Calibration and evaluation of routine methods by serum certified reference material for aldosterone measurement in blood

Renin Inhibition and the Long-Term Renal Function in Patients With Hypertensive Emergency: A Retrospective Cohort Study

BACKGROUND

The rehospitalization rate in a hypertensive emergency is high, indicating the necessity for optimizing its long-term management. The role of the renin-angiotensin system (RAS) blockade in this disorder remains uncertain.

METHODS

We conducted a retrospective analysis involving 20 admitted patients who received aliskiren, a direct renin inhibitor (DRI), for the management of hypertensive emergency associated with elevated plasma renin activity (PRA). We analyzed the changes in blood pressure (BP), kidney function, and RAS activity in the subacute and chronic phases.

RESULTS

The use of DRI was associated with a marked reduction in PRA (median, from 25.0 to 1.2 ng/ml/h) and serum aldosterone levels (from 404 to 130 pg/ml) during the index admission. BP also decreased from 226/143 to 142/80 mm Hg. A comparison of clinical characteristics according to the renal function indicated that dialysis-dependent patients had higher aldosterone levels than non-dialysis-dependent patients at admission, despite comparable BP levels. After a median follow-up of 567 days in non-dialysis-dependent patients with DRI, eGFR levels were significantly increased from 14.3 to 23.1 ml/min/1.73 m2. PRA levels were consistently suppressed at 0.8 ng/ml/h. We found a significant correlation between the degree of PRA suppression and changes in eGFR (r = -0.58), indicating that the effective blockade of RAS is associated with the preservation of eGFR in the study subjects.

CONCLUSIONS

DRI can successfully suppress PRA in patients with high-renin hypertensive emergency in both subacute and chronic phases. An efficient RAS blockade is associated with preserved renal function in these patients.

Glucocorticoid receptor-NECAB1 axis can negatively regulate insulin secretion in pancreatic β-cells

The mechanisms of impaired glucose-induced insulin secretion from the pancreatic β-cells in obesity have not yet been completely elucidated. Here, we aimed to assess the effects of adipocyte-derived factors on the functioning of pancreatic β-cells. We prepared a conditioned medium using 3T3-L1 cell culture supernatant collected at day eight (D8CM) and then exposed the rat pancreatic β-cell line, INS-1D. We found that D8CM suppressed insulin secretion in INS-1D cells due to reduced intracellular calcium levels. This was mediated by the induction of a negative regulator of insulin secretion-NECAB1. LC-MS/MS analysis results revealed that D8CM possessed steroid hormones (cortisol, corticosterone, and cortisone). INS-1D cell exposure to cortisol or corticosterone increased Necab1 mRNA expression and significantly reduced insulin secretion. The increased expression of Necab1 and reduced insulin secretion effects from exposure to these hormones were completely abolished by inhibition of the glucocorticoid receptor (GR). NECAB1 expression was also increased in the pancreatic islets of db/db mice. We demonstrated that the upregulation of NECAB1 was dependent on GR activation, and that binding of the GR to the upstream regions of Necab1 was essential for this effect. NECAB1 may play a novel role in the adipoinsular axis and could be potentially involved in the pathophysiology of obesity-related diabetes mellitus.

Evaluation of standardized uptake value on 131I-6β-iodomethyl-19-norcholesterol scintigraphy for diagnosis of primary aldosteronism and correspondence with adrenal venous sampling

PURPOSE

Adrenal venous sampling (AVS) is a reliable method for lateralization of adrenal hormone secretion, which is important for discriminating between aldosterone-producing adenoma and bilateral adrenal hyperplasia, both of which cause primary aldosteronism (PA). The aim of this study was to evaluate the diagnostic accuracy of the maximum and mean standardized uptake values (SUV_max and SUV_mean, respectively) of ¹³¹I-6β-iodomethyl-19-norcholesterol (NP-59) single-photon emission computed tomography (SPECT) for PA and its correspondence with AVS.

METHODS

Adrenal NP-59 scintigraphy was performed in 14 patients with suspected PA, and AVS was also performed in 7 of them. SUV_max and SUV_mean of the adrenal lesions on the dominant side and their ratios to the values on the non-dominant side (SUVR_max and SUVR_mean, respectively) were calculated on SPECT images using ordered-subset conjugate gradient minimization (OSCGM) and three-dimensional ordered-subset expectation maximization (3D-OSEM) reconstruction algorithms.

RESULTS

SUV_max and SUV_mean on NP-59 SPECT images were significantly higher for aldosterone-producing adenoma than for bilateral adrenal hyperplasia or non-functioning adenoma and slightly superior to SUVR_max and SUVR_mean (P = 0.0475 and P = 0.0447 vs. P = 0.124 and P = 0.132, respectively, with OSCGM). The respective areas under the receiver-operating characteristic curve for SUV and SUVR were 0.933 and 0.725 with OSCGM and 0.844 and 0.750 with 3D-OSEM, while SUV_max and SUVR_max had exactly the same diagnostic accuracy as SUV_mean and SUVR_mean. SUV and SUVR were associated with the diagnostic features on AVS and consistent with lateralization by AVS in most patients.

CONCLUSION

In this study, SUV on NP-59 SPECT helped in the diagnosis of PA and was consistent with the results of AVS in nearly all cases.

International multicenter survey on screening and confirmatory testing in primary aldosteronism

OBJECTIVE

Primary aldosteronism (PA) is one of the most frequent causes of secondary hypertension. Although clinical practice guidelines recommend a diagnostic process, details of the steps remain incompletely standardized.

DESIGN

In the present SCOT-PA survey, we have investigated the diversity of approaches utilized for each diagnostic step in different expert centers through a survey using Google questionnaires. A total of 33 centers from 3 continents participated.

RESULTS

We demonstrated a prominent diversity in the conditions of blood sampling, assay methods for aldosterone and renin, and the methods and diagnostic cutoff for screening and confirmatory tests. The most standard measures were modification of antihypertensive medication and sitting posture for blood sampling, measurement of plasma aldosterone concentration (PAC) and active renin concentration by chemiluminescence enzyme immunoassay, a combination of aldosterone-to-renin ratio with PAC as an index for screening, and saline infusion test in a seated position for confirmatory testing. The cutoff values for screening and confirmatory testing showed significant variation among centers.

CONCLUSIONS

Diversity of the diagnostic steps may lead to an inconsistent diagnosis of PA among centers and limit comparison of evidence for PA between different centers. We expect the impact of this diversity to be most prominent in patients with mild PA. The survey raises 2 issues: the need for standardization of the diagnostic process and revisiting the concept of mild PA. Further standardization of the diagnostic process/criteria will improve the quality of evidence and management of patients with PA.

Visceral Fat Area Measured by Abdominal Bioelectrical Impedance Analysis in School-Aged Japanese Children

Abdominal bioelectrical impedance analysis (aBIA) has been in use to measure visceral fat area (VFA) in adults. Accurately measuring visceral fat using aBIA in children is challenging. Forty-six school-aged Japanese children aged 6–17 years (25 boys and 21 girls) were included in this study. All were measured, and their VFA obtained using aBIA (VFA-aBIA) and abdominal computed tomography (CT) (VFA-CT) were compared. VFA-aBIA was corrected using the Passing–Bablok method (corrected VFA-aBIA). The relationships between corrected VFA-aBIA and obesity-related clinical factors were analyzed, including non-alcoholic fatty liver disease (NAFLD) and serum leptin and adiponectin levels. Boys had higher VFA-CT than girls (p = 0.042), although no significant differences were found in their waist circumference, waist-to-height ratio, and body mass index. The corrected VFA-aBIA using y = 9.600 + 0.3825x (boys) and y = 7.607 + 0.3661x (girls) correlated with VFA-CT in both boys and girls. The corrected VFA-aBIA in patients with NAFLD was higher than that in those without NAFLD. Serum leptin and adiponectin levels were positively and negatively correlated with corrected VFA-aBIA, respectively. In conclusion, corrected VFA-aBIA was clearly correlated with VFA-CT and was related to NAFLD and serum leptin and adiponectin levels in school-aged Japanese children.

Comparison of Echocardiographic Changes Between Surgery and Medication Treatment in Patients With Primary Aldosteronism

Background

Primary aldosteronism can cause cardiac dysfunction, including left ventricular hypertrophy, left ventricular diastolic dysfunction, and left atrial enlargement. A few studies have compared the cardioprotective effects between surgery and medication for primary aldosteronism, although most have not adjusted for baseline disease status. In this study, we investigated the difference in cardiovascular outcomes between surgery and medication treatment for primary aldosteronism after adjusting for baseline clinical characteristics, including aldosterone level and pretreatment echocardiographic information.

Methods and Results

We retrospectively analyzed 220 patients diagnosed with primary aldosteronism who underwent adrenalectomy (n=144) or medication treatment (n=76) between 2009 and 2019. Echocardiographic changes were evaluated pretreatment and 1 year posttreatment. The surgery group had lower potassium, lower plasma renin activity, and higher plasma aldosterone concentration than the medication group, indicating a severe primary aldosteronism phenotype in the former. The decrease in left ventricular mass index after treatment was significantly greater in the surgery group than in the medication group (P=0.047). However, this relationship was not noted after multivariable regression analysis (standard β=−0.08, P=0.17). Additionally, decreased parameter values related to left ventricular diastolic dysfunction and left atrial enlargement were not different between the groups. Pretreatment echocardiographic values were most associated with changes in all echocardiographic parameters. The findings were consistent in the propensity score‐matched analysis.

Conclusions

This study's findings suggest that there is no difference in cardioprotective efficacy between surgical and medication treatment under similar disease severity; however, it should be considered that several study participants with severe hyperaldosteronism were managed surgically.

Japan Endocrine Society clinical practice guideline for the diagnosis and management of primary aldosteronism 2021

Primary aldosteronism (PA) is associated with higher cardiovascular morbidity and mortality rates than essential hypertension. The Japan Endocrine Society (JES) has developed an updated guideline for PA, based on the evidence, especially from Japan. We should preferentially screen hypertensive patients with a high prevalence of PA with aldosterone to renin ratio ≥200 and plasma aldosterone concentrations (PAC) ≥60 pg/mL as a cut-off of positive results. While we should confirm excess aldosterone secretion by one positive confirmatory test, we could bypass patients with typical PA findings. Since PAC became lower due to a change in assay methods from radioimmunoassay to chemiluminescent enzyme immunoassay, borderline ranges were set for screening and confirmatory tests and provisionally designated as positive. We recommend individualized medicine for those in the borderline range for the next step. We recommend evaluating cortisol co-secretion in patients with adrenal macroadenomas. Although we recommend adrenal venous sampling for lateralization before adrenalectomy, we should carefully select patients rather than all patients, and we suggest bypassing in young patients with typical PA findings. A selectivity index ≥5 and a lateralization index >4 after adrenocorticotropic hormone stimulation defines successful catheterization and unilateral subtype diagnosis. We recommend adrenalectomy for unilateral PA and mineralocorticoid receptor antagonists for bilateral PA. Systematic as well as individualized clinical practice is always warranted. This JES guideline 2021 provides updated rational evidence and recommendations for the clinical practice of PA, leading to improved quality of the clinical practice of hypertension.

Comparison and commutability study between standardized liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) and chemiluminescent enzyme immunoassay for aldosterone measurement in blood

A commutability confirmation test for the blood aldosterone measurement was performed on liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) as a designated comparison method (DCM) and four chemiluminescent enzyme immunoassay (CLEIA) measurement procedures based on metrological traceability. A conventional radioimmunoassay (RIA) and two measurement procedures of CLEIA which obtains RIA equivalent values were also compared. The relationship between the DCM value and the CLEIA value with respect to 120 pg/mL of the RIA value, which is the screening criterion of primary aldosteronism (PA) was clarified. For the correlation test, 75 samples of patient serum and plasma were used. Regression analysis revealed that the standardized LC-MS/MS and four CLEIA measurement procedures were in good agreement. This is the effect of measurement specificity and calibration using by certified reference material (CRM). The median of the LC-MS/MS corresponding to 120 pg/mL of RIA was 48.5 pg/mL. In the mean of standardized four CLEIA values corresponding to the 48.5 pg/mL of LC-MS/MS value was 47.51 pg/mL and the standard deviation (SD) was 2.93 pg/mL. However, the correlation between the RIA value and the RIA equivalent of the two measurement procedures by CLEIA differed depending on the measurement procedure. This is due to the influence of RIA measurement performance. Standardized CLEIA measurements are suitable for routine measurement procedure. When converting the LC-MS/MS equivalent value by the standardized CLEIA to the conventional RIA value, it is necessary to use the conversion formula.

Novel chemiluminescent immunoassay to measure plasma aldosterone and plasma active renin concentrations for the diagnosis of primary aldosteronism

Determination of plasma aldosterone concentrations (PAC) and plasma active renin concentrations (ARC) is essential for the diagnosis of primary aldosteronism (PA). In Japan, although PAC and ARC are measured by radioimmunoassay and immunoradiometric assay, respectively, non-radioisotopic methods with better detection sensitivity, measurement accuracy, and technical simplicity are needed. We developed two-site sandwich chemiluminescent enzyme immunoassays (CLEIAs) to measure both PAC and ARC using monoclonal antibodies immobilized onto ferrite particles. The results of both assays are obtained simultaneously from a single plasma sample within 30 min using a fully automated system. The novel CLEIAs were validated using plasma samples from patients with PA (n = 52) and essential hypertension (n = 23). The PAC determined by the CLEIA was significantly correlated with that measured by liquid chromatography/mass spectrometry or conventional radioimmunoassay. The ARC determined by the CLEIA was significantly correlated with that measured by immunoradiometric assay. The limits of detection of the CLEIAs for PAC and ARC were 0.1 ng/dl and 0.04 pg/ml, respectively, which were better than those of conventional methods (PAC: 2.5 ng/dl; ARC: 5 pg/ml). The PAC and PAC/ARC ratio (ARR) were significantly higher, and the ARC significantly lower, in patients with PA than in those with essential hypertension. An ARR cut-off of 1.31 ng/dl per pg/ml showed a sensitivity of 96.2% and specificity of 78.3% for PA screening. The newly developed CLEIAs for measuring PAC and ARC could provide a clinically powerful alternative to conventional methods used for hypertension screening in clinical practice.

Re-Assessment of the Oral Salt Loading Test Using a New Chemiluminescent Enzyme Immunoassay Based on a Two-Step Sandwich Method to Measure 24-Hour Urine Aldosterone Excretion

Since April 2021, the plasma aldosterone concentration has been measured by chemiluminescent enzyme immunoassay (CLEIA) in Japan. In the present study, we developed a new CLEIA using a two-step sandwich method to measure the 24-hour urine aldosterone level. We collected 115 urine samples and measured 24-hour urine aldosterone levels employing radioimmunoassay (RIA), CLEIA, and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that the 24-hour urine aldosterone levels measured using CLEIA and LC-MS/MS were significantly correlated (ρ = 0.992, P < 0.0001). Based on the results of Passing-Bablok regression analysis, the slope was 0.992 and the intercept -19.3. The 24-hour urine aldosterone levels measured using CLEIA and RIA were also significantly correlated (ρ = 0.905, P < 0.0001). However, the aldosterone level measured by CLEIA was lower than that measured by RIA (slope, 0.729; intercept, 120.9). In Japan, a new guideline for primary aldosteronism has been announced, with changes in the aldosterone measurement method. The cutoff values for oral sodium loading test (OSLT) were changed, but clinical verification using real-world urine samples has not been performed. Therefore, we examined the cut-off value of the 24-hour urine aldosterone level after the OSLT. Receiver operating characteristic analysis revealed a cut-off value for primary aldosteronism of 3 μg/day.

Comparisons of plasma aldosterone and renin data between an automated chemiluminescent immunoanalyzer and conventional radioimmunoassays in the screening and diagnosis of primary aldosteronism

Determining values of plasma renin activity (PRA) or plasma active renin concentration (ARC), plasma aldosterone concentration (PAC), and aldosterone-to-renin ratio (ARR) is essential to diagnose primary aldosteronism (PA), but it takes several days with conventional radioimmunoassays (RIAs). Chemiluminescent enzyme immunoassays for PAC and ARC using the Accuraseed^® immunoanalyzer facilitated the determination, but relations between Accuraseed^® immunoanalyzer-based and RIA-based values in samples of PA confirmatory tests and adrenal venous sampling remained to be elucidated. We addressed this issue in the present study. This is a prospective, cross-sectional study. ARC and PAC values were measured by the Accuraseed^® immunoanalyzer in samples, in which PRA and PAC values had been measured by the PRA-FR^® RIA and SPAC^®-S Aldosterone kits, respectively. The relations between Accuraseed^® immunoanalyzer-based and RIA-based values were investigated with regression analyses. The optimal cutoff of Accuraseed^® immunoanalyzer-based ARR for PA screening was determined by the receiver operating characteristic analysis. After log-log transformations, linear relations with high coefficients of determination were observed between Accuraseed^® immunoanalyzer-based and RIA-based data of renin and aldosterone. Following the PA guidelines of Japan Endocrine Society, Accuraseed^® immunoanalyzer-based cutoffs were calculated from the regression equations: the basal PAC for PA screening >12 ng/dL, PAC for the saline infusion test >8.2 ng/dL, ARC for the furosemide-upright test <15 pg/mL, and ARR for the captopril challenge test >3.09 ng/dL per pg/mL. The optimal cutoff of Accuraseed^® immunoanalyzer-based ARR for PA screening was >2.43 ng/dL over pg/mL not to overlook bilateral PA patients. The present study provided conversion formulas between Accuraseed^® immunoanalyzer-based and RIA-based values of renin, aldosterone, and ARR, not only in basal samples but also in samples of PA confirmatory tests and adrenal venous sampling. Although validation studies are awaited, the present study will become priming water of harmonization of renin and aldosterone immunoassays.

Recent Development toward the Next Clinical Practice of Primary Aldosteronism: A Literature Review

For the last seven decades, primary aldosteronism (PA) has been gradually recognized as a leading cause of secondary hypertension harboring increased risks of cardiovascular incidents compared to essential hypertension. Clinically, PA consists of two major subtypes, surgically curable and uncurable phenotypes, determined as unilateral or bilateral PA by adrenal venous sampling. In order to further optimize the treatment, surgery or medications, diagnostic procedures from screening to subtype differentiation is indispensable, while in the general clinical practice, the work-up rate is extremely low even in the patients with refractory hypertension because of the time-consuming and labor-intensive nature of the procedures. Therefore, a novel tool to simplify the diagnostic flow has been recently in enormous demand. In this review, we focus on recent progress in the following clinically important topics of PA: prevalence of PA and its subtypes, newly revealed histopathological classification of aldosterone-producing lesions, novel diagnostic biomarkers and prediction scores. More effective strategy to diagnose PA based on better understanding of its epidemiology and pathology should lead to early detection of PA and could decrease the cardiovascular and renal complications of the patients.

Development of a New Chemiluminescent Enzyme Immunoassay Using a Two-Step Sandwich Method for Measuring Aldosterone Concentrations

In the present study, we developed a new chemiluminescent enzyme immunoassay (CLEIA) using a two-step sandwich method to measure aldosterone concentrations. We investigated serum and plasma aldosterone concentrations in 75 blood samples from 27 patients using a radioimmunoassay (RIA) and the CLEIA (with current and newly improved reagents) as well as liquid chromatography-tandem mass spectrometry (LC-MS/MS). Based on the results of the Passing–Bablok regression analysis, the aldosterone levels measured using CLEIA with the new reagents and those measured by LC-MS/MS were found to be significantly correlated (slope, 0.984; intercept, 0.2). However, aldosterone levels varied depending on the measurement method (i.e., CLEIA with the new reagent, CLEIA with the current reagent, and RIA). Aldosterone levels were lower with the improved CLEIA method than with RIA and CLEIA using the current reagent. Therefore, the cutoff values of the screening test as well as those of the confirmatory test for primary aldosteronism (PA) should be adjusted to follow current clinical practice guidelines for PA. The formula that can be used to obtain the aldosterone level (pg/mL) when using CLEIA with the new reagent is 0.765 × RIA (pg/mL) − 33.7. This formula will enable PA cutoff values to be set for provisional screening and confirmatory tests.

Absolute content determination by quantitative NMR (qNMR) spectroscopy: a curious case of aldosterone

Quantitative NMR spectroscopy has been utilized to calculate the absolute content (g g⁻¹) of aldosterone, which is necessary for electrolyte balance and blood pressure regulation, in commercially available materials. Explanations have been provided for many signals observed in the ¹HNMR spectrum, false interpretation of which can have significant effects if such a value is utilized for the primary calibrators in ID-LC-MS/MS (‘gold standard’) reference methods in clinical chemistry.

1D/2D-NMR based extensive analyses of the real structure of aldosterone, elucidating the plausible diastereomeric hemiacetal/hemiketal tautomers and a qNMR based method of absolute content determination.

Parameters of captopril challenge test can predict results of other confirmatory tests for primary aldosteronism and propose the next test to be done

In Japan, primary aldosteronism (PA) is diagnosed if any one of the captopril challenge test (CCT), saline infusion test (SIT), furosemide-upright test (FUP), and oral salt-loading test (OST) is positive. The present study aimed to investigate if parameters of CCT, the safest confirmatory test, could predict decisions of other tests and propose the next test to diagnose PA in CCT-negative patients. In a cross-sectional design, 142 patients, who were referred to our hospital for the scrutiny of PA and underwent at least two confirmatory tests, were enrolled. While 123 patients underwent all of the CCT, SIT, and FUP, the OST was successfully done in only six patients and excluded from further analyses. CCT parameters showing correlations of higher degrees with SIT and FUP parameters were selected, and their powers to predict SIT and FUP decisions were investigated by receiver operating characteristic analyses. Proposals of the next test based on the CCT parameters were validated with SIT and FUP decisions in subsets of CCT-negative patients divided by cut-offs of the CCT parameters. The plasma aldosterone concentration and plasma renin activity 60 min after the load of CCT (CCT60-PAC and CCT60-PRA) were selected, and CCT60-PAC ≤59.0 pg/mL and CCT60-PRA ≥1.05 ng/mL/h could predict negativities of SIT and FUP, respectively, with >95% specificities. Based on the validation, the present study suggested the SIT as the next test to be done if the CCT-negative patient belonged to the subset with CCT60-PAC >59.0 pg/mL and CCT60-PRA ≥1.05 ng/mL/h, otherwise the FUP should be selected.

Precise Mapping of Intra-Adrenal Aldosterone Activities Provides a Novel Surgical Strategy for Primary Aldosteronism

Segmental selective adrenal venous sampling (sAVS) elucidates an intraadrenal aldosterone activity map (IAMap), which allows us to design a novel surgical treatment strategy for patients with primary aldosteronism. We evaluated the usefulness of sAVS by analyzing 278 patients with whom we had prospectively used IAMap using the criteria of sAVS for surgical indication between 2009 and 2015. We evaluated its diagnostic accuracy using pathological and postsurgical biochemical and clinical outcomes. One hundred twenty and 158 patients were diagnosed with unilateral and bilateral disease, respectively, through sAVS. The concordance of lateralization diagnosis with computed tomography imaging was 66.6%. Among the unilateral patients, we performed partial adrenalectomy in 68 patients whose IAMap showed focal aldosterone hypersecretion from computed tomography-detectable tumor in the affected adrenal gland. All of them achieved complete biochemical success 1 year after surgery. Furthermore, 25 of 158 bilateral disease patients underwent surgical resection because they were preoperatively diagnosed as bilateral aldosterone-producing adenomas by IAMap. These cases showed complete or partial biochemical success (28.0% and 72.0%, respectively); 36.0% showed complete clinical success. Pathological studies demonstrated that all 145 resected specimens possessed aldosterone-producing adenoma or multiple nodules (132 and 13 cases, respectively), and none showed diffuse hyperplasia. IAMap accurately diagnosed both bilateral and unilateral aldosterone-producing adenomas and diffuse hyperplasia before surgery. sAVS allows a novel surgical strategy for selected PA patients with favorable outcomes.

Effects of Repeated Lipopolysaccharide Treatment on Growth Performance, Immune Organ Index, and Blood Parameters of Sprague-Dawley Rats

Introduction

The study was designed to investigate the effects of repeated lipopolysaccharide (LPS) treatment on growth performance, lymphoid organ indexes, and blood cells in Sprague-Dawley rats.

Material and Methods

Forty healthy weaned Sprague-Dawley rats were randomly equally divided into LPS and control groups. Each rat in the LPS group was injected via the caudal vein with LPS (100 μg/kg b.w.) for 10 days, and the control group was treated with an equal volume of normal saline. On the 1^st, 4^th, 7^th, and 10^th days, growth performance, lymphoid organ indexes, and blood cells were evaluated in five necropsied rats.

Results

When rats were treated 3–10 times with LPS, their body weight and average daily gains increased more slowly than in the control group (P < 0.05). Repeated LPS treatment significantly increased spleen weight and the ratio of spleen to body weight (P < 0.05). White blood cells, neutrophils, and neutrophil percentage increased (P < 0.05) remarkably, but lymphocyte percentage, haemoglobin, and blood platelet counts decreased significantly (P < 0.05).

Conclusion

LPS treatment obviously suppresses growth and promotes peripheral immune organ proliferation. It is indicated that host protective mechanism can be activated by multiple small doses of LPS and prevents organs from further damage during stress status.

Clinical Utility of the Adrenocorticotropin Stimulation Test with/without Dexamethasone Suppression for Definitive and Subtype Diagnosis of Primary Aldosteronism

The adrenocorticotropin (ACTH) stimulation test (AST) has been reported to be useful for diagnosing primary aldosteronism (PA), particularly for differentiating PA subtypes under 1-mg dexamethasone suppression (DS). The aim of our study was to clarify the effect of 1-mg DS on AST results. A retrospective cohort study was conducted using data for 48 patients (PA: 30/48). We estimated the difference in plasma aldosterone concentration (PAC) responsiveness to ACTH stimulation with single (AST alone) and combined (AST under 1-mg DS) tests within the same patient. We compared the diagnostic accuracy of these two tests for PA and the laterality of hyperaldosteronism. We found no differences in PAC responsiveness to ACTH stimulation between single and combined tests, and observed a significant positive linear relationship (30 min, R² = 0.75, p-value < 0.01). Both tests showed the highest diagnostic accuracy for PA following 30 min of ACTH stimulation. The ability to detect the laterality of hyperaldosteronism was inconsistent and differed according to the two definitions: lateralization ratio and the absolute aldosterone levels in adrenal venous sampling. PAC responsiveness to ACTH stimulation was similar for AST with and without 1-mg DS. AST can be performed under both conditions with similar accuracy to detect PA.