Incidence and Impact of Preoperative Hiatal Hernia in Patients with Esophageal Carcinoma Undergoing Curative Surgical Resection.

BACKGROUND: Hiatal hernia (HH) and gastroesophageal reflux disease (GERD) are risk factors for esophageal adenocarcinoma. High positive margin rates and poor survival were described among HH patients undergoing esophagectomy. We sought to describe incidence and impact of HH on outcomes following esophagectomy. METHODS: Patients who underwent esophagectomy 2012-2019 for esophago-junctional carcinoma were included. CT studies were blindly reviewed by two radiologists. A third radiologist reviewed cases of disagreement. Hernias ≥ 3 cm were included in the HH group. RESULTS: Overall, 66 patients (33%) had HH ≥ 3 cm. The no hernia group included 12 patients (6%) with < 3 cm HH and 106 (53%) without HH. Preoperative variables were comparable among groups. Location of anastomosis was similar among cohorts and predominantly cervical (n = 97, 82.2% vs 61, 92.4%, p = 0.113). Postoperatively, HH patients had higher incidence of atrial dysrhythmia (n = 11, 16.7% vs n = 6, 5.1% p = 0.015). Rates of R0 resections were similar (n = 62, 93.9%, vs n = 113, 95.8%, p = 0.724). HH patients had higher rates of signet ring cell histology (n = 14, 21.2% vs n = 9, 7.6% p = 0.025); this was confirmed on subgroup analysis including only adenocarcinoma patients (n = 14, 28.6% vs n = 8, 12.3%, p = 0.042). On Cox regression analysis, HH was not associated with disease-free or overall survival (HR 1.308, p = 0.274 and HR .905, p = 0.722). CONCLUSIONS: Patients with preoperative HH had higher rates of postoperative atrial dysrhythmias and signet ring cell features on pathology. In a population with predominant cervical anastomosis, positive margin rates were low and survival comparable among cohorts.

Similar fertilization rates and preimplantation embryo development among testosterone-treated transgender men and cisgender women.

RESEARCH QUESTION: What are the effects of testosterone treatment on oocyte fertilization and preimplantation embryo development among transgender men who have undergone fertility preservation? DESIGN: A retrospective study was undertaken in a university-affiliated tertiary hospital between April 2016 and November 2021. Embryos were divided into three groups by source: 210 embryos from 7 testosterone-exposed transgender men, 135 from 10 cisgender women who cryopreserved embryos, and 276 from 24 cisgender women who underwent fertility treatment. Statistical analyses compared assisted reproductive technology outcomes between the group of transgender men and both groups of cisgender women. Morphokinetic and morphological parameters were compared between the embryos derived from these three groups. RESULTS: The transgender men (30.2 ± 3.5 years of age) were significantly younger than the cisgender women who cryopreserved embryos (35.1 ± 1.8 years; P = 0.005) and the cisgender women who underwent fertility treatment (33.8 ± 3.2 years; P = 0.017). After adjusting for participant age, the fertilization rate was comparable between the transgender men and both groups of cisgender women (P = 0.391 and 0.659). There were no significant differences between the transgender men and the cisgender women who preserved fertility in terms of number of cryopreserved embryos (7.2 ± 5.1 and 3.5 ± 2.6; P = 0.473) or the distribution of embryo age at cryopreservation (P = 0.576). All morphokinetic parameters evaluated by time-lapse imaging, as well as the morphological characteristics, were comparable for the embryos in all three groups. CONCLUSIONS: Testosterone exposure among transgender men has no adverse impact upon fertilization rates or preimplantation embryo development and quality.

High-throughput analysis of CLIC5 interactants using a thermal-stability assay.

BACKGROUND: The chloride intracellular channel (CLIC) protein family consists of six members in humans. CLICs are unique due to their metamorphic property, displaying both soluble and integral membrane forms. The transmembrane conformation was shown to give rise to ion-channel activity in vitro. In recent years, CLICs were implicated in a growing number of physiological processes in various organ systems and associated with distinct disease states. Indeed, the founding member of the family, CLIC5, was shown to be involved in hereditary deafness and various types of cancer. Nevertheless, the natural interactants and endogenous ligands of CLIC5 have not been discovered yet. Objectives: To find ligands that affect the biochemical properties and activity of CLIC5. We hypothesized that such ligands could serve as important tools for resolving the long-sought cellular roles of CLICs and may offer novel therapeutic avenues for CLIC-associated conditions. Methods: Using molecular biology and biochemical methods, CLIC5 was overexpressed in Escherichia coli and purified. Next, a high-throughput differential scanning fluorimetry thermal shift assay (TSA) was established and the interaction of approximately 500 natural compounds was examined. Results: The TSA-based screening approach developed here allows to evaluate the effect of approximately 100 compounds in parallel within approximately 1 hour. Our proof-of-concept screening yielded 11 potential hits, significantly affecting the thermal stability of CLIC5. By examining the dose-dependence of this effect, we identified a specific interaction of CLIC5 with curcumin. Conclusions: Using the approach we developed, large libraries of small molecules can be screened efficiently to identify novel CLIC5 interactants. Considering the participation of CLIC5 in various physiological and pathological processes, uncovering ligands that inhibit or activate CLIC5 may provide tools to modulate its activity and possibly to ameliorate CLIC5-related pathologies in the future.

Nutrient Sensor mTORC1 Regulates Insulin Secretion by Modulating ß-Cell Autophagy.

The dynamic regulation of autophagy in ß-cells by cycles of fasting-feeding and its effects on insulin secretion are unknown. In ß-cells, mechanistic target of rapamycin complex 1 (mTORC1) is inhibited while fasting and is rapidly stimulated during refeeding by a single amino acid, leucine, and glucose. Stimulation of mTORC1 by nutrients inhibited the autophagy initiator ULK1 and the transcription factor TFEB, thereby preventing autophagy when ß-cells were continuously exposed to nutrients. Inhibition of mTORC1 by Raptor knockout mimicked the effects of fasting and stimulated autophagy while inhibiting insulin secretion, whereas moderate inhibition of autophagy under these conditions rescued insulin secretion. These results show that mTORC1 regulates insulin secretion through modulation of autophagy under different nutritional situations. In the fasting state, autophagy is regulated in an mTORC1-dependent manner, and its stimulation is required to keep insulin levels low, thereby preventing hypoglycemia. Reciprocally, stimulation of mTORC1 by elevated leucine and glucose, which is common in obesity, may promote hyperinsulinemia by inhibiting autophagy.

A Combined Drug Treatment That Reduces Mitochondrial Iron and Reactive Oxygen Levels Recovers Insulin Secretion in NAF-1-Deficient Pancreatic Cells.

Decreased insulin secretion, associated with pancreatic ß-cell failure, plays a critical role in many human diseases including diabetes, obesity, and cancer. While numerous studies linked ß-cell failure with enhanced levels of reactive oxygen species (ROS), the development of diabetes associated with hereditary conditions that result in iron overload, e.g., hemochromatosis, Friedreich's ataxia, and Wolfram syndrome type 2 (WFS-T2; a mutation in CISD2, encoding the [2Fe-2S] protein NAF-1), underscores an additional link between iron metabolism and ß-cell failure. Here, using NAF-1-repressed INS-1E pancreatic cells, we observed that NAF-1 repression inhibited insulin secretion, as well as impaired mitochondrial and ER structure and function. Importantly, we found that a combined treatment with the cell permeant iron chelator deferiprone and the glutathione precursor N-acetyl cysteine promoted the structural repair of mitochondria and ER, decreased mitochondrial labile iron and ROS levels, and restored glucose-stimulated insulin secretion. Additionally, treatment with the ferroptosis inhibitor ferrostatin-1 decreased cellular ROS formation and improved cellular growth of NAF-1 repressed pancreatic cells. Our findings reveal that suppressed expression of NAF-1 is associated with the development of ferroptosis-like features in pancreatic cells, and that reducing the levels of mitochondrial iron and ROS levels could be used as a therapeutic avenue for WFS-T2 patients.

Proximal Tubule mTORC1 Is a Central Player in the Pathophysiology of Diabetic Nephropathy and Its Correction by SGLT2 Inhibitors.

Diabetic kidney disease (DKD) increases the risk for mortality and is the leading cause of end-stage renal disease. Treatment with sodium-glucose cotransporter 2 inhibitors (SGLT2i) attenuates the progression of DKD, especially in patients with advanced kidney disease. Herein, we show that in diabetes, mTORC1 activity is increased in renal proximal tubule cells (RPTCs) along with enhanced tubule-interstitial fibrosis; this is prevented by SGLT2i. Constitutive activation of mTORC1 in RPTCs induces renal fibrosis and failure and abolishes the renal-protective effects of SGLT2i in diabetes. On the contrary, partial inhibition of mTORC1 in RPTCs prevents fibrosis and the decline in renal function. Stimulation of mTORC1 in RPTCs turns on a pro-fibrotic program in the renal cortex, whereas its inhibition in diabetes reverses the alterations in gene expression. We suggest that RPTC mTORC1 is a critical node that mediates kidney dysfunction in diabetes and the protective effects of SGLT2i by regulating fibrogenesis.

Inhibition of mTORC1 by ER stress impairs neonatal ß-cell expansion and predisposes to diabetes in the Akita mouse.

Unresolved ER stress followed by cell death is recognized as the main cause of a multitude of pathologies including neonatal diabetes. A systematic analysis of the mechanisms of ß-cell loss and dysfunction in Akita mice, in which a mutation in the proinsulin gene causes a severe form of permanent neonatal diabetes, showed no increase in ß-cell apoptosis throughout life. Surprisingly, we found that the main mechanism leading to ß-cell dysfunction is marked impairment of ß-cell growth during the early postnatal life due to transient inhibition of mTORC1, which governs postnatal ß-cell growth and differentiation. Importantly, restoration of mTORC1 activity in neonate ß-cells was sufficient to rescue postnatal ß-cell growth, and to improve diabetes. We propose a scenario for the development of permanent neonatal diabetes, possibly also common forms of diabetes, where early-life events inducing ER stress affect ß-cell mass expansion due to mTOR inhibition.

Effects of proinsulin misfolding on ß-cell dynamics, differentiation and function in diabetes.

ER stress due to proinsulin misfolding has an important role in the pathophysiology of rare forms of permanent neonatal diabetes (PNDM) and probably also of common type 1 (T1D) and type 2 diabetes (T2D). Accumulation of misfolded proinsulin in the ER stimulates the unfolded protein response (UPR) that may eventually lead to apoptosis through a process called the terminal UPR. However, the ß-cell ER has an incredible ability to cope with accumulation of misfolded proteins; therefore, it is not clear whether in common forms of diabetes the accumulation of misfolded proinsulin exceeds the point of no return in which terminal UPR is activated. Many studies showed that the UPR is altered in both T1D and T2D; however, the observed changes in the expression of different UPR markers are inconsistent and it is not clear whether they reflect an adaptive response to stress or indeed mediate the ß-cell dysfunction of diabetes. Herein, we critically review the literature on the effects of proinsulin misfolding and ER stress on ß-cell dysfunction and loss in diabetes with emphasis on ß-cell dynamics, and discuss the gaps in understanding the role of proinsulin misfolding in the pathophysiology of diabetes.

Opposing effects of intracellular versus extracellular adenine nucleotides on autophagy: implications for ß-cell function.

AMPK-mTORC1 signaling senses nutrient availability, thereby regulating autophagy. Surprisingly, we found that, in ß-cells, the AMPK activator 5-amino-4-imidazolecarboxamide ribofuranoside (AICAR) inhibited, rather than stimulated, autophagy. AICAR is an intermediate in the generation of inosine monophosphate, with subsequent conversion to other purine nucleotides. Adenosine regulated autophagy in a concentration-dependent manner: at high concentrations, it mimicked the AICAR effect on autophagy, whereas at low concentrations it stimulated autophagy through its cognate A1 receptor. Adenosine regulation of autophagy was independent of AMPK or mTORC1 activity. Adenosine kinase (ADK) is the principal enzyme for metabolic adenosine clearance. ADK knockdown and pharmacological inhibition of the enzyme markedly stimulated autophagy in an adenosine A1 receptor-dependent manner. High-concentration adenosine increased insulin secretion in a manner sensitive to treatment with the autophagy inducer Tat-beclin1, and inhibition of autophagy augmented secretion. In conclusion, high concentrations of AICAR or adenosine inhibit autophagy, whereas physiological concentrations of adenosine or inhibition of adenosine clearance by ADK stimulate autophagy via the adenosine receptor. Adenosine might thus be an autocrine regulator of autophagy, independent of AMPK-mTORC1 signaling. Adenosine regulates insulin secretion, in part, through modulation of autophagy.

GLP-1-RA Corrects Mitochondrial Labile Iron Accumulation and Improves ß-Cell Function in Type 2 Wolfram Syndrome.

CONTEXT: Type 2 Wolfram syndrome (T2-WFS) is a neuronal and ß-cell degenerative disorder caused by mutations in the CISD2 gene. The mechanisms underlying ß-cell dysfunction in T2-WFS are not known, and treatments that effectively improve diabetes in this context are lacking. OBJECTIVE: Unraveling the mechanisms of ß-cell dysfunction in T2-WFS and the effects of treatment with GLP-1 receptor agonist (GLP-1-RA). DESIGN AND SETTING: A case report and in vitro mechanistic studies. PATIENT AND METHODS: We treated an insulin-dependent T2-WFS patient with the GLP-1-RA exenatide for 9 weeks. An iv glucose/glucagon/arginine stimulation test was performed off-drug before and after intervention. We generated a cellular model of T2-WFS by shRNA knockdown of CISD2 (nutrient-deprivation autophagy factor-1 [NAF-1]) in rat insulinoma cells and studied the mechanisms of ß-cell dysfunction and the effects of GLP-1-RA. RESULTS: Treatment with exenatide resulted in a 70% reduction in daily insulin dose with improved glycemic control, as well as an off-drug 7-fold increase in maximal insulin secretion. NAF-1 repression in INS-1 cells decreased insulin content and glucose-stimulated insulin secretion, while maintaining the response to cAMP, and enhanced the accumulation of labile iron and reactive oxygen species in mitochondria. Remarkably, treatment with GLP-1-RA and/or the iron chelator deferiprone reversed these defects. CONCLUSION: NAF-1 deficiency leads to mitochondrial labile iron accumulation and oxidative stress, which may contribute to ß-cell dysfunction in T2-WFS. Treatment with GLP-1-RA and/or iron chelation improves mitochondrial function and restores ß-cell function. Treatment with GLP-1-RA, probably aided by iron chelation, should be considered in WFS and other forms of diabetes associated with iron dysregulation.

AMPK regulates ER morphology and function in stressed pancreatic ß-cells via phosphorylation of DRP1.

Experimental lipotoxicity constitutes a model for ß-cell demise induced by metabolic stress in obesity and type 2 diabetes. Fatty acid excess induces endoplasmic reticulum (ER) stress, which is accompanied by ER morphological changes whose mechanisms and relevance are unknown. We found that the GTPase dynamin-related protein 1 (DRP1), a key regulator of mitochondrial fission, is an ER resident regulating ER morphology in stressed ß-cells. Inhibition of DRP1 activity using a GTP hydrolysis-defective mutant (Ad-K38A) attenuated fatty acid-induced ER expansion and mitochondrial fission. Strikingly, stimulating the key energy-sensor AMP-activated protein kinase (AMPK) increased the phosphorylation at the anti-fission site Serine 637 and largely prevented the alterations in ER and mitochondrial morphology. Expression of a DRP1 mutant resistant to phosphorylation at this position partially prevented the recovery of ER and mitochondrial morphology by AMPK. Fatty acid-induced ER enlargement was associated with proinsulin retention in the ER, together with increased proinsulin/insulin ratio. Stimulation of AMPK prevented these alterations, as well as mitochondrial fragmentation and apoptosis. In summary, DRP1 regulation by AMPK delineates a novel pathway controlling ER and mitochondrial morphology, thereby modulating the response of ß-cells to metabolic stress. DRP1 may thus function as a node integrating signals from stress regulators, such as AMPK, to coordinate organelle shape and function.