Membrane lipids couple synaptotagmin to SNARE-mediated granule fusion in insulin-secreting cells.

Insulin secretion depends on the Ca2+-regulated fusion of granules with the plasma membrane. A recent model of Ca2+-triggered exocytosis in secretory cells proposes that lipids in the plasma membrane couple the calcium sensor Syt1 to the membrane fusion machinery (Kiessling et al., 2018). Specifically, Ca2+-mediated binding of Syt1's C2 domains to the cell membrane shifts the membrane-anchored SNARE syntaxin-1a to a more fusogenic conformation, straightening its juxtamembrane linker. To test this model in live cells and extend it to insulin secretion, we enriched INS1 cells with a panel of lipids with different acyl chain compositions. Fluorescence lifetime measurements demonstrate that cells with more disordered membranes show an increase in fusion efficiency, and vice versa. Experiments with granules purified from INS1 cells and recombinant SNARE proteins reconstituted in supported membranes confirmed that lipid acyl chain composition determines SNARE conformation and that lipid disordering correlates with increased fusion. Addition of Syt1's C2AB domains significantly decreased lipid order in target membranes and increased SNARE-mediated fusion probability. Strikingly, Syt's action on both fusion and lipid order could be partially bypassed by artificially increasing unsaturated phosphatidylserines in the target membrane. Thus, plasma membrane lipids actively participate in coupling Ca2+/synaptotagmin-sensing to the SNARE fusion machinery in cells.

Impact of placental mTOR deficiency on peripheral insulin signaling in adult mice offspring.

Suboptimal in utero environments such as poor maternal nutrition and gestational diabetes can impact fetal birth weight and the metabolic health trajectory of the adult offspring. Fetal growth is associated with alterations in placental mechanistic target of rapamycin (mTOR) signaling; it is reduced in fetal growth restriction and increased in fetal overgrowth. We previously reported that when metabolically challenged by a high-fat diet, placental mTORKO (mTORKOpl) adult female offspring develop obesity and insulin resistance, whereas placental TSC2KO (TSC2KOpl) female offspring are protected from diet-induced obesity and maintain proper glucose homeostasis. In the present study, we sought to investigate whether reducing or increasing placental mTOR signaling in utero alters the programming of adult offspring metabolic tissues preceding a metabolic challenge. Adult male and female mTORKOpl, TSC2KOpl, and respective controls on a normal chow diet were subjected to an acute intraperitoneal insulin injection. Upon insulin stimulation, insulin signaling via phosphorylation of Akt and nutrient sensing via phosphorylation of mTOR target ribosomal S6 were evaluated in the offspring liver, white adipose tissue, and skeletal muscle. Among tested tissues, we observed significant changes only in the liver signaling. In the male mTORKOpl adult offspring liver, insulin-stimulated phospho-Akt was enhanced compared to littermate controls. Basal phospho-S6 level was increased in the mTORKOpl female offspring liver compared to littermate controls and did not increase further in response to insulin. RNA sequencing of offspring liver identified placental mTORC1 programming-mediated differentially expressed genes. The expression of major urinary protein 1 (Mup1) was differentially altered in female mTORKOpl and TSC2KOpl offspring livers and we show that MUP1 level is dependent on overnutrition and fasting status. In summary, deletion of placental mTOR nutrient sensing in utero programs hepatic response to insulin action in a sexually dimorphic manner. Additionally, we highlight a possible role for hepatic and circulating MUP1 in glucose homeostasis that warrants further investigation.

Early vs late drain removal after pancreatic resection-a systematic review and meta-analysis.

BACKGROUND: Reducing clinically relevant post-operative pancreatic fistula (CR-POPF) incidence after pancreatic resections has been a topic of great academic interest. Optimizing post-operative drain management is a potential strategy in reducing this major complication. METHODS: Studies involving pancreatic resections, including both pancreaticoduodenectomy (PD) and distal pancreatic resections (DP), with intra-operative drain placement were screened. Early drain removal was defined as removal before or on the 3rd post-operative day (POD) while late drain removal was defined as after the 3rd POD. The primary outcome was CR-POPF, International Study Group of Pancreatic Surgery (ISGPS) Grade B and above. Secondary outcomes were all complications, severe complications, post-operative haemorrhage, intra-abdominal infections, delayed gastric emptying, reoperation, length of stay, readmission, and mortality. RESULTS: Nine studies met the inclusion criteria and were included for analysis. The studies had a total of 8574 patients, comprising 1946 in the early removal group and 6628 in the late removal group. Early drain removal was associated with a significantly lower risk of CR-POPF (OR: 0.24, p < 0.01). Significant reduction in risk of post-operative haemorrhage (OR: 0.55, p < 0.01), intra-abdominal infection (OR: 0.35, p < 0.01), re-admission (OR: 0.63, p < 0.01), re-operation (OR: 0.70, p = 0.03), presence of any complications (OR: 0.46, p < 0.01), and reduced length of stay (SMD: -0.75, p < 0.01) in the early removal group was also observed. CONCLUSION: Early drain removal is associated with significant reductions in incidence of CR-POPF and other post-operative complications. Further prospective randomised trials in this area are recommended to validate these findings.

PACAP and acetylcholine cause distinct Ca2+ signals and secretory responses in chromaffin cells.

The adrenomedullary chromaffin cell transduces chemical messages into outputs that regulate end organ function throughout the periphery. At least two important neurotransmitters are released by innervating preganglionic neurons to stimulate exocytosis in the chromaffin cell-acetylcholine (ACh) and pituitary adenylate cyclase activating polypeptide (PACAP). Although PACAP is widely acknowledged as an important secretagogue in this system, the pathway coupling PACAP stimulation to chromaffin cell secretion is poorly understood. The goal of this study is to address this knowledge gap. Here, it is shown that PACAP activates a Gαs-coupled pathway that must signal through phospholipase C ε (PLCε) to drive Ca2+ entry and exocytosis. PACAP stimulation causes a complex pattern of Ca2+ signals in chromaffin cells, leading to a sustained secretory response that is kinetically distinct from the form stimulated by ACh. Exocytosis caused by PACAP is associated with slower release of peptide cargo than exocytosis stimulated by ACh. Importantly, only the secretory response to PACAP, not ACh, is eliminated in cells lacking PLCε expression. The data show that ACh and PACAP, acting through distinct signaling pathways, enable nuanced and variable secretory outputs from chromaffin cells.

TissueGrinder, a novel technology for rapid generation of patient-derived single cell suspensions from solid tumors by mechanical tissue dissociation.

Introduction: Recent advances hold promise of making personalized medicine a step closer to implementation in clinical settings. However, traditional sample preparation methods are not robust and reproducible. In this study, the TissueGrinder, a novel mechanical semi-automated benchtop device, which can isolate cells from tissue in a very fast and enzyme-free way is tested for cell isolation from surgically resected tumor tissues. Methods: Thirty-three surgically resected tumor tissues from various but mainly pancreatic, liver or colorectal origins were processed by both novel TissueGrinder and explant method. An optimized processing program for tumors from pancreatic, liver or colorectal cancer was developed. The viability and morphological characteristics of the isolated cells were evaluated microscopically. Expression of pancreatic cancer markers was evaluated in cells isolated from pancreatic tumors. Finally, the effect of mechanical stress on the cells was evaluated by assessing apoptosis markers via western blotting. Results: TissueGinder was more efficient in isolating cells from tumor tissue with a success rate of 75% when compared to explant method 45% in terms of cell outgrowth six weeks after processing. Cells isolated with TissueGinder had a higher abundance and were more heterogeneous in composition as compared to explant method. Mechanical processing of the cells with TissueGrinder does not lead to apoptosis but causes slight stress to the cells. Discussion: Our results show that TissueGrinder can process solid tumor tissues more rapidly and efficiently and with higher success rate compared to the conventionally used explant method. The results of the study suggest that the TissueGrinder might be a suitable method for obtaining cells, which is important for its application in individualized therapy. Due to the great variance in different tumor entities and the associated individual tissue characteristics, a further development of the dissociation protocol for other types of tumors and normal tissue will be targeted.

Transgenic overexpression of microRNA-30d in pancreatic beta-cells progressively regulates beta-cell function and identity.

Abnormal microRNA functions are closely associated with pancreatic ß-cell loss and dysfunction in type 2 diabetes. Dysregulation of miR-30d has been reported in the individuals with diabetes. To study how miR-30d affects pancreatic ß-cell functions, we generated two transgenic mouse lines that specifically overexpressed miR-30d in ß-cells at distinct low and high levels. Transgenic overexpressed miR-30d systemically affected ß-cell function. Elevated miR-30d at low-level (TgL, 2-fold) had mild effects on signaling pathways and displayed no significant changes to metabolic homeostasis. In contrast, transgenic mice with high-level of miR-30d expression (TgH, 12-fold) exhibited significant diet-induced hyperglycemia and ß-cell dysfunction. In addition, loss of ß-cell identity was invariably accompanied with increased insulin/glucagon-double positive bihormonal cells and excess plasma glucagon levels. The transcriptomic analysis revealed that miR-30d overexpression inhibited ß-cell-enriched gene expression and induced α-cell-enriched gene expression. These findings implicate that an appropriate miR-30d level is essential in maintaining normal ß-cell identity and function.

Placental Insulin Receptor Transiently Regulates Glucose Homeostasis in the Adult Mouse Offspring of Multiparous Dams.

In pregnancies complicated by maternal obesity and gestational diabetes mellitus, there is strong evidence to suggest that the insulin signaling pathway in the placenta may be impaired. This may have potential effects on the programming of the metabolic health in the offspring; however, a direct link between the placental insulin signaling pathway and the offspring health remains unknown. Here, we aimed to understand whether specific placental loss of the insulin receptor (InsR) has a lasting effect on the offspring health in mice. Obesity and glucose homeostasis were assessed in the adult mouse offspring on a normal chow diet (NCD) followed by a high-fat diet (HFD) challenge. Compared to their littermate controls, InsR KOplacenta offspring were born with normal body weight and pancreatic ß-cell mass. Adult InsR KOplacenta mice exhibited normal glucose homeostasis on an NCD. Interestingly, under a HFD challenge, adult male InsR KOplacenta offspring demonstrated lower body weight and a mildly improved glucose homeostasis associated with parity. Together, our data show that placenta-specific insulin receptor deletion does not adversely affect offspring glucose homeostasis during adulthood. Rather, there may potentially be a mild and transient protective effect in the mouse offspring of multiparous dams under the condition of a diet-induced obesogenic challenge.

Validation of Tokyo Guidelines 2007 and Tokyo Guidelines 2013/2018 Criteria for Acute Cholangitis and Predictors of In-Hospital Mortality.

BACKGROUND: Acute cholangitis (AC) is a common emergency with a significant mortality risk. The Tokyo Guidelines (TG) provide recommendations for diagnosis, severity stratification, and management of AC. However, validation of the TG remains poor. This study aims to validate TG07, TG13, and TG18 criteria and identify predictors of in-hospital mortality in patients with AC. METHODS: This is a retrospective audit of patients with a discharge diagnosis of AC in the year 2016. Demographic, clinical, investigation, management and mortality data were documented. We performed a multinomial logistic regression analysis with stepwise variable selection to identify severity predictors for in-hospital mortality. RESULTS: Two hundred sixty-two patients with a median age of 75.9 years (IQR 64.8-82.8) years were included for analysis. TG13/TG18 diagnostic criteria were more sensitive than TG07 diagnostic criteria (85.1 vs. 75.2%; p < 0.006). The majority of the patients (n = 178; 67.9%) presented with abdominal pain, pyrexia (n = 156; 59.5%), and vomiting (n = 123; 46.9%). Blood cultures were positive in 95 (36.3%) patients, and 79 (83.2%) patients had monomicrobial growth. The 30-day, 90-day, and in-hospital mortality numbers were 3 (1.1%), 11 (4.2%), and 15 (5.7%), respectively. In multivariate analysis, type 2 diabetes mellitus (OR = 12.531; 95% CI 0.354-116.015; p = 0.026), systolic blood pressure <100 mm Hg (OR = 10.108; 95% CI 1.094-93.395; p = 0.041), Glasgow coma score <15 (OR = 38.16; 95% CI 1.804-807.191; p = 0.019), and malignancy (OR = 14.135; 95% CI 1.017-196.394; p = 0.049) predicted in-hospital mortality. CONCLUSION: TG13/18 diagnostic criteria are more sensitive than TG07 diagnostic criteria. Type 2 diabetes mellitus, systolic blood pressure <100 mm Hg, Glasgow coma score <15, and malignant etiology predict in-hospital mortality in patients with AC. These predictors could be considered in acute stratification and treatment of patients with AC.

Pancreatic ß-Cell O-GlcNAc Transferase Overexpression Increases Susceptibility to Metabolic Stressors in Female Mice.

The nutrient-sensor O-GlcNAc transferase (Ogt), the sole enzyme that adds an O-GlcNAc-modification onto proteins, plays a critical role for pancreatic ß-cell survival and insulin secretion. We hypothesized that ß-cell Ogt overexpression would confer protection from ß-cell failure in response to metabolic stressors, such as high-fat diet (HFD) and streptozocin (STZ). Here, we generated a ß-cell-specific Ogt in overexpressing (ßOgtOE) mice, where a significant increase in Ogt protein level and O-GlcNAc-modification of proteins were observed in islets under a normal chow diet. We uncovered that ßOgtOE mice show normal peripheral insulin sensitivity and glucose tolerance with a regular chow diet. However, when challenged with an HFD, only female ßOgtOE (homozygous) Hz mice developed a mild glucose intolerance, despite increased insulin secretion and normal ß-cell mass. While female mice are normally resistant to low-dose STZ treatments, the ßOgtOE Hz mice developed hyperglycemia and glucose intolerance post-STZ treatment. Transcriptome analysis between islets with loss or gain of Ogt by RNA sequencing shows common altered pathways involving pro-survival Erk and Akt and inflammatory regulators IL1ß and NFkß. Together, these data show a possible gene dosage effect of Ogt and the importance O-GlcNAc cycling in ß-cell survival and function to regulate glucose homeostasis.

Robotic versus laparoscopic ventral hernia repair: a systematic review and meta-analysis of randomised controlled trials and propensity score matched studies.

PURPOSE: There has not been a consensus on the superiority of a surgical approach for minimally invasive ventral hernia repair. This systematic review and meta-analysis (SRMA) aims to compare clinical, and patient-reported outcomes of robotic-assisted ventral hernia repair (rVHR) to traditional endo-laparoscopic ventral hernia repair (lapVHR). METHODS: We searched PubMed, EMBASE, Cochrane and Scopus from inception to 16th March 2021. We selected randomised controlled trials and propensity score matched studies comparing rVHR to lapVHR. A meta-analysis was done for the outcomes of operative time, length of hospital stay, open conversion, recurrence, surgical site occurrence and cost. RESULTS: A total of 5 studies (3732 patients) were included in the qualitative and quantitative synthesis. Significantly shorter operative times were reported with the lapVHR as compared to rVHR (weighted mean difference (WMD): 62.52, 95% CI: 50.84-74.19). There was also significantly less rates of open conversion with rVHR as compared to lapVHR (WMD: 0.22, 95% CI: 0.09-0.54). No significant differences in patient-reported outcomes that was discernible from the two papers that reported them. CONCLUSION: Overall, rVHR is comparable to lapVHR with longer operative times but less open conversion. It is, therefore, important to have proper patient selection to maximise the utility of rVHR.

OGT Regulates Mitochondrial Biogenesis and Function via Diabetes Susceptibility Gene Pdx1.

O-GlcNAc transferase (OGT), a nutrient sensor sensitive to glucose flux, is highly expressed in the pancreas. However, the role of OGT in the mitochondria of ß-cells is unexplored. In this study, we identified the role of OGT in mitochondrial function in ß-cells. Constitutive deletion of OGT (ßOGTKO) or inducible ablation in mature ß-cells (ißOGTKO) causes distinct effects on mitochondrial morphology and function. Islets from ßOGTKO, but not ißOGTKO, mice display swollen mitochondria, reduced glucose-stimulated oxygen consumption rate, ATP production, and glycolysis. Alleviating endoplasmic reticulum stress by genetic deletion of Chop did not rescue the mitochondrial dysfunction in ßOGTKO mice. We identified altered islet proteome between ßOGTKO and ißOGTKO mice. Pancreatic and duodenal homeobox 1 (Pdx1) was reduced in in ßOGTKO islets. Pdx1 overexpression increased insulin content and improved mitochondrial morphology and function in ßOGTKO islets. These data underscore the essential role of OGT in regulating ß-cell mitochondrial morphology and bioenergetics. In conclusion, OGT couples nutrient signal and mitochondrial function to promote normal ß-cell physiology.

Elderly patients (≥ 80 years) with acute calculous cholangitis have similar outcomes as non-elderly patients (< 80 years): Propensity score-matched analysis.

BACKGROUND: Acute cholangitis (AC) is a disease spectrum with varying extent of severity. Age ≥ 75 years forms part of the criteria for moderate (Grade II) severity in both the Tokyo Guidelines (TG13 and TG18). Aging is associated with reduced physiological reserves, frailty, and sarcopenia. However, there is evidence that age itself is not the determinant of inferior outcomes in elective and emergency biliary diseases. There is a paucity of reports comparing clinical outcomes amongst elderly patients vs non-elderly patients with AC. AIM: To investigate the effect of age (≥ 80 years) on AC's morbidity and mortality using propensity score matching (PSM). METHODS: This is a single-center retrospective cohort study of all patients diagnosed with calculous AC (January 2016 to December 2016) and ≥ 80 years old (January 2012 to December 2016) at a tertiary university-affiliated teaching hospital. Inclusion criteria were patients who were treated for suspected or confirmed AC secondary to biliary stones. Patients with AC on a background of hepatobiliary malignancy, indwelling permanent metallic biliary stents, or concomitant pancreatitis were excluded. Elderly patients were defined as ≥ 80 years old in our study. A 1:1 PSM analysis was performed to reduce selection bias and address confounding factors. Study variables include comorbidities, vital parameters, laboratory and radiological investigations, and type of biliary decompression, including the time for endoscopic retrograde cholangiopancreatography (ERCP). Primary outcomes include in-hospital mortality, 30-d and 90-d mortality. Length of hospital stay (LOS) was the secondary outcome. RESULTS: Four hundred fifty-seven patients with AC were included in this study (318 elderly, 139 non-elderly). PSM analysis resulted in a total of 224 patients (112 elderly, 112 non-elderly). The adoption of ERCP between elderly and non-elderly was similar in both the unmatched (elderly 64.8%, non-elderly 61.9%, P = 0.551) and matched cohorts (elderly 68.8% and non-elderly 58%, P = 0.096). The overall in-hospital mortality, 30-d mortality and 90-d mortality was 4.6%, 7.4% and 8.5% respectively, with no statistically significant differences between the elderly and non-elderly in both the unmatched and matched cohorts. LOS was longer in the unmatched cohort [elderly 8 d, interquartile range (IQR) 6-13, vs non-elderly 8 d, IQR 5-11, P = 0.040], but was comparable in the matched cohort (elderly 7.5 d, IQR 5-11, vs non-elderly 8 d, IQR 5-11, P = 0.982). Subgroup analysis of patients who underwent ERCP demonstrated the majority of the patients (n = 159/292, 54.5%) had delayed ERCP (> 72 h from presentation). There was no significant difference in LOS, 30-d mortality, 90-d mortality, and in-hospital mortality in patients who had delayed ERCP in both the unmatched and matched cohort (matched cohort: in-hospital mortality [n = 1/42 (2.4%) vs 1/26 (3.8%), P = 0.728], 30-d mortality [n = 2/42 (4.8%) vs 2/26 (7.7%), P = 0.618], 90-d mortality [n = 2/42 (4.8%) vs 2/26 (7.7%), P = 0.618], and LOS (median 8.5 d, IQR 6-11.3, vs 8.5 d, IQR 6-15.3, P = 0.929). CONCLUSION: Mortality is indifferent in the elderly (≥ 80 years old) and non-elderly patients (< 80 years old) with AC.

Placental mTOR complex 1 regulates fetal programming of obesity and insulin resistance in mice.

Fetal growth restriction, or low birth weight, is a strong determinant for eventual obesity and type 2 diabetes. Clinical studies suggest placental mechanistic target of rapamycin (mTOR) signaling regulates fetal birth weight and the metabolic health trajectory of the offspring. In the current study, we used a genetic model with loss of placental mTOR function (mTOR-KOPlacenta) to test the direct role of mTOR signaling on birth weight and metabolic health in the adult offspring. mTOR-KOPlacenta animals displayed reduced placental area and total weight, as well as fetal body weight at embryonic day (E) 17.5. Birth weight and serum insulin levels were reduced; however, ß cell mass was normal in mTOR-KOPlacenta newborns. Adult mTOR-KOPlacenta offspring, under a metabolic high-fat challenge, displayed exacerbated obesity and metabolic dysfunction compared with littermate controls. Subsequently, we tested whether enhancing placental mTOR complex 1 (mTORC1) signaling, via genetic ablation of TSC2, in utero would improve glucose homeostasis in the offspring. Indeed, increased placental mTORC1 conferred protection from diet-induced obesity in the offspring. In conclusion, placental mTORC1 serves as a mechanistic link between placental function and programming of obesity and insulin resistance in the adult offspring.

microRNA-483 Protects Pancreatic ß-Cells by Targeting ALDH1A3.

Pancreatic ß-cell dysfunction is central to the development and progression of type 2 diabetes. Dysregulation of microRNAs (miRNAs) has been associated with pancreatic islet dysfunction in type 2 diabetes. Previous study has shown that miR-483 is expressed relatively higher in ß-cells than in α-cells. To explore the physiological function of miR-483, we generated a ß-cell-specific knockout mouse model of miR-483. Loss of miR-483 enhances high-fat diet-induced hyperglycemia and glucose intolerance by the attenuation of diet-induced insulin release. Intriguingly, mice with miR-483 deletion exhibited loss of ß-cell features, as indicated by elevated expression of aldehyde dehydrogenase family 1, subfamily A3 (Aldh1a3), a marker of ß-cell dedifferentiation. Moreover, Aldh1a3 was validated as a direct target of miR-483 and overexpression of miR-483 repressed Aldh1a3 expression. Genetic ablation of miR-483 also induced alterations in blood lipid profile. Collectively, these data suggest that miR-483 is critical in protecting ß-cell function by repressing the ß-cell disallowed gene Aldh1a3. The dysregulated miR-483 may impair insulin secretion and initiate ß-cell dedifferentiation during the development of type 2 diabetes.

Validation of TG07 and TG13/TG18 criteria for acute cholangitis and predictors of in-hospital mortality in patients over 80 years old.

Aim of the study: This study aims to validate Tokyo guidelines (TG) TG07/TG13/TG18 criteria and identify predictors of in-hospital mortality in acute cholangitis (AC) patients over 80 years old. Material and methods: This is a retrospective audit of AC patients from January 2009 to December 2016. Demographic, clinical, investigation, management, and mortality data were studied. Multinomial logistic regression analysis with stepwise variable selection identified predictors for in-hospital mortality. Results: Three hundred and eighty-eight patients were treated for AC. One hundred and sixty-two (41.8%) patients were male. 230 (59.3%) patients had a history of biliary disease, 161 (41.5%) patients had type 2 diabetes mellitus (T2DM), and 98 (25.3%) patients had ischaemic heart disease (IHD). Abdominal pain (n = 226, 58.2%), pyrexia (n = 247, 63.7%), and vomiting (n = 159, 41.0%) were the common presenting symptoms. 191 (49.2%) patients had abdominal tenderness. Positive blood cultures were recorded in patients 158 (40.7%) patients. Escherichia coli was the most commonly identified organism (n = 117, 30.2%). 77 (19.8%), 188 (48.5%) and 123 (31.7%) patients were graded with mild, moderate, and severe AC, respectively. 30-day, 90-day, and in-hospital mortality were 9 (2.3%), 19 (4.9%) and 38 (9.8%), respectively. On multivariate analysis, systolic blood pressure ≤ 100 mmHg (OR = 3.817, 95% CI: 1.365-10.761, p = 0.011), hypoalbuminaemia < 28 gm/l (OR = 6.052, 95% CI: 2.635-13.904, p < 0.001), serum creatinine ≥ 176.8 (OR = 2.787, 95% CI: 1.146-6.778, p = 0.024) and international normalized ratio (INR) > 1.5 (OR = 3.247, 95% CI: 1.234-8.544, p = 0.017) were independent predictors of in-hospital mortality. Conclusions: Hypotension, hypoalbuminaemia, elevated creatinine, and elevated INR predict in-hospital mortality in AC patients over 80 years old.

Translational Factor eIF4G1 Regulates Glucose Homeostasis and Pancreatic ß-Cell Function.

Protein translation is essential for cell physiology, and dysregulation of this process has been linked to aging-related diseases such as type 2 diabetes. Reduced protein level of a requisite scaffolding protein of the initiation complex, eIF4G1, downstream of nutrients and insulin signaling is associated with diabetes in humans and mice. In the current study, we tested the hypothesis that eIF4G1 is critical for ß-cell function and glucose homeostasis by genetically ablating eIF4G1 specifically in ß-cells in vivo (ßeIF4G1 knockout [KO]). Adult male and female ßeIF4G1KO mice displayed glucose intolerance but normal insulin sensitivity. ß-Cell mass was normal under steady state and under metabolic stress by diet-induced obesity, but we observed increases in proliferation and apoptosis in ß-cells of ßeIF4G1KO. We uncovered deficits in insulin secretion, partly due to reduced mitochondrial oxygen consumption rate, glucose-stimulated Ca2+ flux, and reduced insulin content associated with loss of eIF4E, the mRNA 5' cap-binding protein of the initiation complex and binding partner of eIF4G1. Genetic reconstitution of eIF4E in single ß-cells or intact islets of ßeIF4G1KO mice recovers insulin content, implicating an unexplored role for eIF4G1/eIF4E in insulin biosynthesis. Altogether these data demonstrate an essential role for the translational factor eIF4G1 on glucose homeostasis and ß-cell function.

Analysis of perioperative outcomes following laparoscopic repeat liver resection compared to laparoscopic primary liver resection based on a single surgeon's experience: A 1:2 propensity score-matched study.

BACKGROUND: We report a single surgeon experience with laparoscopic repeat liver resection (LRLR), and analyse short-term outcomes relative to laparoscopic primary liver resection (LPLR). METHODS: Two-hundred and twenty-two laparoscopic liver resections were performed from 2012 to 2019 of which 33 were LRLR. 1:2 propensity-score matching was done to compare 32 LRLR with 64 LPLR cohort. We further analyzed the first 16 LRLR cases compared to the subsequent 17 cases. RESULTS: 32 LRLR cases were matched to 64 LPLR cases. Apart from a higher frequency of Pringle maneuver in the LPLR cohort (p = 0.006), there were no differences in other perioperative outcomes. There were more posterosuperior located tumours (75.0% vs 17.6%, p = 0.003) and higher median difficulty score (8.50 vs 5.00, p = 0.025) in the initial 16 LRLR cases compared to the next 17. The earlier group had higher median blood loss (250.00 ml vs 50.00 ml, p = 0.012), but other outcomes were similar. CONCLUSION: LRLR may be safely performed in selected patients with no difference in key perioperative outcomes compared to LPLR.

Translational Factor eIF4G1 Regulates Glucose Homeostasis and Pancreatic ß-Cell Function.

Protein translation is essential for cell physiology, and dysregulation of this process has been linked to aging-related diseases such as type 2 diabetes. Reduced protein level of a requisite scaffolding protein of the initiation complex, eIF4G1, downstream of nutrients and insulin signaling, is associated with diabetes in both humans and mice. In the present study, we tested the hypothesis that eIF4G1 is critical for ß-cell function and glucose homeostasis by genetically ablating eIF4G1 specifically in ß-cells in vivo (ßeIF4G1KO). Adult male and female ßeIF4G1KO mice displayed glucose intolerance but normal insulin sensitivity. ß-cell mass was normal under steady state and under metabolic stress by diet-induced obesity, but we observed increases in both proliferation and apoptosis in ß-cells of ßeIF4G1KO. We uncovered deficits in insulin secretion, partly due to reduced mitochondrial oxygen consumption rate, glucose-stimulated Ca2+ flux, and reduced insulin content associated with loss of eIF4E, the mRNA 5'-cap binding protein of the initiation complex and binding partner of eIF4G1. Genetic reconstitution of eIF4E in single ß-cells or intact islets of ßeIF4G1KO mice recovers insulin content, implicating an unexplored role for eIF4G1/eIF4E in insulin biosynthesis. Altogether these data demonstrate an essential role for the translational factor eIF4G1 on glucose homeostasis and ß-cell function.

Islet O-GlcNAcylation Is Required for Lipid Potentiation of Insulin Secretion through SERCA2.

During early obesity, pancreatic ß cells compensate for increased metabolic demand through a transient phase of insulin hypersecretion that stabilizes blood glucose and forestalls diabetic progression. We find evidence that ß cell O-GlcNAcylation, a nutrient-responsive post-translational protein modification regulated by O-GlcNAc transferase (OGT), is critical for coupling hyperlipidemia to ß cell functional adaptation during this compensatory prediabetic phase. In mice, islet O-GlcNAcylation rises and falls in tandem with the timeline of secretory potentiation during high-fat feeding while genetic models of ß-cell-specific OGT loss abolish hyperinsulinemic responses to lipids, in vivo and in vitro. We identify the endoplasmic reticulum (ER) Ca2+ ATPase SERCA2 as a ß cell O-GlcNAcylated protein in mice and humans that is able to rescue palmitate-stimulated insulin secretion through pharmacological activation. This study reveals an important physiological role for ß cell O-GlcNAcylation in sensing and responding to obesity, with therapeutic implications for managing the relationship between type 2 diabetes and its most common risk factor.