Alejandro L. Arregger

Salivary testosterone: a reliable approach to the diagnosis of male hypogonadism.

Objective  This study was to demonstrate that Sal‐T is a reliable biomarker of androgen status in the diagnosis of male hypogonadism.

A new less-invasive and more informative low-dose ACTH test: salivary steroids in response to intramuscular corticotrophin.

objective  The intravenous low‐dose ACTH test has been proposed as a sensitive tool to assess adrenal function through circulating steroids. The aims of this study were to: (a) find the minimal intramuscular ACTH dose that induced serum and salivary cortisol and aldosterone responses equivalent to those obtained after a pharmacological dose of ACTH; and (b) define the minimum normal salivary cortisol and aldosterone responses in healthy subjects to that dose of ACTH. We also compared the performances of the standard‐ and low‐dose ACTH intramuscular tests to screen patients with known hypothalamo–pituitary–adrenal impairments.

Assessment of salivary urea as a less invasive alternative to serum determinations

Objective. Experimental studies describe how urea is excreted through salivary glands and correlates with serum levels independently of salivary flow rate. This study confirms that salivary urea (SaU) is a reliable biomarker of uraemic state. In order to validate the SaU methodology, the following factors were taken into account: the independence of urea levels from saliva flow rate in healthy subjects and patients with chronic renal failure and the agreement between SaU and serum urea (U) levels in the entire population. In addition, reference intervals and cut‐off values for SaU and U were established. Material and methods. Urea levels were determined in 268 matched whole saliva (SaU) and serum (U) samples obtained simultaneously from 78 healthy individuals and 154 patients with chronic renal failure. A serum enzymic colorimetric assay was adapted to SaU determinations. Results. SaU was independent of salivary flow rate. The agreement between SaU and U was confirmed by Bland‐Altman analysis with a significant correlation between them (r = 0.91, p = 0.0001). The reference interval of SaU ranged from 1.66 to 7.5 mM. The cut‐off values for SaU and U were 7.5 mM and 8.2 mM, respectively (sensitivity and specificity 100 % for both). Conclusions. SaU testing is harmless and useful for ruling out azotemic states in outpatients. Our results support the inclusion of SaU as a diagnostic test in the clinical laboratory.

Diagnostic value of salivary cortisol in Cushing's syndrome (CS).

Objective  The diagnosis of Cushings syndrome (CS) remains a challenge in clinical endocrinology. The aim of this study was to determine the reproducibility and diagnostic value of late‐night salivary cortisol (SAF23) for CS and its utility along the follow‐up of treated patients. In addition, using the same radioimmunoassay reactives, the cut‐off values for saliva and serum cortisol, assessed synchronically after the overnight 1 mg dexamethasone suppression test (DST), were defined.

Diagnostic value of salivary cortisol in end stage renal disease

OBJECTIVES Salivary cortisol has been proposed a surrogate marker for free serum cortisol measurements. The aim of this study was to ascertain the diagnostic value of basal and stimulated salivary cortisol for the detection of adrenal insufficiency (AI) in hypotensive end stage renal disease (ESRD) patients. Basal salivary cortisol and basal total serum cortisol were studied in order to determine the accuracy of both biomarkers in predicting AI. PATIENTS AND METHODS Twenty-nine ESRD patients with sustained hypotension were investigated for possible AI. Salivary cortisol was assessed at baseline and 30min after 25microg ACTH i.m. (LDTs). The dosage of salivary aldosterone was performed in salivary cortisol hypo-responders. Basal blood samples were drawn for steroids, renin and ACTH measurements. RESULTS A clear separation between patients with normal and impaired adrenal function was obtained through salivary cortisol levels at 30min after ACTH. AI was detected in six cases (21%) through impaired salivary cortisol responses; stimulated salivary aldosterone helped to differentiate primary (n=3) from secondary AI (n=3). ROC curves showed that cutoff values for basal SAF < or =4.4nM and serum cortisol < or =232.0nM suggest AI (sensitivities: 93% and 69%; specificities: 86.4% and 91%, respectively). CONCLUSIONS We conclude that ACTH stimulated SAF is an accurate biomarker for the diagnosis of AI in hypotensive ESRD patients. Neither basal salivary cortisol nor serum cortisol showed 100% sensitivities for the detection of AI.

Salivary testosterone for the diagnosis of androgen deficiency in end-stage renal disease

BACKGROUND Hypogonadism is frequent in patients with end-stage renal disease (ESRD). Salivary testosterone (Sal-T) is a non-invasive tool to screen androgen deficiency in adult male with normal renal function. However, available data on its utility in ESRD are not conclusive. OBJECTIVES The objectives of the study were: (i) to compare free testosterone fractions in saliva (SAL-T) and serum (Free-T); (ii) to establish the correlation of Sal-T with circulating total (TT) and bioavailable testosterone (Bio-T); (iii) to detect androgen deficiency through Sal-T; (iv) to determine the correlation of Sal-T with clinical parameters. METHODS The study included: 60 adult ESRD men on haemodialysis (20-60 years old) with decreased libido referred from two dialysis centres; 112 eugonadic and 40 hypogonadic adult men with normal renal function as controls. Simultaneous morning saliva and serum samples were obtained for testosterone measurements by liquid RIA (SAL-T; TT). Free-T and Bio-T were calculated by the Vermeulen equation. RESULTS Sal-T (0.338±0.177 nM) and Free-T (0.338±0.165 nM) did not differ (P>0.900) in ESRD as well as in control (0.337±0.182 and 0.337±0.172 nM, respectively; P>0.900). Sal-T levels correlated positively (P<0.0001) with Free-T (r=0.95), TT (r=0.80) and Bio-T (r=0.76) in ESRD. Sal-T negatively correlated with age and years on dialytic therapy. Sal-T showed 100% sensitivity and specificity to differentiate patients with androgen deficiency (22%) from those with normal androgen levels (78%). Hypogonadism was hypergonadotrophic in 69% cases and hypogonadotrophic in 31%. CONCLUSIONS These data demonstrate the value of morning Sal-T testing as a non-invasive approach to screen androgen status in ESRD patients.

Assessment of adrenal function by measurement of salivary steroids in response to corticotrophin in patients infected with human immunodeficiency virus

OBJECTIVE Adrenal insufficiency has been reported among critically ill HIV-infected patients. This is the first study that attempts to detect subclinical hypoadrenal states in non-critical HIV patients through salivary steroids in response to intramuscular low-dose ACTH injection. PATIENTS AND METHODS We studied 21 ambulatory adult HIV-infected patients without specific clinical signs or symptoms of adrenal insufficiency. Normal salivary flow-rate and salivary alpha-amylase activity confirmed adequate salivary gland function. Salivary cortisol (SAF) and salivary aldosterone (SAL) were obtained at baseline and 30 min after the injection of 25 microg of ACTH in the deltoid muscle (LDT(s)). Assessment of salivary steroids after stimulation with 250 microg of intramuscular ACTH (HDT(s)) was performed on those who hyporesponded to LDT(s). Basal blood samples were drawn for steroids, renin and ACTH measurements. RESULTS At baseline SAF and SAL correlated significantly (p=0.0001) with basal serum cortisol and aldosterone (r=0.70 and 0.91, respectively). Plasma ACTH and renin concentrations were within the normal range in all patients. Eight of the twenty-one HIV(+) patients were LDT(s) hyporesponders in either SAF (n:1) or SAL (n:7). LDT(s) repeated in six cases after a year reconfirmed the impairment of aldosterone secretion. LDT(s) hyporesponders had normal steroid responses to HDT(s). CONCLUSIONS LDT(s) is a simple, safe, well-accepted and non-invasive approach to assess adrenal function in HIV-infected ambulatory patients. It revealed subnormal cortisol (5%) and aldosterone responses (33%) when HDT(s) results were normal.

Adrenocortical function in hypotensive patients with end stage renal disease.

BACKGROUND Sustained hypotension among patients with end stage renal disease on dialysis (ESRDh) varies from 5.0% to 12.0%. Despite their role in the regulation of blood pressure (BP) corticoadrenal hormones have been poorly investigated. OBJECTIVES This study aims to detect adrenal insufficiency in ESRDh and follow their clinical outcome. METHODS Fifty ESRDh and 30 healthy volunteers were studied. In all cases basal blood and saliva were obtained. Synthetic ACTH (25μg) was injected intramuscularly and at 30min saliva was collected. Circulating ACTH, renin, cortisol and aldosterone were measured and steroids were also assessed in saliva by immunoassay. RESULTS Fifteen ESRDh achieved steroid responses not different than healthy volunteers; four had primary adrenal insufficiency; six had secondary adrenal insufficiency; nine had selective hypoaldosteronism and sixteen secondary hyperaldosteronism. The years on dialysis did not differ among subgroups. ROC analysis defined the following cut-offs for basal cortisol to predict adrenal insufficiency: in serum ⩽232.0nM (sensitivity (S) 100.0% and specificity (E) 90.0%); in saliva ⩽4.4nM (100.0% S and E). Basal aldosterone cut-off values to predict hyperaldosteronism were: in serum >500.0pM and saliva >60.0pM (100.0% S and E, for both). For the prediction of hypoaldosteronism the basal serum aldosterone was ⩽260.0pM (100% S; 53% E) and in saliva it was ⩽20.1pM (100% S; 58.5% E). Three patients with primary adrenal insufficiency and six with secondary adrenal insufficiency improved general clinical condition and normalized BP on steroids. One patient died before initiation of steroid therapy. CONCLUSION Adrenal function should be assessed in ESRDh in order to unmask adrenal insufficient states.

Effect of translocator protein (18 kDa)‐ligand binding on neurotransmitter‐induced salivary secretion in rat submandibular glands

Background information. TSPO (translocator protein), previously known as PBR (peripheral‐type benzodiazepine receptor), is a ubiquitous 18 kDa transmembrane protein that participates in diverse cell functions. High‐affinity TSPO ligands are best known for their ability to stimulate cholesterol transport in organs synthesizing steroids and bile salts, although they modulate other physiological functions, including cell proliferation, apoptosis and calcium‐dependent transepithelial ion secretion. In present study, we investigated the localization and function of TSPO in salivary glands.

Dynamics of salivary cortisol in chronic kidney disease patients at stages 1 through 4.

End‐stage renal disease has been associated with derangement of the HPA function. The dynamics of this axis in early stages of renal disease (CKD) has not been assessed.