Adrenal nodularity and somatic mutations in primary aldosteronism: one node is the culprit?

CONTEXT: Somatic mutations in genes that influence cell entry of calcium have been identified in aldosterone-producing adenomas (APAs) of adrenal cortex in primary aldosteronism (PA). Many adrenal glands removed for suspicion of APA do not contain a single adenoma but nodular hyperplasia. OBJECTIVE: The objective of the study was to assess multinodularity and phenotypic and genotypic characteristics of adrenals removed because of the suspicion of APAs. DESIGN AND METHODS: We assessed the adrenals of 53 PA patients for histopathological characteristics and immunohistochemistry for aldosterone (P450C18) and cortisol (P450C11) synthesis and for KCNJ5, ATP1A1, ATP2B3, and CACNA1D mutations in microdissected nodi. RESULTS: Glands contained a solitary adenoma in 43% and nodular hyperplasia in 53% of cases. Most adrenal glands contained only one nodule positive for P450C18 expression, with all other nodules negative. KCNJ5 mutations were present in 22 of 53 adrenals (13 adenoma and nine multinodular adrenals). An ATP1A1 and a CACNA1D mutation were found in one multinodular gland each and an ATP2B3 mutation in five APA-containing glands. Mutations were always located in the P450C18-positive nodule. In one gland two nodules containing two different KCNJ5 mutations were present. Zona fasciculata-like cells were more typical for KCNJ5 mutation-containing nodules and zona glomerulosa-like cells for the other three genes. CONCLUSIONS: Somatic mutations in KCNJ5, ATP1A1, or CACNA1D genes are not limited to APAs but are also found in the more frequent multinodular adrenals. In multinodular glands, only one nodule harbors a mutation. This suggests that the occurrence of a mutation and nodule formation are independent processes. The implications for clinical management remain to be determined.

Menstrual blood closely resembles the uterine immune micro-environment and is clearly distinct from peripheral blood.

STUDY QUESTION: Is menstrual blood a suitable source of endometrial derived lymphocytes? SUMMARY ANSWER: Mononuclear cells isolated from menstrual samples (menstrual blood mononuclear cells (MMC)) are clearly distinct from peripheral blood mononuclear cells (PBMC) and show a strong resemblance with biopsy-derived endometrial mononuclear cells. WHAT IS KNOWN ALREADY: A critical event in the onset of pregnancy is the implantation of the embryo in the uterine wall. The immune cell composition in the endometrium at the time of implantation is considered pivotal for success. Despite advancing knowledge on the composition of the immune cell population in the uterus, the role of endometrial immune cells in reproductive disorders is still not fully resolved, mainly due to the fact that this type of research requires invasive techniques. Here, we collected menstrual fluid and validated this unique non-invasive technique to obtain and study the endometrium-derived immune cells which would be present around the time of implantation. STUDY DESIGN, SIZE, DURATION: Five healthy non-pregnant females with regular menstruation cycles and not using oral contraceptives collected their menstrual blood using a menstrual cup in five consecutive cycles. Sampling took place over the first 3 days of menses, with 12 h intervals. Peripheral blood samples, taken before and after each menstruation, were obtained for comparative analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: MMC and PBMC samples were characterized for the different lymphocyte subsets by flow cytometry, with emphasis on NK cells and T cells. Next, the functional capacity of the MMC-derived NK cells was determined by measuring intracellular production of IFN-γ, granzyme B and perforin after culture in the presence of IL-2 and IL-15. MAIN RESULTS AND THE ROLE OF CHANCE: In support of their endometrial origin, MMC samples contained the typical composition of mononuclear cells expected of endometrial tissue, were phenotypically similar to the reported phenotype for biopsy-derived endometrial cells, and were distinct from PBMC. Increased percentages of NK cells and decreased percentages of T cells were found in MMC when compared with PBMC from the same female. The MMC-derived NK cells were pre-dominantly CD56(bright)/CD16(-), in contrast to the primarily CD56(dim)/CD16(+) peripheral blood NK cells. MMC-derived NK cells expressed CD103, indicating their mucosal origin. In addition, the pattern of natural cytotoxicity receptor (NCR) expression in MMC-derived NK cells was comparable with that in endometrial biopsy-derived NK cells. Compared with PBMC, the NKp30 expression was decreased, while the percentage of NKp44 positive cells was increased in MMC samples. CXCR3 and CXCR4 were hardly expressed by MMC-derived NK cells, indicating that these cells are not of PBMC origin. NK cells from MMC samples were functional as shown by their capacity to produce IFN-γ, granzyme B and perforin, upon stimulation with IL-2 and IL-15. MMC-derived T cells revealed an increased expression of CD103, CD69 and CXCR4 compared with PBMC-derived T cells. Importantly, MMC collection using a menstrual cup proved highly reliable and reproducible between women and between cycles. LIMITATIONS, REASONS FOR CAUTION: Based on the parameters we studied, MMC appear similar to biopsy-derived endometrial mononuclear cells. However, sampling is not done at the exact same time in the menstrual cycle, and thus we cannot exclude some, as yet undetected, differences. Also, it should be considered that for some women, the use of the menstrual cup may be unpleasant. WIDER IMPLICATIONS OF THE FINDINGS: Menstrual blood may be a source of endometrial cells and may create new opportunities to study uterine immunological cells in fertility issues. STUDY FUNDING/COMPETING INTEREST(S): No external funding was obtained for the present study. None of the authors have any conflict of interest to declare. TRIAL REGISTRATION NUMBER: NA.