The electroneutral Na+-HCO3- cotransporter NBCn1 (SLC4A7) modulates colonic enterocyte pHi, proliferation, and migration.

NBCn1 (SLC4A7) is one of the two major Na+-HCO3- cotransporters in the human colonic epithelium, expressed predominantly in the highly proliferating colonocytes at the cryptal base. Increased NBCn1 expression levels are reported in tumors, including colorectal cancer. The study explores its importance for maintenance of the intracellular pH (pHi), as well as the proliferative, adhesive, and migratory behavior of the self-differentiating Caco2BBe colonic tumor cell line. In the self-differentiating Caco2BBe cells, NBCn1 mRNA was highly expressed from the proliferative stage until full differentiation. The downregulation of NBCn1 expression by RNA interference affected proliferation and differentiation and decreased intracellular pH (pHi) of the cells in correlation with the degree of knockdown. In addition, a disturbed cell adhesion and reduced migratory speed were associated with NBCn1 knockdown. Murine colonic Nbcn1-/- enteroids also displayed reduced proliferative activity. In the migrating Caco2BBe cells, NBCn1 was found at the leading edge and in colocalization with the focal adhesion markers vinculin and paxillin, which suggests that NBCn1 is involved in the establishment of cell-matrix adhesion. Our data highlight the physiological significance of NBCn1 in modulating epithelial pH homeostasis and cell-matrix interactions in the proliferative region of the colonic epithelium and unravel the molecular mechanism behind pathological overexpression of this transporter in human colorectal cancers.NEW & NOTEWORTHY The transporter NBCn1 plays a central role in maintaining homeostasis within Caco2BBe colonic epithelial cells through its regulation of intracellular pH, matrix adhesion, migration, and proliferation. These observations yield valuable insights into the molecular mechanism of the aberrant upregulation of this transporter in human colorectal cancers.

pH-regulated single cell migration.

Over the last two decades, extra- and intracellular pH have emerged as fundamental regulators of cell motility. Fundamental physiological and pathological processes relying on appropriate cell migration, such as embryonic development, wound healing, and a proper immune defense on the one hand, and autoimmune diseases, metastatic cancer, and the progression of certain parasitic diseases on the other, depend on surrounding pH. In addition, migrating single cells create their own localized pH nanodomains at their surface and in the cytosol. By this means, the migrating cells locally modulate their adhesion to, and the re-arrangement and digestion of, the extracellular matrix. At the same time, the cytosolic nanodomains tune cytoskeletal dynamics along the direction of movement resulting in concerted lamellipodia protrusion and rear end retraction. Extracellular pH gradients as found in wounds, inflamed tissues, or the periphery of tumors stimulate directed cell migration, and long-term exposure to acidic conditions can engender a more migratory and invasive phenotype persisting for hours up to several generations of cells after they have left the acidic milieu. In the present review, the different variants of pH-dependent single cell migration are described. The underlying pH-dependent molecular mechanisms such as conformational changes of adhesion molecules, matrix protease activity, actin (de-)polymerization, and signaling events are explained, and molecular pH sensors stimulated by H+ signaling are presented.

Circulating Tumor Cells: Does Ion Transport Contribute to Intravascular Survival, Adhesion, Extravasation, and Metastatic Organotropism?

Survival in the circulation, extravasation from vasculature, and colonizing new tissues represent major steps of the metastatic cascade and pose a big challenge for metastasizing tumor cells. Tumor cells circulating in blood and lymph vessels need to overcome anoikis, cope with mechanical stimuli including shear stress, and defeat attacks by the immune system. Once adhered to the vessel wall, a circulating tumor cell (CTC) can trick the endothelial cells into loosening their intercellular junctions so that the endothelium becomes penetrable for the tumor cell. Since tumor cells tend to metastasize to predestinated target organs and tissues, called organotropism, the distribution of metastases is anything but random. The molecular-physiological mechanisms underlying CTC survival, extravasation, and organotropism are very likely to include the presence and activity of ion channels/transporters due to the latter's key function in cytophysiological processes. To date, a very limited number of studies explicitly show the involvement of ion transport. This review describes the contribution of ion channels and transporters to CTC survival, extravasation, and organotropism where known and possible. In addition, supposed connections between ion transport and CTC behavior are demonstrated and imply the potential to be therapeutically taken advantage of.

Effects of nintedanib in patients with limited cutaneous systemic sclerosis and interstitial lung disease.

OBJECTIVES: To investigate the course of interstitial lung disease (ILD) and the effects of nintedanib in patients with limited cutaneous systemic sclerosis (lcSSc). METHODS: In the SENSCIS trial, patients with SSc-ILD were randomized to receive nintedanib or placebo. Patients who completed the SENSCIS trial were eligible to enter SENSCIS-ON, in which all patients received open-label nintedanib. RESULTS: Among 277 patients with lcSSc treated in the SENSCIS trial, the rate (s.e.) of decline in forced vital capacity (FVC; ml/year) over 52 weeks was -74.5 (19.2) in the placebo group and -49.1 (19.8) in the nintedanib group (difference: 25.3 [95% CI -28.9, 79.6]). Among 249 patients with data at week 52, mean (s.e.) change in FVC at week 52 was -86.4 (21.1) ml in the placebo group and -39.1 (22.2) ml in the nintedanib group. Among 183 patients with lcSSc who participated in SENSCIS-ON and had data at week 52, mean (s.e.) change in FVC from baseline to week 52 of SENSCIS-ON was -41.5 (24.0) ml in patients who took placebo in the SENSCIS trial and initiated nintedanib in SENSCIS-ON and -45.1 (19.1) ml in patients who took nintedanib in the SENSCIS trial and continued it in SENSCIS-ON. CONCLUSION: Patients with lcSSc may develop progressive fibrosing ILD. By targeting pulmonary fibrosis, nintedanib slows decline in lung function in patients with lcSSc and ILD. TRIAL REGISTRATION: ClinicalTrials.gov (https://clinicaltrials.gov), NCT02597933 and NCT03313180.

Intraoperative liver deformation and organ motion caused by ventilation, laparotomy, and pneumoperitoneum in a porcine model for image-guided liver surgery.

BACKGROUND: Image-guidance promises to make complex situations in liver interventions safer. Clinical success is limited by intraoperative organ motion due to ventilation and surgical manipulation. The aim was to assess influence of different ventilatory and operative states on liver motion in an experimental model. METHODS: Liver motion due to ventilation (expiration, middle, and full inspiration) and operative state (native, laparotomy, and pneumoperitoneum) was assessed in a live porcine model (n = 10). Computed tomography (CT)-scans were taken for each pig for each possible combination of factors. Liver motion was measured by the vectors between predefined landmarks along the hepatic vein tree between CT scans after image segmentation. RESULTS: Liver position changed significantly with ventilation. Peripheral regions of the liver showed significantly higher motion (maximal Euclidean motion 17.9 ± 2.7 mm) than central regions (maximal Euclidean motion 12.6 ± 2.1 mm, p < 0.001) across all operative states. The total average motion measured 11.6 ± 0.7 mm (p < 0.001). Between the operative states, the position of the liver changed the most from native state to pneumoperitoneum (14.6 ± 0.9 mm, p < 0.001). From native state to laparotomy comparatively, the displacement averaged 9.8 ± 1.2 mm (p < 0.001). With pneumoperitoneum, the breath-dependent liver motion was significantly reduced when compared to other modalities. Liver motion due to ventilation was 7.7 ± 0.6 mm during pneumoperitoneum, 13.9 ± 1.1 mm with laparotomy, and 13.5 ± 1.4 mm in the native state (p < 0.001 in all cases). CONCLUSIONS: Ventilation and application of pneumoperitoneum caused significant changes in liver position. Liver motion was reduced but clearly measurable during pneumoperitoneum. Intraoperative guidance/navigation systems should therefore account for ventilation and intraoperative changes of liver position and peripheral deformation.

How Dysregulated Ion Channels and Transporters Take a Hand in Esophageal, Liver, and Colorectal Cancer.

Over the last two decades, the understanding of how dysregulated ion channels and transporters are involved in carcinogenesis and tumor growth and progression, including invasiveness and metastasis, has been increasing exponentially. The present review specifies virtually all ion channels and transporters whose faulty expression or regulation contributes to esophageal, hepatocellular, and colorectal cancer. The variety reaches from Ca2+, K+, Na+, and Cl- channels over divalent metal transporters, Na+ or Cl- coupled Ca2+, HCO3- and H+ exchangers to monocarboxylate carriers and organic anion and cation transporters. In several cases, the underlying mechanisms by which these ion channels/transporters are interwoven with malignancies have been fully or at least partially unveiled. Ca2+, Akt/NF-κB, and Ca2+- or pH-dependent Wnt/ß-catenin signaling emerge as cross points through which ion channels/transporters interfere with gene expression, modulate cell proliferation, trigger epithelial-to-mesenchymal transition, and promote cell motility and metastasis. Also miRs, lncRNAs, and DNA methylation represent potential links between the misexpression of genes encoding for ion channels/transporters, their malfunctioning, and cancer. The knowledge of all these molecular interactions has provided the basis for therapeutic strategies and approaches, some of which will be broached in this review.

Extent of fibrosis and lung function decline in patients with systemic sclerosis and interstitial lung disease: data from the SENSCIS trial.

OBJECTIVE: To assess associations between the extent of fibrotic interstitial lung disease (ILD) and forced vital capacity (FVC) at baseline and change in FVC over 52 weeks in patients with systemic sclerosis-associated ILD (SSc-ILD) in the SENSCIS trial. MATERIAL AND METHODS: We used generalized additive models, which involve few assumptions and allow for interaction between non-linear effects, to assess associations between the extent of fibrotic ILD on high-resolution computed tomography (HRCT), and the interplay of extent of fibrotic ILD on HRCT and FVC % predicted, at baseline and FVC decline over 52 weeks. RESULTS: In the placebo group (n = 288), there was weak evidence of a modest association between a greater extent of fibrotic ILD at baseline and a greater decline in FVC % predicted at week 52 [r: -0.09 (95% CI -0.2, 0.03)]. Higher values of both the extent of fibrotic ILD and FVC % predicted at baseline tended to be associated with greater decline in FVC % predicted at week 52. In the nintedanib group (n = 288), there was no evidence of an association between the extent of fibrotic ILD at baseline and decline in FVC % predicted at week 52 [r: 0.01 (95% CI: -0.11, 0.12)] or between the interplay of extent of fibrotic ILD and FVC % predicted at baseline and decline in FVC % predicted at week 52. CONCLUSIONS: Data from the SENSCIS trial suggest that patients with SSc-ILD are at risk of ILD progression and benefit from nintedanib largely irrespective of their extent of fibrotic ILD at baseline. STUDY REGISTRATION: ClinicalTrials.gov, https://clinicaltrials.gov, NCT02597933.

Decline in forced vital capacity as a surrogate for mortality in patients with pulmonary fibrosis.

BACKGROUND AND OBJECTIVE: Surrogate endpoints enable determination of meaningful treatment effects more efficiently than applying the endpoint of ultimate interest. We used data from trials of nintedanib in subjects with pulmonary fibrosis to assess decline in forced vital capacity (FVC) as a surrogate for mortality. METHODS: Data from the nintedanib and placebo groups of trials in subjects with idiopathic pulmonary fibrosis, other forms of progressive pulmonary fibrosis, and pulmonary fibrosis due to systemic sclerosis (NCT00514683, NCT01335464, NCT01335477, NCT01979952, NCT02999178, NCT02597933) were pooled. Using joint models for longitudinal and time-to-event data, we assessed the association between decline in FVC % predicted and time to death over 52 weeks. The rate of change in FVC % predicted and the current value of FVC % predicted were modelled longitudinally and estimates applied as predictors in time-to-event models. RESULTS: Among 2583 subjects with pulmonary fibrosis, both a greater rate of decline in FVC % predicted and a lower current value of FVC % predicted were associated with an increased risk of death over 52 weeks (HR 1.79 [95% CI: 1.57, 2.03] and HR 1.24 [1.17, 1.32] per 5-percentage point decrease, respectively). Associations between the rate of change in FVC % predicted and the risk of death were consistent between patients with IPF and other ILDs. CONCLUSION: Data from clinical trials in subjects with pulmonary fibrosis of diverse aetiology demonstrate a strong association between decline in FVC % predicted and mortality over 52 weeks, supporting FVC decline as a surrogate for mortality in these patients.

The ACE Inhibitor Lisinopril Stimulates Melanoma Cell Invasiveness by Inducing MMP2 Secretion.

BACKGROUND/AIMS: Hypertension is treated primarily with angiotensin II (ATII) receptor blockers (ARBs) and angiotensin converting enzyme (ACE) inhibitors (ACEIs). Both ATII and ACEIs can trigger signal transduction via ACE, and a possible correlation between ARB/ACEI therapy and an increased risk of cancer is highly controversial. The question of whether or not ACE as a potential signal transducer affects human melanoma (MV3) cell behavior prompted the present study. METHODS: Expression of ACE, ATII receptor types 1, 2 (AT1R, AT2R), COX2 and MMP2 in MV3 cells was examined by qPCR. AT1R, AT2R and ACE were inhibited with losartan, EMA401 and lisinopril, respectively. Adhesion, migration and invasiveness of MV3 cells seeded on a hepatocyte (Huh7) monolayer or a reconstituted collagen type I matrix were analyzed using video microscopy and Boyden chambers. Integrity of the Huh7 cell layer was confirmed by measuring transepithelial electrical resistance (TEER). ERK1/2 phosphorylation and MMP2 secretion were evaluated by Western blotting. MMP2 activity was inhibited with ARP-100. RESULTS: Losartan, EMA401 and lisinopril stimulated MV3 melanoma cell migration and invasion in a coculture model with Huh7 cells while leaving proliferation and adhesion largely unaffected. The drugs did not interfere with TEER of the hepatocyte monolayer nor with MV3 cell proliferation, but tended to increase the phosphorylation of ERK1/2 and the expression of both COX2 and MMP2. Lisinopril caused a significant increase in MV3 cells' MMP2 secretion and an accelerated MV3 cell-mediated TEER breakdown. The MMP2 inhibitor ARP-100 could antagonize the lisinopril-stimulated invasion of the hepatocyte layer. CONCLUSION: Lisinopril stimulates MV3 cell invasion by increasing the expression and secretion of MMP2.

Decline in forced vital capacity in subjects with systemic sclerosis-associated interstitial lung disease in the SENSCIS trial compared with healthy reference subjects.

BACKGROUND: The forced vital capacity (FVC) of healthy individuals depends on their age, sex, ethnicity and height. Systemic sclerosis-associated interstitial lung disease (SSc-ILD) is characterised by loss of FVC. We compared FVC values in the subjects with SSc-ILD in the SENSCIS trial of nintedanib versus placebo with values from hypothetical matched healthy references. METHODS: The SENSCIS trial enrolled subjects with SSc with first non-Raynaud symptom in the prior ≤ 7 years, extent of fibrotic ILD on HRCT ≥ 10%, and FVC ≥ 40% predicted. FVC at baseline and decline in FVC over 52 weeks were compared with FVC values in hypothetical healthy reference subjects matched 1:1 to the subjects in the trial for age, sex, ethnicity and height, determined using equations published by the European Respiratory Society Global Lung Function Initiative. RESULTS: At baseline, mean (SD) FVC was 2460 (737) mL in the nintedanib group (n = 287) compared with 3403 (787) mL in the hypothetical matched healthy references. Mean (SD) FVC was 2544 (817) mL in the placebo group (n = 286) compared with 3516 (887) mL in the hypothetical matched healthy references. Mean (SE) changes in FVC at week 52, i.e., age-related loss of lung function, in the hypothetical healthy references matched to the nintedanib and placebo groups, respectively, were - 26.3 (0.5) mL and - 25.8 (0.5) mL. The difference in the change in FVC at week 52 between the nintedanib group and the hypothetical healthy references was 26.6 mL (95% CI: 1.2, 52.0; p = 0.04). The difference in the change in FVC at week 52 between the placebo group and the hypothetical healthy references was 77.5 mL (95% CI: 51.4, 103.7; p < 0.0001). CONCLUSIONS: Subjects with SSc-ILD in the SENSCIS trial had impaired lung function at baseline and experienced further deterioration over 52 weeks. The decline in FVC in the placebo group was four-fold greater than in a hypothetical group of matched healthy references, whereas the decline in FVC in patients who received nintedanib was two-fold greater than in hypothetical healthy references. These data highlight the clinical relevance of the slowing of FVC decline provided by nintedanib. Trial registration Registered 5 November 2015, https://clinicaltrials.gov/ct2/show/NCT02597933 .

Effects of laparoscopy, laparotomy, and respiratory phase on liver volume in a live porcine model for liver resection.

BACKGROUND: Hepatectomy, living donor liver transplantations and other major hepatic interventions rely on precise calculation of the total, remnant and graft liver volume. However, liver volume might differ between the pre- and intraoperative situation. To model liver volume changes and develop and validate such pre- and intraoperative assistance systems, exact information about the influence of lung ventilation and intraoperative surgical state on liver volume is essential. METHODS: This study assessed the effects of respiratory phase, pneumoperitoneum for laparoscopy, and laparotomy on liver volume in a live porcine model. Nine CT scans were conducted per pig (N = 10), each for all possible combinations of the three operative (native, pneumoperitoneum and laparotomy) and respiratory states (expiration, middle inspiration and deep inspiration). Manual segmentations of the liver were generated and converted to a mesh model, and the corresponding liver volumes were calculated. RESULTS: With pneumoperitoneum the liver volume decreased on average by 13.2% (112.7 ml ± 63.8 ml, p < 0.0001) and after laparotomy by 7.3% (62.0 ml ± 65.7 ml, p = 0.0001) compared to native state. From expiration to middle inspiration the liver volume increased on average by 4.1% (31.1 ml ± 55.8 ml, p = 0.166) and from expiration to deep inspiration by 7.2% (54.7 ml ± 51.8 ml, p = 0.007). CONCLUSIONS: Considerable changes in liver volume change were caused by pneumoperitoneum, laparotomy and respiration. These findings provide knowledge for the refinement of available preoperative simulation and operation planning and help to adjust preoperative imaging parameters to best suit the intraoperative situation.

Socioeconomic deprivation is inversely associated with measles incidence: a longitudinal small-area analysis, Germany, 2001 to 2017.

BackgroundAlthough measles is endemic throughout the World Health Organization European Region, few studies have analysed socioeconomic inequalities and spatiotemporal variations in the disease's incidence.AimTo study the association between socioeconomic deprivation and measles incidence in Germany, while considering relevant demographic, spatial and temporal factors.MethodsWe conducted a longitudinal small-area analysis using nationally representative linked data in 401 districts (2001-2017). We used spatiotemporal Bayesian regression models to assess the potential effect of area deprivation on measles incidence, adjusted for demographic and geographical factors, as well as spatial and temporal effects. We estimated risk ratios (RR) for deprivation quintiles (Q1-Q5), and district-specific adjusted relative risks (ARR) to assess the area-level risk profile of measles in Germany.ResultsThe risk of measles incidence in areas with lowest deprivation quintile (Q1) was 1.58 times higher (95% credible interval (CrI): 1.32-2.00) than in those with highest deprivation (Q5). Areas with medium-low (Q2), medium (Q3) and medium-high deprivation (Q4) had higher adjusted risks of measles relative to areas with highest deprivation (Q5) (RR: 1.23, 95%CrI: 0.99-1.51; 1.05, 95%CrI: 0.87-1.26 and 1.23, 95%CrI: 1.05-1.43, respectively). We identified 54 districts at medium-high risk for measles (ARR > 2) in Germany, of which 22 were at high risk (ARR > 3).ConclusionSocioeconomic deprivation in Germany, one of Europe's most populated countries, is inversely associated with measles incidence. This association persists after demographic and spatiotemporal factors are considered. The social, spatial and temporal patterns of elevated risk require targeted public health action and policy to address the complexity underlying measles epidemiology.

An R package for an integrated evaluation of statistical approaches to cancer incidence projection.

BACKGROUND: Projection of future cancer incidence is an important task in cancer epidemiology. The results are of interest also for biomedical research and public health policy. Age-Period-Cohort (APC) models, usually based on long-term cancer registry data (> 20 yrs), are established for such projections. In many countries (including Germany), however, nationwide long-term data are not yet available. General guidance on statistical approaches for projections using rather short-term data is challenging and software to enable researchers to easily compare approaches is lacking. METHODS: To enable a comparative analysis of the performance of statistical approaches to cancer incidence projection, we developed an R package (incAnalysis), supporting in particular Bayesian models fitted by Integrated Nested Laplace Approximations (INLA). Its use is demonstrated by an extensive empirical evaluation of operating characteristics (bias, coverage and precision) of potentially applicable models differing by complexity. Observed long-term data from three cancer registries (SEER-9, NORDCAN, Saarland) was used for benchmarking. RESULTS: Overall, coverage was high (mostly > 90%) for Bayesian APC models (BAPC), whereas less complex models showed differences in coverage dependent on projection-period. Intercept-only models yielded values below 20% for coverage. Bias increased and precision decreased for longer projection periods (> 15 years) for all except intercept-only models. Precision was lowest for complex models such as BAPC models, generalized additive models with multivariate smoothers and generalized linear models with age x period interaction effects. CONCLUSION: The incAnalysis R package allows a straightforward comparison of cancer incidence rate projection approaches. Further detailed and targeted investigations into model performance in addition to the presented empirical results are recommended to derive guidance on appropriate statistical projection methods in a given setting.

Cross-lagged analyses of the bidirectional relationship between depression and markers of chronic heart failure.

BACKGROUND: Depression is common in patients with chronic heart failure (CHF) and is a predictor of rehospitalization and mortality. However, the complex bidirectional relationships between these two conditions are barely understood. We investigated the course of depression and markers of CHF (New York Heart Association [NYHA] functional class, N-terminal-prohormone B-type natriuretic peptide [NT-proBNP], and left ventricular ejection fraction [LVEF]) in a longitudinal study over a period of 2 years, using three assessment points. METHODS: Data of n = 446 patients with documented CHF were analyzed using structural equation modeling. Specifically, a Bayesian cross-lagged structural equation model was applied. RESULTS: Our study revealed that an aggravation of depression predicted an increase in NYHA functional class (significant cross-lagged effect γh = 0.103, 95% confidence interval [CI] [0.017; 0.194]), whereas an increase in NYHA functional class did not predict an aggravation of depression (γd = 0.002 95% CI [-0.057; 0.194]). This association was found only for NYHA functional class and depression-not for NT-proBNP and LVEF. CONCLUSIONS: Experiencing depression and associated symptoms, such as lack of energy and fatigue, may lead to a further decrease of functional capacity, and consequently to a higher NYHA functional class in CHF patients. As NYHA functional class is associated with higher mortality, this may be a critical development for affected patients. Further studies are required to investigate whether or not this association could be an essential key that explains the pathway from depression to increased mortality in heart failure patients.

Role of ion channels and transporters in cell migration.

Cell motility is central to tissue homeostasis in health and disease, and there is hardly any cell in the body that is not motile at a given point in its life cycle. Important physiological processes intimately related to the ability of the respective cells to migrate include embryogenesis, immune defense, angiogenesis, and wound healing. On the other side, migration is associated with life-threatening pathologies such as tumor metastases and atherosclerosis. Research from the last ≈ 15 years revealed that ion channels and transporters are indispensable components of the cellular migration apparatus. After presenting general principles by which transport proteins affect cell migration, we will discuss systematically the role of channels and transporters involved in cell migration.

Utilization and determinants of follow-up colonoscopies within 6 years after screening colonoscopy: Prospective cohort study.

Previous studies have reported that repeat colonoscopies were often not conducted in the recommended time interval after screening colonoscopy. We prospectively followed participants of screening colonoscopy from Germany for 6 years to investigate utilization and determinants of repeat colonoscopies. In a longitudinal study on the effectiveness of screening colonoscopy in the state of Saarland (Germany), participants who had a screening colonoscopy between 2005 and 2007 were contacted by mail 6 years after screening and requested to fill in a standardized questionnaire on utilization of repeat colonoscopies. For all colonoscopies reported, colonoscopy and histology reports were requested from the physician(s). Of 6,407 screening participants, 2,212 (35%) have utilized another colonoscopy. Among participants with negative findings at screening (no adenomas), 962 (22%) had a subsequent colonoscopy within 6 years from screening, accounting for 43% of all patients with a repeat colonoscopy. Family history of CRC and detection of hyperplastic polyps were found to be determinants of higher repeat colonoscopy use. As many as 44% of the participants with low-risk adenomas (N = 509) and 39% with high-risk adenomas (N = 290) at screening did not utilize surveillance colonoscopy within 6 years. Utilization was better with higher school education, prior cancer screening participation and if high-risk adenomas were detected, lower among current smokers and lowest among participants ≥70 years. New strategies will be required considering determinants of adherence to avoid unnecessary colonoscopies and to improve utilization of surveillance according to recommended time intervals among patients at higher risk of CRC in the future.

MMP3 activity rather than cortical stiffness determines NHE1-dependent invasiveness of melanoma cells.

BACKGROUND: Both cell adhesion and matrix metalloproteinase (MMP) activity depend on pH at the cell surface. By regulating extracellular juxtamembrane pH, the Na+/H+ exchanger NHE1 plays a significant part in human melanoma (MV3) cell migration and invasion. Because NHE1, besides its pH-regulatory transport function, also serves as a structural element tying the cortical actin cytoskeleton to the plasma membrane, we investigated whether NHE1 affects cortical stiffness of MV3 cells, and how this makes an impact on their invasiveness. METHODS: NHE1 overexpressing MV3 cells were compared to the corresponding mock-transfected control cells. NHE1 expression was verified by Western blotting, cariporide (HOE642) was used to inhibit NHE1 activity, cell stiffness was determined by atomic force microscopy, and F-actin was visualized by phalloidin-staining. Migration on, and invasion of, native and glutaraldehyde-fixed collagen I substrates were analyzed using time-lapse video microscopy and Boyden-chamber assays, respectively. MMP secretion and activity were detected by Western blot and zymography, respectively. MMP activity was inhibited with NNGH. RESULTS: The cortical, but not the bulk stiffness, was significantly higher in NHE1 overexpressing cells. This increase in cortical stiffness was accompanied by a reorganization of the cortical cytoskeleton, i.e. a condensation of F-actin underneath and along the plasma membrane. However, it was not affected by NHE1 inhibition. Nevertheless, actin dynamics is required for cell invasion as demonstrated with the application of cytochalasin D. NHE1 overexpression was associated with an elevated MMP3 secretion and an increase in the invasion of a native matrix. This increase in invasiveness could be antagonized by the MMP inhibitor NNGH. Transmigration through a glutaraldehyde-fixed, indigestible substrate was not affected by NHE1 overexpression. CONCLUSION: NHE1, as a structural element and independently of its transport activity, contributes to the organization of the cortical F-actin meshwork and thus impacts cortical stiffness. Since NHE1 overexpression stimulates MMP3 secretion but does not change transmigration through a fixed substrate, MV3 cell invasion of a native substrate depends on MMP activity rather than on a modifiable cortical stiffness.

Optimal age for screening colonoscopy: a modeling study.

BACKGROUND AND AIMS: Recent guidelines on colorectal cancer (CRC) screening recommend starting screening earlier than before. We performed a simulation study to examine and compare the optimal ages to have once-only screening colonoscopy and repeated colonoscopies. METHODS: A Markov model was set up using data from the German national screening colonoscopy registry to simulate the natural history of the adenoma-carcinoma process. CRC deaths and years of potential life lost (YPLL) for a hypothetical unscreened 50-year-old German population were estimated for a single screening colonoscopy or 2 or 3 screening colonoscopies with 10-year intervals at various ages. RESULTS: One single screening colonoscopy performed between 50 and 65 years of age was expected to reduce CRC death by 49% to 69% and YPLL by 51% to 68%. An inverted U-shaped association was found between screening age and proportion of CRC deaths or YPLL prevented. The optimal age for once-only colonoscopy that yielded the highest reductions in YPLL was around 54 years for men and 56 years for women. Estimates were approximately 6 to 8 years higher when proportions of CRC deaths prevented were examined. For 2 or 3 screening colonoscopies, the optimal starting age fell to around 50 years or even younger for both genders. CONCLUSIONS: Based on the YPLL estimates, in a high CRC incidence and high life expectancy country like Germany, the optimal age for once-only screening colonoscopy is around 55 years and possibly slightly younger for men than for women. When 2 or more screening colonoscopies are offered with 10-year intervals, screening should start at age 50 at the latest or possibly even younger for both genders.

Trends in colonoscopy and fecal occult blood test use after the introduction of dual screening offers in Germany: Results from a large population-based study, 2003-2016.

An increasing number of countries have recently introduced colorectal cancer (CRC) screening programs. Typically, one specific screening exam, such as fecal occult blood test (FOBT) or flexible sigmoidoscopy, is offered as a primary screening test. We aimed to assess trends in FOBT and colonoscopy use in Germany following the introduction of the offer of screening colonoscopy as an alternative to FOBT in 2002. We used data from 4052 control participants aged 50-79 years recruited during 2003-2016 for a population-based case-control study in Germany. Prevalence of FOBT and colonoscopy lifetime and recent use was analyzed and trends over time were examined. The percentage of all respondents who had ever undergone a colonoscopy (for either screening or diagnostic purpose) increased markedly over time from 44.6% in 2003-2005 to 57.5% in 2013-2016 (p < 0.0001). Large increases were also observed for colonoscopy use within 10 years (from 38.0% to 52.8%, p < 0.0001), whereas FOBT uptake within one to two years declined from 54.0% to 33.3%. By 2013-2016, 67.2% of respondents either had an FOBT within one to two years or a colonoscopy within 10 years, and this percentage had remained relatively stable over time. This study demonstrates a large increase in colonoscopy utilization since colonoscopy was included as an alternative primary screening test, which was accompanied by a substantial decline in FOBT use. Although the overall adherence to CRC screening recommendations remained stable, the substantial shift of share from FOBT to colonoscopy is expected to yield more protection against CRC incidence and mortality.