The importance of nuclear RAGE-Mcm2 axis in diabetes or cancer-associated replication stress

An elevated frequency of DNA replication defects is associated with diabetes and cancer. However, data linking these nuclear perturbations to the onset or progression of organ complications remained unexplored. Here, we report that RAGE (Receptor for Advanced Glycated Endproducts), previously believed to be an extracellular receptor, upon metabolic stress localizes to the damaged forks. There it interacts and stabilizes the minichromosome-maintenance (Mcm2-7) complex. Accordingly, RAGE deficiency leads to slowed fork progression, premature fork collapse, hypersensitivity to replication stress agents and reduction of viability, which was reversed by the reconstitution of RAGE. This was marked by the 53BP1/OPT-domain expression and the presence of micronuclei, premature loss-of-ciliated zones, increased incidences of tubular-karyomegaly, and finally, interstitial fibrosis. More importantly, the RAGE-Mcm2 axis was selectively compromised in cells expressing micronuclei in human biopsies and mouse models of diabetic nephropathy and cancer. Thus, the functional RAGE-Mcm2/7 axis is critical in handling replication stress in vitro and human disease.

Verification of sex- and age-specific reference intervals for 13 serum steroids determined by mass spectrometry: evaluation of an indirect statistical approach

OBJECTIVES

Conventionally, reference intervals are established by direct methods, which require a well-characterized, obviously healthy study population. This elaborate approach is time consuming, costly and has rarely been applied to steroid hormones measured by mass spectrometry. In this feasibility study, we investigate whether indirect methods based on routine laboratory results can be used to verify reference intervals from external sources.

METHODS

A total of 11,259 serum samples were used to quantify 13 steroid hormones by mass spectrometry. For indirect estimation of reference intervals, we applied a "modified Hoffmann approach", and verified the results with a more sophisticated statistical method (refineR). We compared our results with those of four recent studies using direct approaches.

RESULTS

We evaluated a total of 81 sex- and age-specific reference intervals, for which at least 120 measurements were available. The overall agreement between indirectly and directly determined reference intervals was surprisingly good as nearly every fourth reference limit could be confirmed by narrow tolerance limits. Furthermore, lower reference limits could be provided for some low concentrated hormones by the indirect method. In cases of substantial deviations, our results matched the underlying data better than reference intervals from external studies.

CONCLUSIONS

Our study shows for the first time that indirect methods are a valuable tool to verify existing reference intervals for steroid hormones. A simple "modified Hoffmann approach" based on the general assumption of a normal or lognormal distribution model is sufficient for screening purposes, while the refineR algorithm may be used for a more detailed analysis.

The value of intraoperative MRI for resection of functional pituitary adenomas-a critical assessment of a consecutive single-center series of 114 cases

This series sought to evaluate the role of intraoperative MRI (iMRI) for resection of functional pituitary adenomas (FPAs). We retrospectively reviewed clinical data of 114 consecutive FPAs with excessive hormone secretion treated with transsphenoidal surgery and iMRI during 01/2010–12/2017. We focused on iMRI findings, extend of resection and postoperative hormonal remission. Variables of incomplete resections and persistent hormone excess were evaluated by binary regression. Patients with FPAs presented with hypercortisolism (n = 23, 20%), acromegaly (n = 56, 49%), and as prolactinomas (n = 35, 31%) resistant to medical treatment. Preoperative MRI showed 81 macroadenomas (71%) and optic system involvement in 41 cases (36%). IMRI was suggestive for residual tumor in 51 cases (45%). Re-inspection of the cavity cleared equivocal findings in 16 cases (14%). Additional tumor was removed in 22 cases (19%). Complete resection was achieved in 95 cases (83%). Postoperative morbidity was low (1.7% revision surgeries, 0.8% permanent diabetes insipidus). Overall hormonal remission-rate was 59% (hypercortisolism 78%, acromegaly 52%, prolactinoma 57%). Supra- and parasellar invasion and preoperative visual impairment were significant predictors for incomplete resections despite use of iMRI. Risk for persistent hormone excess was increased sevenfold after incomplete resections. IMRI enabled reliable identification of tumor remnants during surgery and triggered further resection in a considerable proportion of cases. Nevertheless, tumor size and invasiveness set persistent boundaries to the completeness of resections. The low rate of surgical complications could point at a less invasive iMRI-guided surgical approach while achieving a complete tumor resection was a crucial determinant for hormonal outcome.

EASIX for Prediction of Outcome in Hospitalized SARS-CoV-2 Infected Patients

Background

The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and has evoked a pandemic that challenges public health-care systems worldwide. Endothelial cell dysfunction plays a key role in pathophysiology, and simple prognosticators may help to optimize allocation of limited resources. Endothelial activation and stress index (EASIX) is a validated predictor of endothelial complications and outcome after allogeneic stem cell transplantation. Aim of this study was to test if EASIX could predict life-threatening complications in patients with COVID-19.

Methods

SARS-CoV-2-positive, hospitalized patients were enrolled onto a prospective non-interventional register study (n=100). Biomarkers were assessed at hospital admission. Primary endpoint was severe course of disease (mechanical ventilation and/or death, V/D). Results were validated in 126 patients treated in two independent institutions.

Results

EASIX at admission was a strong predictor of severe course of the disease (odds ratio for a two-fold change 3.4, 95%CI 1.8-6.3, p<0.001), time to V/D (hazard ratio (HR) for a two-fold change 2.0, 95%CI 1.5-2.6, p<0.001) as well as survival (HR for a two-fold change 1.7, 95%CI 1.2-2.5, p=0.006). The effect was retained in multivariable analysis adjusting for age, gender, and comorbidities and could be validated in the independent cohort. At hospital admission EASIX correlated with increased suppressor of tumorigenicity-2, soluble thrombomodulin, angiopoietin-2, CXCL8, CXCL9 and interleukin-18, but not interferon-alpha.

Conclusion

EASIX is a validated predictor of COVID19 outcome and an easy-to-access tool to segregate patients in need for intensive surveillance.

Elevated Expression of the RAGE Variant-V in SCLC Mitigates the Effect of Chemotherapeutic Drugs

Simple Summary

Radiomimetic drugs induce extensive genotoxic insults to their target cells. Irreparable DNA damage leaves cells with the choice between a program leading to cell death or senescence, but not DNA repair. Among the challenges of an advanced stage of small cell lung carcinoma (SCLC), the resistance to radiomimetic drugs is the most prominent one. In SCLC, the initial chemotherapeutic treatment primes cell to modify their DNA repair and cell cycle regulatory systems, using alternative but highly efficient forms of DNA repair and auxiliary factors. This modulated system now bypasses several regulatory controls. Thus, at this stage, cells become resistant to any beneficial effects of chemotherapeutic drugs. In the present study, we observed that variant-V of the receptor for advanced glycation end-products (RAGE) is abundantly expressed in advancing and metastasizing SCLC. Therefore, it may serve as a potential target for specific therapeutic interventions directed to SCLC.

Abstract

Small cell lung carcinoma (SCLC) is a highly aggressive malignancy with a very high mortality rate. A prominent part of this is because these carcinomas are refractory to chemotherapies, such as etoposide or cisplatin, making effective treatment almost impossible. Here, we report that elevated expression of the RAGE variant-V in SCLC promotes homology-directed DNA DSBs repair when challenged with anti-cancer drugs. This variant exclusively localizes to the nucleus, interacts with members of the double-strand break (DSB) repair machinery and thus promotes the recruitment of DSBs repair factors at the site of damage. Increased expression of this variant thus, promotes timely DNA repair. Congruently, the tumor cells expressing high levels of variant-V can tolerate chemotherapeutic drug treatment better than the RAGE depleted cells. Our findings reveal a yet undisclosed role of the RAGE variant-V in the homology-directed DNA repair. This variant thus can be a potential target to be considered for future therapeutic approaches in advanced SSLC.

Interpretation of myocardial injury subtypes in COVID-19 disease per fourth version of Universal Definition of Myocardial Infarction

BACKGROUND

Application of the 4th version of Universal Definition of Myocardial Infarction (UDMI) to characterize rates and prognostic relevance of myocardial injury in COVID-19 disease.

METHODS

This retrospective, single-centre observational study enrolled 104 patients hospitalized with SARS-CoV-2 infection. Kaplan-Meier analysis and multivariate Cox regression were used to identify influence of acute or chronic myocardial injury on a composite primary (mortality, incident acute respiratory distress syndrome, incident mechanical ventilation) and secondary endpoint (mortality, incident acute myocardial injury during hospitalization, incident venous thrombosis, pulmonary embolism or stroke).

RESULTS

A total of 27 (26.0%) patients presented with chronic myocardial injury, and 19 (18.3%) with acute myocardial injury. 42 patients(40.4%) developed an incident myocardial injury during hospitalization. The presence of acute or chronic myocardial injury on admission and incident myocardial injury during hospitalization were associated with higher rates of endpoints. Independent predictors for the primary endpoint were higher severity stages according to Siddiqi et al. classification system and history of dyslipidaemia. Maximal hs-cTnT and D-dimer concentrations during hospitalization showed an association (r = 0.61).

CONCLUSIONS

Objective description of myocardial injury according to the 4th UDMI in the current COVID-19 pandemic is crucial in order to discriminate patients with acute myocardial infarction and acute, chronic or incident myocardial injury.

Appropriateness of CT pulmonary angiograms according to current diagnostic guidelines based on risk stratification: A retrospective single-center study

BACKGROUND AND AIM

Assessment of appropriateness of CT pulmonary angiograms (CTPA) in patients with suspected pulmonary embolism (PE) is based on risk stratification algorithms such as simplified the Geneva Score (sGS) in combination with D-dimer blood tests. The aim of this study was to validate the diagnostic yield and appropriateness of CTPA examinations in accordance with 2014 European Society of Cardiology (ESC) guidelines.

MATERIALS AND METHODS

Data from 155 outpatients who underwent CTPA for clinical suspicion of PE were gathered from the radiology information system (RIS) and the clinical information system (CIS). We assessed the presence of sGS items and D-dimer blood test results in RIS from CTPA request forms and from clinical documentation in CIS.

RESULTS

Based on the RIS, there were 2.6% patients with high (sGS≥3) and 97.4% patients with low pre-test PE probability (sGS<3), and CTPA indication was formally comprehendible in 75.5% using sGS and D-dimer blood tests. Based on RIS and CIS data in combination, there were 41.3% patients with high and 58.7% patients with low pre-test PE probability, and CTPA indication was formally comprehendible in 88.4%. Using RIS and CIS in combination, PE probability was upgraded from low to high probability in 39.7% compared with RIS alone. In 12.9%, there was a lack of data in RIS for CTPA justification.

CONCLUSION

There is a high diagnostic yield when applying current diagnostic guidelines to our data. There was however a notable discrepancy between the data transferred to the CTPA request forms from the full clinical documentation, therefore not readily available for clinical decision making.

[Surgery of adrenal diseases]

Incidentally discovered adrenal alterations should be separated into those without any clinical importance and adrenal diseases that have to be surgically or conservatively treated. Before operative treatment, in addition to the possible different functional activity of tumors, a differentiation must be made between sporadically arising singular or multiple adrenal tumors or nodular adrenal hyperplasia, adrenal tumors as part of a familial syndrome and metastases of other primary malignant tumors into the adrenal glands. Benign hormonally active adrenal tumors as well as questionable malignant tumors of the adrenal cortex are resected by minimally invasive techniques. For large malignant tumors infiltrating into surrounding tissues and tumors with proven lymph node metastases, the primarily open approach is indicated. Patients with adrenal diseases should always undergo an interdisciplinary assessment and in cases with clear indications for surgery, sometimes transferred to a center with experience in surgery and postoperative management of these patients.

Asprosin response in hypoglycemia is not related to hypoglycemia unawareness but rather to insulin resistance in type 1 diabetes

Asprosin is a counter-regulatory hormone to insulin which plays a role in fasting. It may therefore also play a role in hypoglycaemia unawareness, which has been subsequently examined in this pilot study. Intravenous glucose tolerance test was used to induce controlled hyperglycemia whereas a hyperinsulinemic clamp test was used to induce a controlled hypoglycaemia in 15 patients with diabetes type 1, with and without hypoglycaemia unawareness. Changes in asprosin plasma levels did not differ between patients with and without hypoglycaemia unawareness. However, nine patients with insulin resistance as well as higher liver stiffness values and low-density lipoprotein but lower high-density lipoprotein levels did not show the expected increase in asprosin plasma levels during hypoglycemia. Therefore, insulin resistance and alterations in liver structure, most likely early stages of non-alcoholic fatty liver disease, seem to be relevant in type 1 diabetes and do not only lead to elevated plasma levels of asprosin, but also to a blunted asprosin response in hypoglycemia.

Cell cycle arrest and cell death correlate with the extent of ischaemia and reperfusion injury in patients following kidney transplantation - results of an observational pilot study

A prolonged cold ischaemia time (CIT) is suspected to be associated with an increased ischaemia and reperfusion injury (IRI) resulting in an increased damage to the graft. In total, 91 patients were evaluated for a delayed graft function within 7 days after kidney transplantation (48 deceased, 43 living donors). Blood and urine samples were collected before, immediately after the operation, and 1, 3, 5, 7 and 10 days later. Plasma and/or urine levels of total keratin 18 (total K18), caspase-cleaved keratin 18 (cc K18), the soluble receptor for advanced glycation end products (sRAGE), tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein-7 (IGFBP7) were measured. As a result of prolonged CIT and increased IRI, deceased donor transplantations were shown to suffer from a more distinct cell cycle arrest and necrotic cell death. Plasmatic total K18 and urinary TIMP-2 and IGFBP7 were therefore demonstrated to be of value for the detection of a delayed graft function (DGF), as they improved the diagnostic performance of a routinely used clinical scoring system. Plasmatic total K18 and urinary TIMP-2 and IGFBP7 measurements are potentially suitable for early identification of patients at high risk for a DGF following kidney transplantation from deceased or living donors.

Sodium-glucose Cotransporter 2 Inhibitors: Glucose Lowering Against other Hypoglycemic Agents

BACKGROUND

The treatment of diabetes remains challenging over the decades, even after the introduction of numerous novel drugs of different classes. Most patients with type 2 diabetes require a combination of multiple agents and eventually the use of insulin. The newest antidiabetic drugs, possibly with the most pleiotropic actions after metformin are the sodium-glucose cotransporter 2 (SGLT-2) inhibitors (SGLT-2i). This class has a unique mechanism inhibiting the glucose reabsorption in the proximal tubule of the kidney.

OBJECTIVE

The purpose of this review is to critically discuss the beneficial effect of SGLT-2i on glycemic control as monotherapy or in combination with other hypoglycemic agents.

METHODS

A systematic review of randomised clinical trials on SGLT-2i vs placebo, other glucoselowering drugs or insulin was performed, and studies assessing glycemic control, mainly expressed through glycated hemoglobin and fasting plasma glucose levels (FPG) were included in the review. Electronic and manual searches on MEDLINE, EMBASE and Cochrane Library were performed.

RESULTS

In our review, we mainly focused on dapagliflozin, empaglifozin and canagliflozin. All agents exhibited a sufficient reduction of HbA1c as well as FPG.

CONCLUSIONS

SGLT-2i are a reliable second-line therapy of T2DM, since they can be combined safely with metformin, sulfonylures, incretin mimetics, insulin as well as in triple combinations. In many studies, they were prioritised as monotherapy with satisfying effects regarding HbA1c and FPG level reductions.

Hypercalcemia, necrotizing pancreatitis and bone lesions: a benign cause

Primary Hyperparathyroidism is asymptomatic in most patients (PHPT). We report a case of PHPT in a young male patient. He presented with severe pancreatitis due to hypercalcemia and multiple bone lesions resulting in pathological fractures. The patients recovered rapidly after parathyroidectomy.

Genetic Polymorphisms of Antioxidant and Antiglycation Enzymes and Diabetic Complications. How Much Can we Learn from the Genes?

There is growing evidence that reactive metabolites, such as reactive oxygen species and dicarbonyls contribute to diabetic complications. Formation, accumulation, and detoxification of these metabolites are controlled by several enzymes, some of which have genetically determined levels of expression or function. This review not only gives an overview of the different SNPs studied in patients with diabetes mellitus type 1 and type 2, but in addition attempts to bridge the gap between a genetic study and clinical use. Therefore, not only the results of the studies are reviewed, but also their use in identification of subgroups where an increased or decreased risk for a diabetic complication is described, as well as their use in developing novel therapeutic options based on understanding the contribution of an enzyme to a given complication.

Methylglyoxal and Advanced Glycation End Products in Patients with Diabetes – What We Know so Far and the Missing Links

Hyperglycemia explains the development of late diabetic complications in patients with diabetes type 1 and type 2 only partially. Most therapeutic efforts relying on intensive glucose control failed to decrease the absolute risk for complications by more than 10%, especially in patients with diabetes type 2. Therefore, alternative pathophysiological pathways have to be examined, in order to develop more individualized treatment options for patients with diabetes in the future. One such pathway might be the metabolism of dicarbonyls, among them methylglyoxal and the accumulation of advanced glycation end products. Here we review currently available epidemiological data on dicarbonyls and AGEs in association with human diabetes type 1 and type 2.

TNF Signaling in Peritoneal Mesothelial Cells: Pivotal Role of cFLIPL

♦ BACKGROUND: Peritoneal dialysis (PD) coincides with high concentrations of proinflammatory cytokines, such as tumor necrosis factor (TNF), in the peritoneal cavity. During treatment, chronic inflammatory processes lead to damage of the peritoneal membrane and a subsequent ultrafiltration failure. Human peritoneal mesothelial cells (HPMCs) play a central role as mediators and targets of PD-related inflammatory changes. Although TNF Receptor 1 (TNFR1) is expressed in high numbers on the cells, TNF-induced apoptosis is inhibited. Here, the underlying molecular mechanisms of TNFR1 signaling in HPMCs are investigated. ♦ METHODS: Human peritoneal mesothelial cells were isolated from the omentum of healthy donors and the dialysis solution of PD patients. Flow cytometry was applied to determine cell surface expression of TNFR1 on HPMCS from healthy donors in absence or presence of TNF or PD fluid (PDF) and were compared to TNFR1 expression on cells from PD patients. To investigate TNFR1-mediated signaling, HPMCs were treated with PDF or TNF, and expression patterns of proteins involved in the TNFR1 signaling pathway were assessed by western blot. ♦ RESULTS: Incubation with PDF led to a significant up-regulation of TNFR1 on the cell surface correlating with elevated TNFR1 numbers on HPMCs from PD patients. Investigations of underlying molecular mechanisms of TNFR1 signaling showed that PDF affects TNFR1 signaling at the proapoptotic signaling pathway by upregulation of IκBα and downregulation of cFLIP_L. In contrast, TNF exclusively induces the activation of NFκB by an increase of phosphorylated IκBα. ♦ CONCLUSIONS: Novel and relevant insights into the mechanisms of TNFR1-mediated signaling in HPMCs with an impact on our understanding of PD-associated damage of the peritoneal membrane are shown.

Group Singing as a Therapy during Diabetes Training--A Randomized Controlled Pilot Study

Comprehensive diabetes treatment has been shown to reduce quality of life in diabetic patients. However, there is evidence to suggest that group singing can have positive effects on quality of life in various clinical settings. In this randomized controlled pilot study, the effect of singing as a therapy to reduce stress and improve quality of life was investigated in insulin-dependent diabetic patients, undergoing a lifestyle intervention program. Patients from the singing group felt less discontented following treatment. This effect, however, was lost after 3 months. No effect on serum cortisol and plasma adrenocorticotropic hormone (ACTH) levels could be seen when comparing the singing group with the control group, although reduced levels of ACTH and cortisol 3 days after treatment could be found and were still present after 3 months within the group of patients who undertook singing as a therapy. Singing led to an increase in bodyweight, which interestingly had no effect on glucose control or methylglyoxal levels. Therefore, singing during a lifestyle intervention program for insulin-dependent diabetic patients had a short lasting and weak effect on patients' mood without affecting glucose control, but no significant effect on stress related hormones.

Peritoneal ultrafiltration in end-stage chronic heart failure

Background

Cardiorenal syndrome type 2 (CRS-2) is common in end-stage chronic heart failure (CHF). Peritoneal ultrafiltration (pUF) may entail clinical functional improvement and a reduction in hospitalizations.

Methods

Thirty-nine consecutive end-stage CHF patients with stable CRS-2 were initiated on ambulatory pUF after interdisciplinary cardiological/nephrological evaluation and prospectively followed for 1 year. All-cause hospitalization was the primary end point. Secondary end points included mortality, treatment alteration and change in weight, NYHA functional class or quality of life (QoL). Outcomes were compared both within the pUF cohort (365 prior to initiation) and with 39 matched CHF patients receiving standard medical treatment.

Results

Compared with pretreatment, there was a trend to a reduction in 1-year hospitalization days in the pUF group (P = 0.07). One-year mortality was 33% in the pUF group and 23% in the matched control cohort. pUF was stopped in eight patients (18%) due to recurrent peritonitis (n = 3), insufficient ultrafiltration (n = 3) or cardiac recompensation (n = 1). Compared with standard medical treatment, pUF significantly improved volume overload (P < 0.05), NYHA functional class (P < 0.001) and mental health (P < 0.05). Moreover, hospitalization days for all causes as well as cardiovascular hospitalization days were significantly reduced during the interim periods in the pUF group (P < 0.05 and P < 0.001, respectively).

Conclusions

pUF is effective in improving the clinical condition of end-stage CHF patients suffering from CRS-2. Randomized controlled trials are needed to clarify the effects of pUF on hospitalization and mortality in these patients.

Nanotube action between human mesothelial cells reveals novel aspects of inflammatory responses

A well-known role of human peritoneal mesothelial cells (HPMCs), the resident cells of the peritoneal cavity, is the generation of an immune response during peritonitis by activation of T-cells via antigen presentation. Recent findings have shown that intercellular nanotubes (NTs) mediate functional connectivity between various cell types including immune cells - such as T-cells, natural killer (NK) cells or macrophages - by facilitating a spectrum of long range cell-cell interactions. Although of medical interest, the relevance of NT-related findings for human medical conditions and treatment, e.g. in relation to inflammatory processes, remains elusive, particularly due to a lack of appropriate in vivo data. Here, we show for the first time that primary cultures of patient derived HPMCs are functionally connected via membranous nanotubes. NT formation appears to be actin cytoskeleton dependent, mediated by the action of filopodia. Importantly, significant variances in NT numbers between different donors as a consequence of pathophysiological alterations were observable. Furthermore, we show that TNF-α induces nanotube formation and demonstrate a strong correlation of NT connectivity in accordance with the cellular cholesterol level and distribution, pointing to a complex involvement of NTs in inflammatory processes with potential impact for clinical treatment.

Aquaporin-1 channel function is positively regulated by protein kinase C

Aquaporin-1 (AQP1) channels contribute to osmotically induced water transport in several organs including the kidney and serosal membranes such as the peritoneum and the pleura. In addition, AQP1 channels have been shown to conduct cationic currents upon stimulation by cyclic nucleotides. To date, the short term regulation of AQP1 function by other major intracellular signaling pathways has not been studied. In the present study, we therefore investigated the regulation of AQP1 by protein kinase C. AQP1 wild type channels were expressed in Xenopus oocytes. Water permeability was assessed by hypotonic challenges. Activation of protein kinase C (PKC) by 1-oleoyl-2-acetyl-sn-glycerol (OAG) induced a marked increase of AQP1-dependent water permeability. This regulation was abolished in mutated AQP1 channels lacking both consensus PKC phosphorylation sites Thr(157) and Thr(239) (termed AQP1 DeltaPKC). AQP1 cationic currents measured with double-electrode voltage clamp were markedly increased after pharmacological activation of PKC by either OAG or phorbol 12-myristate 13-acetate. Deletion of either Thr(157) or Thr(239) caused a marked attenuation of PKC-dependent current increases, and deletion of both phosphorylation sites in AQP1 DeltaPKC channels abolished the effect. In vitro phosphorylation studies with synthesized peptides corresponding to amino acids 154-168 and 236-250 revealed that both Thr(157) and Thr(239) are phosphorylated by PKC. Upon stimulation by cyclic nucleotides, AQP1 wild type currents exhibited a strong activation. This regulation was not affected after deletion of PKC phosphorylation sites in AQP1 DeltaPKC channels. In conclusion, this is the first study to show that PKC positively regulates both water permeability and ionic conductance of AQP1 channels. This new pathway of AQP1 regulation is independent of the previously described cyclic nucleotide pathway and may contribute to the PKC stimulation of AQP1-modulated processes such as endothelial permeability, angiogenesis, and urine concentration.