needed to validate these pathways and therapeutic approaches. Collectively, this dual-hub paradigm reframes CKM syndrome as a life-course continuum rather than a late-stage comorbidity cluster, emphasizing the necessity of early, mechanism-driven interventions to stabilize the brain–kidney axis and improve long-term cardiovascular–kidney–metabolic outcomes. Full article

The vagus nerve (innervating the gut from esophagus to proximal colon) and sacral nerve (innervating distal colon and rectum) are key parasympathetic regulators of gastrointestinal (GI) function. While vagus nerve stimulation (VNS) has shown therapeutic potential in upper GI disorders, its role in modulating distal colon and rectal function remains poorly understood. This study investigated the effects and mechanisms of VNS on distal colon transit and rectal tone in rats. Adult male Sprague Dawley rats were implanted with stimulation electrodes at the cervical or auricular vagal afferent nerve. VNS was applied with varying frequencies, pulse widths, and amplitudes. Rectal tone was assessed using a barostat device, and distal colon transit was evaluated using bead expulsion. Nitrergic and cholinergic contributions were examined using L-NAME and nNOS expression, and acetylcholine ELISA and ChAT expression, respectively. Central pathways were investigated by immunofluorescence staining of c-fos and ChAT in the nucleus tractus solitarius (NTS). Sacral efferent pathway was assessed by chemogenetic inhibition of the dorsal motor nucleus of the vagus (DMV) and Barrington nucleus (BN/PMC). VNS (5 Hz, 0.1 and 0.5 ms, 0.5 mA) significantly increased rectal volume, indicating relaxation, and accelerated distal colon transit. L-NAME abolished VNS-induced rectal relaxation, while nNOS expression in the rectum was upregulated, confirming nitrergic mediation. Distal colon transit was associated with increased acetylcholine release and ChAT expression, highlighting cholinergic involvement. VNS enhanced c-fos and ChAT-positive neurons in the NTS, suggesting central integration of vagal afferent signals. Chemogenetic inhibition of DMV and BN attenuated rectal relaxation, indicating that VNS effects are mediated via a vagal–NTS–sacral pathway. VNS modulates distal colon transit and rectal tone through coordinated nitrergic and cholinergic signaling and central vagal-to-sacral circuits. These findings reveal functional crosstalk between vagal and sacral parasympathetic pathways and provide mechanistic insight into potential VNS therapy for lower GI disorders. Full article

For decades, researchers have explored the therapeutic potential of the vagus nerve through vagus nerve stimulation (VNS). Initially developed for epilepsy, VNS has since been applied to treat resistant depression, stroke recovery, and inflammatory conditions. Transcutaneous VNS (tVNS) now offers a noninvasive alternative, fueling clinical trials in disorders ranging from rheumatoid arthritis and migraines to long COVID-19. Mechanistic studies suggest that afferent and efferent vagal fibers modulate immune responses, mood regulation, and neurotransmitter systems. The SPARC initiative has accelerated mapping of vagal circuits, enabling more precise approaches to stimulation. Despite progress, the results remain mixed: while some patients experience lasting symptom relief, others respond no better than to placebo. Depression studies, in particular, highlight both the promise and the complexity of VNS, as inflammation, motivation circuits, and gut–brain signaling emerge as key modulators. Next-generation closed-loop devices and circuit-specific targeting may improve efficacy and reduce adverse effects. VNS research thus lies at the intersection of neuromodulation, psychiatry, and immunology—offering hope for hard-to-treat conditions, yet demanding rigorous trials to separate myths from medicine. In this article, we review the current clinical and experimental applications of tVNS, analyze its mixed efficacy across psychiatric, immunological, and neurological disorders, and highlight the mechanistic insights, stimulation parameters, and emerging technologies that may shape next-generation therapies. Full article

Overactivation of the renin–angiotensin–aldosterone system (RAAS) promotes haemodynamic overload, inflammation, and fibrosis in the heart and kidneys. Recently, sodium–glucose cotransporter-2 (SGLT2) inhibitors have emerged as a cornerstone therapy in cardiorenal protection. Emerging data indicate that adding SGLT2 inhibitors to angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers, mineralocorticoid receptor antagonists, or angiotensin receptor–neprilysin inhibitors confers additional cardiorenal protection, yet their mechanistic basis and optimal clinical use in cardiovascular (CV) disease remain unclear. This review will integrate pre-clinical and clinical evidence on dual RAAS/SGLT2 modulation in CV disease, providing mechanistic insight into dual therapy. The review will finally outline priorities for future translational and outcome studies. Clinically, adding SGLT2 inhibitors to RAAS-based therapy reduces heart failure hospitalizations and slows kidney disease progression without new safety liabilities in type 2 diabetes, heart failure, and chronic kidney disease. Mechanistically, SGLT2 inhibition restores tubuloglomerular feedback and constricts the afferent arteriole; RAAS blockade dilates the efferent arteriole, and together, they lower intraglomerular pressure. Both classes also reduce oxidative stress, inflammatory signalling, and pro-fibrotic pathways, with SGLT2 inhibitors in several settings shifting RAAS balance toward the protective ACE2/angiotensin-(1–7)/Mas receptor axis. Key gaps include the scarcity of adequately powered trials designed to test combination therapy versus either component alone, limited evidence on timing and sequencing, incomplete characterization in high-risk groups, and mechanistic insight limited by study design in animal and cell models. Collectively, current data support layering SGLT2 inhibitors onto RAAS-based therapy, while definitive evidence from dedicated clinical trials is awaited. Full article

Oxytocin (OT), traditionally associated with reproduction and social bonding, has emerged as a key modulator of gastrointestinal (GI) physiology and appetite regulation behavior through its actions within the gut–brain axis. Central to this regulation are vagal oxytocin receptors (VORs), which are located along vagal afferent and efferent fibers and within brainstem nuclei such as the nucleus tractus solitarius and dorsal motor nucleus of the vagus. This review presents a comprehensive synthesis of current knowledge on the anatomical distribution, molecular signaling, developmental plasticity, and functional roles of VORs in the regulation of GI motility, satiety, and energy homeostasis. We highlight how VORs integrate hormonal, microbial, and stress-related cues and interact with other neuropeptidergic systems including GLP-1, CCK, and nesfatin-1. Recent advances in spatial transcriptomics, single-nucleus RNA sequencing, chemogenetics, and optogenetics are discussed as transformative tools for mapping and manipulating VOR-expressing circuits. Particular attention is given to sex differences, translational challenges, and the limited understanding of VOR function in humans. This article proposes VORs as promising therapeutic targets in dysphagia, obesity, and functional GI disorders. We outline future research priorities, emphasizing the need for integrative, cross-species approaches to clarify VOR signaling and guide the development of targeted, personalized interventions. Full article

Arterial hypertension is highly prevalent among individuals with chronic kidney disease (CKD), exhibiting a bidirectional association and playing a critical role in the progression of renal dysfunction. CKD affects approximately 10–12% of the global population and is often a common comorbidity in patients with true resistant hypertension. The sympathetic nervous system (SNS) plays a key role in the pathophysiological cascade of CKD-mediated hypertension. Current pharmacological therapies do not directly target SNS overactivity, highlighting the need for alternative approaches. Renal denervation (RDN), an interventional procedure that modulates both afferent and efferent renal nerve signaling, has emerged as a promising strategy for resistant hypertension with multiple pleiotropic benefits. Both preclinical and clinical trial data indicate that RDN is safe, with no significant deterioration of renal function reported in both early-stage CKD and end-stage renal disease (ESRD), as well as effective in reducing both office and ambulatory blood pressure in most studies. This review examines the pathophysiological basis for SNS overactivity in CKD, summarizes preclinical and clinical data on the safety and efficacy of RDN in this population, and discusses ongoing and future trials that may further clarify the role of RDN in CKD management and its long-term impact on renal and cardiovascular outcomes. Full article

(1) Background: Based on the reafference principle, our system creates an efferent signal copy to distinguish external inputs from our activities in the afferent signal. According to this principle, sensory and motor information from the outside world travel together from the periphery to the brain. (2) Methods: This work introduces signal processing methods that extract contextual sensory preferences from motor streams. Speed and acceleration data were collected as participants walked under different conditions: in silence (with open and closed eyes), while listening to two different songs (each with open and closed eyes), and finally while walking to their favorite song. Ten individuals completed a total of seven conditions. (3) Results: Variations in the walking patterns of each participant were identified, revealing the sensory inputs they perceived. The results also indicated the audio and visual conditions that optimized the participant’s sensory–motor system performance. (4) Conclusions: The outcomes suggest that we can extract from motor stream particulars that go beyond an individual’s movement qualities and toward the contextual sensory inputs accompanying the movement data, even when participants execute the very same task of walking. Full article

Non-muscle invasive bladder cancer (NMIBC) accounts for approximately 70–75% of all bladder cancer cases. The standard treatment for high-risk NMIBC involves transurethral tumour resection followed by intravesical Bacillus Calmette–Guerin (BCG) immunotherapy. While BCG immunotherapy is both safe and effective, it frequently leads to the development of lower urinary tract symptoms (LUTS) such as urinary urgency, frequency, dysuria, and pelvic discomfort. These symptoms can significantly diminish patients’ quality of life and may result in the discontinuation of BCG treatment, adversely affecting oncological outcomes. Despite the considerable clinical impact of BCG-induced LUTS, the underlying mechanisms remain unclear, hindering the implementation or development of effective treatments. This review provides novel insights into the potential mechanisms underlying BCG-induced LUTS, focusing on the integrated roles of afferent and efferent nerves in both normal and pathological bladder sensation and function. Specifically, this review examines how the body’s response to BCG—through the development of inflammation, increased urothelial permeability, and altered urothelial signalling—might contribute to LUTS development. Drawing from known mechanisms in other common urological disorders and data from successful clinical trials involving NMIBC patients, this review summarises evidence supporting the likely changes in both sensory nerve signalling and bladder muscle function in the development of BCG-induced LUTS. However, further research is required to understand the intricate mechanisms underlying the development of BCG-induced LUTS and identify why some patients are more likely to experience BCG intolerance. Addressing these knowledge gaps could have profound implications for patients’ quality of life, treatment adherence, and overall outcomes in NMIBC care. Full article

Type 2 diabetes mellitus (T2DM) is one of the most significant health issues worldwide, with associated healthcare costs estimated to surpass USD 1054 billion by 2045. The leading cause of death in T2DM patients is the development of cardiovascular disease (CVD). In the early stages of T2DM, patients develop cardiovascular autonomic dysfunction due to the withdrawal of cardiac parasympathetic activity. Diminished cardiac parasympathetic tone can lead to cardiac arrhythmia-related sudden cardiac death, which accounts for 50% of CVD-related deaths in T2DM patients. Regulation of cardiovascular parasympathetic activity is integrated by neural circuitry at multiple levels including afferent, central, and efferent components. Efferent control of cardiac parasympathetic autonomic tone is mediated through the activity of preganglionic parasympathetic neurons located in the cardiac extensions of the vagus nerve that signals to postganglionic parasympathetic neurons located in the intracardiac ganglia (ICG) on the heart. Postganglionic parasympathetic neurons exert local control on the heart, independent of higher brain centers, through the release of neurotransmitters, such as acetylcholine. Structural and functional alterations in cardiac parasympathetic postganglionic neurons contribute to the withdrawal of cardiac parasympathetic tone, resulting in arrhythmogenesis and sudden cardiac death. This review provides an overview of the remodeling of parasympathetic postganglionic neurons in the ICG, and potential mechanisms contributing to the withdrawal of cardiac parasympathetic tone, ventricular arrhythmogenesis, and sudden cardiac death in T2DM. Improving cardiac parasympathetic tone could be a therapeutic avenue to reduce malignant ventricular arrhythmia and sudden cardiac death, increasing both the lifespan and improving quality of life of T2DM patients. Full article

When an organism detects decreases in their core body temperature, the hypothalamus, the main thermoregulatory center, triggers compensatory responses. These responses include vasomotor changes to prevent heat loss and physiological mechanisms (e.g., shivering and non-shivering thermogenesis) for heat production. Both types of changes require the participation of peripheral thermoreceptors, afferent signaling to the spinal cord and hypothalamus, and efferent pathways to motor and/or sympathetic neurons. The present review aims to analyze the scientific evidence of the hypothalamic control of hypothermia and the central and peripheral changes that are triggered in domestic animals. Full article

Bacteria in the gut microbiome play an intrinsic part in immune activation, intestinal permeability, enteric reflex, and entero-endocrine signaling. The gut microbiota communicates with the central nervous system (CNS) through the production of bile acids, short-chain fatty acids (SCFAs), glutamate (Glu), γ-aminobutyric acid (GABA), dopamine (DA), norepinephrine (NE), serotonin (5-HT), and histamine. A vast number of signals generated in the gastrointestinal tract (GIT) reach the brain via afferent fibers of the vagus nerve (VN). Signals from the CNS are returned to entero-epithelial cells (EES) via efferent VN fibers and communicate with 100 to 500 million neurons in the submucosa and myenteric plexus of the gut wall, which is referred to as the enteric nervous system (ENS). Intercommunications between the gut and CNS regulate mood, cognitive behavior, and neuropsychiatric disorders such as autism, depression, and schizophrenia. The modulation, development, and renewal of nerves in the ENS and changes in the gut microbiome alter the synthesis and degradation of neurotransmitters, ultimately influencing our mental health. The more we decipher the gut microbiome and understand its effect on neurotransmission, the closer we may get to developing novel therapeutic and psychobiotic compounds to improve cognitive functions and prevent mental disorders. In this review, the intricate control of entero-endocrine signaling and immune responses that keep the gut microbiome in a balanced state, and the influence that changing gut bacteria have on neuropsychiatric disorders, are discussed. Full article

Gut bacteria play an important role in the digestion of food, immune activation, and regulation of entero-endocrine signaling pathways, but also communicate with the central nervous system (CNS) through the production of specific metabolic compounds, e.g., bile acids, short-chain fatty acids (SCFAs), glutamate (Glu), γ-aminobutyric acid (GABA), dopamine (DA), norepinephrine (NE), serotonin (5-HT) and histamine. Afferent vagus nerve (VN) fibers that transport signals from the gastro-intestinal tract (GIT) and gut microbiota to the brain are also linked to receptors in the esophagus, liver, and pancreas. In response to these stimuli, the brain sends signals back to entero-epithelial cells via efferent VN fibers. Fibers of the VN are not in direct contact with the gut wall or intestinal microbiota. Instead, signals reach the gut microbiota via 100 to 500 million neurons from the enteric nervous system (ENS) in the submucosa and myenteric plexus of the gut wall. The modulation, development, and renewal of ENS neurons are controlled by gut microbiota, especially those with the ability to produce and metabolize hormones. Signals generated by the hypothalamus reach the pituitary and adrenal glands and communicate with entero-epithelial cells via the hypothalamic pituitary adrenal axis (HPA). SCFAs produced by gut bacteria adhere to free fatty acid receptors (FFARs) on the surface of intestinal epithelial cells (IECs) and interact with neurons or enter the circulatory system. Gut bacteria alter the synthesis and degradation of neurotransmitters. This review focuses on the effect that gut bacteria have on the production of neurotransmitters and vice versa. Full article

Traditional cognitive linguistic theories acknowledge that human emotions are embodied, yet they fail to distinguish the dimensions that reflect the direction of neural signaling between the brain and body. Differences exist across languages and cultures in whether embodied emotions are conceptualized as afferent (feelings from the body) or efferent (enacted through the body). This important distinction has been neglected in academic discourse, arguably as a consequence of the ‘lexical approach’, and the dominance within the affective psychology of the cognitive and semantic models that overlook the role of interoception as an essential component of affective experience. Empirical and theoretical advances in human neuroscience are driving a reappraisal of the relationships between the mind, brain and body, with particular relevance to emotions. Allostatic (predictive) control of the internal bodily states is considered fundamental to the experience of emotions enacted through interoceptive sensory feelings and through the evoked physiological and physical actions mediated through efferent neural pathways. Embodied emotion concepts encompass these categorized outcomes of bidirectional brain–body interactions yet can be differentiated further into afferent or interoceptive and efferent or autonomic processes. Between languages, a comparison of emotion words indicates the dominance of afferent or interoceptive processes in how embodied emotions are conceptualized in Chinese, while efferent or autonomic processes feature more commonly in English. Correspondingly, in linguistic expressions of emotion, Chinese-speaking people are biased toward being more receptive, reflective, and adaptive, whereas native English speakers may tend to be more reactive, proactive, and interactive. Arguably, these distinct conceptual models of emotions may shape the perceived divergent values and ‘national character’ of Chinese- and English-speaking cultures. Full article

Oxidative stress and sustained sympathetic over-activity contribute to the pathogenesis of hypertension. Catheter-based renal denervation has been used as a strategy for treatment of resistant hypertension, which interrupts both afferent and efferent renal fibers. However, it is unknown whether selective renal afferent denervation (RAD) may play beneficial roles in attenuating oxidative stress and sympathetic activity in hypertension. This study investigated the impact of selective RAD on hypertension and vascular remodeling. Nine-week-old normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were subjected to selective renal afferent denervation (RAD) with 33 mM of capsaicin for 15 min. Treatment with the vehicle of capsaicin was used as a control. The selective denervation was confirmed by the reduced calcitonin gene-related peptide expression and the undamaged renal sympathetic nerve activity response to the stimulation of adipose white tissue. Selective RAD reduced plasma norepinephrine levels, improved heart rate variability (HRV) and attenuated hypertension in SHR.It reduced NADPH oxidase (NOX) expression and activity, and superoxide production in the hypothalamic paraventricular nucleus (PVN), aorta and mesenteric artery of SHR. Moreover, the selective RAD attenuated the vascular remodeling of the aorta and mesenteric artery of SHR. These results indicate that selective removal of renal afferents attenuates sympathetic activity, oxidative stress, vascular remodeling and hypertension in SHR. The attenuated superoxide signaling in the PVN is involved in the attenuation of sympathetic activity in SHR, and the reduced sympathetic activity at least partially contributes to the attenuation of vascular oxidative stress and remodeling in the arteries of hypertensive rats. Full article