Using Machine Learning to Aid the Interpretation of Urine Steroid Profiles.

BACKGROUND: Urine steroid profiles are used in clinical practice for the diagnosis and monitoring of disorders of steroidogenesis and adrenal pathologies. Machine learning (ML) algorithms are powerful computational tools used extensively for the recognition of patterns in large data sets. Here, we investigated the utility of various ML algorithms for the automated biochemical interpretation of urine steroid profiles to support current clinical practices. METHODS: Data from 4619 urine steroid profiles processed between June 2012 and October 2016 were retrospectively collected. Of these, 1314 profiles were used to train and test various ML classifiers' abilities to differentiate between "No significant abnormality" and "?Abnormal" profiles. Further classifiers were trained and tested for their ability to predict the specific biochemical interpretation of the profiles. RESULTS: The best performing binary classifier could predict the interpretation of No significant abnormality and ?Abnormal profiles with a mean area under the ROC curve of 0.955 (95% CI, 0.949-0.961). In addition, the best performing multiclass classifier could predict the individual abnormal profile interpretation with a mean balanced accuracy of 0.873 (0.865-0.880). CONCLUSIONS: Here we have described the application of ML algorithms to the automated interpretation of urine steroid profiles. This provides a proof-of-concept application of ML algorithms to complex clinical laboratory data that has the potential to improve laboratory efficiency in a setting of limited staff resources.

Development of a highly sensitive ELISA for aldosterone in mouse urine: validation in physiological and pathophysiological states of aldosterone excess and depletion.

BACKGROUND: Clinical studies have established aldosterone as a critical physiological and pathophysiological factor in salt and water homeostasis, blood pressure control and in heart failure. Genetic and physiological studies of mice are used to model these processes. A sensitive and specific assay for aldosterone is therefore needed to monitor adrenocortical activity in murine studies of renal function and cardiovascular diseases. METHODS: Antibodies against aldosterone were raised in sheep as previously described. HRP-Donkey-anti-sheep IgG enzyme tracer was produced in our laboratory using the Lightning-Link HRP technique. Aldosterone ELISA protocol was validated and optimised to achieve the best sensitivity. The assay was validated by analysing the urine of mice collected under various experimental conditions designed to stimulate or suppress aldosterone in the presence of other potentially interfering steroid hormones. RESULTS: Cross-reactivity with the steroids most likely to interfere was minimal: corticosterone=0.0028%, cortisol=0.0006%, DOC=0.0048% except for 5alpha-dihydro-aldosterone=1.65%. Minimum detection limit of this ELISA was 5.2 pmole/L (1.5 pg/mL). The validity of urinary aldosterone ELISA was confirmed by the excellent correlation between results obtained before and after solvent extraction and HPLC separation step (Y=1.092X+0.03, R(2)=0.995, n=54). Accuracy studies, parallelism and imprecision data were determined and all found to be satisfactory. Using this assay, mean urinary aldosterone levels were (i) approximately 60-fold higher in females than males mice; (ii) increased 6-fold by dietary sodium restriction; (iii) increased 10-fold by ACTH infusion and (iv) reduced by >60% in Cyp11b1 null mice. CONCLUSION: We describe an ELISA for urinary aldosterone that is suitable for repeated non-invasive measurements in mice. Female aldosterone levels are higher than males. Unlike humans, most aldosterone in mouse urine is not conjugated. Increased levels were noted in response to dietary sodium restriction and ACTH treatment. The sensitivity of the assay is sufficient to detect suppressed levels in mouse models of congenital adrenal hyperplasia.

Steroid biomarkers in human adrenal disease.

Adrenal steroidogenesis is a robust process, involving a series of enzymatic reactions that facilitate conversion of cholesterol into biologically active steroid hormones under the stimulation of angiotensin II, adrenocorticotropic hormone and other regulators. The biosynthesis of mineralocorticoids, glucocorticoids, and adrenal-derived androgens occur in separate adrenocortical zones as a result of the segregated expression of steroidogenic enzymes and cofactors. This mini review provides the principles of adrenal steroidogenesis, including the classic and under-appreciated 11-oxygenated androgen pathways. Several adrenal diseases result from dysregulated adrenal steroid synthesis. Herein, we review growing evidence that adrenal diseases exhibit characteristic modifications from normal adrenal steroid pathways that provide opportunities for the discovery of biomarker steroids that would improve diagnosis and monitoring of adrenal disorders.

Urine aldosterone radioimmunoassay: validation of a method without chromatography.

A simplified radioimmunoassay of urinary aldosterone is reported. Acid-hydrolyzed urine was extracted with dichloromethane and the extract assayed without further purification, Urinary aldosterone values in patients with Cushing's syndrome, low and normal-renin essential hypertension, congenital adrenal hyperplasia, and primary aldosteronism determined by this method agreed closely (r = 0.95, P less than 0.01) with values obtained using a standardized chromatographic method. This simplified assay represents a significant advance in out capabilitites for evaluating patients for abnormalities in aldosterone physiology.

Adrenal virilism due to 21-hydroxylase deficiency in the postmenarchial female.

Five new patients with postmenarchial onset of adrenal virilism related to 21-hydroxylase deficiency are presented. Diagnostic criteria are reviewed. Four pregnancies resulting in 3 term infants occurred after instigation of therapy. Eleven patients similar in clinical presentation are reviewed for comparison. Findings of value in distinguishing these two groups of patients are discussed.

Urinary steroid profile analysis.

BACKGROUND: A detailed analysis (profile) of the steroid metabolites in urine is useful for diagnosis of adrenal problems. Hospitals from many of UK health regions and around the world use the specialist assay and advisory service at UCLH. According to the total workload, samples are from patients with precocious puberty/premature adrenarche (21%), ambiguous genitalia (17%), Cushing's syndrome (13%), tumors (11%), polycystic ovaries (9%), hypertension (6%), problems of growth and development (5%), salt-loss (3%) and male pseudohermaphroditism (3%). Sixty percent of samples are from children and comprehensive reference data for steroid excretion rates in childhood unique to this laboratory were essential for interpretation of the results. CONCLUSION: The recognition and high excretion rates of certain steroids not easily measured in blood or urine by any other assays was particularly in cases of hypertension and tumors. The assay is cost effective by comparison with the combined costs of several individual hormone measurements but that cost may delay early referral to a specialist centre and that is not in the best interests of the families involved.

Pregnanetriolone, a normal steroid metabolite: its excretion by normal, Cushing's syndrome and congenital adrenal hyperplasia subjects.

Synthesis of 3H-pregnanetriolone permitted the estimation of pregnanetriolone in urine with a sensitivity in excess of most previous claims. A good correlation (r = +0.97) was obtained between the values from gas liquid chromatography and those of a double isotope derivative method. In contrast to previous reports, these methods indicated that pregnanetriolone is excreted by normal adults. Urinary pregnanetriolone levels were 18-59 mug/24hr for normal subjects, 35-290mug/24hr in Cushing's syndrome and 250-7000 mug/24hr with congenital adrenal hyperplasia. It is concluded that pregnanetriolone is a normal steroid metabolite and its occurrence in Cushing's syndrome does not necessary indicate an abnormal steroid biosynthetic pathway.

Gas chromatography of C19 and 17-oxogenic steroids in urine.

17-oxogenic steroids have been analysed by gas chromatography (GC) with capillary column and flame ionization detector. The best separation of steroid products was gained after ethyloxime-trimethylsilyl ether formation. The value of the GC method as a screening procedure for patients with suspected adrenal disease is illustrated in selected cases where the diagnosis was equivocal from data derived by RIA analysis of plasma steroids.

The regularity of intersteroidal relations in urine as related to the law of mass action.

The relation between 14 urinary steroid excretions was investigated by intersteroidal regression analysis with urine from 59 follicular stage women, 135 luteal stage women and 5 female patients with adrenal disorders. The regularity of intersteroidal relation in urine, as detected for all steroid pairs of all groups studied, was explained in terms of the law of mass action, and a chemical equilibrium point was located with a high degree of reproducibility for each steroid and for each group. The theoretical and practical usefulness of urinary steroid regression analysis is emphasized in relation to the possible impact of multihormonal information on endocrinology.

Elevated urinary catecholamines and adrenal haemorrhage mimicking phaeochromocytoma.

A 51-year-old woman was admitted with left-sided flank pain initially thought to be renal colic. However, a CT urogram was normal. During the course of the admission the pain persisted and she developed severe sustained hypertension. A repeat CT scan of the abdomen revealed a 5×3 cm left adrenal abnormality consistent with haemorrhage, not seen on the original scan. Further assessment revealed elevated urine catecholamines and a short synacthen test showed a suboptimal cortisol response. The diagnosis was initially considered as a phaeochromocytoma, she received phenoxybenzamine with good resolution of hypertension and was referred for surgical opinion. However, serial urinary catecholamine concentrations returned to within the normal range and the diagnosis was revised to adrenal infarction and haemorrhage due to antiphospholipid syndrome. This case illustrates the importance of recognising adrenal infarction as a potential cause of 'pseudophaeochromocytoma'.

Aberrant cortisol regulations in bilateral macronodular adrenal hyperplasia: a frequent finding in a prospective study of 32 patients with overt or subclinical Cushing's syndrome.

CONTEXT: ACTH-independent macronodular adrenal hyperplasia (AIMAH) is a rare and heterogeneous condition characterized by abnormal steroid production. Cortisol secretion can be regulated by aberrant hormone receptors. OBJECTIVE: A large series of patients with AIMAH were evaluated to provide information on the prevalence and profile of aberrant regulations, in relation with the functional status. DESIGN AND PATIENTS: Thirty-two consecutive patients with AIMAH were prospectively studied: 10 had a Cushing's syndrome (CS), and 22 had a subclinical CS (SCS). METHODS: A baseline endocrine evaluation was followed by an in vivo protocol in search of aberrant cortisol responses (seven provocative tests). An acute inhibition test with the somatostatin analog octreotide was also performed. RESULTS: At least one aberrant cortisol response was identified in 28 of 32 (87%) patients. The overall prevalence of aberrant responses was independent of the functional status. Responses to the upright posture and to metoclopramide were frequently observed (67 and 56% respectively). A glucagon response was frequently observed in the SCS group (58%). A cortisol inhibition by octreotide was specifically found in the three CS patients who positively responded to the mixed meal, and was observed also in 12 of 13 (92%) patients with SCS. CONCLUSIONS: Cortisol responses indicative of aberrant receptor expression were highly prevalent in AIMAH. Thorough phenotyping of AIMAH may help uncover the underlying pathophysiology.

Associations among systemic blood pressure, microalbuminuria and albuminuria in dogs affected with pituitary- and adrenal-dependent hyperadrenocorticism.

BACKGROUND: Hypertension and proteinuria are medical complications associated with the multisystemic effects of long-term hypercortisolism in dogs with hyperadrenocorticism (HAC). METHODS: This study investigated the relationships among adrenocorticotropic hormone (ACTH)-stimulation test results, systemic blood pressure, and microalbuminuria in clinically-healthy dogs (n = 100), in dogs affected with naturally occurring pituitary-dependent (PDH; n = 40), or adrenal-dependent hyperadrenocorticism (ADH; n = 30). RESULTS: Mean systemic blood pressure was similar between clinically healthy dogs and dogs with HAC (p = 0.803). However the incidence of hypertension was highest in dogs with ADH (p = 0.017), followed by dogs with PDH, with the lowest levels in clinically healthy dogs (p = 0.019). Presence of microalbuminuria and albuminuria in clinically healthy dogs and dogs affected with HAC was significantly different (p < 0.001); incidences of albuminuria followed the same pattern of hypertension; highest incidence in dogs with ADH, and lowest level in clinically healthy dogs; but microalbuminuria showed a different pattern: clinically healthy dogs had highest incidences and dogs with ADH had lowest incidence. The presence of albuminuria was not associated with blood pressure values, regardless of whether dogs were clinically healthy or affected with ADH or PDH (p = 0.306). CONCLUSIONS: Higher incidence of hypertension and albuminuria, not microalbuminuria was seen in dogs affected with HAC compared to clinically healthy dogs; incidence of hypertension and albuminuria was significantly higher in dogs affected with ADH compared to PDH. However, presence of albuminuria was not correlated with systemic blood pressure.