Although the polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women with vast metabolic consequences, its etiology remains unknown and its diagnosis is still made by ...exclusion. This study aimed at characterizing a large number of urinary steroid hormone metabolites and enzyme activities in women with and without PCOS in order to test their value for diagnosing PCOS.
Comparative steroid profiling of 24h urine collections using an established in-house gas-chromatography mass spectrometry method. Data were collected mostly prospectively. Patients were recruited in university hospitals in Switzerland. Participants were 41 women diagnosed with PCOS according to the current criteria of the Androgen Excess and PCOS Society Task Force and 66 healthy controls. Steroid profiles of women with PCOS were compared to healthy controls for absolute metabolite excretion and for substrate to product conversion ratios. The AUC for over 1.5 million combinations of metabolites was calculated in order to maximize the diagnostic accuracy in patients with PCOS. Sensitivity, specificity, PPV, and NPV were indicated for the best combinations containing 2, 3 or 4 steroid metabolites.
The best single discriminating steroid was androstanediol. The best combination to diagnose PCOS contained four of the forty measured metabolites, namely androstanediol, estriol, cortisol and 20βDHcortisone with AUC 0.961 (95% CI 0.926 to 0.995), sensitivity 90.2% (95% CI 76.9 to 97.3), specificity 90.8% (95% CI 81.0 to 96.5), PPV 86.0% (95% CI 72.1 to 94.7), and NPV 93.7% (95% CI 84.5 to 98.2).
PCOS shows a specific 24h urinary steroid profile, if neglected metabolites are included in the analysis and non-conventional data analysis applied. PCOS does not share a profile with hyperandrogenic forms of congenital adrenal hyperplasias due to single steroid enzyme deficiencies. Thus PCOS diagnosis by exclusion may no longer be warranted. Whether these findings also apply to spot urine and serum, remains to be tested as a next step towards routine clinical applicability.
Nephrolithiasis is one of the most common conditions affecting the kidney and is characterized by a high risk of recurrence. Thiazide diuretic agents are widely used for prevention of the recurrence ...of kidney stones, but data regarding the efficacy of such agents as compared with placebo are limited. Furthermore, dose-response data are also limited.
In this double-blind trial, we randomly assigned patients with recurrent calcium-containing kidney stones to receive hydrochlorothiazide at a dose of 12.5 mg, 25 mg, or 50 mg once daily or placebo once daily. The main objective was to investigate the dose-response effect for the primary end point, a composite of symptomatic or radiologic recurrence of kidney stones. Radiologic recurrence was defined as the appearance of new stones on imaging or the enlargement of preexisting stones that had been observed on the baseline image. Safety was also assessed.
In all, 416 patients underwent randomization and were followed for a median of 2.9 years. A primary end-point event occurred in 60 of 102 patients (59%) in the placebo group, in 62 of 105 patients (59%) in the 12.5-mg hydrochlorothiazide group (rate ratio vs. placebo, 1.33; 95% confidence interval CI, 0.92 to 1.93), in 61 of 108 patients (56%) in the 25-mg group (rate ratio, 1.24; 95% CI, 0.86 to 1.79), and in 49 of 101 patients (49%) in the 50-mg group (rate ratio, 0.92; 95% CI, 0.63 to 1.36). There was no relation between the hydrochlorothiazide dose and the occurrence of a primary end-point event (P = 0.66). Hypokalemia, gout, new-onset diabetes mellitus, skin allergy, and a plasma creatinine level exceeding 150% of the baseline level were more common among patients who received hydrochlorothiazide than among those who received placebo.
Among patients with recurrent kidney stones, the incidence of recurrence did not appear to differ substantially among patients receiving hydrochlorothiazide once daily at a dose of 12.5 mg, 25 mg, or 50 mg or placebo once daily. (Funded by the Swiss National Science Foundation and Inselspital; NOSTONE ClinicalTrials.gov number, NCT03057431.).
Diagnostic ratios calculated from urinary steroid hormone metabolites are used as a measure for the relative activity of steroidogenic enzymes or pathways in the clinical investigation of steroid ...metabolism disorders. However, population-based sex- and age-specific reference intervals and day-night differences in adults are lacking. Sixty-five diagnostic ratios were calculated from steroid metabolites measured by GC-MS in day- and night-time and in 24-hour urine from 1128 adults recruited within the Swiss Kidney Project on Genes in Hypertension (SKIPOGH), a population-based, multicenter cohort study. Differences related to sex, age and day- and night-time were evaluated and reference curves in function of age and sex were modelled by multivariable linear mixed regression for diagnostic ratios and were compared to values from the literature. Most ratios had sex- and age-specific relationships. For each ratio, percentiles were plotted in function of age and sex in order to create reference curves and sex- and age-specific reference intervals derived from 2.5.sup.th and 97.5.sup.th percentiles were obtained. Most ratios reflected a higher enzyme activity during the day compared to the night. Sex- and age-specific references for 24 hours, day and night urine steroid metabolite ratios may help distinguishing between health and disease when investigating human disorders affecting steroid synthesis and metabolism. The day-night differences observed for most of the diagnostic ratios suggest a circadian rhythm for enzymes involved in human steroid hormones metabolism.
Sex-specific differences in nephrolithiasis with respect to both distribution of prevalence and stone composition are widely described and may be influenced by sex hormones.
We conducted a ...cross-sectional analysis of the relationship between 24-h urinary sex hormone metabolites measured by gas chromatography-mass spectrometry with urinary calcium, oxalate and citrate excretion in a cohort of 628 kidney stone formers from a tertiary care hospital in Switzerland, taking demographic characteristics, kidney function and dietary factors into account.
We observed a positive association of urinary calcium with urinary testosterone and 17β-oestradiol. Positive associations of urinary calcium with dehydroepiandrosterone (DHEA), 5α-DH-testosterone, aetiocholanolone, androsterone and oestriol were modified by net gastrointestinal alkali absorption or urinary sulphate excretion. As the only sex hormone, DHEA was inversely associated with urinary oxalate excretion in adjusted analyses. Urinary citrate correlated positively with urinary testosterone. Associations of urinary citrate with urinary androsterone, 17β-oestradiol and oestriol were modified by urinary sulphate or sodium or by sex.
Urinary androgens and oestrogens are significantly associated with urinary calcium and citrate excretion and associations are modified in part by diet. Our data furthermore reveal DHEA as a novel factor associated with urinary oxalate excretion in humans.
Urinary steroid metabolomics by GC-MS is an established method in both clinical and research settings to describe steroidogenic disorders. However, population-based reference intervals for adults do ...not exist.
We measured daytime and night time urinary excretion of 40 steroid metabolites by GC-MS in 1128 adult participants of European ancestry, aged 18 to 90 years, within a large population-based, multicentric, cross-sectional study. Age and sex-related patterns in adjacent daytime and night time urine collections over 24 hours were modelled for each steroid metabolite by multivariable linear mixed regression. We compared our results with those obtained through a systematic literature review on reference intervals of urinary steroid excretion.
Flexible models were created for all urinary steroid metabolites thereby estimating sex- and age-related changes of the urinary steroid metabolome. Most urinary steroid metabolites showed an age-dependence with the exception of 6β-OH-cortisol, 18-OH-cortisol, and β-cortol. Reference intervals for all metabolites excreted during 24 hours were derived from the 2.5th and 97.5th percentile of modelled reference curves. The excretion rate per period of metabolites predominantly derived from the adrenals was mainly higher during the day than at night and the correlation between day and night time metabolite excretion was highly positive for most androgens and moderately positive for glucocorticoids.
This study gives unprecedented new insights into sex- and age-specificity of the human adult steroid metabolome and provides further information on the day/night variation of urinary steroid hormone excretion. The population-based reference ranges for 40 GC-MS-measured metabolites will facilitate the interpretation of steroid profiles in clinical practice.
Nephrolithiasis is a common health problem in autosomal dominant polycystic kidney disease (ADPKD) and significantly contributes to patient morbidity. Recently, Tolvaptan has been introduced for the ...treatment of ADPKD, but whether it is associated with alterations of the urinary lithogenic risk profile remains unknown.
We conducted an analysis of participants enrolled in the Bern ADPKD registry, a prospective observational cohort study. Twenty-four-hour urine analyses were performed at baseline and then at yearly follow-ups. Relative supersaturation ratios for calcium oxalate, brushite, and uric acid were calculated with the program EQUIL2. Unadjusted and multivariable mixed-effects linear regression models, adjusted for age, sex, body mass index, eGFR, net acid excretion, and height-adjusted total kidney volume, were used to assess the association of Tolvaptan with urinary parameters relevant for kidney stone formation. The maximum individual follow-up time was 3 years, median follow-up time 1.9 years, and cumulative follow-up time 169 years.
In total, 125 participants (38 with and 87 without Tolvaptan treatment) were included in the analysis. In multivariable analysis, Tolvaptan treatment was associated adjusted estimate of the difference between Tolvaptan and no Tolvaptan; 95% confidence interval (CI) with lower urine relative supersaturation ratios for calcium oxalate (-0.56; 95% CI, -0.82 to -0.3;
<0.001), brushite (-0.33; 95% CI, -0.54 to -0.11;
=0.004), and uric acid (-0.62; 95% CI, -0.88 to -0.37;
<0.001), and with higher urine citrate in mmol/mmol creatinine per day (0.25; 95% CI, 0.05 to 0.46;
=0.02) and calcium in mmol/mmol creatinine per day (0.31; 95% CI, 0.09 to 0.53;
=0.006) excretion. In addition, Tolvaptan treatment was associated with lower net acid excretion in mEq/mmol creatinine per day (-0.54; 95% CI, -0.90 to -0.17;
=0.004) and higher net gastrointestinal alkali absorption in mEq/mmol creatinine per day (0.57; 95% CI, 0.26 to 0.88;
<0.001).
Tolvaptan treatment is associated with a significantly improved urinary lithogenic risk profile in patients with ADPKD.
In the kidney, final urinary acidification is achieved by V-ATPases expressed in type A intercalated cells. The B1 subunit of the V-ATPase is required for maximal urinary acidification, while the ...role of the homologous B2 subunit is less clear. Here we examined the effect of acute acid/alkali loading in humans on B1 and B2 subunit abundance in urinary exosomes in normal individuals and of acid loading in patients with distal renal tubular acidosis (dRTA). Specificities of B1 and B2 subunit antibodies were verified by yeast heterologously expressing human B1 and B2 subunits, and murine wild-type and B1-deleted kidney lysates. Acute ammonium chloride loading elicited systemic acidemia, a drop in urinary pH, and increased urinary ammonium excretion. Nadir urinary pH was achieved at four to five hours, and exosomal B1 abundance was significantly increased at two through six hours after ammonium chloride loading. After acute equimolar sodium bicarbonate loading, blood and urinary pH rose rapidly, with a concomitant reduction of exosomal B1 abundance within two hours, which remained lower throughout the test. In contrast, no change in exosomal B2 abundance was found following acid or alkali loading. In patients with inherited or acquired distal RTA, the urinary B1 subunit was extremely low or undetectable and did not respond to acid loading in urine, whereas no change in B2 subunit was found. Thus, both B1 and B2 subunits of the V-ATPase are detectable in human urinary exosomes, and acid and alkali loading or distal RTA cause changes in the B1 but not B2 subunit abundance in urinary exosomes.
ABSTRACT
Background
Autosomal dominant polycystic kidney disease (ADPKD) is characterized by a unique bone and mineral phenotype. The impact of tolvaptan treatment on mineral metabolism and bone ...mineral density (BMD) is unknown.
Methods
We conducted an analysis in the Bern ADPKD Registry, a prospective observational cohort study. Mineral metabolism parameters were measured at baseline and every 12 months thereafter. BMD was determined by dual-energy X-ray absorptiometry at baseline and after 3 years. Multivariable mixed-effects regression models were applied to assess changes in mineral metabolism parameters and BMD associated with tolvaptan treatment.
Results
A total of 189 participants (122 without and 67 with subsequent tolvaptan treatment) were included in the analysis. During follow-up, tolvaptan treatment was associated with increased BMD at the femoral neck {β = 0.092 95% confidence interval (CI) 0.001–0.183, P = .047}. In addition, tolvaptan treatment was associated with higher plasma magnesium β = 0.019 (95% CI 0.001–0.037), P = .037, bicarbonate β = 0.972 (95% CI 0.242–1.702), P = .009 and urine pH β = 0.214 (95% CI 0.056–0.372), P = .008 and lower parathyroid hormone β = −0.191 (95% CI −0.328 to −0.053), P = .006, 1,25(OH)D3 β = −0.126 (95% CI −0.235 to −0.164), P = .024 and fractional urinary magnesium excretion β = −0.473 (95% CI −0.622 to −0.324), P < .001.
Conclusions
Chronic tolvaptan treatment is associated with increased femoral BMD and significant changes in both mineral metabolism and acid–base parameters in ADPKD patients.
Graphical Abstract
Graphical Abstract
Mutations in the vacuolar-type H(+)-ATPase B1 subunit gene ATP6V1B1 cause autosomal-recessive distal renal tubular acidosis (dRTA). We previously identified a single-nucleotide polymorphism (SNP) in ...the human B1 subunit (c.481G>A; p.E161K) that causes greatly diminished pump function in vitro To investigate the effect of this SNP on urinary acidification, we conducted a genotype-phenotype analysis of recurrent stone formers in the Dallas and Bern kidney stone registries. Of 555 patients examined, 32 (5.8%) were heterozygous for the p.E161K SNP, and the remaining 523 (94.2%) carried two wild-type alleles. After adjustment for sex, age, body mass index, and dietary acid and alkali intake, p.E161K SNP carriers had a nonsignificant tendency to higher urinary pH on a random diet (6.31 versus 6.09; P=0.09). Under an instructed low-Ca and low-Na diet, urinary pH was higher in p.E161K SNP carriers (6.56 versus 6.01; P<0.01). Kidney stones of p.E161K carriers were more likely to contain calcium phosphate than stones of wild-type patients. In acute NH4Cl loading, p.E161K carriers displayed a higher trough urinary pH (5.34 versus 4.89; P=0.01) than wild-type patients. Overall, 14.6% of wild-type patients and 52.4% of p.E161K carriers were unable to acidify their urine below pH 5.3 and thus, can be considered to have incomplete dRTA. In summary, our data indicate that recurrent stone formers with the vacuolar H(+)-ATPase B1 subunit p.E161K SNP exhibit a urinary acidification deficit with an increased prevalence of calcium phosphate-containing kidney stones. The burden of E161K heterozygosity may be a forme fruste of dRTA.
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