Soluble Alpha Klotho in Acromegaly: Comparison With Traditional Markers of Disease Activity.
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ABSTRACT: Context
Soluble alpha klotho (sαKL) has been linked to growth hormone (GH) action, but systematic evaluation and comparisons with traditional biomarkers in acromegaly are lacking.Objective
To evaluate the potential of sαKL to aid classification of disease activity.Methods
This retrospective study at 2 academic centers included acromegaly patients before surgery (A, n = 29); after surgery (controlled, discordant, or uncontrolled) without (B1, B2, B3, n = 28, 11, 8); or with somatostatin analogue treatment (C1, C2, C3, n = 17, 11, 5); nonfunctioning pituitary adenomas (n = 20); and healthy controls (n = 31). sαKL was measured by immunoassay and compared with traditional biomarkers (random and nadir GH, insulin-like growth factor I [IGF-I], IGF binding protein 3). Associations with disease activity were assessed.Results
sαKL was correlated to traditional biomarkers, particularly IGF-I (rs=0.80, P <0.0001). High concentrations before treatment (A, median, interquartile range: 4.04 × upper limit of normal [2.26-8.08]) dropped to normal after treatment in controlled and in most discordant patients. A cutoff of 1548 pg/mL for sαKL discriminated controlled (B1, C1) and uncontrolled (B3, C3) patients with 97.8% (88.4%-99.9%) sensitivity and 100% (77.1%-100%) specificity. sαKL was below the cutoff in 84% of the discordant subjects. In the remaining 16%, elevated sαKL and IGF-I persisted, despite normal random GH. Sex, age, body mass index, and markers of bone and calcium metabolism did not significantly affect sαKL concentrations.Conclusion
Our data support sαKL as a biomarker to assess disease activity in acromegaly. sαKL exhibits close association with GH secretory status, large dynamic range, and robustness toward biological confounders. Its measurement could be helpful particularly when GH and IGF-I provide discrepant information.
SUBMITTER: Schweizer JROL
PROVIDER: S-EPMC8277223 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:ObjectiveAccumulating experimental evidence has identified the beneficial effects of the anti-aging protein, serum soluble α-Klotho, on longevity, and the cardiovascular system. Although a previous study has revealed the predictive value of α-Klotho on total cardiovascular disease (CVD), the associations between α-Klotho and specific CVDs, including congestive heart failure (CHF), coronary heart disease (CHD), myocardial infarction (MI), and stroke, remains to be fully elucidated in humans.MethodsFor 8,615 adults in the 2007 to 2016 National Health and Nutrition Examination Survey, stratified multivariable logistic regression models, restricted cubic spline curves, and subgroup analyses were used to evaluate the associations between α-Klotho and the four specific CVDs.ResultsIn the quartile analyses, compared to those in the highest quartile, participants in the lowest level of α-Klotho were significantly associated with CHF [odds ratio (OR) = 1.46, 95% CI: 1.09-1.97] and MI (1.33, 1.02-1.74), which was not the case for CHD (1.12, 0.91-1.38) or stroke (0.96, 0.73-1.25). Each unit increment in the ln-transformed α-Klotho concentrations was only positively associated with a 38 and 24% reduction in the prevalence of CHF and MI, respectively. Restricted cubic spline curves indicated that the α-Klotho was correlated with CHF and MI in linear-inverse relationships.ConclusionThe present findings suggested that the serum soluble α-Klotho is significantly associated with the prevalence of CHF and MI. To better determine whether α-Klotho is a specific biomarker of CVD, particularly for CHD and stroke, further research in humans is needed.
| S-EPMC9251131 | biostudies-literature
Project description:Alpha-Klotho (alphaKl) regulates mineral metabolism such as calcium ion (Ca(2+)) and inorganic phosphate (Pi) in circulation. Defects in mice result in clinical features resembling disorders found in human aging. Although the importance of transmembrane-type alphaKl has been demonstrated, less is known regarding the physiological importance of soluble-type alphaKl (salphaKl) in circulation.The aims of this study were: (1) to establish a sandwich ELISA system enabling detection of circulating serum salphaKl, and (2) to determine reference values for salphaKl serum levels and relationship to indices of renal function, mineral metabolism, age and sex in healthy subjects.We successively developed an ELISA to measure serum salphaKl in healthy volunteers (n=142, males 66) of ages (61.1+/-18.5year). The levels (mean+/-SD) in these healthy control adults were as follows: total calcium (Ca; 9.46+/-0.41mg/dL), Pi (3.63+/-0.51mg/dL), blood urea nitrogen (BUN; 15.7+/-4.3mg/dL), creatinine (Cre; 0.69+/-0.14mg/dL), 1,25 dihydroxyvitamin D (1,25(OH)(2)D; 54.8+/-17.7pg/mL), intact parathyroid hormone (iPTH; 49.2+/-20.6pg/mL), calcitonin (26.0+/-12.3pg/mL) and intact fibroblast growth factor (FGF23; 43.8+/-17.6pg/mL). Serum levels of salphaKl ranged from 239 to 1266pg/mL (mean+/-SD; 562+/-146pg/mL) in normal adults. Although salphaKl levels were not modified by gender or indices of mineral metabolism, salphaKl levels were inversely related to Cre and age. However, salphaKl levels in normal children (n=39, males 23, mean+/-SD; 7.1+/-4.8years) were significantly higher (mean+/-SD; 952+/-282pg/mL) than those in adults (mean+/-SD; 562+/-146, P<0.001). A multivariate linear regression analysis including children and adults in this study demonstrated that salphaKl correlated negatively with age and Ca, and positively with Pi. Finally, we measured a serum salphaKl from a patient with severe tumoral calcinosis derived from a homozygous missense mutation of alpha-klotho gene. In this patient, salphaKl level was notably lower than those of age-matched controls.We established a detection system to measure human serum salphaKl for the first time. Age, Ca and Pi seem to influence serum salphaKl levels in a normal population. This detection system should be an excellent tool for investigating salphaKl functions in mineral metabolism.
| S-EPMC4130489 | biostudies-other
Project description:BackgroundThroughout life, physiological homeostasis is challenged and the capacity to cope with such challenges declines with increasing age. In many species, sex differences exist in life expectancy. Sex-specific differences have been related to extrinsic factors like mate competition and/or intrinsic proximate mechanisms such as hormonal changes. In humans, an intrinsic factor related to aging is soluble alpha klotho (?-Kl). Both sexes show an age-related decline in ?-Kl, but throughout life women have higher levels than men of the same age. Sex differences in ?-Kl have been linked to a shorter lifespan, as well as to specific morbidity factors such as atherosclerosis and arteries calcifications. In non-human animals, information on ?-Kl levels is rare and restricted to experimental work. Our cross-sectional study is the first on ?-Kl levels in two long-lived species: bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). As in most mammals, female bonobos and chimpanzees have longer life expectancy than males.MethodsWe measured serum ?-Kl levels of 140 subjects from 16 zoos with an ELISA to examine if ?-Kl levels reflect this difference in life expectancy.ResultsIn both species and in both sexes, ?-Kl levels declined with age suggesting that this marker has potential for aging studies beyond humans. We also found species-specific differences. Adult female bonobos had higher ?-Kl levels than males, a difference that corresponds to the pattern found in humans. In chimpanzees, we found the opposite: males had higher ?-Kl levels than females.ConclusionWe suggest that contrasting sex differences in adult ?-Kl levels mirror the dominance relations between females and males of the two Pan species; and that this might be related to corresponding sex differences in their exposure to stress. In humans, higher cortisol levels were found to be related to lower ?-Kl levels. We conclude that there is great potential for studying aging processes in hominoids, and perhaps also in other non-human primates, by measuring ?-Kl levels. To better understand the causes for sex differences in this aging marker, consideration of behavioural parameters such as competition and stress exposure will be required as well as other physiological markers.
| S-EPMC6146871 | biostudies-other
Project description:Background:Soluble Klotho has multiple systemic salutary effects. In animals, both acute and chronic kidney disease models display systemic Klotho deficiency. As such, there is considerable interest in investigating soluble Klotho as a biomarker in patients with different types and severity of kidney diseases. Unfortunately, there remains uncertainty regarding the best method to measure soluble Klotho in human serum samples. Methods:Using human serum samples obtained from several clinical cohorts with a wide range of kidney function, we measured soluble Klotho using a commercial enzyme-linked immunosorbent assay (ELISA) as well as with an immunoprecipitation-immunoblot (IP-IB) assay utilizing a synthetic antibody with high affinity and specificity for Klotho. Recovery of spiking with a known amount of exogenous Klotho was tested. A subset of samples was analyzed with and without the addition of a protease inhibitor cocktail at the time of collection or after the first freeze-thaw cycle to determine if these maneuvers influenced performance. Results:The IP-IB assay was superior to the ELISA at recovery of exogenous Klotho (81-115% versus 60-81%) across the spectrum of kidney function. Klotho measurements by IP-IB were highly correlated with estimated glomerular filtration rate (eGFR) (R?=?0.80, P?<?0.001) in comparison with the commercial ELISA, which exhibited minimal correlation with eGFR (R?=?0.18, P?=?0.12). Use of a protease inhibitor cocktail neither improved nor impaired performance of the IP-IB assay; however, subsequent freeze-thaw cycle resulted in a significant reduction in Klotho recovery and dissipated the correlation between Klotho levels and eGFR. With the ELISA, the use of protease inhibitor cocktail resulted in an increase in intrasubject variability. Conclusions:The IP-IB assay is preferable to the commercial ELISA to measure soluble Klotho concentrations in never-thawed serum samples of humans with varying severity of kidney disease. However, due to the labor-intensive nature of the IP-IB assay, further research is needed to secure an assay suitable for high-throughput work.
| S-EPMC7147321 | biostudies-literature
Project description:PurposeTo determine how patients define acromegaly disease activity and treatment success and to quantify from the patients' perspective the relative importance of each disease parameter included in the ACRODAT®.MethodsOne hundred acromegaly patients on medical therapy (mean age = 47.1 years; SD = 11.96) completed an online preference study evaluating hypothetical patient profiles described in terms of insulin-like growth factor-I (IGF-I) levels, tumor size, comorbid conditions, signs/symptoms, and quality of life (QoL). Participants first completed a single-profile task experiment by rating 20 single patient profiles as exhibiting stable, mild, or significant disease activity based on treatment success. Next, participants completed a double-profile discrete choice experiment (DCE) by selecting the patient that was doing "better" from 15 profile pairs. Results were analyzed using logistic and conditional logistic models.ResultsWhen choosing between stable vs. mild or significant disease activity, signs/symptoms, tumor size, and IGF-I levels were weighted equally; IGF-I and signs and symptoms were valued equally when selecting mild vs. significant disease activity. The DCE showed that, statistically, all disease parameters, except comorbid conditions, predicted health status equally. Tumor size and IGF-I levels each accounted for 23% of the decision-making process; QoL, signs/symptoms, and comorbid conditions accounted for 21%, 19%, and 14%, respectively.ConclusionAll five ACRODAT® parameters had some influence on disease activity from the patients' perspective. To account for patients' preferences and optimize treatment and outcomes, a holistic disease management approach should be employed.
| S-EPMC6373299 | biostudies-literature
Project description:Background: Membrane-bound ?-klotho functions as a co-receptor with fibroblast growth factor receptor at the renal tubule conferring specificity to fibroblast growth factor-23 (FGF-23), allowing it to inhibit tubular phosphate reabsorption at physiological concentrations. ?-klotho also exists as a soluble protein. However, the complex interrelationships between soluble ?-klotho (sKl), FGF-23 and phosphate reabsorption are poorly understood, with little known about the links between sKl, FGF-23 and phosphate reabsorption in chronic kidney disease (CKD). This study addresses this issue in a cohort of patients with and without CKD. Methods: We conducted a single-centre, cross-sectional study of contemporaneously obtained samples of blood and 24-h urine biochemistry along with sKl and intact FGF-23 (iFGF-23) from non-dialysis-dependent CKD patients and healthy volunteers. Pearson's correlation coefficients were used to determine correlations between natural log-transformed (Ln) sKl and iFGF-23 with other parameters of interest. Backward multivariate analysis was undertaken to evaluate the relationship between mineral parameters. Results: One hundred and sixteen participants (77 with CKD and 39 healthy volunteers) were studied, of which 74 (63.8%) were male. The median age was 61 (interquartile range 49-71) years. Those with CKD had lower sKl (408 versus 542?pg/mL), higher iFGF-23 (94 versus 41?pg/mL), higher fractional excretion of phosphate (25.05 versus 10.98%) and lower daily urinary phosphate excretion (UPE) (24.8 versus 32.3?mmol/L) compared with healthy volunteers (all P ?? 0.002). Age correlated inversely and estimated glomerular filtration rate (eGFR) correlated positively with phosphate reabsorption and Ln(sKl), while the opposite was seen with Ln(iFGF23). Upon multivariate analysis, eGFR, Ln(sKl) and parathyroid hormone were independently associated with phosphate reabsorption, whereas Ln(iFGF-23) was not, after adjustment for age. Conclusions: Abnormalities in phosphate regulatory pathways are disturbed early in CKD. While iFGF-23 is associated with phosphate excretion on univariate analyses, sKl demonstrates a significant association with phosphate reabsorption independent of iFGF-23, and this relationship deserves further exploration.
| S-EPMC5466110 | biostudies-literature
Project description:α-Klotho has emerged as a powerful regulator of the ageing process. To-date, the expression profile of α-Klotho in human tissues is unknown and its existence in some human tissue types is subject to much controversy. Objective: This is the first study to characterize system-wide tissue expression of transmembrane α-Klotho in humans. We have employed next generation targeted proteomic analysis using Parallel Reaction Monitoring (PRM) in parallel with conventional antibody-based methods to determine the expression and spatial distribution of human α-Klotho expression in health. Results: The distribution of α-Klotho in human tissues from various organ systems, including arterial, epithelial, endocrine, reproductive and neuronal tissues was first identified by immunohistochemistry. Kidney tissues showed strong α-Klotho expression, while liver did not reveal a detectable signal. These results were next confirmed by western blotting of both whole tissues and primary cells. To validate our antibody-based results, α-Klotho expressing tissues were subjected to PRM mass spectrometry identifying peptides specific for the full length, transmembrane α-Klotho isoform. Conclusions: The data presented confirms α-Klotho expression in the kidney tubule and in artery, and provides evidence of α-Klotho expression across organ systems and cell-types that have not previously been described in humans.
2015-10-13 | PXD002775 | Pride
Project description:Renal cell carcinoma (RCC) accounts for approximately 3% of adult malignancies, and clear cell RCC (ccRCC), that has a high metastatic index and high relapse rate, is the most common histological subtype. The identification of new biomarkers in ccRCC is fundamental for stratifying patients into prognostic risk groups and to guide therapy. The renoprotective antiaging gene, ?Klotho, has recently been found to work as a tumor suppressor in different human cancers. Here, we evaluated ?Klotho expression in tissue and serum of ccRCC patients and correlated it with disease progression. Tissue ?Klotho expression was studied by quantitative RT-PCR and immunohistochemistry. In addition, soluble serum ?Klotho levels were preoperatively measured in 160 patients who underwent nephrectomy for RCC with ELISA. Estimates of cancer-specific (CSS) and progression-free survival (PFS) were calculated according to the Kaplan-Meier method. Multivariate analysis was performed to identify the most significant variables for predicting CSS and PFS. ?Klotho protein levels were significantly decreased in RCC tissues compared with normal tissues (P?<?0.01) and the more advanced the disease, the more evident the down-regulation. This trend was also observed in serum samples. Statistically significant differences resulted between serum ?Klotho levels and tumor size (P = 0.003), Fuhrman grade (P = 0.007), and clinical stage (P = 0.0004). CSS and PFS were significantly shorter in patients with lower levels of ?Klotho (P?<?0.0001 and P = 0.0004, respectively). At multivariate analysis low serum levels of ?Klotho were independent adverse prognostic factors for CSS (HR = 2.11; P = 0.03) and PFS (HR = 2.18; P = 0.03).These results indicate that a decreased ?Klotho expression is correlated with RCC progression, and suggest a key role of declining ?Klotho in the onset of cancer metastasis.
| S-EPMC4912252 | biostudies-literature
Project description:A growing body of evidence suggests a role for soluble alpha-amyloid precursor protein (sAPPalpha) in pathomechanisms of Alzheimer disease (AD). This cleavage product of APP was identified to have neurotrophic properties. However, it remained enigmatic what proteins, targeted by sAPPalpha, might be involved in such neuroprotective actions. Here, we used high-resolution two-dimensional polyacrylamide gel electrophoresis to analyze proteome changes downstream of sAPPalpha in neurons. We present evidence that sAPPalpha regulates expression and activity of CDK5, a kinase that plays an important role in AD pathology. We also identified the cytoprotective chaperone ORP150 to be induced by sAPPalpha as part of this protective response. Finally, we present functional evidence that the sAPPalpha receptor SORLA is essential to mediate such molecular functions of sAPPalpha in neurons.
| S-EPMC3679172 | biostudies-literature
Project description:Chemokines and cytokines are key signaling molecules that orchestrate the trafficking of immune cells, direct them to sites of tissue injury and inflammation and modulate their states of activation and effector cell function. We have measured, using a multiplex-based approach, the levels of 58 immune mediators and 7 acute phase markers in sera derived from of a cohort of patients diagnosed with acute Lyme disease and matched controls. This analysis identified a cytokine signature associated with the early stages of infection and allowed us to identify two subsets (mediator-high and mediator-low) of acute Lyme patients with distinct cytokine signatures that also differed significantly (p<0.0005) in symptom presentation. In particular, the T cell chemokines CXCL9 (MIG), CXCL10 (IP-10) and CCL19 (MIP3B) were coordinately increased in the mediator-high group and levels of these chemokines could be associated with seroconversion status and elevated liver function tests (p=0.027 and p=0.021 respectively). There was also upregulation of acute phase proteins including CRP and serum amyloid A. Consistent with the role of CXCL9/CXCL10 in attracting immune cells to the site of infection, CXCR3+ CD4 T cells are reduced in the blood of early acute Lyme disease (p=0.01) and the decrease correlates with chemokine levels (p=0.0375). The levels of CXCL9/10 did not relate to the size or number of skin lesions but elevated levels of serum CXCL9/CXCL10 were associated with elevated liver enzymes levels. Collectively these results indicate that the levels of serum chemokines and the levels of expression of their respective chemokine receptors on T cell subsets may prove to be informative biomarkers for Lyme disease and related to specific disease manifestations. A total of 65 immune and inflammatory mediators were profiled in serum samples derived from early Lyme disease patients and age- and sex-matched controls. These samples have been generated as part of a prospective cohort study that includes a well-defined cohort of patients with acute Lyme disease enrolled from a Lyme endemic area of the mid-Atlantic United States. Only patients with untreated, confirmed early Lyme disease manifesting an active EM skin lesion at the time of enrollment, as defined by CDC case criteria are eligible. Patients with a history of prior Lyme disease or the presence of confounding preexisting medical conditions associated with prolonged fatigue, pain or neurocognitive symptoms are excluded. Controls are nonhospitalized age- and sex-matched and have no prior history of Lyme disease or any exclusionary medical conditions including lack of inflammatory disorders.
2014-04-25 | E-GEOD-55815 | biostudies-arrayexpress