Single-cell and spatial transcriptomics analysis of human adrenal aging.

OBJECTIVE: The human adrenal cortex comprises three functionally and structurally distinct layers that produce layer-specific steroid hormones. With aging, the human adrenal cortex undergoes functional and structural alteration or "adrenal aging", leading to the unbalanced production of steroid hormones. Given the marked species differences in adrenal biology, the underlying mechanisms of human adrenal aging have not been sufficiently studied. This study was designed to elucidate the mechanisms linking the functional and structural alterations of the human adrenal cortex. METHODS: We conducted single-cell RNA sequencing and spatial transcriptomics analysis of the aged human adrenal cortex. RESULTS: The data of this study suggest that the layer-specific alterations of multiple signaling pathways underlie the abnormal layered structure and layer-specific changes in steroidogenic cells. We also highlighted that macrophages mediate age-related adrenocortical cell inflammation and senescence. CONCLUSIONS: This study is the first detailed analysis of the aged human adrenal cortex at single-cell resolution and helps to elucidate the mechanism of human adrenal aging, thereby leading to a better understanding of the pathophysiology of age-related disorders associated with adrenal aging.

Steroids-producing nodules: a two-layered adrenocortical nodular structure as a precursor lesion of cortisol-producing adenoma.

BACKGROUND: The human adrenal cortex consists of three functionally and structurally distinct layers; zona glomerulosa, zona fasciculata (zF), and zona reticularis (zR), and produces adrenal steroid hormones in a layer-specific manner; aldosterone, cortisol, and adrenal androgens, respectively. Cortisol-producing adenomas (CPAs) occur mostly as a result of somatic mutations associated with the protein kinase A pathway. However, how CPAs develop after adrenocortical cells acquire genetic mutations, remains poorly understood. METHODS: We conducted integrated approaches combining the detailed histopathologic studies with genetic, RNA-sequencing, and spatially resolved transcriptome (SRT) analyses for the adrenal cortices adjacent to human adrenocortical tumours. FINDINGS: Histopathological analysis revealed an adrenocortical nodular structure that exhibits the two-layered zF- and zR-like structure. The nodular structures harbour GNAS somatic mutations, known as a driver mutation of CPAs, and confer cell proliferative and autonomous steroidogenic capacities, which we termed steroids-producing nodules (SPNs). RNA-sequencing coupled with SRT analysis suggests that the expansion of the zF-like structure contributes to the formation of CPAs, whereas the zR-like structure is characterised by a macrophage-mediated immune response. INTERPRETATION: We postulate that CPAs arise from a precursor lesion, SPNs, where two distinct cell populations might contribute differently to adrenocortical tumorigenesis. Our data also provide clues to the molecular mechanisms underlying the layered structures of human adrenocortical tissues. FUNDING: KAKENHI, The Uehara Memorial Foundation, Daiwa Securities Health Foundation, Kaibara Morikazu Medical Science Promotion Foundation, Secom Science and Technology Foundation, ONO Medical Research Foundation, and Japan Foundation for Applied Enzymology.

Dectin-2 Deficiency Promotes Proinflammatory Cytokine Release From Macrophages and Impairs Insulin Secretion.

Pancreatic islet inflammation plays a crucial role in the etiology of type 2 diabetes (T2D). Macrophages residing in pancreatic islets have emerged as key players in islet inflammation. Macrophages express a plethora of innate immune receptors that bind to environmental and metabolic cues and integrate these signals to trigger an inflammatory response that contributes to the development of islet inflammation. One such receptor, Dectin-2, has been identified within pancreatic islets; however, its role in glucose metabolism remains largely unknown. Here we have demonstrated that mice lacking Dectin-2 exhibit local inflammation within islets, along with impaired insulin secretion and ß-cell dysfunction. Our findings indicate that these effects are mediated by proinflammatory cytokines, such as interleukin (IL)-1α and IL-6, which are secreted by macrophages that have acquired an inflammatory phenotype because of the loss of Dectin-2. This study provides novel insights into the mechanisms underlying the role of Dectin-2 in the development of islet inflammation.

Adrenal steroid metabolites and bone status in patients with adrenal incidentalomas and hypercortisolism.

BACKGROUND: Autonomous cortisol secretion (ACS), resulting from cortisol-producing adenomas (CPA), causes endogenous steroid-induced osteoporosis (SIOP). However, the risk of endogenous SIOP cannot be explained by cortisol excess alone, and how other steroid metabolites affect bone status is unclear. METHODS: ACS was diagnosed as serum cortisol ≥1.8 µg/dL after the 1-mg dexamethasone suppression test (DST-cortisol). Using liquid chromatography tandem mass spectrometry, 21 plasma steroid metabolites were measured in 73 patients with ACS and 85 patients with non-functioning adrenal tumors (NFAT). Expression of steroidogenic enzymes and relevant steroid metabolites were analyzed in some of CPA tissues. FINDINGS: Discriminant and principal component analyses distinguished steroid profiles between the ACS and NFAT groups in premenopausal women. Premenopausal women with ACS exhibited higher levels of a mineralocorticoid metabolite, 11-deoxycorticosterone (11-DOC), and lower levels of androgen metabolites, dehydroepiandrosterone-sulfate, and androsterone-glucuronide. In premenopausal women with ACS, DST-cortisol negatively correlated with trabecular bone score (TBS). Additionally, 11-DOC negatively correlated with lumbar spine-bone mineral density, whereas androsterone-glucuronide positively correlated with TBS. The CPA tissues showed increased 11-DOC levels with increased expression of CYP21A2, essential for 11-DOC synthesis. Adrenal non-tumor tissues were atrophied with reduced expression of CYB5A, required for androgen synthesis. INTERPRETATION: This study demonstrates that unbalanced production of adrenal steroid metabolites, derived from both adrenal tumor and non-tumor tissues, contributes to the pathogenesis of endogenous SIOP in premenopausal women with ACS. FUNDING: JSPS KAKENHI, Secom Science and Technology Foundation, Takeda Science Foundation, Japan Foundation for Applied Enzymology, AMED-CREST, JSTA-STEP, JST-Moonshot, and Ono Medical Research Foundation.

Do multiple types of confirmatory tests improve performance in predicting subtypes of primary aldosteronism?

OBJECTIVE: The clinical practice guideline for primary aldosteronism (PA) places a high value on confirmatory tests to sparing patients with false-positive results in case detection from undergoing adrenal venous sampling (AVS). However, it is unclear whether multiple types of confirmatory tests are more useful than a single type. To evaluate whether the machine-learned combination of two confirmatory tests is more useful in predicting subtypes of PA than each test alone. DESIGN: A retrospective cross-sectional study in referral centres. PATIENTS: This study included 615 patients with PA randomly assigned to the training and test data sets. The participants underwent saline infusion test (SIT) and captopril challenge test (CCT) and were subtyped by AVS (unilateral, n = 99; bilateral, n = 516). MEASUREMENTS: The area under the curve (AUC) and clinical usefulness using decision curve analysis for the subtype prediction in the test data set. RESULTS: The AUCs for the combination of SIT and CCT, SIT alone and CCT alone were 0.850, 0.813 and 0.786, respectively, with no significant differences between them. The AUC for the baseline clinical characteristics alone was 0.872, whereas the AUCs for these combined with SIT, combined with CCT and combined with both SIT and CCT were 0.868, 0.854 and 0.855, respectively, with no significant improvement in AUC. The additional clinical usefulness of the second confirmatory test was unremarkable on decision curve analysis. CONCLUSIONS: Our data suggest that patients with positive case detection undergo one confirmatory test to determine the indication for AVS.

Identification of a drug-response gene in multiple myeloma through longitudinal single-cell transcriptome sequencing.

Despite recent therapeutic advances for multiple myeloma (MM), relapse is very common. Here, we conducted longitudinal single-cell transcriptome sequencing (scRNA-seq) of MM cells from a patient with relapsed MM, treated with multiple anti-myeloma drugs. We observed five subclusters of MM cells, which appeared and/or disappeared in response to the therapeutic pressure, and identified cluster 3 which emerged during lenalidomide treatment and disappeared after proteasome inhibitor (PI) treatment. Among the differentially expressed genes in cluster 3, we found a candidate drug-response gene; pellino E3 ubiquitin-protein ligase family member 2 (PELI2), which is responsible for PI-induced cell death in in vitro assay. Kaplan-Meier survival analysis of database revealed that higher expression of PELI2 is associated with a better prognosis. Our integrated strategy combining longitudinal scRNA-seq analysis, in vitro functional assay, and database analysis would facilitate the understanding of clonal dynamics of MM in response to anti-myeloma drugs and identification of drug-response genes.

Coexistence of bone and vascular disturbances in patients with endogenous glucocorticoid excess.

Purpose: Bone and vascular diseases are considered to share pathogenic mechanisms. Excess glucocorticoids, key regulators of cardiovascular and metabolic homeostasis, may promote both diseases simultaneously. We used endogenous Cushing's syndrome (CS) to investigate whether glucocorticoid excess underlies coexisting bone and vascular diseases. Methods: We included 194 patients with adrenal tumors (ATs): autonomous cortisol secretion (ACS, n = 97) and non-functional AT (n = 97). ACS was further classified into overt CS (n = 17) and subclinical CS (SCS, n = 80). Arterial stiffness was defined as a brachial-ankle pulse wave velocity (baPWV) ≥ 1800 cm/s. Results: Patients with ACS had higher coexistence rates of vertebral fracture and arterial stiffness (23 % vs. 2 %; p < 0.001) and vertebral fracture and abdominal aortic calcification (22 % vs. 1 %; p < 0.001) than those with non-functional AT. In patients with ACS, baPWV was negatively correlated with trabecular bone score (TBS, r = -0.33; p = 0.002), but not with bone mineral density, and vertebral fracture was associated with arterial stiffness in the logistic regression analysis. In the multivariate analysis of variance, the degree of cortisol excess (defined as CS, SCS, and non-functional AT) determined the correlation between TBS and baPWV (partial η2 = 0.07; p < 0.001). In the analysis of covariance, patients with coexisting vertebral fracture and arterial stiffness had higher levels of serum cortisol after the 1-mg dexamethasone suppression test than those without. Conclusion: In endogenous glucocorticoid excess, bone and vascular diseases frequently coexisted, and deteriorated bone quality, not bone loss, was related to arterial stiffness. Thus, glucocorticoid excess may perturb the bone-vascular axis.

Characterization of Aldosterone-producing Cell Cluster (APCC) at Single-cell Resolution.

CONTEXT: The adrenal cortex consists of zona glomerulosa (ZG), fasciculata (ZF), and reticularis. Aldosterone-producing cell clusters (APCCs) that strongly express aldosterone synthase (CYP11B2) are frequently found in adult adrenals and harbor somatic mutations that are also detected in aldosterone-producing adenomas (APAs). Primary aldosteronism is mainly caused by APAs or idiopathic hyperaldosteronism (IHA). We presume that APCCs are causing IHA and are precursors of APAs. However, the gene expression characteristics and especially the development of APCCs are not well understood. OBJECTIVE: This study aimed to analyze the transcriptome of APCCs at single-cell resolution and infer the developmental trajectory. METHODS: Single-cell RNA sequencing (scRNA-seq) of 2 adult adrenals was performed. RESULTS: Immunohistochemical analyses confirmed the 2 adrenals had APCCs. scRNA-seq data of 2928 adrenal cells were obtained and 1765 adrenocortical cells were identified based on unsupervised clustering and the marker gene expression. The adrenocortical cells were divided into 6 clusters, of which 3 clusters (923 cells) were composed of APCC/ZG cells. By further subclustering, the APCC/ZG cells were divided into 3 clusters (clusters C1, C2, and C3), we finally identified APCC cluster (C3) and ZG cluster (C1). Cluster C2 seemed to be ZG-to-ZF transitional cells. RNA velocity analysis inferred the developmental direction from cluster ZG-cluster-C1 to APCC-cluster-C3. The scRNA-seq additionally revealed that many CYP11B2-positive cells were positive for CYP11B1 and/or CYP17A1, which were essential for cortisol but not for aldosterone production. CONCLUSIONS: Our results revealed the gene expression characteristics of APCC at single-cell resolution and show that some ZG cells remodel to APCC.

Machine learning-based models for predicting clinical outcomes after surgery in unilateral primary aldosteronism.

Unilateral subtype of primary aldosteronism (PA) is a common surgically curable form of endocrine hypertension. However, more than half of the patients with PA who undergo unilateral adrenalectomy suffer from persistent hypertension, which may discourage those with PA from undergoing adrenalectomy even when appropriate. The aim of this retrospective cross-sectional study was to develop machine learning-based models for predicting postoperative hypertensive remission using preoperative predictors that are readily available in routine clinical practice. A total of 107 patients with PA who achieved complete biochemical success after adrenalectomy were included and randomly assigned to the training and test datasets. Predictive models of complete clinical success were developed using supervised machine learning algorithms. Of 107 patients, 40 achieved complete clinical success after adrenalectomy in both datasets. Six clinical features associated with complete clinical success (duration of hypertension, defined daily dose (DDD) of antihypertensive medication, plasma aldosterone concentration (PAC), sex, body mass index (BMI), and age) were selected based on predictive performance in the machine learning-based model. The predictive accuracy and area under the curve (AUC) for the developed model in the test dataset were 77.3% and 0.884 (95% confidence interval: 0.737-1.000), respectively. In an independent external cohort, the performance of the predictive model was found to be comparable with an accuracy of 80.4% and AUC of 0.867 (95% confidence interval: 0.763-0.971). The duration of hypertension, DDD of antihypertensive medication, PAC, and BMI were non-linearly related to the prediction of complete clinical success. The developed predictive model may be useful in assessing the benefit of unilateral adrenalectomy and in selecting surgical treatment and antihypertensive medication for patients with PA in clinical practice.

Whole Transcriptome Profiling of Adrenocortical Tumors Using Formalin-Fixed Paraffin-Embedded Samples.

Whole transcriptome profiling is a promising technique in adrenal studies; however, whole transcriptome profiling of adrenal disease using formalin-fixed paraffin-embedded (FFPE) samples has to be further explored. The aim of this study was to evaluate the utility of transcriptome data from FFPE samples of adrenocortical tumors. We performed whole transcriptome profiling of FFPE and fresh frozen samples of adrenocortical carcinoma (ACC, n = 3), aldosterone-producing adenoma (APA, n = 3), and cortisol-producing adenoma (CPA, n = 3), and examined the similarity between the transcriptome data. We further examined whether the transcriptome data of FFPE samples could be used to distinguish tumor types and detect marker genes. The number of read counts was smaller in FFPE samples than in fresh frozen samples (P < 0.01), while the number of genes detected was similar (P = 0.39). The gene expression profiles of FFPE and fresh frozen samples were highly correlated (r = 0.93, P < 0.01). Tumor types could be distinguished by consensus clustering and principal component analysis using transcriptome data from FFPE samples. In the differential expression analysis between ACC and APA-CPA, known marker genes of ACC (e.g., CCNB2, TOP2A, and MAD2L1) were detected in FFPE samples of ACC. In the differential expression analysis between APA and CPA, known marker genes of APA (e.g., CYP11B2, VSNL1, and KCNJ5) were detected in the APA of FFPE samples. The results suggest that FFPE samples may be a reliable alternative to fresh frozen samples for whole transcriptome profiling of adrenocortical tumors.

Impact of Cortisol on Reduction in Muscle Strength and Mass: A Mendelian Randomization Study.

CONTEXT: Prolonged exposure to pathological cortisol, as in Cushing's syndrome causes various age-related disorders, including sarcopenia. However, it is unclear whether mild cortisol excess, for example, accelerates sarcopenia due to aging or chronic stress. OBJECTIVE: We used Mendelian randomization (MR) analysis to assess whether cortisol was causally associated with muscle strength and mass. METHODS: Three single-nucleotide polymorphisms associated with plasma cortisol concentrations in the CORtisol NETwork consortium (n = 12 597) were used as instrumental variables. Summary statistics with traits of interest were obtained from relevant genome-wide association studies. For the primary analysis, we used the fixed-effects inverse-variance weighted analysis accounting for genetic correlations between variants. RESULTS: One SD increase in cortisol was associated with SD reduction in grip strength (estimate, -0.032; 95% CI -0.044 to -0.020; P = 3e-04), whole-body lean mass (estimate, -0.032; 95% CI, -0.046 to -0.017; P = 0.004), and appendicular lean mass (estimate, -0.031; 95% CI, -0.049 to -0.012; P = 0.001). The results were supported by the weighted-median analysis, with no evidence of pleiotropy in the MR-Egger analysis. The association of cortisol with grip strength and lean mass was observed in women but not in men. The association was attenuated after adjusting for fasting glucose in the multivariable MR analysis, which was the top mediator for the association in the MR Bayesian model averaging analysis. CONCLUSION: This MR study provides evidence for the association of cortisol with reduced muscle strength and mass, suggesting the impact of cortisol on the development of sarcopenia.

Protective Role of DHEAS in Age-related Changes in Bone Mass and Fracture Risk.

PURPOSE: Dehydroepiandrosterone sulfate (DHEAS) from the adrenal cortex substantially decreases with age, which may accelerate osteoporosis. However, the association of DHEAS with bone mineral density (BMD) and fracture is inconclusive. We conducted a Mendelian randomization (MR) analysis to investigate the role of DHEAS in age-related changes in BMD and fracture risk. METHODS: Single nucleotide polymorphisms (SNPs) associated with serum DHEAS concentrations were used as instrumental variables (4 SNPs for main analysis; 4 SNPs for men and 5 SNPs for women in sex-related analysis). Summary statistics were obtained from relevant genome-wide association studies. RESULTS: A log-transformed unit (µmol/L) increase in serum DHEAS concentrations was associated with an SD increase in estimated BMD at the heel (estimate, 0.120; 95% CI, 0.081-0.158; P = 9 × 10-10), and decreased fracture (odds ratio, 0.989; 95% CI, 0.981-0.996; P = 0.005), consistent with dual-energy X-ray absorptiometry-derived BMD at the femoral neck and lumbar spine. Their associations remained even after adjusting for height, body mass index, testosterone, estradiol, sex hormone-binding globulin, and insulin-like growth factor 1. The association of DHEAS with fracture remained after adjusting for falls, grip strength, and physical activity but was attenuated after adjusting for BMD. The MR-Bayesian model averaging analysis showed BMD was the top mediating factor for association of DHEAS with fracture. The association between DHEAS and BMD was observed in men but not in women. CONCLUSION: DHEAS was associated with increased BMD and decreased fracture. DHEAS may play a protective role in decreasing fracture risk, mainly by increasing bone mass.

Machine learning based models for prediction of subtype diagnosis of primary aldosteronism using blood test.

Primary aldosteronism (PA) is associated with an increased risk of cardiometabolic diseases, especially in unilateral subtype. Despite its high prevalence, the case detection rate of PA is limited, partly because of no clinical models available in general practice to identify patients highly suspicious of unilateral subtype of PA, who should be referred to specialized centers. The aim of this retrospective cross-sectional study was to develop a predictive model for subtype diagnosis of PA based on machine learning methods using clinical data available in general practice. Overall, 91 patients with unilateral and 138 patients with bilateral PA were randomly assigned to the training and test cohorts. Four supervised machine learning classifiers; logistic regression, support vector machines, random forests (RF), and gradient boosting decision trees, were used to develop predictive models from 21 clinical variables. The accuracy and the area under the receiver operating characteristic curve (AUC) for predicting of subtype diagnosis of PA in the test cohort were compared among the optimized classifiers. Of the four classifiers, the accuracy and AUC were highest in RF, with 95.7% and 0.990, respectively. Serum potassium, plasma aldosterone, and serum sodium levels were highlighted as important variables in this model. For feature-selected RF with the three variables, the accuracy and AUC were 89.1% and 0.950, respectively. With an independent external PA cohort, we confirmed a similar accuracy for feature-selected RF (accuracy: 85.1%). Machine learning models developed using blood test can help predict subtype diagnosis of PA in general practice.

Role of deteriorated bone quality in the development of osteoporosis in pheochromocytoma and paraganglioma.

CONTEXT: Pheochromocytoma (PHEO) and paraganglioma (PGL) (PHEO and PGL: PPGLs), catecholamine-producing tumors, represent an emerging cause of secondary osteoporosis. However, despite decreased bone mineral density (BMD), vertebral fracture (VF) is not associated with BMD in PPGLs. OBJECTIVE: To evaluate whether deteriorated bone quality is involved in the development of osteoporosis in PPGLs. PARTICIPANTS: Trabecular bone score (TBS), used to assess trabecular bone quality, was examined in 56 patients with PPGLs and 52 with non-functional adrenal tumors (AT). Radiograph of the spine was carried out in 35 patients with PPGLs, and TBS was analyzed in 18 patients with PPGLs at follow-up. MAIN OUTCOME MEASURE: TBS and BMD at the lumbar spine in patients with PPGLs with and without VF. RESULTS: PPGLs had a lower TBS (n = 56, 1.338 [1.294-1.420]) than non-functional AT (n = 52, 1.394 [1.342-1.444]; p = 0.033). Among those with PPGLs, patients with VF (n = 14, 1.314 [1.289-1.346]) had a lower TBS than those without VF (n = 21, 1.383 [1.324-1.426]; p = 0.046), despite no significant difference in BMD at the lumbar spine between the two groups (p = 0.501). An optimal cut-off level of TBS for diagnosing VF in PPGLs was 1.323, and its area under the curve was 0.702. The severity of catecholamine excess and maximal size of tumor were associated with decreased TBS in PPGLs patients (p = 0.016 and p = 0.020, respectively). Surgical resection of PPGLs improved TBS at follow-up, with 2.5% increase (p = 0.007). CONCLUSIONS: This study provides evidence for the importance of deteriorated bone quality rather than decreased bone mass in the development of VF in PPGLs.

Significance of Discordant Results Between Confirmatory Tests in Diagnosis of Primary Aldosteronism.

CONTEXT: Current clinical guidelines recommend confirmation of a positive result in at least one confirmatory test in the diagnosis of primary aldosteronism (PA). Clinical implication of multiple confirmatory tests has not been established, especially when patients show discordant results. OBJECTIVE: The aim of the present study was to explore the role of 2 confirmatory tests in subtype diagnosis of PA. DESIGN AND SETTING: A retrospective cross-sectional study was conducted at two referral centers. PARTICIPANTS AND METHODS: We identified 360 hypertensive patients who underwent both a captopril challenge test (CCT) and a saline infusion test (SIT) and exhibited at least one positive result. Among them, we studied 193 patients with PA whose data were available for subtype diagnosis based on adrenal vein sampling (AVS). MAIN OUTCOME MEASURE: The prevalence of bilateral subtype on AVS according to the results of the confirmatory tests was measured. RESULTS: Of patients studied, 127 were positive for both CCT and SIT (double-positive), whereas 66 were positive for either CCT or SIT (single-positive) (n = 34 and n = 32, respectively). Altogether, 135 were diagnosed with bilateral subtype on AVS. The single-positive patients had milder clinical features of PA than the double-positive patients. The prevalence of bilateral subtype on AVS was significantly higher in the single-positive patients than in the double-positive patients. (63/66 [95.5%] vs 72/127 [56.7%], P < .01). Several clinical parameters were different between CCT single-positive and SIT single-positive patients. CONCLUSION: Patients with discordant results between CCT and SIT have a high probability of bilateral subtype of PA on AVS.