Neuroprotective Roles of Apelin-13 in Neurological Diseases

Exercise-mediated muscle-hypothalamus crosstalk: Improvement for cognitive dysfunction caused by disrupted circadian rhythm

In contemporary societal evolution, the increasing disruption of the natural sleep-wake cycle, attributable to factors such as shift work and overexposure to artificial light, has been paralleled by a marked escalation in the incidence of cognitive impairments and the prevalence of neurodegenerative diseases. Current management strategies for cognitive impairments include pharmacological and non-pharmacological interventions. Pharmacological interventions for cognitive impairments typically involve medications to manage cognitive symptoms and improve neurological functions. However, these drugs show limited long-term efficacy in slowing disease progression and may cause side effects. Given the widespread occurrence of cognitive dysfunction, it is crucial to develop accessible non-pharmacological interventions. Physical activity and exercise have emerged as pivotal lifestyle determinants known to exert a modulatory effect on the risk profile for cognitive dysfunction caused by disrupted circadian rhythms. The skeletal muscle, a dynamic tissue, undergoes a profound morphological and metabolic reconfiguration in response to physical exertion, along with the secretion of myokines. Additionally, the hypothalamus, particularly the ventromedial nuclei, arcuate nuclei, and the suprachiasmatic nucleus, have crucial functions in regulating physical activity, influencing energy metabolism, and managing circadian cycles. Nevertheless, the communication between the hypothalamus and skeletal muscle during exercise is not fully understood. This narrative review integrates current knowledge on the interaction between the hypothalamus and skeletal muscle during exercise, emphasizing its neuroendocrine effects and potential therapeutic implications for alleviating cognitive dysfunction associated with disrupted circadian rhythms.

Apelin-13 enhances neurofunctional recovery and suppresses neuroinflammation via the SIRT1/NF-κB axis in ischemic stroke

BACKGROUND

Ischemic stroke is a major cause of mortality and disability, with neuroinflammation driving secondary brain injury. Microglial activation contributes to neuronal apoptosis, BBB disruption, and prolonged neurological deficits. Apelin-13, an endogenous peptide, has demonstrated neuroprotective potential, but its precise mechanisms remain unclear. This study investigates how Apelin-13 modulates neuroinflammation and the molecular pathways involved in ischemic stroke.

METHODS

Mice underwent middle cerebral artery occlusion-reperfusion (MCAO/R) to model ischemic stroke, followed by Apelin-13 administration. Neurological function was assessed using Garcia scoring, adhesive removal, rotarod, and grid-walking tests. Infarct volume was quantified via TTC staining, and MRI evaluated cerebral edema. Immunofluorescence staining and Western blotting were used to assess neuronal apoptosis and BBB integrity. Microglial activation and polarization were analyzed via Iba1 co-immunostaining with CD16 (pro-inflammatory) and Arg1 (anti-inflammatory) markers. In vitro, primary microglia and BV2 cells were exposed to oxygen-glucose deprivation (OGD) to mimic ischemia, and Apelin-13's effects on inflammatory signaling were examined. The role of the SIRT1/NF-κB axis was evaluated using the SIRT1 inhibitor EX-527.

RESULTS

Apelin-13 significantly improved post-stroke neurological function, reduced infarct volume, and alleviated cerebral edema. It preserved BBB integrity by reducing vascular leakage and albumin extravasation and suppressed neuronal apoptosis by downregulating cleaved caspase-3. Apelin-13 also mitigated neuroinflammation by decreasing microglial activation and shifting polarization toward an anti-inflammatory phenotype, as evidenced by reduced CD16+ and increased Arg1+ microglia. In vitro, Apelin-13 suppressed OGD-induced pro-inflammatory cytokine release while promoting anti-inflammatory responses. Mechanistically, Apelin-13 upregulated SIRT1, inhibiting NF-κB signaling and reducing inflammatory mediator expression. SIRT1 inhibition with EX-527 reversed these effects, restoring NF-κB activation and pro-inflammatory microglial polarization.

CONCLUSIONS

Apelin-13 exerts neuroprotective effects in ischemic stroke by preserving BBB integrity, reducing neuronal apoptosis, and suppressing neuroinflammation. These effects are mediated through SIRT1 activation and NF-κB inhibition. Targeting the Apelin-13/SIRT1/NF-κB axis may offer a promising therapeutic strategy for mitigating neuroinflammation and improving stroke recovery.

Evaluation of Orexin-A, Adiponectin and Apelin-13 Serum Levels in Children Diagnosed With Attention Deficit Hyperactivity Disorder

OBJECTIVE

This study investigates the role of orexin-a, adiponectin (HMWA) and apelin-13 serum levels in the etiopathogenesis of attention deficit hyperactivity disorder (ADHD), a neurodevelopmental disorder with unclear aetiology involving neuropathological, genetic and environmental factors.

METHODS

The study involved 37 children with ADHD and 35 healthy controls, aged 6-18 years, with no history of other physical or psychiatric illnesses and no psychotropic medication use in the last 6 months. Serum levels of orexin-a, adiponectin (HMWA) and apelin-13 were measured using enzyme-linked immunosorbent assay (ELISA). ADHD symptoms were assessed through Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5)-based clinical interviews, Conners Parent and Teacher Rating Scales and Wisconsin Card Sorting Test.

RESULTS

No significant differences in serum orexin-a, adiponectin (HMWA) and apelin-13 levels were found between the ADHD and control groups. Additionally, there was no relationship between orexin-a, apelin-13 and adinopectin levels and ADHD symptoms and Wisconsin Card Sorting Test results. Analysis of adiponectin levels in preadolescent children aged 6-11, adjusting for age and BMI, revealed a statistically significant reduction in the ADHD group (p = 0.002).

CONCLUSION

The results did not demonstrate any correlation between ADHD and the levels of orexin-a and apelin-13. However, the study revealed that children with ADHD, aged 6-11, exhibited decreased adiponectin concentrations. These results suggest that a decrease in serum adinopectin levels may be associated with ADHD in children.

Apelin-13 Protects Against Myocardial Hypoxia/Reoxygenation (H/R) Injury by Inhibiting Ferroptosis Via Nrf2 Activation

Ischemia-reperfusion (IR)-induced myocardial damage represents a major pathological event in coronary artery disease (CAD). Effective therapeutic strategies are urgently needed to improve clinical outcomes for CAD patients. Apelin-13, primarily produced by magnocellular neurons, exhibits diverse biological functions across various cell types and tissues. However, its role in myocardial IR injury remains unexplored. In this study, we utilized an in vitro model of myocardial IR injury using H9c2 cardiomyocytes to investigate the potential protective effects of Apelin-13. Our findings reveal that Apelin-13 protects against hypoxia/reoxygenation (H/R)-induced oxidative stress in H9c2 cells by reducing mitochondrial reactive oxygen species (ROS) and malondialdehyde (MDA) levels, while enhancing superoxide dismutase (SOD) activity. Additionally, Apelin-13 alleviates H/R-induced mitochondrial dysfunction, as evidenced by increased mitochondrial membrane potential (MMP) and adenosine triphosphate (ATP) production. Crucially, Apelin-13 mitigates H/R-induced cardiomyocyte injury, as shown by reduced levels of creatine kinase-myocardial band (CK-MB), cardiac troponin I (cTnI), and lactate dehydrogenase (LDH). Remarkably, Apelin-13 also counteracts ferroptosis during H/R by decreasing ferrous iron (Fe²⁺) concentrations, increasing glutathione (GSH) levels, and suppressing glutathione peroxidase 4 (GPX4) and ferritin heavy chain 1 (FTH1) expression. These protective actions were negated by the ferroptosis inducer Erastin. Further investigation revealed that Apelin-13 activates the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) through enhanced nuclear translocation and upregulation of heme oxygenase-1 (HO-1). Conversely, Nrf2 knockdown nullified the protective effects of Apelin-13 against ferroptosis and cardiomyocyte injury, underscoring the critical involvement of Nrf2 in mediating these benefits. Collectively, our results highlight the promising therapeutic potential of Apelin-13 in managing CAD.

Advances in the therapeutic potentials of ligands of the apelin receptor APJ

Angiotensin II protein J receptor, APJ, is a type A G protein coupled receptor. Endogenous apelin and elabela peptides stimulate APJ via distinct signalling profiles. A complex signalling map of elabela-stimulated APJ was published in 2022. Dimerization or oligomerization of APJ with itself or other receptor(s) can affect APJ signalling. Apelin has been shown to tolerate mutations and/or modifications at multiple sites without abolishing activity. This offers a great opportunity to design and engineer variants with desired signalling profiles and enhanced resistance to breakdown by peptidases. Several biased agonists with enhanced therapeutic potential have been generated. APJ agonists have therapeutic potential in multiple diseases including cardiovascular, renal, pulmonary and metabolic diseases, and viral infections. APJ antagonists may have therapeutic potential in cancer and retinopathy, and in related diseases in which unwanted angiogenesis is to be halted. A growing understanding of APJ signalling pathways and the robust therapeutic potential of associated ligands for many serious diseases will stimulate the clinical development of APJ ligands.

Saponins from Aralia taibaiensis protect against brain ischemia/reperfusion injuries by regulating the apelin/AMPK pathway

Aralia taibaiensi, widely distributed in western China, particularly in the Qinba Mountains, has been utilized as a folk medicine for treating diabetes, gastropathy, rheumatism, and cardiovascular diseases. Saponins from A. taibaiensis (sAT) have demonstrated protective effects against oxidative stress and mitochondrial dysfunction induced by ischemia/reperfusion (I/R). However, the underlying mechanisms remain unclear. In vivo, middle cerebral artery occlusion/reperfusion (MCAO/R) induced inflammatory infiltration, neuronal injury, cell apoptosis, mitochondrial dysfunction, and oxidative stress in the ischaemic penumbra, which were effectively mitigated by sAT. sAT increased the mRNA and protein expression levels of apelin and its receptor apelin/apelin receptors (ARs) both in vivo and in vitro. (Ala13)-Apelin-13 (F13A) and small interfering RNA (siRNA) abolished the regulatory effects of sAT on neuroprotection mediated by adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/protein kinase B (Akt). Furthermore, sAT induced apelin/AR expression by simultaneously inhibiting P38 mitogen-activated protein kinase (P38 MAPK)/activating transcription factor 4 (ATF4) and upregulating hypoxia-inducible factor-1α (HIF-1α). Our findings indicate that sAT regulates apelin/AR/AMPK by inhibiting P38 MAPK/ATF4 and upregulating HIF-1a, thereby suppressing oxidative stress and mitochondrial dysfunction.

A reactive oxygen species-responsive hydrogel loaded with Apelin-13 promotes the repair of spinal cord injury by regulating macrophage M1/M2 polarization and neuroinflammation

Spinal cord injury (SCI) is a chronic condition whereby persistent aberrant macrophage activation hinders the repair process. During acute trauma, dominant M1 macrophages produce high levels of reactive oxygen species (ROS), leading to increased apoptosis in neurons, glial cells, and oligodendrocytes. This study investigated the specific effects of a ROS-responsive hydrogel loaded with Apelin-13 (Apelin-13@ROS-hydrogel) on macrophage polarization and neuroinflammation, thereby exploring its role in boosting SCI repair. Apelin-13@ROS-hydrogel was prepared, and its ROS-scavenging capacities were evaluated using DPPH, H2O2, and ·O2- assays. The effects of Apelin-13@ROS-hydrogel on macrophage polarization, inflammatory mediators and oxidative stress were assessed in LPS-pre-treated microglia BV2 cells and an SCI rat model. Apelin-13 was downregulated in SCI rats. Treatment with Apelin-13 improved functional recovery and reduced inflammatory factors and M1 markers but increased the M2 marker Arg-1. Apelin-13@ROS-hydrogel showed significantly higher ROS-scavenging capacities compared to the control hydrogel. Apelin-13@ROS-hydrogel decreased pro-inflammatory mediators and increased anti-inflammatory mediators in BV2 cells. Apelin-13@ROS-hydrogel enhanced the healing process and neurological functions, reducing inflammatory factors and M1 markers while increasing Arg-1 levels by day 28 in SCI rats. Collectively, Apelin-13 enhances SCI repair through macrophage regulation, M1/M2 polarization, and neuroinflammation. The ROS-responsive hydrogel further amplifies these effects, offering a promising therapeutic strategy for SCI.

Apelin-13 Ameliorates Sepsis-induced Brain Injury by Activating Phosphatase and Tensin Homolog-induced Putative Kinase 1/Parkin-mediated Mitophagy and Modulating Nucleotide-binding Oligomerization Domain-like Receptor Pyrin Domain-Containing 3-driven Pyroptosis in Rats

ABSTRACT

Sepsis is a life-threatening condition that often results in severe brain injury, primarily due to excessive inflammation and mitochondrial dysfunction. This study aims to investigate the neuroprotective effects of Apelin-13, a bioactive peptide, in a rat model of sepsis-induced brain injury (SBI). Specifically, we examined the role of Apelin-13 in regulating mitophagy through the phosphatase and tensin homolog-induced putative kinase 1 (PINK1)/Parkin pathway and its impact on nucleotide-binding oligomerization domain-like receptor pyrin domain-containing 3 (NLRP3) inflammasome-mediated pyroptosis and oxidative stress. A sepsis model was induced in male Sprague-Dawley rats ( n = 110, 200-230 g, 12 weeks old) through cecal ligation and puncture (CLP). The septic rats received Apelin-13 (20 μg/kg, intravenously), either alone or combined with mitochondrial division inhibitor-1 (Mdv-1), a mitophagy inhibitor, before undergoing CLP surgery. Survival rates were assessed over a 72-h period, while the cognitive function was evaluated using the Morris water maze over 5 days. Western blotting and immunohistochemistry were utilized to measure the expression levels of NLRP3, cleaved caspase-1, N-terminal fragment of gasdermin D, PINK1, and Parkin in the brains of the rats. In addition, enzyme-linked immunosorbent assays were conducted to evaluate markers of oxidative stress and inflammatory responses in brain samples. Apelin-13 significantly improved survival rates and cognitive function and mitigated brain injury in septic rats. The treatment enhanced PINK1/Parkin-mediated mitophagy and suppressed NLRP3 inflammasome activation, leading to a reduction in pyroptosis, inflammation, and oxidative stress. Inhibition of mitophagy by Mdv-1 significantly reversed the protective effects of Apelin-13 in septic rats. Our findings suggest that Apelin-13 provides neuroprotection in sepsis by modulating mitophagy and inhibiting pyroptosis. These results highlight the potential of Apelin-13 as a therapeutic strategy for SBI.

Protective effect of Apelin-13 on D-glutamic acid-induced excitotoxicity in SH-SY5Y cell line: An in-vitro study

Excitotoxicity, resulting from excessive accumulation of glutamate in the extracellular space, leads to neuronal cell death. This study investigates the protective effects of Apelin-13 on D-Glutamic acid-induced excitotoxicity in SH-SY5Y human neuroblastoma cells, an in-vitro model for neurodegenerative diseases. Unlike the commonly studied L-glutamic acid, this research focuses on D-Glutamic acid to understand its specific impacts. SH-SY5Y cells were treated with varying concentrations of D-Glutamic acid and Apelin-13, followed by analyses at 12 and 24 h to evaluate cell viability, oxidative stress markers, and inflammatory cytokine levels. Cell viability assays revealed significant cytotoxic effects of D-Glutamic acid at doses of 10 mM and 20 mM, reducing viability by over 50 %. However, Apelin-13 treatment mitigated these effects, especially at 2 μg/ml, enhancing cell viability and reducing inflammatory cytokine levels (IL-1β and TNF-α). Apelin-13 also increased anti-inflammatory cytokine levels (IL-10 and TGF-β1) and brain-derived neurotrophic factor (BDNF), indicating its neuroprotective role. Oxidative stress markers, including ROS, AGE, AOPP, DT, T-SH, were significantly elevated by D-Glutamic acid but effectively reduced by Apelin-13. The neuroprotective mechanisms of Apelin-13 involve modulation of cAMP/PKA and MAPK signaling pathways, enhancing BDNF synthesis and suppressing oxidative stress and inflammatory responses. This study is the first to demonstrate the effects of D-Glutamic acid on SH-SY5Y cells. It highlights Apelin-13's potential as a therapeutic agent against excitotoxicity-induced neuronal damage, emphasizing its ability to modulate key molecular pathways involved in inflammation and oxidative stress. Further in-vivo studies are warranted to explore the long-term neuroprotective effects of Apelin-13 in treating neurodegenerative diseases.

The Aggravating Role of Failing Neuropeptide Networks in the Development of Sporadic Alzheimer's Disease

Alzheimer's disease imposes an increasing burden on aging Western societies. The disorder most frequently appears in its sporadic form, which can be caused by environmental and polygenic factors or monogenic conditions of incomplete penetrance. According to the authors, in the majority of cases, Alzheimer's disease represents an aggravated form of the natural aging of the central nervous system. It can be characterized by the decreased elimination of amyloid β1-42 and the concomitant accumulation of degradation-resistant amyloid plaques. In the present paper, the dysfunction of neuropeptide regulators, which contributes to the pathophysiologic acceleration of senile dementia, is reviewed. However, in the present review, exclusively those neuropeptides or neuropeptide families are scrutinized, and the authors' investigations into their physiologic and pathophysiologic activities have made significant contributions to the literature. Therefore, the pathophysiologic role of orexins, neuromedins, RFamides, corticotrope-releasing hormone family, growth hormone-releasing hormone, gonadotropin-releasing hormone, ghrelin, apelin, and natriuretic peptides are discussed in detail. Finally, the therapeutic potential of neuropeptide antagonists and agonists in the inhibition of disease progression is discussed here.

Apelin-13-Loaded Macrophage Membrane-Encapsulated Nanoparticles for Targeted Ischemic Stroke Therapy via Inhibiting NLRP3 Inflammasome-Mediated Pyroptosis

Purpose

Ischemic stroke is a refractory disease wherein the reperfusion injury caused by sudden restoration of blood supply is the main cause of increased mortality and disability. However, current therapeutic strategies for the inflammatory response induced by cerebral ischemia-reperfusion (I/R) injury are unsatisfactory. This study aimed to develop a functional nanoparticle (MM/ANPs) comprising apelin-13 (APNs) encapsulated in macrophage membranes (MM) modified with distearoyl phosphatidylethanolamine-polyethylene glycol-RVG29 (DSPE-PEG-RVG29) to achieve targeted therapy against ischemic stroke.

Methods

MM were extracted from RAW264.7. PLGA was dissolved in dichloromethane, while Apelin-13 was dissolved in water, and CY5.5 was dissolved in dichloromethane. The precipitate was washed twice with ultrapure water and then resuspended in 10 mL to obtain an aqueous solution of PLGA nanoparticles. Subsequently, the cell membrane was evenly dispersed homogeneously and mixed with PLGA-COOH at a mass ratio of 1:1 for the hybrid ultrasound. DSPE-PEG-RVG29 was added and incubated for 1 h to obtain MM/ANPs.

Results

In this study, we developed a functional nanoparticle delivery system (MM/ANPs) that utilizes macrophage membranes coated with DSPE-PEG-RVG29 peptide to efficiently deliver Apelin-13 to inflammatory areas using ischemic stroke therapy. MM/ANPs effectively cross the blood-brain barrier and selectively accumulate in ischemic and inflamed areas. In a mouse I/R injury model, these nanoparticles significantly improved neurological scores and reduced infarct volume. Apelin-13 is gradually released from the MM/ANPs, inhibiting NLRP3 inflammasome assembly by enhancing sirtuin 3 (SIRT3) activity, which suppresses the inflammatory response and pyroptosis. The positive regulation of SIRT3 further inhibits the NLRP3-mediated inflammation, showing the clinical potential of these nanoparticles for ischemic stroke treatment. The biocompatibility and safety of MM/ANPs were confirmed through in vitro cytotoxicity tests, blood-brain barrier permeability tests, biosafety evaluations, and blood compatibility studies.

Conclusion

MM/ANPs offer a highly promising approach to achieve ischemic stroke-targeted therapy inhibiting NLRP3 inflammasome-mediated pyroptosis.

Potential Involvement of Apelin/APJ System in Addiction and Neuroprotection Against Drugs of Abuse

Addiction, characterized by compulsive drug-seeking behavior and impaired self-control, remains a significant public health concern. Understanding the neurobiology of addiction is crucial for identifying novel therapeutic targets and further developing effective treatments. Recently, the apelin/APJ system, an emerging signaling pathway, has attracted attention for its involvement in various neuropsychiatric disorders. The cross-talk between the apelin/APJ system and hypothalamic mu opioid signaling, as well as its heterodimerization with kappa opioid receptors (KORs), supports the potential relevance of this system to addiction. Moreover, several protective effects of apelin against various addictive substances, including methamphetamine, morphine, and alcohol, underscore the need for further investigation into its role in substance use disorder. Understanding the contribution of the apelin/APJ system in addiction may offer valuable insights into the underlying neurobiology and pave the way for novel therapeutic interventions in substance use disorders. This review provides a concise overview of the apelin/APJ system, emphasizing its physiological roles and highlighting its relevance to addiction research.

The biological efficacy of Apelin against focal transient cerebral ischemia-reperfusion injury. A systematic review and meta-analysis of animal studies

BACKGROUND

Apelin has been extensively studied, and emerging experimental evidence suggests that Apelin may have effects on stroke by reducing infarct volume and neurological deficits, inhibiting the apoptosis process and reducing brain water content. However, the credibility of the evidence is uncertain. Thus, we aimed to perform a systematic review and meta-analysis to evaluate preclinical studies that used Apelin for the treatment of transient focal cerebral ischemia.

METHODS

Electronic bibliographic databases including PubMed, EMBASE, Scopus, and Google Scholar were searched for finding relevant studies from January 2000 to July 2023. The methodological quality and risk of bias scores for animal studies were calculated based on the CAMARADES and the SYRCLE's RoB tools, respectively. The effect sizes were assessed using Comprehensive Meta-Analysis (CMA) software.

RESULTS

A total of twelve eligible studies were used for the systematic review and meta-analysis. The median scores of study quality and risk of bias were 7.5 out of 10, and 5 out of 10, respectively. Apelin treatment effectively decreased infarct volume (primary outcome) [Hedges' g = 2.72, 95 % CI (1.93, 3.51), p < 0.001], neurological deficit [Hedges' g = 1.76, 95 % CI (0.96, 2.55), p < 0.001], cleaved caspase 3 [Hedges' g = 2.16, 95 % CI (0.87, 3.44), p = 0.001], and apoptotic cell number [Hedges' g = 4.07, 95 % CI (1.25,6.89), p = 0.005] compared with the control group. According to subgroup analysis, more notable neuroprotective effects were observed with intravenous administration than with intracerebroventricular (ICV) administration. Moreover, we determined that effect size of infarct volume was markedly related to the species. The combined measurement of two studies demonstrated that Apelin could reduce BCL2 and TNF-α levels as well as brain water content compared with the control group. However, pooled measurement of two studies showed that no relevancy was discovered between CHOP and altering infarct volume.

CONCLUSION

The present meta-analysis was conducted to assess preclinical studies related to Apelin treatment in rodent ischemic stroke. Apelin can exert promising neuroprotective effects by reducing infarct volume, neurological deficit, caspase 3, apoptotic cell number, TNF- α and brain water content and increasing BCL2. The current evidence supports the anti-apoptotic and anti-inflammatory properties of Apelin, but its effectiveness in decreasing CHOP level in animal models of ischemic stroke needs further elucidation. This study was registered within the International Prospective Register of Systematic Reviews (PROSPERO) as number CRD42023460926.

Intranasal Administration of Apelin-13 Ameliorates Cognitive Deficit in Streptozotocin-Induced Alzheimer's Disease Model via Enhancement of Nrf2-HO1 Pathways

BACKGROUND

The discovery of novel diagnostic methods and therapies for Alzheimer's disease (AD) faces significant challenges. Previous research has shed light on the neuroprotective properties of Apelin-13 in neurodegenerative disorders. However, elucidating the mechanism underlying its efficacy in combating AD-related nerve injury is imperative. In this study, we aimed to investigate Apelin-13's mechanism of action in an in vivo model of AD induced by streptozocin (STZ).

METHODS

We utilized an STZ-induced nerve injury model of AD in mice to investigate the effects of Apelin-13 administration. Apelin-13 was administered intranasally, and cognitive impairment was assessed using standardized behavioral tests, primarily, behavioral assessment, histological analysis, and biochemical assays, in order to evaluate synaptic plasticity and oxidative stress signaling pathways.

RESULTS

Our findings indicate that intranasal administration of Apelin-13 ameliorated cognitive impairment in the STZ-induced AD model. Furthermore, we observed that this effect was potentially mediated by the enhancement of synaptic plasticity and the attenuation of oxidative stress signaling pathways.

CONCLUSIONS

The results of this study suggest that intranasal administration of Apelin-13 holds promise as a therapeutic strategy for preventing neurodegenerative diseases such as AD. By improving synaptic plasticity and mitigating oxidative stress, Apelin-13 may offer a novel approach to neuroprotection in AD and related conditions.

The Fetal Alcohol Spectrum Disorders-An Overview of Experimental Models, Therapeutic Strategies, and Future Research Directions

Since the establishment of a clear link between maternal alcohol consumption during pregnancy and certain birth defects, the research into the treatment of FASD has become increasingly sophisticated. The field has begun to explore the possibility of intervening at different levels, and animal studies have provided valuable insights into the pathophysiology of the disease, forming the basis for implementing potential therapies with increasingly precise mechanisms. The recent reports suggest that compounds that reduce the severity of neurodevelopmental deficits, including glial cell function and myelination, and/or target oxidative stress and inflammation may be effective in treating FASD. Our goal in writing this article was to analyze and synthesize current experimental therapeutic interventions for FASD, elucidating their potential mechanisms of action, translational relevance, and implications for clinical application. This review exclusively focuses on animal models and the interventions used in these models to outline the current direction of research. We conclude that given the complexity of the underlying mechanisms, a multifactorial approach combining nutritional supplementation, pharmacotherapy, and behavioral techniques tailored to the stage and severity of the disease may be a promising avenue for further research in humans.

Salivary apelin hormone response and dysfunctional attitudes in adolescents in Türkiye: a relational screening model

BACKGROUND

Adolescence is the period in which physical and emotional changes occur through hormones, the individual acquires gender characteristics and prepares for the adult role psychologically and physically. Dysfunctional attitudes are beliefs and attitudes that can lead to depression by causing negative thoughts about oneself, others, and the future.Dysfunctional attitudes negatively affect children's mental health. Hormones have a significant impact on human behavior and cognitive functions. However, little is known about the role and influence of hormones on dysfunctional attitudes. Apelin is a hormone responsible for controlling emotions by regulating emotional behavior. The level of dysfunctional attitudes is one of the important issues in nursing practice in terms of protecting and improving children's mental health. However, little is known about the role and impact of hormones on dysfunctional attitudes.This study aimed to examine adolescents' dysfunctional attitudes and salivary apelin hormone levels in terms of sociodemographic variables.

METHODS

The study was conducted in a relational screening model with 151 adolescents aged 9-14 years who were reported to be clinically healthy in Türkiye. Apelin hormone levels were analyzed by ELISA technique in the saliva samples of the participants. In the evaluation of dysfunctional attitudes, the relationship between the score obtained from the dysfunctional attitude scale and salivary hormone levels was evaluated.

RESULTS

In the study, a negative, strong and statistically significant correlation was found between the average salivary apelin hormone level and dysfunctional attitudes of adolescents (p =.000). Mean salivary hormone levels of apelin in adolescent girls and boys were 0.696 (SD 0.052) ng/ml, respectively; while 0.671 (SD 0.047) ng/ml was determined (p =.002), dysfunctional attitudes scale scores were 52.95 (SD 14.43); it was determined as 59.04 (SD 14.22) (p =.006). On the other hand, the highest average salivary apelin hormone level (p =.038). and the lowest level of dysfunctional attitudes were determined in adolescent girls aged 13-14 years (p =.028).

CONCLUSIONS

In our study, we found that while the salivary apelin hormone levels of adolescents decreased, their dysfunctional attitudes increased. We found that adolescents' dysfunctional attitudes decreased with age. In contrast, apelin hormone levels increased with age.

The Association of Adipokines and Myokines in the Blood of Obese Children and Adolescents with Lipoprotein Lipase rs328 Gene Variants

Obesity develops largely due to genetic factors, with the genetic polymorphism of lipid metabolism enzymes being of particular importance. However, it is still unclear how the genetic variants of one of the key enzymes in lipid transport, lipoprotein lipase (LPL), are associated with the endocrine function of mesenchymal tissues in obesity. The current study was aimed at the investigation of the LPL rs328 gene variant association with adipokines and myokines levels, as well as lipid metabolism indices in the blood of children and adolescents of both genders with obesity. We found that LPL polymorphism rs328 is not characterized by the differences in the levels of hormones, adipokines, and myokines and in the blood of healthy children and adolescents; however, it significantly affects these indices during obesity in gender-dependent manner. The shifts in hormones, adipokines, and myokines manifest mostly in the obese individuals with Ser447Ser genotype rather than with 447Ter genotype. Obese boys homozygous for Ser447Ser have more elevated leptin levels than girls. They also demonstrate lower adiponectin, apelin, prolactin, and osteocrine levels than those in obese girls with the same genotype. The gender-based differences are less pronounced in individuals with 447Ter genotype than in the homozygotes for 447Ser. Thus, we conclude that the polymorphism rs328 of the lipoprotein lipase gene is accompanied by the changes in hormones, adipokines, and myokines levels in the blood of children and adolescents with obesity in gender-dependent manner.

A prospective cohort study on decreased serum apelin-13 levels after human aneurysmal subarachnoid hemorrhage: associations with severity and prognosis

Apelin-13 may have neuroprotective effects. We aimed to determine whether serum apelin-13 could serve as a potential biomarker for severity, delayed cerebral ischemia (DCI), and prognosis after human aneurysmal subarachnoid hemorrhage (aSAH). In this prospective, observational, cohort, single-center study of 139 patients with aSAH and 139 healthy individuals, serum apelin-13 levels were determined. The indicators of stroke severity were the Hunt-Hess scale and the modified Fisher grading scale. The prognostic parameters were DCI and 6-month worse prognosis (Extended Glasgow Outcome Scale scores of 1-4). Using binary logistic regression analysis, the relationship between serum apelin-13 levels and prognosis was reported as odds ratios (ORs) with 95% confidence intervals (CIs). Under the receiver operating characteristic curve, prognostic abilities were shown as areas under the curve (AUCs) with 95% CIs. Serum apelin-13 levels were substantially lower in patients than in controls (median, 28.8 versus 48.6 ng/ml; P < 0.001), in patients with DCI than in non-DCI patients (median, 14.9 versus 31.6 ng/ml; P < 0.001), and in patients with worse prognosis than in those with good prognosis (median, 16.3 versus 33.7 ng/ml; P < 0.001). Serum apelin-13 levels were independently correlated with Hunt-Hess scores (beta, -6.836; 95% CI, -8.963-4.708; VIF, 2.219; P = 0.001) and modified Fisher scores (beta, -3.350; 95% CI, -6.151-0.549; VIF, 1.562; P = 0.019). Serum apelin-13 levels were an independent predictor of DCI (OR, 0.951; 95% CI, 0.914-0.990; P = 0.022) and worse prognosis (OR, 0.954; 95% CI, 0.916-0.993; P = 0.013). Serum apelin-13 levels significantly differentiated DCI and poor prognosis, with AUCs of 0.753 (95% CI, 0.656-0.850) and 0.791 (95% CI, 0.713-0.868) respectively. Using the Youden method, serum apelin-13 levels < 19.3 ng/ml distinguished the risk of DCI with 64.7% sensitivity and 77.1% specificity, and serum apelin-13 levels < 30.2 ng/ml discriminated the development of worse prognosis with 89.1% sensitivity and 63.4% specificity. Serum apelin-13 levels combined with Hunt-Hess scores and modified Fisher scores displayed a significantly higher AUC than any one of them for prognostic prediction (all P < 0.05). Decreased serum apelin-13 levels, which are strongly correlated with disease severity, independently predicted poor outcomes following aSAH, substantializing serum apelin-13 as a useful prognostic biomarker of aSAH.

Multi-scale, multi-level anisotropic silk fibroin/metformin scaffolds for repair of peripheral nerve injury

Silk fibroin (SF) as a natural polymer has a long history of application in various regenerative medicine fields, but there are still many shortcomings in silk fibroin for using as nerve scaffolds, which limit its clinical application in peripheral nerve regeneration (PNR). In this work, a multi-scale and multi-level metformin (MF)-loaded silk fibroin scaffold with anisotropic micro-nano composite topology was prepared by micromolding electrospinning for accelerating PNR. The scaffolds were characterized for morphology, wettability, mechanical properties, degradability, and drug release, and Schwann cells (SCs) and dorsal root ganglia (DRG) were cultured on the scaffolds to assess their effects on neural cell behavior. Finally, the gene expression differences of neural cells cultured on scaffolds were analyzed by gene sequencing and RT-qPCR to explore the possible signaling pathways and mechanisms. The results showed that the scaffolds had excellent mechanical properties and hydrophilicity, slow degradation rate and drug release rate, which were enough to support the repair of peripheral nerve injury for a long time. In Vitro cell experiments showed that the scaffolds could significantly promote the orientation of SCs and axons extension of DRG. Gene sequencing and RT-qPCR revealed that the scaffolds could up-regulate the expression of genes related to SCs proliferation, adhesion, migration, and myelination. In summary, the scaffolds hold great potential for promoting PNR at the micro/nano multiscale and physical/chemical levels and show promising application for the treatment of peripheral nerve injury in the future.