The adaptive growth of the uterus is a critical event that involves changes in cellular phenotypes throughout pregnancy. In early pregnancy, uterine growth is due to hyperplasia of uterine smooth muscle cells (SMCs) within the myometrium; however, the major component of myometrial growth occurs after mid-gestation. This study sought to test the hypothesis that increase in myometrial growth seen during late pregnancy is due to SMC hypertrophy caused by mechanical stretch of uterine tissue by a growing fetus(es) by providing direct measurements of individual SMC size. We employed a stereological approach to calculate the average cell volumes of uterine myocytes through diameter measurements using the Stereoinvestigator statistical software. Uterine tissues were collected from nonpregnant Wistar rats, as well as from gravid and nongravid horns of unilaterally pregnant animals on gestational days (d) 8 (early gestation), 14 (mid-gestation), 19 (late gestation), 22 (term), and 4 days post partum. Anti-caveolin-1 immunostaining was used to clearly delineate SMC boundaries. The stereological analysis revealed that the dramatic increase in myometrial growth seen during late gestation (d19-22) is due to a threefold increase in the size of uterine myocytes. A significant increase in SMC volumes was detected in the gravid uterine horn as compared with the corresponding empty horn of unilateral term pregnant animals (day 22, mean cell volume 1114 vs 361 mm 3 , P!0.05), indicating the effect of uterine occupancy. The restriction of the hypertrophy to cells within the gravid horn suggests that it may be a response to the biological mechanical stretch of uterine walls by the growing fetus(es) and placenta(s).

Objective Adrenocortical carcinomas (ACCs) are invasive tumours arising in the adrenal cortex, and steroidogenic tumours are associated with worse prognostic outcomes. Loss-of-function mutations in sphingosine-1-phosphate lyase (SGPL1) cause primary adrenal insufficiency and as a key degradative enzyme in the sphingolipid pathway, SGPL1 also influences the balance of pro-proliferative and pro-apoptotic sphingolipids. We, therefore, hypothesized increased SGPL1 may be linked to increased disease severity in ACC. Design Analyse SGPL1 expression impact on patient survival and adrenal cancer cell phenotype. We analysed two ACC cohorts with survival and corresponding transcriptomic data, focusing on SGPL1 and sphingolipid pathway genes. In vitro, we generated SGPL1-knockout and overexpressing H295R adrenocortical cells to investigate the role of SGPL1 in cell signalling in ACCs. Results We found increased expression of several sphingolipid pathway receptors and enzymes, most notably SGPL1 correlated with reduced patient survival in both cohorts. Overexpression of SGPL1 in the H295R cell line increased proliferation and migration while reducing apoptosis, while SGPL1 knockout had the opposite effect. RNA-seq revealed a global increase in the expression of genes in the electron transport chain in overexpressing cells, correlating with increased aerobic respiration and glycolysis. Furthermore, the opposite phenotype was seen in cells lacking SGPL1. We subsequently found the increased proliferation is linked to metabolic substrate availability and increased capacity to use different fuel sources, but particularly glucose, in overexpressing cells. Conclusions We, therefore, propose that SGPL1-overexpressing ACC tumours reduce patient survival by increasing fuel usage for anabolism and energy production to facilitate growth and invasion.

Sphingosine-1-phosphate lyase (SGPL1) insufficiency syndrome (SPLIS) is an autosomal recessive multi-system disorder, which mainly incorporates steroid-resistant nephrotic syndrome and primary adrenal insufficiency. Further variable endocrine manifestations are described. We aimed to comprehensively annotate the endocrinopathies associated with pathogenic SGPL1 variants and assess for genotype-phenotype correlations by retrospectively reviewing reports of endocrine disease within our patient cohort and all published cases in the wider literature up to January 2022. Glucocorticoid insufficiency in early childhood is the most common endocrine manifestation affecting 64% of the 50 patients reported with SPLIS, a third of these individuals have additional mineralocorticoid deficiency. Whilst most individuals also have nephrotic syndrome, SGPL1 variants also account for isolated adrenal insufficiency at presentation. Primary gonadal insufficiency, manifesting with microphallus and cryptorchidism, is reported in less than one third of affected boys, all with concomitant adrenal disease. Mild primary hypothyroidism affects approximately a third of patients. There is paucity of data on the impact of SGPL1 deficiency on growth, and pubertal development, limited by the early and high mortality rate (approximately 50%). There is no clear genotype-phenotype correlation overall in the syndrome, with variable disease penetrance within individual kindreds. However, with regards to endocrine phenotype the most prevalent disease variant p.R222Q (affecting 22%) is most consistently associated with isolated glucocorticoid deficiency. We conclude that SPLIS is associated with significant multiple endocrine disorders. Whilst endocrinopathy in the syndrome generally presents in infancy, late onset disease also occurs. Screening for these is therefore warranted both at diagnosis and through follow-up.

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Sphingosine 1-phosphate lyase insufficiency syndrome (SPLIS) was described in 2017 as a novel condition affecting sphingolipid metabolism. There is a multisystemic phenotype including nephrotic syndrome and primary adrenal insufficiency (PAI) and to a lesser extent ichthyosis, neurological disease and lymphopenia. A proportion of patients also presented with hypothyroidism and hypogonadism. To interrogate the endocrine aspect of the syndrome we reviewed clinical data within our patient cohort with SPLIS and those within the wider literature. To date there have been 45 patients identified with SPLIS with significant associated mortality (n=23/45, 51%; 4 of these in utero). There is no clear genotype-phenotype correlation. Whilst nephrotic syndrome is most prevalent (n=34/45; 76%), a significant proportion of patients (n=27/45, 60%) also presented with glucocorticoid deficiency, some with additional mineralocorticoid deficiency (n=7/27). Five further patients were noted to have adrenal calcifications though biochemistry was not undertaken. Most patients presented with PAI in the first 2 years of life (n=21/27), with the oldest presentation being 11 years of age. Adrenal calcifications are a common finding in those who had documented imaging (n=13/15, 87%). Primary gonadal failure has been reported in 8 male cases, all with concomitant PAI. Presenting features included microphallus (n=7/8) and cryptorchidism (n=8/8), indicating reduced in utero androgen exposure. All who had biochemical evaluation demonstrated raised basal LH and FSH/ exaggerated response to LHRH stimulation, a lack of testosterone response to HCG stimulation and low antimullerian hormone (AMH) levels. To date there are no reports of pubertal delay in female patients, and those of age within our cohort have normal ovarian reserve as evidenced by AMH levels (n=2). Primary hypothyroidism, with mildly raised TSH and low Free T4 is reported in 12 patients. Most did not have goiters and had concomitant PAI and nephrotic syndrome (n=11/12). SPLIS is unique amongst sphingolipid disorders in presenting with significant endocrinopathy. This may be the consequence of the particular sphingolipid signature of the disease and the pathogenic mechanisms need to be explored further. It is clear that endocrine dysfunction needs to be considered at diagnosis and surveillance undertaken to detect evolving disease which could have a significant impact on morbidity and mortality.

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