Pathobiology of the Klotho Antiaging Protein and Therapeutic Considerations

Endothelin System Blockade Extenuates Sepsis-Induced Acute Heart and Kidney Injuries via Modulating ET-1/Klotho/p38-MAPK

Sepsis-induced organ failure is a major health problem, characterised by massive inflammatory and oxidative stress responses. Endothelin-1 (ET-1) is one of the peptides expressed during septicemia with proapoptotic, proinflammatory, and oxidant effects. ET-1 plays a role in heart and kidney injuries in sepsis. Accordingly, the current study was conducted to investigate, on a mechanistic basis, whether inhibition of ET-1 signalling either by blocking its receptors or inhibiting its formation attenuates sepsis-induced acute cardiorenal injuries. To analyse the role of ET-1 in sepsis, we used a cecal ligation and puncture (CLP) model of sepsis. The animals were divided into five groups: CLP non-treated group, CLP-treated groups with bosentan, ambrisentan, and phosphoramidon (30, 5, and 0.5 mg/kg, respectively), and sham-operated group. In addition to the same set of groups, survival analysis was assigned Survival rate, histopathological assessment, and cardiorenal functions were analysed. Oxidant and antioxidant activities, ET-1, IL-6, and lactate were measured. The expression of TNF-α, p38, Klotho, and caspase-3 was evaluated by immunohistochemistry. CLP caused acute cardiorenal damage, high mortality, upregulated levels of ET-1, IL-6, and lactate, as well as an imbalance in oxidant/antioxidant activities, elevated expression of TNF-α, p38, caspase-3 and reduced expression of klotho. Bosentan, ambrisentan, or phosphoramidon improved survival, reduced the levels of inflammatory and oxidative stress parameters, improved cardiorenal functions and structure, elevated the tissue contents of GSH and SOD, raised the expression of klotho protein, and reduced the cardiorenal expression of p38, TNF-α and caspase-3. Endothelin receptor antagonists (ERAs); bosentan and ambrisentan, or endothelin converting enzyme inhibitor (ECE-i) phosphoramidon, are promising agents against sepsis-induced organ damage. This was evident in their cardiorenal protective effects, up-regulation of klotho, suppression of inflammation, oxidation, apoptosis, and enhancement of the antioxidant status.

Neuroprotective effects of selenium against lithium-induced cerebellar toxicity in rats: The role of apoptosis, gliosis, and aging markers

BACKGROUND

Prolonged lithium therapy in psychiatric disorders may be complicated by multi-organ dysfunction, particularly in the nervous system. Toxicity to the cerebellum is one of these, which, while uncommon, inevitably emerges negatively and permanently. Selenium is a trace element regarded as one of the critical antioxidants. Numerous investigations have validated selenium's neuroprotective properties against various neurotoxic medications. The degree of affliction of the nerve cells is assessed using GFAP, a marker of astrocytosis; Caspase-3, a marker of apoptosis; and klotho, a marker of anti-aging.

AIM OF THE STUDY

This study is designed to investigate the cerebellar structural and functional changes in lithium-treated rats and the postulated neuroprotective role of selenium.

METHODOLOGY

A total of 24 adult male albino rats were divided into 4 groups: control, selenium (1 mg/kg in water solution by gavage daily), lithium (by intraperitoneal injection of 25 mg/kg lithium carbonate dissolved in 0.9 % NaCL twice daily for 4 weeks), and lithium-selenium group. Motor coordination was evaluated using the rotarod test. Cerebellar malonaldehyde (MDA) and reduced glutathione (GSH) were measured, and histopathological examination and immunohistochemical expression of Klotho, GFAP, and Caspase 3 were evaluated.

RESULTS

The lithium-treated group exhibited reduced latency on the rotarod test, elevated oxidative stress indicators, and an altered cerebellar structure in HE and cresyl violet-stained sections. Moreover, there was a diminished Klotho expression and increased levels of both caspase-3 and GFAP expression. Selenium administration reduced latency time, diminished oxidative stress markers, mitigated lithium-induced cerebellar alterations, increased Klotho expression, and lowered the expression of caspase-3 and GFAP.

CONCLUSION

Lithium exposure causes alterations in the cerebellar cortical structure in albino rats. Selenium protected the cerebellar cortex from such changes by enhancing Klotho expression, diminishing oxidative stress, and reducing apoptosis.

A cohort study on the correlation between serum Klotho levels and all-cause mortality in American diabetic populations

BACKGROUND

The global prevalence of diabetes is on an upward trajectory. The management of complications related to the condition has seen limited progress in recent years. Klotho, characterized as an anti-aging protein that mitigates oxidative stress and inflammation, has previously been correlated with all-cause mortality in the broader United States population. The objective of this research was to investigate the persistence of this relationship among diabetic patients.

METHODS

This study meticulously analyzed data (2007-2016) sourced from the National Health and Nutrition Examination Survey, encompassing a cohort of 3,560 individuals. To elucidate the links of Klotho with all-cause mortality in diabetic patients, a multivariate Cox proportional hazards regression model was employed. The relationship was further explored using the restricted cubic spline model, threshold analysis, and subgroup analysis. Additionally, a mediation analysis was conducted to unravel the influence of age on the observed correlations.

RESULTS

Throughout the observation period, which had a median duration of 84 months, the incidence of all-cause mortality reached 18.511%. The Cox model analysis revealed a statistically significant association between Klotho levels and all-cause mortality. Further, the application of restricted cubic splines revealed a nuanced, nonlinear relationship between exposure factors and outcome across the entire study population (nonlinear P < 0.001), pinpointing a critical threshold at 829.138 pg/mL. Subgroup analyses showed consistent correlation between Klotho levels and mortality across various groups. Intriguingly, mediation analysis indicated that age was a significant mediator, accounting for 76.1% of the observed correlation of Klotho levels with all-cause mortality among diabetic patients.

CONCLUSIONS

Low levels of Klotho were found to be strongly associated with an increased risk of all-cause mortality in individuals with diabetes (Klotho levels < 829.138 pg/ml), and a nonlinear relationship was observed between these two variables. These associations were largely mediated by age.

Soluble average Klotho level as a prognostic marker for acute kidney injury outcomes: a 90-day follow-up study

BACKGROUND

Klotho is highly expressed in the kidney and confers pleiotropic kidney protective effects. This study aimed to assess the soluble average Klotho level and its relationship to renal function and outcomes in participants with acute kidney injury (AKI).

METHODS

We recruited 102 participants with AKI and 30 healthy controls (HCs). For patients with AKI, serum soluble (sKlotho) levels upon admission to and discharge from hospital were measured to assess the relationship between sKlotho level and kidney function. Individuals with AKI were followed up for 90 days to determine the association between their average sKlotho level and short-term AKI outcomes.

RESULTS

The baseline sKlotho level in individuals with AKI at admission was significantly lower than that in HCs. For individuals with AKI, the sKlotho level was significantly lower in stage 3 than in stage 1 or 2. The sKlotho level was restored along with renal function improvement at discharge. During follow-up, a lower average, but not baseline, sKlotho level, or average sKlotho/creatinine ration predicted more AKI clinical outcomes.

CONCLUSION

The sKlotho level decreased significantly with kidney injury and represented severity. The average sKlotho level inversely correlated with detrimental kidney outcomes and may have potential diagnostic and predictive roles in AKI.

Klotho in age-related cardiovascular diseases: Insights into mitochondrial dysfunction and cell death

Aging is a major risk factor for the development of cardiovascular diseases (CVD), leading to specific alterations in the heart and vasculature. Besides, the mechanisms and intracellular pathways of aging and the factors affecting it are still not completely clear. Age-related complications such as oxidative stress, decreased autophagy, mitochondrial dysfunction, inflammatory responses, and cardiac dysfunction are associated with relative Klotho deficiency. Klotho, an anti-aging protein, with anti-oxidative and anti-inflammatory properties, has been shown to modulate calcium regulation and autophagy. It also protects against endothelial dysfunction by increasing nitric oxide production. Furthermore, emerging research has revealed that klotho significantly impacts vascular smooth muscle cells (VSMC) energetics and survival. This article has focused on recent advances in using Klotho in age-related CVD and summarizes the pre-clinical evidence supporting this approach. Based on the research, Klotho could provide more therapeutic options for ameliorating aging-related CVD.

Melatonin and Exercise Restore Myogenesis and Mitochondrial Dynamics Deficits Associated With Sarcopenia in iMS-Bmal1-/- Mice

Sarcopenia, a condition associated with aging, involves progressive loss of muscle mass, strength, and function, leading to impaired mobility, health, and increased mortality. The underlying mechanisms remain unclear, which limits the development of effective therapeutic interventions. Emerging evidence implicates chronodisruption as a key contributor to sarcopenia, emphasizing the role of Bmal1, a circadian clock gene critical for muscle integrity and mitochondrial function. In a skeletal muscle-specific and inducible Bmal1 knockout model (iMS-Bmal1-/-), we observed hallmark features of sarcopenia, including disrupted rhythms, impaired muscle function, and mitochondrial dysfunction. Exercise and melatonin treatment reversed these deficits independently of Bmal1. Building on these findings, the present study elucidates several mechanisms underlying these changes and the pathways by which melatonin and exercise exert their beneficial effects. Our findings indicate that iMS-Bmal1-/- mice exhibit reduced expression of satellite cell and muscle regulatory factors, indicating impaired muscle regeneration. While mitochondrial respiration remained unchanged, notable alterations in mitochondrial dynamics disrupted mitochondria in skeletal muscle. In addition, these mice showed alterations in muscle energy metabolism, compromised antioxidant defense, and inflammatory response. Remarkably, exercise and/or melatonin successfully mitigated these deficits, restoring muscle health in Bmal1-deficient mice. These findings position exercise and melatonin as promising therapeutic candidates for combating sarcopenia and emphasize the need to elucidate the molecular pathways underlying their protective effects.

Dysregulation of Circadian Markers, HAT1 and Associated Epigenetic Proteins, and the Anti-Aging Protein KLOTHO in Placenta of Pregnant Women with Chronic Venous Disease

Background: Chronic venous disease (CVD) is a vascular disorder common among pregnant women, due to the impairment in the venous function associated with the mechanical, hemodynamical, and hormonal changes that occur during pregnancy. CVD is linked to venous hypertension, inflammation, oxidative stress, and hypoxia, which alter placental structure and function, as demonstrated in previous works. The placenta fulfills several roles in fetal development and maternal well-being by mediating nutrient exchange; acting as a mechanical, chemical, and immunological shield; and producing essential hormones, making it crucial to investigate the effects of CVD in this organ. Patients and methods: This work specifically analyzes the gene expression of circadian markers (CLOCK, BMAL1, PER1, and PER2), epigenetic regulators (HAT1 and associated molecules like histones H3, H4, RBBP7, and ASF1), and the anti-aging protein KLOTHO in placental tissue of pregnant women with CVD (CVD-PW, N = 98) compared to healthy pregnant controls (HC-PW, N = 82), using RT-qPCR and immunohistochemistry (IHC) to determine protein expression. Results: Our study demonstrates that the placentas of CVD-PW exhibit the reduced gene and protein levels of circadian regulators (clock, bmal1, per1, and per2), increased expression of hat1 and related proteins (h3, h4, rbbp7, and asf1), and decreased klotho expression, indicative of accelerated aging. Conclusions: These findings highlight profound molecular disturbances in the placentas of women with CVD, offering insights into the disease's pathophysiology and potential implications for maternofetal well-being. While this study deepens our understanding of the relationship between CVD and placental dysfunction, further research is required to fully elucidate these mechanisms and their long-term effects.

A possible important regulatory role of estrogen in obstructive sleep apnea hypoventilation syndrome

Obstructive sleep apnea-hypoventilation syndrome (OSAHS) is a prevalent clinical sleep breathing disorder that affects both pediatric and adult populations. If left untreated, OSAHS can induce or aggravate systemic dysfunction across multiple organ systems, with a particularly pronounced impact on cardiovascular health, thereby posing a substantial threat to overall human well-being. Notably, there exists a significant sex disparity in the prevalence and severity of OSAHS, with a higher incidence and greater severity observed in males. However, this disparity tends to diminish post-menopause. Research indicates that sex differences in OSAHS are associated with gonadal function, wherein estrogen exerts a protective effect by modulating pharyngeal muscle tone and mitigating oxidative stress. This regulatory role of estrogen partially reduces the incidence of OSAHS and attenuates its pathological impact. Conversely, OSAHS may adversely affect gonadal function, resulting in decreased estrogen levels, which can exacerbate the condition. This review examines the beneficial role of estrogen in the progression of OSAHS and explores the potential impact of OSAHS on estrogen levels.

A PDE1 inhibitor, vinpocetine, ameliorates epithelial-mesenchymal transition and renal fibrosis in adenine-induced chronic kidney injury in rats by targeting the DNMT1/Klotho/β-catenin/Snail 1 and MMP-7 pathways

Tubulointerstitial fibrosis (TIF) is present with chronic kidney disease (CKD). Vinpocetine (Vinpo) is used for treating cerebrovascular deficits, exhibiting some kidney-beneficial effects; however, its role in TIF is uncertain. So, the aim of this study was to investigate its potential impact on adenine-induced fibrotic CKD and explore the underlying mechanistic aspects. Eighteen male Wistar rats were categorized into three groups (n = 6 each). Group I was kept as controls and given saline; group II received adenine (300 mg/kg, twice weekly, i.p.) for induction of the CKD model; and group III was administered Vinpo (20 mg/kg/d, orally) concurrently with adenine. All treatments were administered for 4 weeks. Vinpo revealed an improvement in renal function and an alleviation of inflammation triggered by adenine via diminishing serum tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) levels. Further, Vinpo repressed the epithelial-mesenchymal transition (EMT) with preserved E-cadherin mRNA expression and lowered gene and immune expression of fibronectin and vimentin, respectively, besides attenuating the elevated G2/M arrest-related molecules (renal Ki67 protein contents and p21 gene expression). Renal pathological alterations caused by adenine were attenuated upon Vinpo administration. Interestingly, Vinpo suppressed abnormal renal β-catenin immunoreactivity, Snail 1, and MMP-7 gene expression while simultaneously restored Klotho protein expression by downregulating DNA methyltransferase 1 enzyme (DNMT1) protein expression in the kidney. These data indicated that Vinpo effectively mitigated EMT and G2/M arrest-induced renal fibrosis in adenine-induced CKD rats by targeting DNMT1-associated Klotho suppression, subsequently inhibiting β-catenin and its fibrotic downstream genes.

Reducing early pregnancy loss with vitamin D3: an analysis of serum 1,25-(OH)D3 modulation and miscarriage risk

This case-control study of 124 early-pregnant women found that daily supplementation with 400 IU of vitamin D3 significantly increased serum 1,25-(OH)D3 levels and was associated with a lower incidence of threatened miscarriage. The study suggests that vitamin D3 supplementation could reduce the risk of early miscarriage and improve pregnancy outcomes by modulating immune responses and hormonal stability.

Exploring the potential anti-senescence effects of soybean-derived peptide Soymetide in mice hippocampal neurons via the Wnt/β-catenin pathway

Soybean-based foods enhance cognitive functions by influencing hippocampal mechanisms. These salutary effects have so far been attributed to isoflavones present in soybeans. Considering cellular senescence contributes to cognitive decline and that no specific soy-derived peptides are known for their potential to mitigate senescence, we examined the efficacy of a thirteen amino acid soy-derived peptide, Soymetide, on a doxorubicin-induced senescence mice model. Soymetide pretreatment lowered the senescence markers p53, p21 and p16, pro-inflammatory cytokines, and Senescence β-Galactosidase staining while enhancing the mature neuronal marker NeuN in the hippocampus. This anti-senescent effect was comparable with that of a well-known senolytic combination (dasatinib and quercetin). Research indicates that Wnt signaling influences cellular senescence, and our findings here demonstrate that doxorubicin decreased hippocampal Wnt3a, p-LRP6, Frizzled, Dishevelled, Axin1, and β-catenin levels and increased GSK-3β, while Soymetide mitigated these effects. Additionally, upon inhibition of the Wnt/β-catenin pathway, Soymetide's ability to reduce senescence markers and restore NeuN expression was reduced. We validated the anti-senescence impact on hippocampal neurons by co-immunostaining Wnt/β-catenin and senescence indicators alongside NeuN in mice and assessed it in primary hippocampal neurons. Further examining the neuronal survival and functions revealed that Soymetide blocked the doxorubicin-induced loss in Nissl-stained surviving neurons and learning-memory performances, measured by Y-Maze and Passive Avoidance tests, which Wnt/β-catenin inhibitors could counteract. In conclusion, our study identifies a novel Wnt/β-catenin-linked mechanism of doxorubicin-induced senescence in the hippocampal neurons and demonstrates Soymetide's effectiveness in reversing this process. Hence, this suggests Soymetide's potential therapeutic application in addressing cognitive decline associated with cellular aging.

Influence of Klotho Protein Levels in Obesity and Sarcopenia: A Systematic Review

The Klotho gene is recognized for its anti-aging properties. Its downregulation leads to aging-like phenotypes, whereas overexpression can extend lifespan. Klotho protein exists in three forms: α-klotho, β-klotho and γ-klotho. The α-klotho has two isoforms: a membrane-bound form, primarily in the kidney and brain, and a secreted klotho protein present in blood, urine, and cerebrospinal fluid. Klotho functions as a co-receptor for fibroblast growth factor-23 (FGF23), regulating phosphate metabolism. The membrane-bound form controls various ion channels and receptors, while the secreted form regulates endocrine FGFs, including FGF19 and FGF21. The interaction between β-klotho and FGF21 in muscle is critical in the development of sarcopenic obesity. This systematic review, registered in PROSPERO and conducted following PRISMA guidelines, evaluates klotho levels in individuals with obesity or sarcopenic obesity. The study includes overweight, obese, and sarcopenic obese adults compared to those with a normal body mass index. After reviewing 713 articles, 20 studies were selected, including observational, cross-sectional, cohort studies, and clinical trials. Significant associations between klotho levels and obesity, metabolic syndrome (MS), and cardiovascular risk were observed. Exercise and dietary interventions positively influenced klotho levels, which were linked to improved muscle strength and slower decline. Klotho is a potential biomarker for obesity, MS, and sarcopenic obesity. Further research is needed to explore its mechanisms and therapeutic potential.

The Potential Mechanism and the Role of Antioxidants in Mitigating Oxidative Stress in Alzheimer's Disease

Alzheimer's disease (AD) is the most prevalent cause of dementia and a significant contributor to health issues and mortality among older individuals. This condition involves a progressive deterioration in cognitive function and the onset of dementia. Recent advancements suggest that the development of AD is more intricate than its underlying brain abnormalities alone. In addition, Alzheimer's disease, metabolic syndrome, and oxidative stress are all intricately linked to one another. Increased concentrations of circulating lipids and disturbances in glucose homeostasis contribute to the intensification of lipid oxidation, leading to a gradual depletion of the body's antioxidant defenses. This heightened oxidative metabolism adversely impacts cell integrity, resulting in neuronal damage. Pathways commonly acknowledged as contributors to AD pathogenesis include alterations in synaptic plasticity, disorganization of neurons, and cell death. Abnormal metabolism of some membrane proteins is thought to cause the creation of amyloid (Aβ) oligomers, which are extremely hazardous to neurotransmission pathways, especially those involving acetylcholine. The interaction between Aβ oligomers and these neurotransmitter systems is thought to induce cellular dysfunction, an imbalance in neurotransmitter signaling, and, ultimately, the manifestation of neurological symptoms. Antioxidants have a significant impact on human health since they may improve the aging process by combating free radicals. Neurodegenerative diseases are currently incurable; however, they may be effectively managed. An appealing alternative is the utilization of natural antioxidants, such as polyphenols, through diet or dietary supplements, which offer numerous advantages. Within this framework, we have extensively examined the importance of oxidative stress in the advancement of Alzheimer's disease, as well as the potential influence of antioxidants in mitigating its effects.

Systematic Mendelian Randomization Exploring Druggable Genes for Hemorrhagic Strokes

Patients with hemorrhagic stroke have high rates of morbidity and mortality, and drugs for prevention are very limited. Mendelian randomization (MR) analysis can increase the success rate of drug development by providing genetic evidence. Previous MR analyses only analyzed the role of individual drug target genes in hemorrhagic stroke; therefore, we used MR analysis to systematically explore the druggable genes for hemorrhagic stroke. We sequentially performed summary-data-based MR analysis and two-sample MR analysis to assess the associations of all genes within the database with intracranial aneurysm, intracerebral hemorrhage, and their subtypes. Validated genes were further analyzed by colocalization. Only genes that were positive in all three analyses and were druggable were considered desirable genes. We also explored the mediators of genes affecting hemorrhagic stroke incidence. Finally, the associations of druggable genes with other cardiovascular diseases were analyzed to assess potential side effects. We identified 56 genes that significantly affected hemorrhagic stroke incidence. Moreover, TNFSF12, SLC22A4, SPARC, KL, RELT, and ADORA3 were found to be druggable. The inhibition of TNFSF12, SLC22A4, and SPARC can reduce the risk of intracranial aneurysm, subarachnoid hemorrhage, and intracerebral hemorrhage. Gene-induced hypertension may be a potential mechanism by which these genes cause hemorrhagic stroke. We also found that blocking these genes may cause side effects, such as ischemic stroke and its subtypes. Our study revealed that six druggable genes were associated with hemorrhagic stroke, and the inhibition of TNFSF12, SLC22A4, and SPARC had preventive effects against hemorrhagic strokes.

Potential of Klotho as a Biomarker for Overwork: A Study of Frontline Medical Workers

OBJECTIVE

This study evaluates the utility of serum s-αKlotho levels as a quantifiable biomarker for overwork.

METHODS

Frontline medical workers aged 20-55 years from Yiling People's Hospital of Yichang were recruited. Criteria included nonsmokers, non-heavy drinkers, no chronic medication use, and no acute illnesses recently. Participants worked over 10 hours per day, 60 hours weekly, and had at least 3 years of experience. A control group was matched except for work conditions. Data were collected through surveys, and serum levels were measured.

RESULTS

Significant differences in serum Klotho were found between overwork and control groups. The overwork group had higher median s-αKlotho levels (49.99 pg/mL) compared to controls (27.88 pg/mL).

CONCLUSION

Overworked medical workers exhibited elevated serum s-αKlotho, suggesting s-αKlotho as a potential biomarker for overwork. Future research should use multicenter designs with larger samples to validate findings.

Pathophysiology of vascular ageing and the effect of novel cardio-renal protective medications in preventing progression of chronic kidney disease in people living with diabetes

AIM

Among people with diabetes those with chronic kidney disease (CKD) have a reduced life expectancy with increased risk of cardiovascular disease (CVD) a major contributor to morbidity and mortality. CKD related to diabetes is growing worldwide and is one of the leading causes of kidney failure globally. Diabetes is associated with accelerated vascular ageing and the related mechanisms and mediators that drive the progression of CKD and CVD disease in people with diabetes may help provide insights into the pathophysiology of cardio-renal complications and guide treatment interventions in people with diabetes.

METHODS

We conducted a narrative review of the literature using PubMed for English language articles that contained keywords that related to diabetes, chronic or diabetic kidney disease, ageing, cellular senescence, arterial stiffness, Klotho and sirtuins, sodium-glucose co-transporter-2 (SGLT-2) inhibitors, renin angiotensin aldosterone system (RAAS) and glucagon-like peptide-1 (GLP-1) receptor agonists.

RESULTS

Progressive kidney disease in diabetes is associated with accelerated ageing driven in part by multiple processes such as cellular senescence, inflammation, oxidative stress and circulating uremic toxins. This accelerated ageing phenotype contributes to increased arterial stiffness, endothelial dysfunction, cognitive decline and muscle wasting, thereby elevating morbidity and mortality in individuals with diabetes and CKD. Deficiency of the kidney-derived anti-ageing hormone Klotho and reduced sirtuin levels play pivotal roles in these ageing pathways. Dietary, lifestyle and pharmacological interventions targeting vascular ageing may help reduce the progression of CKD and associated CVD in people with diabetes. The current standard of care and pillars of treatment for kidney disease such as RAAS inhibitors, SGLT-2 inhibitors and GLP-1 receptor agonists all influence pathways involved in vascular ageing.

CONCLUSIONS

A multifactorial intervention to prevent the development of CKD by targeting traditional risk factors as well as treatment with novel agents with cardio-renal beneficial effects can prevent accelerated ageing and extend lifespan in people with diabetes.

Renoprotective effect of berberine in cisplatin-induced acute kidney injury: Role of Klotho and the AMPK/mtor/ULK1/Beclin-1 pathway

Cisplatin (Cisp) is a potent cancer drug, but its use is limited by acute kidney injury (AKI). Autophagy, a process that removes damaged proteins and maintains cellular homeostasis, has been shown to alleviate Cisp-induced AKI. The balance between autophagy and apoptosis is crucial to kidney protection. Treatment with Berberine, known for its antioxidant and anti-inflammatory effects in nephrotoxicity models, was studied for its potential to enhance autophagy in Cisp-induced AKI. Treatment with Berberine (Berb) upregulated Klotho gene expression, enhancing autophagy as indicated by elevated protein levels of pS486-AMPK, pS638-ULK1, and Beclin-1, accompanied by a decrease in pS248-mTOR protein expression. Also, Berb mitigated oxidative stress by reducing elevated MDA levels and boosting SOD activity, which in turn suppressed inflammation by down-regulating HMGB1 and RAGE gene expression, as well as reducing pS536-NF-κB and IL-6 protein contents. Additionally, Berb reduced apoptosis by increasing Bcl-2 and decreasing Bax. This coordinated action preserved kidney function, evidenced by reductions in early injury markers (cystatin C, KIM-1, NGAL) and late markers (creatinine, BUN), along with attenuation of histopathological alterations. The use 3-MA, autophagy inhibitor, nullified these protective effects, highlighting Berb's role in promoting autophagy, reducing oxidative stress, inflammation, and apoptosis, and preserving renal health in Cisp-induced AKI.

Use of FGF-23 and sαKlotho for Risk Stratification in Patients with Acute Heart Failure

Background/Objectives: Soluble αKlotho (sαKlotho) and fibroblast growth factor 23 (FGF-23) are increased in acute heart failure (AHF). This study aimed to assess changes in serum sαKlotho and FGF-23 concentrations during an episode of AHF as well as the usefulness of both biomarkers for predicting long-term prognosis. Methods: The study included 104 consecutive patients hospitalized in t he intensive cardiac care unit due to AHF (mean age, 65.8 ± 14.6 years; mean ejection fraction, 31.4% ± 14). New-onset AHF was reported in 43.3% of the population. Blood samples were measured at entry and on discharge from hospital. The main clinical outcomes assessed in this study were all-cause mortality or rehospitalization due to HF during a 3-year follow-up. Results: At admission sαKlotho, FGF-23, and NT-pro BNP levels, compared with discharge, were significantly higher at p < 0.001, p < 0.001, and p < 0.001 respectively. The 3-year Kaplan-Meier analysis, based on tertiles, revealed, for sαKlotho levels from Tertile 1 on admission and at discharge, a 2-fold higher rate of all-cause mortality or rehospitalization for HF compared with Tertile 3 (p = 0.006 and p = 0.028, respectively). One-third of patients showed an increase in FGF-23 and sαKlotho levels during hospitalization. Patients with the highest percentage increase in the levels of both biomarkers had an elevated risk of all-cause morality or hospitalization for HF (hazard ratio, 2.75; confidence interval, 1.19-6.35; p = 0.02). Conclusions: sαKlotho and FGF-23 levels are elevated during an episode of AHF. Low sαKlotho levels are associated with an increased risk of all-cause mortality or rehospitalization for HF. Increases in sαKlotho and FGF-23 values during hospitalization identify patients with poor prognosis.

The Impact of Klotho in Cancer: From Development and Progression to Therapeutic Potential

Klotho, initially identified as an anti-aging gene, has been shown to play significant roles in cancer biology. Alongside α-Klotho, the β-Klotho and γ-Klotho isoforms have also been studied; these studies showed that Klotho functions as a potential tumor suppressor in many different cancers by inhibiting cancer cell proliferation, inducing apoptosis and modulating critical signaling pathways such as the Wnt/β-catenin and PI3K/Akt pathways. In cancers such as breast cancer, colorectal cancer, hepatocellular carcinoma, ovarian cancer, and renal cell carcinoma, reduced Klotho expression often correlates with a poor prognosis. In addition, Klotho's role in enhancing chemotherapy sensitivity and its epigenetic regulation further underscores its potential as a target for cancer treatments. This review details Klotho's multifaceted contributions to cancer suppression and its potential as a therapeutic target, enhancing the understanding of its significance in cancer treatment and prognoses.

Risk factors for developing osteoporosis in diabetic kidney disease and its correlation with calcium-phosphorus metabolism, FGF23, and Klotho

BACKGROUND

The progression of diabetic kidney disease (DKD) affects the patient's kidney glomeruli and tubules, whose normal functioning is essential for maintaining normal calcium (Ca) and phosphorus (P) metabolism in the body. The risk of developing osteoporosis (OP) in patients with DKD increases with the aggravation of the disease, including a higher risk of fractures, which not only affects the quality of life of patients but also increases the risk of death.

AIM

To analyze the risk factors for the development of OP in patients with DKD and their correlation with Ca-P metabolic indices, fibroblast growth factor 23 (FGF23), and Klotho.

METHODS

One hundred and fifty-eight patients with DKD who were admitted into the Wuhu Second People's Hospital from September 2019 to May 2021 were selected and divided into an OP group (n = 103) and a normal bone mass group (n = 55) according to their X-ray bone densitometry results. Baseline data and differences in Ca-P biochemical indices, FGF23, and Klotho were compared. The correlation of Ca-P metabolic indices with FGF23 and Klotho was discussed, and the related factors affecting OP in patients with DKD were examined by multivariate logistic regression analysis.

RESULTS

The OP group had a higher proportion of females, an older age, and a longer diabetes mellitus duration than the normal group (all P < 0.05). Patients in the OP group exhibited significantly higher levels of intact parathyroid hormone (iPTH), blood P, Ca-P product (Ca × P), fractional excretion of phosphate (FeP), and FGF23, as well as lower estimated glomerular filtration rate, blood Ca, 24-hour urinary phosphate excretion (24-hour UPE), and Klotho levels (all P < 0.05). In the OP group, 25-(OH)-D3, blood Ca, and 24-hour UPE were negatively correlated with FGF23 and positively correlated with Klotho. In contrast, iPTH, blood Ca, Ca × P, and FeP exhibited a positive correlation with FGF23 and an inverse association with Klotho (all P < 0.05). Moreover, 25-(OH)-D3, iPTH, blood Ca, FePO4, FGF23, Klotho, age, and female gender were key factors that affected the lumbar and left femoral neck bone mineral density.

CONCLUSION

The Ca-P metabolism metabolic indexes, FGF23, and Klotho in patients with DKD are closely related to the occurrence and development of OP.

Resilience mechanisms underlying Alzheimer's disease

Alzheimer's disease (AD) consists of two main pathologies, which are the deposition of amyloid plaque as well as tau protein aggregation. Evidence suggests that not everyone who carries the AD-causing genes displays AD-related symptoms; they might never acquire AD as well. These individuals are referred to as non-demented individuals with AD neuropathology (NDAN). Despite the presence of extensive AD pathology in their brain, it was found that NDAN had better cognitive function than was expected, suggesting that they were more resilient (better at coping) to AD due to differences in their brains compared to other demented or cognitively impaired patients. Thus, identification of the mechanisms underlying resilience is crucial since it represents a promising therapeutic strategy for AD. In this review, we will explore the molecular mechanisms underpinning the role of genetic and molecular resilience factors in improving resilience to AD. These include protective genes and proteins such as APOE2, BDNF, RAB10, actin network proteins, scaffolding proteins, and the basal forebrain cholinergic system. A thorough understanding of these resilience mechanisms is crucial for not just comprehending the development of AD but may also open new treatment possibilities for AD by enhancing the neuroprotective pathway and targeting the pathogenic process.

Affordable mRNA Novel Proteins, Recombinant Protein Conversions, and Biosimilars-Advice to Developers and Regulatory Agencies

mRNA technology can replace the expensive recombinant technology for every type of protein, making biological drugs more affordable. It can also expedite the entry of new biological drugs, and copies of approved mRNA products can be treated as generic or biosimilar products due to their chemical nature. The introduction of hundreds of new protein drugs have been blocked due to the high cost of recombinant development. The low CAPEX and OPEX associated with mRNA technology bring it within the reach of developing countries that are currently deprived of life-saving biological drugs. In this paper, we advise developers to introduce novel proteins and switch recombinant manufacturing to mRNA delivery, and we further advise regulatory authorities to allow for the approval of copies of mRNA products with less testing. We anticipate that mRNA technology will make protein drugs, such as natural and engineered proteins, monoclonal antibodies, and vaccines, accessible to billions of patients worldwide.

Rare germline structural variants increase risk for pediatric solid tumors

Pediatric solid tumors are a leading cause of childhood disease mortality. In this work, we examined germline structural variants (SVs) as risk factors for pediatric extracranial solid tumors using germline genome sequencing of 1765 affected children, their 943 unaffected parents, and 6665 adult controls. We discovered a sex-biased association between very large (>1 megabase) germline chromosomal abnormalities and increased risk of solid tumors in male children. The overall impact of germline SVs was greatest in neuroblastoma, where we uncovered burdens of ultrarare SVs that cause loss of function of highly expressed, mutationally constrained genes, as well as noncoding SVs predicted to disrupt chromatin domain boundaries. Collectively, we estimate that rare germline SVs explain 1.1 to 5.6% of pediatric cancer liability, establishing them as an important component of disease predisposition.

Unveiling the Emerging Role of Klotho: A Comprehensive Narrative Review of an Anti-aging Factor in Human Fertility

Klotho, an anti-aging protein, plays a vital role in diverse biological functions, such as regulating calcium and vitamin D levels, preventing chronic fibrosis, acting as an antioxidant and anti-inflammatory agent, safeguarding against cardiovascular and neurodegenerative conditions, as well as exerting anti-apoptotic, anti-senescence effects. Additionally, it contributes to metabolic processes associated with diabetes and exhibits anti-cancer properties. This protein is commonly expressed in organs, such as kidneys, brain, pancreas, parathyroid glands, ovaries, and testes. Recent research has highlighted its significance in human fertility. This narrative review provides insight into the involvement of Klotho protein in male and female fertility, as well as its potential role in managing human infertility in the future. In this study, a search was conducted on literature spanning from November 1997 to June 2024 across multiple databases, including PUBMED, SCOPUS, and Google Scholar, focusing on Klotho proteins. The search utilized keywords, such as "discovery of Klotho proteins," "Biological functions of Klotho," "Klotho in female fertility," "Klotho and PCOS," "Klotho and cryopreservation," and "Klotho in male infertility." Inclusion criteria comprised full-length original or review articles, as well as abstracts, discussing the role of Klotho protein in human fertility, published in English in various peer-reviewed journals. Exclusion criteria involved articles published in languages other than English. Hence, due to its anti-aging characteristics, Klotho protein presents potential roles in male and female fertility and holds promising prospects for reproductive medicine. Further, it holds the potential to become a valuable asset in addressing infertility concerns for both males and females.

Association of serum Klotho with the severity and mortality among adults with cardiovascular-kidney-metabolic syndrome

BACKGROUND

Cardiovascular-kidney-metabolic (CKM) syndrome is characterized as a systemic disease resulting from the pathophysiological interplay among metabolic risk factors, chronic kidney disease (CKD), and cardiovascular disease (CVD). The Klotho protein may serve as a novel biomarker. However, the utility of serum Klotho levels as an indicator of severity and mortality risk in CKM syndrome remains uncertain.

METHODS

This study involved 9,871 participants from the National Health and Nutrition Examination Survey (NHANES) conducted between 2007 and 2016. Serum Klotho levels were measured using an enzyme-linked immunosorbent assay kit. The optimal cutoff value was established through the maximum Youden's index. Multivariable weighted regression models were employed to calculate the odds ratio and hazard ratio, along with the 95% confidence interval, to evaluate the association between serum Klotho levels and the severity of CKM syndrome, as well as all-cause and cardiovascular mortality. Additionally, the receiver operating characteristic curve and restricted cubic spline curves were utilized to assess predictive efficacy and to explore nonlinear relationships.

RESULTS

After adjusting for potential confounding factors, a non-linear relationship was seen between the Klotho protein, and CKM syndrome. In the multivariable, piecewise logistic regression, when the Serum klotho was less than 801, the risk of CKM syndrome decreased with the increase in Serum klotho (OR = 0.82, 95%CI 0.70, 0.96; p < 0.001). Furthermore, we observed the association when the Serum klotho was greater than 801 (OR = 0.94, 95%CI 0.89, 0.99; p = 0.035). The relationship between serum Klotho levels and all-cause mortality was U-shaped, while the relationship with cardiovascular mortality was L-shaped. Specifically, low serum Klotho levels were associated with an increase in all-cause mortality by 21% and cardiovascular mortality by 76% among patients with CKM syndrome. Furthermore, serum Klotho levels demonstrated excellent predictive efficacy for both the severity and mortality associated with CKM syndrome.

CONCLUSIONS

This study indicates that low serum Klotho levels serve as reliable indicators of both the severity of CKM syndrome and the associated risk of mortality.

Insights and progress on the biosynthesis, metabolism, and physiological functions of gamma-aminobutyric acid (GABA): a review

GABA (γ-aminobutyric acid) is a non-protein amino acid that occurs naturally in the human brain, animals, plants and microorganisms. It is primarily produced by the irreversible action of glutamic acid decarboxylase (GAD) on the α-decarboxylation of L-glutamic acid. As a major neurotransmitter in the brain, GABA plays a crucial role in behavior, cognition, and the body's stress response. GABA is mainly synthesized through the GABA shunt and the polyamine degradation pathways. It works through three receptors (GABAA, GABAB, and GABAC), each exhibiting different pharmacological and physiological characteristics. GABA has a variety of physiological roles and applications. In plants, it regulates growth, development and stress responses. In mammals, it influences physiological functions such as nervous system regulation, blood pressure equilibrium, liver and kidneys enhancement, hormone secretion regulation, immunity enhancement, cancer prevention, as well as anti-aging effects. As a biologically active ingredient, GABA possesses unique physiological effects and medicinal value, leading to its widespread application and substantially increased market demand in the food and pharmaceutical industries. GABA is primarily produced through chemical synthesis, plant enrichment and microbial fermentation. In this review, we first make an overview of GABA, focusing on its synthesis, metabolism, GABA receptors and physiological functions. Next, we describe the industrial production methods of GABA. Finally, we discuss the development of ligands for the GABA receptor binding site, the prospects of GABA production and application, as well as its clinical trials in potential drugs or compounds targeting GABA for the treatment of epilepsy. The purpose of this review is to attract researchers from various fields to focus on GABA research, promote multidisciplinary communications and collaborations, break down disciplinary barriers, stimulate innovative research ideas and methods, and advance the development and application of GABA in medicine, agriculture, food and other fields.

Association of Klotho and Gout in Middle-Aged and Older Adults: National Health and Nutrition Survey (2007-2016)

BACKGROUND

Klotho, which is known to negatively regulate metabolic disorders and kidney disease, has a role in gout that remains unclear. This research explored how klotho levels correlate with the prevalence of gout.

METHODS

Participants aged 40 to 79 from the National Health and Nutrition Examination Survey (2007-2016) were examined in both lines. The connection between klotho levels and gout was analyzed through weighted multivariate logistic regression. Restricted cubic splines were used to assess linearity and investigate the dose-response relationship. To ensure the stability of the results, subgroup and sensitivity analyses were conducted.

RESULTS

In total, 9660 individuals participated, with the weighted sample size calculated at 88,892,738.77. The group included 47.79% males (4793), with the median age being 57.00 years. Upon adjusting for all covariates, the multivariate analysis indicated an odds ratio of 0.51 (95% confidence interval [CI]: 0.33~0.78, p = 0.003) for the likelihood of occurrence of gout. When compared with the lowest klotho quartile Q1 (≥151.3, <655.3 pg/mL), the adjusted odds ratios for the subsequent quartiles Q2 (≥655.5, <800.9 pg/mL), Q3 (≥801.0, <991.6 pg/mL), and Q4 (≥991.7, ≤3998.5 pg/mL) were 0.97 (95% CI: 0.68~1.38), 0.78 (95% CI: 0.50~1.21), and 0.48 (95% CI: 0.32~0.73), respectively. Analyses focusing on subgroups and sensitivity confirmed these results.

CONCLUSIONS

This research found a negative correlation between serum α-klotho concentrations and the occurrence of gout. Those with the highest levels of klotho exhibited the lowest likelihood of gout, indicating potential importance for future studies and clinical uses.

Associations between dietary carotenoid and biological age acceleration: insights from NHANES 2009-2018

Carotenoids are naturally occurring pigments found in plants and certain microorganisms. Some carotenoids act as precursors to vitamin A, which is essential for various health aspects, including vision, immune function, and skin health. Carotenoids, including α-carotene, β-carotene, β-cryptoxanthin, lycopene, lutein and zeaxanthin, are known to reduce the risk of age-related diseases and promote healthy aging. This study examines the relationship between dietary carotenoid levels and biological age. This study utilized data from the National Health and Nutrition Examination Survey (NHANES) from 2009 to 2018, and 19,280 participants were included. The Phenotypic Age (PhenoAge) was used to measure biological age, and the Klemera-Doubal Method (KDM) was employed in sensitivity analyses. Biological age acceleration was determined by calculating the residuals of PhenoAge or KDM after regressing them against chronological age. Weighted multivariate linear and logistic regressions were conducted to examine the relationship between carotenoids and biological age acceleration. Additionally, restricted cubic spline regression, subgroup analysis, interaction analysis, and sensitivity analyses were employed for further examination. Both linear regression and logistic regression analyses indicated that participants with higher carotenoid intake exhibited lower rates of phenotypic age acceleration, with α-carotene, β-carotene, β-cryptoxanthin, lutein and zeaxanthin, and lycopene all demonstrating protective effects. Restricted cubic spline regression indicates non-linear associations between carotenoid levels and phenotypic age acceleration. Subgroup analyses revealed that younger participants, females, and individuals with hypertension or diabetes benefited more from higher carotenoid intake. Sensitivity analyses further confirmed the robustness of inverse relationship. The WQS analysis identifies β-carotene and β-cryptoxanthin as the most influential compounds. Higher dietary intake of carotenoids is associated with reduced biological age acceleration, underscoring their protective role against aging. Further longitudinal studies are needed to establish causal relationships and explore the underlying mechanisms of carotenoid benefits on aging.

The relationship between serum α-Klotho with all-cause and cause-specific mortality

AIMS

The relationship between α-Klotho (αK) and mortality is controversial and has not been examined in a large, diverse cohort. We investigated the association between serum αK protein levels with all-cause and cause-specific mortality in a cohort representative of the US population.

METHODS

We used National Health and Nutrition Examination Survey (NHANES) data from 2007 to 2016. A nonlinear association between mortality and αK levels as a quadratic variable were examined using Cox proportional hazard models and competing risk models. Multivariable models were adjusted for age, gender, race, hypertension, diabetes, smoking, alcohol use, physical activity, body mass index (BMI), serum cholesterol, estimated glomerular filtration rate, highest educational status attained and family income to poverty threshold ratio.

RESULTS

Of the 13 749 participants, 1569 (11%) died, 7092 (52%) were female, and 5918 (43%) were Caucasian. The mean (SD) of age was 58 (11) years, BMI 29.7 (6.7) kg/m2, and αK was 0.85 (0.31) ng/mL. In the adjusted Cox proportional hazards model with quadratic αK, we found a U-shaped relationship between all-cause mortality and αK levels (continuous αK hazard ratio [HR] = 0.56, 95% confidence interval [CI]: 0.37, 0.85; P = .007; squared-αK HR = 1.25, 95% CI: 1.11, 1.41; P < 0.001). A similar U-shaped relationship was noted between αK and cancer mortality in the adjusted Cox proportional hazards model (continuous αK HR = 0.45, 95% CI: 0.19, 1.06; P = 0.07; squared αK HR = 1.32, 95% CI: 1.07, 1.61; P = 0.009). No relationship was present with cardiovascular or other-cause mortality.

CONCLUSIONS

In this large diverse cohort, we report a U-shaped relationship between αK with all-cause and cancer mortality. Further research to elucidate the underlying biological mechanism of these relationships is needed.

Effects of GHRH and its analogues on the Vascular System

Growth hormone-releasing hormone (GHRH) is a crucial endocrine hormone that exerts its biological effects by binding to specific receptors on the cell surface, known as GHRH receptors (GHRH-R). This binding activates downstream signaling pathways. In addition to promoting growth hormone secretion by the pituitary gland, GHRH also functions to maintain multisystem homeostasis by interacting with peripheral tissues that express GHRH-R. Due to the multiple roles of GHRH in body development and tissue repair, a variety of GHRH analogue peptides have been synthesized. Based on their effects on GHRH-R, these GHRH analogues can be classified as GHRH-R agonists and antagonists. Recently, the interaction of GHRH and its analogues with blood vessels, such as promoting angiogenesis and inhibiting vascular calcification (VC), has gained significant attention. This article reviews the effects of GHRH and its analogues on blood vessels.

Klotho relieves H2O2-induced lens epithelial cell damage via suppression of NOX4

BACKGROUND

Age-related cataract (ARC) is a common eye disease and represents a common contributing factor to visual damage and loss. Klotho is a longevity gene and has been reported to participate in aging-related disorders. This work aims to investigate the potential role of klotho in ARC.

METHODS

In human lens epithelial cells (HLECs) induced by varying concentrations of hydrogen peroxide (H2O2), CCK-8 assay was used to detect cell viability. DCFH-DA probe was used to detect reactive oxygen species (ROS) level. Western blot was used to detect klotho expression. JC-1 fluorochrome assay was used to detect mitochondrial membrane potential (MMP). The concentrations of oxidative stress markers malondialdehyde (MDA) and superoxide dismutase (SOD) were detected by related assay kits. Flow cytometry analysis, immunofluorescence staining and western blot were used to detect cell apoptosis. SA-β-gal staining and western blot were used to detect cell senescence.

RESULTS

Klotho expression was decreased in HLECs induced by increasing concentrations of H2O2. Overexpression of klotho significantly inhibited ROS generation, decreased MDA content, increased SOD content, promoted cell viability and suppressed cell apoptosis and senescence in H2O2-induced HLECs. Furthermore, klotho down-regulated NOX4 expression and NOX4 elevation partially reversed the effects of klotho on H2O2-induced HLECs.

CONCLUSIONS

To sum up, klotho may down-regulate NOX4 to protect against H2O2-induced HLECs damage. This finding suggested the potential therapeutic use of klotho in ARC, which needs further investigation.

Is age more than a number? Accounting for adult development and aging in the study of psychoneuroimmunology, stress, and health

Traditional stress-and-health models link stressors to their health consequences through a well-characterized cascade. Most of the research assumes that the stress-health sequence unfolds in the same way across adulthood, whether a person is 25 years old or 80. Taking a "developmental" or "lifespan" approach has been synonymous with studying the lasting health impacts of early life experiences. However, theories and evidence from adult development and geroscience suggest that stress-health dynamics evolve in important ways over the adult lifespan-from the stressors that we encounter, to the emotion regulation strategies that we use to confront challenges, to the psychosocial resources at our disposal, to the cellular milieu, and thus to the magnitude of stressors' biological and functional consequences. This critical review synthesizes theoretical perspectives and selected empirical literature on the social-emotional and biological dimensions of aging to promote an Integrative Model of Aging, Stress, and Health. Through this integration, the model illustrates how an interdisciplinary, developmental perspective can enrich our understanding of stress's consequences for health across adulthood. It also seeks to guide a new generation of research questions that confront aging with a multidimensional approach. The piece concludes with personal reflections on the foundational legacy of the author's mentor, Dr. Janice Kiecolt-Glaser.

The association between the triglyceride-glucose index and serum anti-aging protein α- Klotho: a population-based study

BACKGROUND

Both anti-aging protein α-Klotho and the triglyceride-glucose (TyG) index hold predictive value for the incidence, progression, and outcomes of cardiovascular disease, diabetes and many other diseases. However, their relationship remains unclear.

METHODS

We conducted a cross-sectional analysis using data from the National Health and Nutrition Examination Survey (NHANES) 2007-2016. Weighted multivariate linear regression models and subgroup analysis were constructed to assess the association between TyG index and α-Klotho levels. Nonlinear correlations were explored using restricted cubic splines (RCS), generalized additive models (GAM) and smooth curve fitting. Segmented regression model was conducted to explore potential threshold effects and identify the inflection point.

RESULTS

A total of 2568 participants satisfied the predetermined criteria were enrolled in the final analysis. After fully adjusting for covariates, TyG index was shown to be markedly negatively correlated with α-Klotho [β=-74.07, 95%CI (-100.29,-47.85), p < 0.001]. Gender was significantly correlated with this negative connection according to subgroup analysis and interaction testing (p for interaction < 0.05).Additionally, we discovered a linear association between TyG index and α-Klotho in all participants (p for nonlinear = 0.761), while non-linear association in female (p for nonlinear = 0.016).The analysis of threshold effect in the female participants found that the inflection point of TyG index was 8.01, exceed which the level of α-Klotho decreased significantly with increasing TyG index[β=-151.72, 95%CI (-201.93, -101.50), p < 0.001].

CONCLUSION

Our findings demonstrate a negative association between TyG index and α-Klotho levels, with the effect being more pronounced in females. TyG index may serve as an early indicator of individuals with low α-Klotho levels, especially among females. These findings highlight the need for gender-specific considerations in clinical interventions to improve public health. Further research is needed to clarify the causal direction of this association.

Regulation of renal ischemia-reperfusion injury and tubular epithelial cell ferroptosis by pparγ m6a methylation: mechanisms and therapeutic implications

This study aimed to elucidate the role and underlying mechanisms of Peroxisome proliferator-activated receptor gamma (PPARγ) and its m6A methylation in renal ischemia-reperfusion (I/R) injury and ferroptosis of tubular epithelial cells (TECs). High-throughput transcriptome sequencing was performed on renal tissue samples from I/R injury models and sham-operated mice, complemented by in vivo and in vitro experiments focusing on the PPARγ activator Rosiglitazone and the manipulation of METTL14 and IGF2BP2 expression. Key evaluations included renal injury assessment, ferroptosis indicator measurement, and m6A methylation analysis of PPARγ. Our findings highlight the critical role of the PPARγ pathway and ferroptosis in renal I/R injury, with Rosiglitazone ameliorating renal damage and TEC ferroptosis. METTL14-mediated m6A methylation of PPARγ, dependent on IGF2BP2, emerged as a pivotal regulator of PPARγ expression, renal injury, and ferroptosis. This study reveals that PPARγ m6A methylation, orchestrated by METTL14 through an IGF2BP2-dependent mechanism, plays a crucial role in mitigating renal I/R injury and TEC ferroptosis. These insights offer promising avenues for therapeutic strategies targeting acute kidney injury.

Inverted U-shaped relationship between serum vitamin B12 and α-Klotho levels in US adults: a cross-sectional study

Background

Serum vitamin B12 and α-Klotho are important markers associated with aging. Limited studies have been conducted on the relationship between vitamin B12 and α-Klotho.

Objectives

This study investigated the relationship between circulating α-Klotho and vitamin B12.

Methods

A total of 4,502 American adults with circulating vitamin B12 levels and α-Klotho levels from the National Health and Nutrition Examination Survey (2011-2014) were included. A weighted multiple linear regression model was used to evaluate the correlation between vitamin B12 and α-Klotho levels. To clarify potential non-linearities, smoothed curve fitting and threshold effects analysis were employed.

Results

A statistically significant non-linear relationship was found between vitamin B12 levels and circulating α-Klotho levels after adjusting for potential confounders. We observed an inverted U-shaped relationship between serum vitamin B12 levels and circulating α-Klotho levels. Notably, serum vitamin B12 levels below the threshold (1,020 pg/mL) exhibited a positive correlation with circulating α-Klotho levels (β = 0.14, 95% confidence interval (CI): 0.09-0.18, p < 0.0001). Conversely, serum vitamin B12 levels above the threshold (1,020 pg/mL) exhibited a negative correlation with circulating α-Klotho levels (β = -0.12,95% CI: -0.17--0.06, p < 0.0001). Sensitivity analyses were performed and consistent results were obtained.

Conclusion

This study demonstrated an inverted U-shaped relationship between circulating vitamin B12 and α-Klotho in American adults. The optimal concentration of serum vitamin B12 in American adults was found.

Distinct role of Klotho in long bone and craniofacial bone: skeletal development, repair and regeneration

Bone defects are highly prevalent diseases caused by trauma, tumors, inflammation, congenital malformations and endocrine abnormalities. Ideally effective and side effect free approach to dealing with bone defects remains a clinical conundrum. Klotho is an important protein, which plays an essential role in regulating aging and mineral ion homeostasis. More recently, research revealed the function of Klotho in regulating skeleton development and regeneration. Klotho has been identified in mesenchymal stem cells, osteoblasts, osteocytes and osteoclasts in different skeleton regions. The specific function and regulatory mechanisms of Klotho in long bone and craniofacial bone vary due to their different embryonic development, ossification and cell types, which remain unclear and without conclusion. Moreover, studies have confirmed that Klotho is a multifunctional protein that can inhibit inflammation, resist cancer and regulate the endocrine system, which may further accentuate the potential of Klotho to be the ideal molecule in inducing bone restoration clinically. Besides, as an endogenous protein, Klotho has a promising potential for clinical therapy without side effects. In the current review, we summarized the specific function of Klotho in long bone and craniofacial skeleton from phenotype to cellular alternation and signaling pathway. Moreover, we illustrated the possible future clinical application for Klotho. Further research on Klotho might help to solve the existing clinical difficulties in bone healing and increase the life quality of patients with bone injury and the elderly.

Correlation of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio with serum α-klotho levels in US middle-aged and older individuals: Results from NHANES 2007-2016

Background

The α-klotho (αKl) is widely accepted as an anti-aging and anti-inflammatory protein. However, it is rarely reported on the function and mechanism of αKl in the overall population (including healthy people and those with history of chronic disease). The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are established as predictors of systemic inflammation. This study aims to investigate the relationship between NLR, PLR, and αKl levels in the overall population.

Methods

Data from 10,124 adults aged 40 years old and above, collected from NHANES 2007-2016, were analyzed. Associations between NLR, PLR, and αKl levels were assessed by weighted multivariate linear regression analyses, adjusting for potential confounders. Subgroup analysis was conducted by gender, age, diabetes, cardiovascular disease, and chronic kidney disease.

Results

Weighted linear regression models showed that a significant negative correlation was observed between both NLR and PLR with αKl levels. Subgroup analysis revealed that the negative correlation between NLR and serum αKl levels was not significant in individuals aged 40-59 years and males, while this relationship remained stable across most other subgroups. The negative correlation between PLR and serum αKl levels was consistent across most subgroups but not significant in individuals with cardiovascular disease.

Conclusion

Our study revealed a significant negative relationship between inflammatory markers (NLR and PLR) and serum αKl levels, suggesting systemic inflammation may be linked to reduced αKl expression. Subgroup analyses showed that the relationship varies across different demographic and health-related factors. We provided insight into the significance of managing inflammation and preserving αKl levels.

Klotho in pregnancy and intrauterine development-potential clinical implications: a review from the European Renal Association CKD-MBD Working Group

Intrauterine development is crucial for life-long health; therefore, elucidation of its key regulators is of interest for their potential prognostic and therapeutic implications. Originally described as a membrane-bound anti-aging protein, Klotho has evolved as a regulator of numerous functions in different organ systems. Circulating Klotho is generated by alternative splicing or active shedding from cell membranes. Recently, Klotho was identified as a regulator of placental function, and while Klotho does not cross the placental barrier, increased levels of circulating α-Klotho have been identified in umbilical cord blood compared with maternal blood, indicating that Klotho may also play a role in intrauterine development. In this narrative review, we discuss novel insights into the specific functions of the Klotho proteins in the placenta and in intrauterine development, while summarizing up-to-date knowledge about their structures and functions. Klotho plays a role in stem cell functioning, organogenesis and haematopoiesis. Low circulating maternal and foetal levels of Klotho are associated with preeclampsia, intrauterine growth restriction, and an increased perinatal risk for newborns, indicating a potential use of Klotho as biomarker and therapeutic target. Experimental administration of Klotho protein indicates a neuro- and nephroprotective potential, suggesting a possible future role of Klotho as a therapeutic agent. However, the use of Klotho as intervention during pregnancy is as yet unproven. Here, we summarize novel evidence, suggesting Klotho as a key regulator for healthy pregnancies and intrauterine development with promising potential for clinical use.

Fibroblast growth-factor 23-Klotho axis is associated with systemic inflammation and myokine profile in children with chronic kidney disease

BACKGROUND

Chronic kidney disease is linked to a disturbed fibroblast growth factor-23 (FGF23)-Klotho axis and an imbalance between myostatin and insulin-like growth factor-1 (IGF-1) expression. This cross-sectional study investigates the association of the FGF23-Klotho axis and myokine profile with serum interleukin-6 (IL-6) and their interactions in pediatric patients.

METHODS

Serum calcium, phosphorus, 25-hydroxyvitamin D, parathormone, c-terminal FGF23, a-Klotho, myostatin, follistatin, IGF-1, and IL-6 were measured in 53 patients with GFR < 60 ml/min/1,73m2. Myostatin to lean mass (LM) and to IGF-1 ratios were calculated. IL-6 level > 3rd quartile was considered as high.

RESULTS

Myostatin, IGF-1, and follistatin were correlated to LM (rs = 0.513, p < 0.001, rs = 0.652, p < 0.001, rs=-0.483, p < 0.001). Myostatin and follistatin were correlated to IGF-1 (rs = 0.340, p = 0.014, rs=-0.385, p = 0.005). Myostatin/LM but not myostatin or myostatin/IGF-1 ratio was significantly higher in CKD 5D patients (p = 0.001,p = 0.844, p = 0.111). Among mineral bone parameters, lnFGF23 was correlated to lnIL-6 (rs = 0.397, p = 0.004) and associated with high IL-6 (OR 1.905, 95% CI 1.023-3.548). Among myokines, myostatin/IGF-1 ratio was correlated to lnIL-6 (rs = 0.395, p = 0.004) and associated with high IL-6 (OR 1.113, 95% CI 1.028-1.205). All associations were adjusted to CKD stage. Myostatin was correlated to lnFGF23 (rs = 0.331, p = 0.025) and myostatin/IGF-1 ratio to lnKlotho (rs=-0.363, p = 0.013), after adjustment for CKD stage, lnIL-6 and other mineral bone parameters.

CONCLUSIONS

In pediatric CKD, FGF23 and myostatin/IGF-1 ratio are associated with IL-6, indicating a link between systemic inflammation, mineral bone, and myokine disorders. The correlations between myostatin and FGF23 and between myostatin/IGF-1 and Klotho suggest an interaction between mineral bone and muscle metabolism.

Anti-Inflammatory Role of the Klotho Protein and Relevance to Aging

The α-Klotho protein (hereafter Klotho) is an obligate coreceptor for fibroblast growth factor 23 (FGF23). It is produced in the kidneys, brain and other sites. Klotho insufficiency causes hyperphosphatemia and other anomalies. Importantly, it is associated with chronic pathologies (often age-related) that have an inflammatory component. This includes atherosclerosis, diabetes and Alzheimer's disease. Its mode of action in these diseases is not well understood, but it inhibits or regulates multiple major pathways. Klotho has a membrane form and a soluble form (s-Klotho). Cytosolic Klotho is postulated but not well characterized. s-Klotho has endocrine properties that are incompletely elucidated. It binds to the FGF receptor 1c (FGFR1c) that is widely expressed (including endothelial cells). It also attaches to soluble FGF23, and FGF23/Klotho binds to FGFRs. Thus, s-Klotho might be a roaming FGF23 coreceptor, but it has other functions. Notably, Klotho (cell-bound or soluble) counteracts inflammation and appears to mitigate related aging (inflammaging). It inhibits NF-κB and the NLRP3 inflammasome. This inflammasome requires priming by NF-κB and produces active IL-1β, membrane pores and cell death (pyroptosis). In accord, Klotho countered inflammation and cell injury induced by toxins, damage-associated molecular patterns (DAMPs), cytokines, and reactive oxygen species (ROS). s-Klotho also blocks the TGF-β receptor and Wnt ligands, which lessens fibrotic disease. Low Klotho is associated with loss of muscle mass (sarcopenia), as occurs in aging and chronic diseases. s-Klotho counters the inhibitory effects of myostatin and TGF-β on muscle, reduces inflammation, and improves muscle repair following injury. The inhibition of TGF-β and other factors may also be protective in diabetic retinopathy and age-related macular degeneration (AMD). This review examines Klotho functions especially as related to inflammation and potential applications.

Insulin Resistance, a Risk Factor for Alzheimer's Disease: Pathological Mechanisms and a New Proposal for a Preventive Therapeutic Approach

Peripheral insulin resistance (IR) is a well-documented, independent risk factor for the development of type 2 diabetes, cardiovascular disease, cancer and cellular senescence. Recently, the brain has also been identified as an insulin-responsive region, where insulin acts as regulator of the brain metabolism. Despite the clear link between IR and the brain, the exact mechanisms underlying this relationship remain unclear. Therapeutic intervention in patients showing symptoms of neurodegenerative diseases has produced little or no results. It has been demonstrated that insulin resistance plays a significant role in the pathogenesis of neurodegenerative diseases, particularly cognitive decline. Peripheral and brain IR may represent a modifiable state that could be used to prevent major brain disorders. In this review, we will analyse the scientific literature supporting IR as a risk factor for Alzheimer's disease and suggest some therapeutic strategies to provide a new proposal for the prevention of brain IR and its consequences.

Klotho: molecular mechanisms and emerging therapeutics in central nervous system diseases

Klotho is recognized as an aging-suppressor protein that is implicated in a variety of processes and signaling pathways. The anti-inflammatory, anti-apoptotic, anti-oxidant, and anti-tumor bioactivities of klotho have extended its application in neurosciences and made the protein popular for its lifespan-extending capacity. Furthermore, it has been demonstrated that klotho levels would reduce with aging and numerous pathologies, particularly those related to the central nervous system (CNS). Evidence supports the idea that klotho can be a key therapeutic target in CNS diseases such as amyotrophic lateral sclerosis, Parkinson's disease, stroke, and Alzheimer's disease. Reviewing the literature suggests that the upregulation of klotho expression regulates various signaling pathways related to autophagy, oxidative stress, inflammation, cognition, and ferroptosis in neurological disorders. Therefore, it has been of great interest to develop drugs or agents that boost or restore klotho levels. In this regard, the present review was designed and aimed to gather the delegated documents regarding the therapeutic potential of Klotho in CNS diseases focusing on the molecular and cellular mechanisms.

Association between the triglyceride-glucose index and serum soluble Klotho in middle-aged and older adults from NHANES 2007-2016

Klotho, an anti-aging protein, is believed to participate in metabolic diseases and play a potential protective role by regulating insulin sensitivity. This study aimed to explore the relationship between the triglyceride-glucose (TyG) index (a simple marker of insulin resistance) and serum soluble Klotho (S-Klotho) levels. The cross-sectional study comprised 5237 adults aged 40-79 years who participated in the National Health and Nutrition Examination Surveys (NHANES) 2007-2016. The TyG index was calculated as ln [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2]. The serum levels of S-Klotho were measured by enzyme-linked immunosorbent assay. The association between the TyG index and S-Klotho levels was investigated by multiple linear regression models, smoothed curve fitting, segmented linear regression models, subgroup analyses, and interaction tests. The TyG index was inversely associated with serum S-Klotho level after full adjustment (β = - 45.11, 95% CI (- 79.53, - 10.69), P = 0.011). Furthermore, we also found a non-linear correlation and saturation phenomenon between the TyG index and serum S-Klotho levels, with a turning point of 9.56. In addition, a significant interaction effect of sex was found between the two (P for interaction < 0.001), with a more pronounced association observed in females. Further studies are required to explore the mechanisms and verify the correlation.

Abnormal Histopathological Expression of Klotho, Ferroptosis, and Circadian Clock Regulators in Pancreatic Ductal Adenocarcinoma: Prognostic Implications and Correlation Analyses

Pancreatic ductal adenocarcinoma (PDAC) is an extremely lethal tumor with increasing incidence, presenting numerous clinical challenges. The histopathological examination of novel, unexplored biomarkers offers a promising avenue for research, with significant translational potential for improving patient outcomes. In this study, we evaluated the prognostic significance of ferroptosis markers (TFRC, ALOX-5, ACSL-4, and GPX-4), circadian clock regulators (CLOCK, BMAL1, PER1, PER2), and KLOTHO in a retrospective cohort of 41 patients deceased by PDAC. Immunohistochemical techniques (IHC) and multiple statistical analyses (Kaplan-Meier curves, correlograms, and multinomial linear regression models) were performed. Our findings reveal that ferroptosis markers are directly associated with PDAC mortality, while circadian regulators and KLOTHO are inversely associated. Notably, TFRC emerged as the strongest risk marker associated with mortality (HR = 35.905), whereas CLOCK was identified as the most significant protective marker (HR = 0.01832). Correlation analyses indicate that ferroptosis markers are positively correlated with each other, as are circadian regulators, which also positively correlate with KLOTHO expression. In contrast, KLOTHO and circadian regulators exhibit inverse correlations with ferroptosis markers. Among the clinical variables examined, only the presence of chronic pathologies showed an association with the expression patterns of several proteins studied. These findings underscore the complexity of PDAC pathogenesis and highlight the need for further research into the specific molecular mechanisms driving disease progression.

The immune and metabolic milieu of the choroid plexus as a potential target in brain protection

The brain's choroid plexus (CP), which operates as an anatomical and functional 'checkpoint', regulates the communication between brain and periphery and contributes to the maintenance of healthy brain homeostasis throughout life. Evidence from mouse models and humans reveals a link between loss of CP checkpoint properties and dysregulation of the CP immune milieu as a conserved feature across diverse neurological conditions. In particular, we suggest that an imbalance between different immune signals at the CP, including CD4+ T cell-derived cytokines, type-I interferon, and complement components, can perpetuate brain inflammation and cognitive deterioration in aging and neurodegeneration. Furthermore, we highlight the role of CP metabolism in controlling CP inflammation, and propose that targeting molecules that regulate CP metabolism could be effective in safeguarding brain function.

Crosstalk between bone and brain in Alzheimer's disease: Mechanisms, applications, and perspectives

Alzheimer's disease (AD) is a neurodegenerative disease that involves multiple systems in the body. Numerous recent studies have revealed bidirectional crosstalk between the brain and bone, but the interaction between bone and brain in AD remains unclear. In this review, we summarize human studies of the association between bone and brain and provide an overview of their interactions and the underlying mechanisms in AD. We review the effects of AD on bone from the aspects of AD pathogenic proteins, AD risk genes, neurohormones, neuropeptides, neurotransmitters, brain-derived extracellular vesicles (EVs), and the autonomic nervous system. Correspondingly, we elucidate the underlying mechanisms of the involvement of bone in the pathogenesis of AD, including bone-derived hormones, bone marrow-derived cells, bone-derived EVs, and inflammation. On the basis of the crosstalk between bone and the brain, we propose potential strategies for the management of AD with the hope of offering novel perspectives on its prevention and treatment. HIGHLIGHTS: The pathogenesis of AD, along with its consequent changes in the brain, may involve disturbing bone homeostasis. Degenerative bone disorders may influence the progression of AD through a series of pathophysiological mechanisms. Therefore, relevant bone intervention strategies may be beneficial for the comprehensive management of AD.

Association between α-klotho levels and adults with COPD in the United States

Purpose

Chronic obstructive pulmonary disease (COPD) is accompanied by increased inflammation, persistent lung function decline, and extensive lung injury. Klotho, a well-known antiaging protein, has anti-inflammatory and antioxidative effects. However, the effects of klotho on COPD have yet to be thoroughly elucidated. This study examined the association among COPD adults and their α-klotho level.

Patients and methods

Data were collected from the 2007 to 2012 National Health and Nutrition Examination Survey (NHANES). A total of 676 participants were analyzed and divided into COPD (n = 403) and non-COPD (n = 273) groups. The two groups were compared with respect to clinical characteristics. Logistic regression analysis and a generalized additive model were used to estimate the association between COPD incidence and serum α-klotho concentration. All COPD participants were stratified according to the levels of α-klotho (Q1: <687 pg./mL; Q2: 687-900 pg./mL; Q3: ≥900 pg./mL), and clinical characteristics were compared.

Results

Non-COPD individuals had higher α-klotho levels than did COPD individuals (863.09 ± 267.13 vs. 817.51 ± 302.20, p < 0.05). Logistic regression analysis revealed that the Q2 and Q3 layers had a lower risk of COPD than did the Q1 layer, with odds ratios (ORs) of 0.73 (0.50, 0.99) for Q2 and 0.58 (0.41, 0.86) for Q3 (p < 0.001). The generalized additive model showed that the risk of COPD gradually decreased with increasing α-klotho concentration when the α-klotho concentration < 1,500 pg./mL, while the risk of COPD increased as the α-klotho concentration increased to ≥1,500 pg./mL. Compared with individuals in the Q2 or Q3 groups, individuals with COPD in the Q1 group were more likely to be current smokers, have lower levels of erythrocytes, and have higher levels of creatinine and leukocytes.

Conclusion

Increased α-klotho levels were negatively correlated with the risk of COPD in participants over 40 years old with α-klotho <1,500 pg./mL. When α-klotho was ≥1,500 pg./mL, the risk of COPD increased as α-klotho levels increased. Pulmonary ventilation function and the number of hemocytes differed among COPD patients with different levels of α-klotho.

Association Between the Serum Phosphate Levels and Hospital Mortality as Well as 90-Day Mortality Among Critically Ill Patients with Chronic Obstructive Pulmonary Disease: A Retrospective Cohort Study

Purpose

COPD patients frequently have abnormal serum phosphorus levels. The objective of this study was to examine the correlation between serum phosphorus levels with hospital and 90-day mortality in critically ill patients with COPD.

Patients and Methods

The MIMIC IV database was used for this retrospective cohort analysis. We extracted demographics, vital signs, laboratory tests, comorbidity, antibiotic usage, ventilation and scoring systems within the first 24 hours of ICU admission. Restricted cubic splines and multivariate cox regression analysis models were used to evaluate the connection between serum phosphorus with hospital and 90-day mortality. We assessed and classified various factors including gender, age, renal disease, severe liver disease, the utilization of antibiotics and congestive heart failure.

Results

We included a total of 3611 patients with COPD, with a median age of 70.7 years. After adjusting for all other factors, we observed a significant positive association between serum phosphate levels with both hospital mortality (HR 1.19, 95% CI: 1.07-1.31, p<0.001) and 90-day mortality (HR 1.15, 95% CI: 1.06-1.24, p<0.001). Compared to the medium group (Q2 ≥3.15, <4.0), the adjusted hazard ratios for hospital mortality were 1.47 (95% CI: 1.08-2, p=0.013), and 1.31 (95% CI: 1.06-1.61, p=0.013) for 90-day mortality in the high group (Q3≥4.0). Hospital mortality decreased at serum phosphate levels below 3.8 mg/dl (HR 0.664, 95% CI: 0.468-0.943, p=0.022), but increased for both hospital (HR 1.312, 95% CI: 1.141-1.509, p<0.001) and 90-day mortality (HR 1.236, 95% CI: 1.102-1.386, p<0.001) when levels were above 3.8 mg/dl. Subgroup and sensitivity analyses yielded consistent results.

Conclusion

In critical ill COPD patients, this study demonstrated a non-linear association between serum phosphate levels and both hospital and 90-day mortality. Notably, there was an inflection point at 3.8 mg/dl, indicating a significant shift in outcomes. Future prospective research is necessary to validate this correlation.

Cardiovascular health in pediatric patients with X-linked hypophosphatemia under two years of burosumab therapy

Introduction

X-linked hypophosphatemia (XLH) is caused by an inactivating mutation in the phosphate-regulating endopeptidase X-linked (PHEX) gene whose defective product fails to control phosphatonin fibroblast growth factor 23 (FGF23) serum levels. Although elevated FGF23 levels have been linked with detrimental cardiac effects, the cardiologic outcomes in XLH patients have been subject to debate. Our study aimed to evaluate the prevalence and severity of cardiovascular morbidity in pediatric XLH patients before, during, and after a 2-year treatment period with burosumab, a recombinant anti-FGF23 antibody.

Methods

This prospective observational study was conducted in a tertiary medical center, and included 13 individuals with XLH (age range 0.6-16.2 years) who received burosumab every 2 weeks. Clinical assessment at treatment initiation and after .5, 1, and 2 years of uninterrupted treatment included anthropometric measurements and cardiologic evaluations (blood pressure [BP], electrocardiogram, conventional echocardiography, and myocardial strain imaging).

Results

The linear growth of all patients improved significantly (mean height z-score: from -1.70 ± 0.80 to -0.96 ± 1.08, P=0.03). Other favorable effects were decline in overweight/obesity rates (from 46.2% to 23.1%) and decreased rates of elevated BP (systolic BP from 38.5% to 15.4%; diastolic BP from 38.5% to 23.1%). Electrocardiograms revealed no significant abnormality throughout the study period. Cardiac dimensions and myocardial strain parameters were within the normative range for age at baseline and remained unchanged during the study period.

Conclusion

Cardiologic evaluations provided reassurance that 2 years of burosumab therapy did not cause cardiac morbidity. The beneficial effect of this treatment was a reduction in cardiovascular risk factors, as evidenced by the lower prevalence of both overweight/obesity and elevated BP.

Rare germline structural variants increase risk for pediatric solid tumors

Pediatric solid tumors are rare malignancies that represent a leading cause of death by disease among children in developed countries. The early age-of-onset of these tumors suggests that germline genetic factors are involved, yet conventional germline testing for short coding variants in established predisposition genes only identifies pathogenic events in 10-15% of patients. Here, we examined the role of germline structural variants (SVs)-an underexplored form of germline variation-in pediatric extracranial solid tumors using germline genome sequencing of 1,766 affected children, their 943 unaffected relatives, and 6,665 adult controls. We discovered a sex-biased association between very large (>1 megabase) germline chromosomal abnormalities and a four-fold increased risk of solid tumors in male children. The overall impact of germline SVs was greatest in neuroblastoma, where we revealed burdens of ultra-rare SVs that cause loss-of-function of highly expressed, mutationally intolerant, neurodevelopmental genes, as well as noncoding SVs predicted to disrupt three-dimensional chromatin domains in neural crest-derived tissues. Collectively, our results implicate rare germline SVs as a predisposing factor to pediatric solid tumors that may guide future studies and clinical practice.