Takuyuki Katabami

Histopathological Diagnosis of Primary Aldosteronism Using CYP11B2 Immunohistochemistry

CONTEXT Although primary aldosteronism (PA) is the most common cause of endocrine hypertension, histopathological methods to reveal the presence and sites of aldosterone overproduction remain to be established. OBJECTIVE The objective of the study was to investigate the significance of immunohistochemical staining to detect CYP11B2 and CYP11B1 in adrenal tissue of patients with PA. DESIGN AND PATIENTS Thirty-two patients with PA who underwent unilateral adrenalectomy were studied. Immunohistochemical staining was performed using anti-CYP11B2 and anti-CYP11B1 antibodies on paraffin-embedded sections. We analyzed the expression of each enzyme semiquantitatively by scoring staining intensity and correlating it with clinical findings. RESULTS Twenty-two patients showed positive CYP11B2 immunostaining in their tumors (aldosterone producing adenoma, APA). Four patients with CYP11B2-negative unilateral adenomas and 4 patients without tumors on computed tomography showed aldosterone-producing cell clusters (APCCs) with CYP11B2 immunostaining in the zona glomerulosa (multiple APCCs). The remaining 2 patients had unilateral multiple adrenocortical micronodules and diffuse adrenocortical hyperplasia, respectively. In APA, CYP11B2 score adjusted for tumor volume was positively correlated with plasma aldosterone and negatively correlated with serum potassium. The APA group was divided into 3 subgroups based on relative CYP11B2 and CYP11B1 immunostaining levels. The CYP11B2/CYP11B1-equivalent and CYP11B1-dominant APA groups showed significantly higher serum cortisol after 1 mg dexamethasone and larger tumor size than the CYP11B2-dominant APA group. CONCLUSIONS The present study clearly demonstrates that CYP11B2 immunostaining is a powerful tool for histopathological diagnosis of aldosterone overproduction in PA and for subtype classification of APA, multiple APCCs, unilateral multiple adrenocortical micronodules, and diffuse hyperplasia.

Intracellular signal transduction for interleukin-1β-induced endothelin production in human umbilical vein endothelial cells

The authors investigated the intracellular signal transduction for interleukin (IL)-1 beta-induced endothelin (ET) production by endothelial cells from cultured human umbilical vein (HUVEC). Cultured HUVEC released immunoreactive (iR)-ET into the media in a time-dependent manner and a significant increase of iR-ET production was observed by the addition of IL-1 beta. The stimulating effect of IL-1 beta on iR-ET production was respectively inhibited by protein kinase C (C kinase) inhibitor (H-7), Ca-calmodulin inhibitor (W-7), cyclic AMP-dependent protein kinase (A kinase) inhibitor (H-8) and tyrosine kinase inhibitor (genistain) in a dose-dependent fashion. The data suggested that intracellular signal transduction for IL-1 beta-induced iR-ET production were via such pathways as C kinase, A kinase, Ca-calmodulin and tyrosine kinase in combination or independently, though possible mediation by other pathways cannot be ruled out.

Importance of contralateral aldosterone suppression during adrenal vein sampling in the subtype evaluation of primary aldosteronism

Adrenal vein sampling (AVS) is the standard criterion for the subtype diagnosis in primary aldosteronism (PA). Although lateralized index (LI) ≥4 after cosyntropin stimulation is the commonly recommended cut‐off for unilateral aldosterone hypersecretion, many of the referral centres in the world use LI cut‐off of <4 without sufficient evidence for its diagnostic accuracy.

Evaluation of whole-abdominal fat volume by 700-slice CT scanning and comparison with the umbilical fat area anthropometric indices

SUMMARY BACKGROUND The fat area at the umbilical region on CT scans is widely used to identify visceral obesity. However, whether it precisely represents the abdominal visceral fat volume is uncertain, because of technical difficulty in evaluating whole-abdominal visceral fat volume. In this study, we compared the whole-abdominal visceral fat and subcutaneous fat volumes with the visceral fat area at the umbilical region and anthropometric indices. METHODS The study population consisted of 131 Japanese diabetic and non-diabetic subjects (72 males and 59 females) who underwent anthropometric measurements (height, weight, waist circumference, and hip circumference) and CT scanning from the top of the liver to the pelvic floor (about 700 slices) to analyze the whole-abdominal and umbilical contents of visceral and subcutaneous fat. RESULTS The visceral fat volume of the male group was 1.3-fold higher than that of the female group, while the subcutaneous fat volume of the female group was 1.3-fold higher than that of the male group. The visceral fat area at the umbilical region was strongly correlated with visceral fat volume (r = 0.921 in males and 0.931 in females). Both visceral and subcutaneous fat volumes were strongly correlated with the waist circumference (r = 0.768 and 0.809 in males and 0.744 and 0.803 in females), but not with the BMI or waist/hip ratio. CONCLUSION The visceral fat area at the umbilical region is an optimal indicator for whole-abdominal visceral fat volume, and the waist circumference is the anthropometric index that reflects visceral obesity more closely than BMI or the waist/hip ratio.

Chronic kidney disease score for predicting postoperative masked renal insufficiency in patients with primary aldosteronism.

Chronic kidney disease (CKD) is sometimes unmasked after unilateral adrenalectomy in patients with primary aldosteronism (PA) without expectation.

Intrahepatic lipid content is linked to insulin resistance in obese subjects

SUMMARY BACKGROUND Abdominal visceral fat (VAT) and intrahepatic lipid (IHL) are associated with insulin resistance in obese subjects, but VAT is usually measured on CT scans at the umbilical level or on MRI images of the partial abdomen. Thus, the association of the total abdominal visceral fat volume (VFV) with insulin resistance is unclear. In this study, we evaluated the correlations of obesity-related factors, including VFV and IHL, with clinical markers of insulin resistance (HOMA-R and the MATSUDA Index), and then assessed the effect of weight loss on these factors and markers. METHODS The study population consisted of 30 obese Japanese subjects with a BMI > 25 kg/m(2) (13 men and 17 women) who underwent a 75-g oral glucose tolerance test to calculate HOMA-R and the MATSUDA Index, dual energy X-ray absorptiometry (DEXA) for measurement of body fat (%-Fat), proton magnetic resonance spectroscopy ((1)H MRS) to assess IHL, and whole abdominal CT scanning (from the top of the liver to the floor of the pelvic cavity = about 700 slices) to determine the total abdominal subcutaneous fat volume (SFV) and VFV. Seven subjects from the original population were placed on a diet and exercise program, and these indices were examined again after 5% reduction of body weight. RESULTS Abdominal SFV, VFV, and IHL were mutually independent, but BMI and %-Fat were not independent of the other factors. According to multiple regression analysis, IHL (but not SFV or VFV) was significantly correlated with both HOMA-R and the MATSUDA Index in obese patients. Weight reduction by 5% led to improvement of the MATSUDA Index and decreased the number of subjects with metabolic syndrome, and the reduction of IHL was greater than that of SFV or VFV. These results suggest that IHL may be a superior marker of insulin resistance.

Adrenal black adenoma associated with preclinical Cushing's syndrome

A black adenoma of the adrenal gland was laparoscopically removed from a 60‐year‐old man who presented with severe hypertension. Although laboratory findings were indicative of preclinical Cushings syndrome, there were no clinical features characteristic of Cushings syndrome. Microscopically, the tumor showed a proliferation of polygonal cells containing numerous brown‐pigmented granules. Special staining studies revealed these granules to be lipofuscin. Electron microscopy also identified lipofuscin and lysosomes in these cells. The morphological appearance of the tumor and the adjacent atrophic non‐tumorous adrenal cortex supports the assumption that the black adenoma caused preclinical Cushings syndrome.

Accuracy of adrenal computed tomography in predicting the unilateral subtype in young patients with hypokalaemia and elevation of aldosterone in primary aldosteronism

The current Endocrine Society Guideline suggests that patients aged <35 years with marked primary aldosteronism (PA) and unilateral adrenal lesions on adrenal computed tomography (CT) scan may not need adrenal vein sampling (AVS) before proceeding to unilateral adrenalectomy. This suggestion is, however, based on the data from only one report in the literature.

Intracellular lipid content of liver and skeletal muscle in patients with adult growth hormone deficiency without diabetes mellitus

SUMMARY BACKGROUND Insulin resistance (IR) and visceral obesity are often observed in adult growth hormone deficiency patients (AGHDs). However, there is little information regarding the intrahepatic lipid (IHL) or the intramyocellular lipid (IMCL) content and their association with IR in AGHDs. The aim of this study was to directly assess IHL and IMCL in AGHDs by proton magnetic resonance spectroscopy and to evaluate the association of lipid levels with IR. METHODS Appropriate hormone replacement therapy (RT) other than GH and estrogen was prescribed before evaluation. Ten AGHDs (aged 23-75 years) without diabetes or elevation of aminotransferases were examined the percent body fat, visceral fat area (VFA), IHL, IMCL, adipokines and glucose metabolism. In two AGHDs, changes of these parameters were evaluated after GHRT. RESULTS Visceral obesity and metabolic syndrome was found in 100% and in 80% of the patients, respectively. IHL was significantly higher than that in non-obese healthy controls (12.5 ± 4.6 vs. 0.69 ± 0.46%, M ± SE, p = 0.0330), while IMCL did not differ between AGHDs and controls (528.8 ± 137.2 vs. 378 ± 51.1 mM, p = 0.2728). Homeostasis model assessment of IR was significantly correlated with IHL (r = 0.896, p = 0.0001) and IMCL (r = 0.749, p = 0.0102), but not with the VFA or percent truncal fat mass. A decrease of IHL and improvement of glucose tolerance were observed in the two patients after 6 M GHRT. CONCLUSION These results demonstrated that IHL, but not IMCL, may increase in AGHDs, and that IHL may associate with IR. GHRT may decrease IHL along with amelioration of IR.

Prevalence of Cardiovascular Disease and Its Risk Factors in Primary AldosteronismNovelty and Significance: A Multicenter Study in Japan

There have been several clinical studies examining the factors associated with cardiovascular disease (CVD) in patients with primary aldosteronism (PA); however, their results have left it unclear whether CVD is affected by the plasma aldosterone concentration or hypokalemia. We assessed the PA database established by the multicenter JPAS (Japan Primary Aldosteronism Study) and compared the prevalence of CVD among patients with PA with that among age-, sex-, and blood pressure-matched essential hypertension patients and participants with hypertension in a general population cohort. We also performed binary logistic regression analysis to determine which parameters significantly increased the odds ratio for CVD. Of the 2582 patients with PA studied, the prevalence of CVD, including stroke (cerebral infarction, cerebral hemorrhage, or subarachnoid hemorrhage), ischemic heart disease (myocardial infarction or angina pectoris), and heart failure, was 9.4% (stroke, 7.4%; ischemic heart disease, 2.1%; and heart failure, 0.6%). The prevalence of CVD, especially stroke, was higher among the patients with PA than those with essential hypertension/hypertension. Hypokalemia (K+ ⩽3.5 mEq/L) and the unilateral subtype significantly increased adjusted odds ratios for CVD. Although aldosterone levels were not linearly related to the adjusted odds ratio for CVD, patients with plasma aldosterone concentrations ≥125 pg/mL had significantly higher adjusted odds ratios for CVD than those with plasma aldosterone concentrations <125 pg/mL. Thus, patients with PA seem to be at a higher risk of developing CVD than patients with essential hypertension. Moreover, patients with PA presenting with hypokalemia, the unilateral subtype, or plasma aldosterone concentration ≥125 pg/mL are at a greater risk of CVD and have a greater need for PA-specific treatments than others.