Modeling preeclampsia remains difficult due to the nature of the disease and the unique characteristics of the human placenta. Members of the Hominidae superfamily have a villous hemochorial placenta that is different in structure from those of other therian mammals, including the mouse hemochorial placenta, making this common animal model less ideal for studying this disease. Human placental tissues delivered from pregnancies complicated by preeclampsia are excellent for assessing the damage the disease causes but cannot answer how or when the disease begins. Symptoms of preeclampsia manifest halfway through pregnancy or later, making it currently impossible to identify preeclampsia in human tissues obtained from an early stage of pregnancy. Many animal and cell culture models recapitulate various aspects of preeclampsia, though none can on its own completely capture the complexity of human preeclampsia. It is particularly difficult to uncover the cause of the disease using models in which the disease is induced in the lab. However, the many ways by which preeclampsia-like features can be induced in a variety of laboratory animals are consistent with the idea that preeclampsia is a two-stage disease, in which a variety of initial insults may lead to placental ischemia, and ultimately systemic symptoms. The recent development of stem cell-based models, organoids, and various coculture systems have brought in vitro systems with human cells ever closer to recapitulating in vivo events that lead to placental ischemia.
Jessica Milano-Foster and Laura C Schulz
K David, V Dubois, A Verhulst, V Sommers, D Schollaert, L Deboel, K Moermans, G Carmeliet, P D’Haese, D Vanderschueren, F Claessens, P Evenepoel, and B Decallonne
Patients suffering from chronic kidney disease (CKD) often experience bone loss and arterial calcifications. It is unclear if hypogonadism contributes to the development of these complications and whether androgen therapy might prevent them. Male adult rats were randomized into four groups. The first group received standard chow (control), while three other groups were fed a 0.25% adenine/low vitamin K diet (CKD). Two CKD groups were treated with testosterone or dihydrotestosterone (DHT), whereas the control group and one CKD group received vehicle (VEH). CKD animals had 10-fold higher serum creatinine and more than 15-fold higher parathyroid hormone levels compared to controls. Serum testosterone levels were more than two-fold lower in the CKDVEH group compared to control + VEH and CKD + testosterone groups. Seminal vesicle weight was reduced by 50% in CKDVEH animals and restored by testosterone and DHT. CKD animals showed a low bone mass phenotype with decreased trabecular bone volume fraction and increased cortical porosity, which was not rescued by androgen treatment. Aortic calcification was much more prominent in CKD animals and not unequivocally prevented by androgens. Messenger RNA expression of the androgen receptor-responsive genes Acta1 and Col1a1 was reduced by CKD and stimulated by androgen treatment in levator ani muscle but not in the bone or aortic tissue. We conclude that adenine-induced CKD results in the development of hypogonadism in male rats. Androgen therapy is effective in restoring serum testosterone levels and androgen-sensitive organ weights but does not prevent bone loss or arterial calcifications, at least not in the presence of severe hyperparathyroidism.
Emma J Hamilton and Stephen M Twigg
Diabetes-related foot disease (DFD), defined as ulceration, infection or destruction of tissues of the foot in a person with current or previously diagnosed diabetes mellitus, is associated with a heavy burden for both patients and the healthcare system with high morbidity, mortality and costs. Improved outcomes for people with DFD are achieved with an interdisciplinary approach and adherence to best practice clinical guidelines; however, in the Australian context, the vastness of the country presents unique challenges in achieving optimal outcomes for all people with DFD, with variation in service delivery, availability and accessibility between metropolitan, rural and remote areas. Aboriginal and Torres Strait Islander Australians and people with diabetes living in rural and remote areas experience higher rates of lower-extremity amputation, and further efforts and resources are required to improve outcomes for these high-risk groups. In recent years, there have been advances in knowledge, including the understanding of the pathogenesis of diabetes-related peripheral neuropathy, genetic polymorphisms and mechanisms of disease associated with acute Charcot neuroarthropathy, biomarkers and potential mediators of diabetes-related foot ulcer (DFU) healing, the microbiology and microbiome profile of DFUs, pressure assessment and management as well as an expanded understanding of DFU sequelae and comorbidities. In this review, we describe new insights into pathophysiology, sequelae and comorbidities of DFD with a focus on basic and translational aspects and contributions to the field from Australian and New Zealand DFD researchers.
T'ng Choong Kwok and Roland H Stimson
The identification of brown adipose tissue (BAT) as a thermogenic organ in human adults approximately 20 years ago raised the exciting possibility of activating this tissue as a new treatment for obesity and cardiometabolic disease. 18Fluoro-2-deoxyglucose (18F-FDG) combined positron emission tomography and computed tomography (PET/CT) scanning is the most commonly used imaging modality to detect and quantify human BAT activity in vivo. This technique exploits the substantial glucose uptake by BAT during thermogenesis as a marker for BAT metabolism. 18F-FDG PET has provided substantial insights into human BAT physiology, including its regulatory pathways and the effect of obesity and cardiometabolic disease on BAT function. The use of alternative PET tracers and the development of novel techniques such as magnetic resonance imaging, supraclavicular skin temperature measurements, contrast enhanced ultrasound, near infrared spectroscopy and microdialysis have all added complementary information to improve our understanding of human BAT. However, many questions surrounding BAT physiology remains unanswered, highlighting the need for further research and novel approaches to investigate this tissue. This review critically discusses current techniques to assess human BAT function in vivo, the insights gained from these modalities and their limitations. We also discuss other promising techniques in development that will help dissect the pathways regulating human thermogenesis and determine the therapeutic potential of BAT activation.
Sunita M C De Sousa, Nèle F Lenders, Lydia S Lamb, Warrick J Inder, and Ann McCormack
‘Pituitary tumours’ is an umbrella term for various tumours originating from different regions of the hypothalamic–pituitary system. The vast majority of pituitary tumours are pituitary adenomas, also recently referred to as pituitary neuroendocrine tumours. The prevalence of clinically relevant pituitary adenomas is approximately 1 in 1000; other pituitary tumours such as craniopharyngioma and pituicytoma are comparatively very rare. This review addresses the molecular and genetic aspects of pituitary adenomas. We first discuss the germline genetic variants underlying familial pituitary tumours, which account for approximately 5% of all pituitary adenoma cases. This includes variants in established pituitary adenoma/hyperplasia predisposition genes (MEN1, PRKAR1A, AIP, CDKN1B, GPR101, SDHA, SDHB, SDHC, SDHD, SDHAF2) as well as emerging genetic associations. In addition, we discuss McCune–Albright syndrome which lies between the germline and somatic pituitary tumour genes as the causative GNAS mutations are postzygotic rather than being inherited, and the condition is associated with multiglandular features due to the involvement of different cell lines rather than being limited to the pituitary. By contrast, somatic GNAS mutations contribute to sporadic acromegaly. USP8 is the only other gene where somatic driver mutations have been established in sporadic pituitary tumorigenesis. However, there are now known to be a variety of other somatic genetic and molecular changes underpinning sporadic pituitary adenomas which we review here, namely: copy number variation, molecular changes in signalling and hypoxia pathways, epithelial–mesenchymal transition, DNA repair, senescence, the immune microenvironment and epigenetics.
Chau Thien Tay, Rhonda Garrad, Aya Mousa, Mahnaz Bahri, Anju Joham, and Helena Teede
Polycystic ovary syndrome (PCOS) affects 8–13% of reproductive-aged women, impacts biopsychosocial factors and creates a significant health-related economic burden across the reproductive, metabolic and psychological spectrum of complications. Despite being a heterogenous condition, recent genomic studies indicate that PCOS, regardless of diagnostic criteria and clinical features, shares similar underlying biologic mechanisms. However, recent advances have shown that clinical reproductive and diagnostic features are poorly correlated to genotypes and do not represent true phenotypes. Until we have a better understanding of genetic and epigenetic influences on PCOS and long-term outcomes, targeted treatment is limited.
In the interim, a unified approach to integrate evidence, optimise management and guide future research in PCOS is necessary. This has motivated an international collaboration to develop an International Evidence-Based PCOS Guideline to improve health outcomes in women with PCOS. Dissemination and translation of the guideline into health policy and clinical practice are crucial steps to close the knowledge–-practice gap, guide future research and enhance positive impact on the health of women with PCOS.
Here, we review the (i) understanding of aetiology and genetics of PCOS; (ii) development and translation efforts of the 2018 International Evidence-based PCOS Guideline; (iii) current progress and plans for the guideline update, including the involvement of an early career researcher network to assist with evidence synthesis and (iv) the opportunity to target and guide future research for PCOS.
Virginia L Pszczolkowski, Meghan K Connelly, Adam D Beard, Amara D Benn, Jimena Laporta, Laura L Hernandez, and Sebastian I Arriola Apelo
Energy partitioning in lactating cows affects milk production, feed efficiency, and body reserves, with the latter having health implications for the transition into the following lactation. One molecule likely involved in the regulation of energy partitioning is serotonin. The objective of this experiment was to explore how increasing circulating serotonin, by intravenous infusion of the serotonin precursor 5-hydroxytryptophan (5-HTP), affects metabolic responses to a glucose challenge in midlactation cows as a means to manipulate energy partitioning. We intravenously infused Holstein cows with 5-HTP (1 mg/kg bodyweight dissolved in saline, n = 11) or saline alone as control (n = 9) over 1 h/day for 3 days. Cows were fasted overnight on day 2. On day 3, fasted cows were given an intravenous bolus of glucose (0.092 g/kg bodyweight). Blood samples were collected for the following 120 min for metabolic and hormonal analysis. Infusion of 5-HTP elevated circulating concentrations of serotonin and free fatty acids, reduced the concentration of insulin and amino acids, and did not affect the concentration of glucose and glucagon before the glucose challenge. Surrogate insulin sensitivity indices indicated improved insulin sensitivity in 5-HTP cows, but due to the unique metabolism of lactating ruminants, these index changes may instead reflect effects in insulin-independent glucose disposal, like milk synthesis. Challenging 5-HTP-treated cows with a glucose bolus reduced the insulin spike and blunted the decrease in free fatty acids, compared to saline cows, without changing glucose dynamics. Overall, these results suggest that serotonin stimulates insulin-independent glucose disposal, requiring less insulin to maintain normoglycemia.
Hikari Hirakida, Taiga Okumura, Ryosuke Fujita, Yoshiki Kuse, Takahiro Mizoguchi, Satoshi Inagaki, Shinsuke Nakamura, Masamitsu Shimazawa, and Hideaki Hara
VGF nerve growth factor inducible (VGF) is a secreted polypeptide involved in metabolic regulation. VGF-derived peptides have been reported to regulate insulin secretion in the plasma of patients with type 2 diabetes and model mice. However, the protective effects of VGF on pancreatic β-cells in diabetic model are not well understood. In this study, we aimed to elucidate the β-cell protective effect of VGF on a streptozotocin (STZ)-induced diabetic model using VGF-overexpressing (OE) mice and also examined the therapeutic effect by a small molecule, SUN N8075 which is an inducer of VGF. VGF-OE mice improved blood glucose levels and maintained β-cell mass compared to wild-type (WT) mice on STZ-induced diabetic model. In addition, VGF-OE mice showed better glucose tolerance than WT mice. In culture, AQEE-30, a VGF-derived peptide, suppressed STZ-induced β-cell death in vitro and attenuated the decrease in the phosphorylation of Akt and GSK3β. Furthermore, SUN N8075 suppressed the blood glucose levels and increased VGF expression in the pancreatic islet. SUN N8075 also protected STZ-induced β-cell death in vitro. These findings indicate that VGF plays a hypoglycemic role in response to blood glucose levels in diabetes and protects β-cells from STZ-induced cell death. Therefore, VGF and its inducer have the therapeutic potential by preserving β-cells in diabetes.
James Cantley, Vincent Poitout, and Rebecca L Hull-Meichle
The year 2023 marks 100 years since publication of the first report of a hyperglycemic factor in pancreatic extracts which CP Kimball and John R Murlin named glucagon (from GLUCose AGONist). Glucagon has a range of profound effects on metabolism including, but not limited to, stimulation of hepatic glucose production. Dysregulation of glucagon secretion is a key feature of both major forms of diabetes, leading to the concept that diabetes is a bihormonal disorder. Still, work to fully understand the production and biological effects of glucagon has proceeded at a slower pace compared to that of insulin. A recent resurgence of interest in the islet α cell, the predominant site of glucagon production, has been facilitated in part by technological innovations. This work has led to significant developments in the field, from defining how alpha cells develop, how glucagon is secretion from pancreatic alpha cells is regulated, through to determining the role of glucagon in metabolic homeostasis and the progression of both major forms of diabetes. In addition, glucagon is considered to be a promising target for diabetes therapy, with many new potential applications arising from research in this field. This collection of reviews, led by Guest Editors James Cantley, Rebecca Hull-Meichle and Vincent Poitout, is intended to capture the field’s current understanding of glucagon and alpha cell biology, as well stimulate additional interest and research on this important hormone.
Renea A Taylor, Mitchell G Lawrence, and Gail P Risbridger
There is longstanding interest in the role of androgens in the aetiology of prostate cancer, one of the most common malignancies worldwide. In this review, we reflect on the ways that knowledge of prostate development and hormone action have catalysed advances in the management of patients with prostate cancer. The use of hormone therapies to treat prostate cancer has changed significantly over time, including the emergence of androgen receptor signalling inhibitors (ARSI). These compounds have improved outcomes for patients with castration-resistant prostate cancer, which was once considered ‘androgen-independent’ but is clearly still driven by androgen receptor signalling in many cases. There is also a need for new therapies to manage neuroendocrine prostate cancer, which is not responsive to hormonal agents. One of the major gaps is understanding how treatment-induced neuroendocrine prostate cancer emerges and whether it can be re-sensitised to treatment. Patient-derived models, including patient-derived xenografts (PDXs), will be instrumental in facilitating future discoveries in these areas. Developments in the use of PDXs have been fostered by lessons from the field of endocrinology, such as the role of stroma and hormones in normal and developmental tissues. Thus, there is ongoing reciprocity between the discoveries in endocrinology and advances in prostate cancer research and treatment.
