Sporadic deficient mismatch repair in colorectal cancer increases the risk for non-colorectal malignancy: A European multicenter cohort study.

BACKGROUND AND OBJECTIVES: Disparities between tumors arising via different sporadic carcinogenetic pathways have not been studied systematically. This retrospective multicenter cohort study evaluated the differences in the risk for non-colorectal malignancy between sporadic colorectal cancer (CRC) patients from different DNA mismatch repair status. METHODS: A retrospective European multicenter cohort study including in total of 1706 CRC patients treated between 1996 and 2019 in three different countries. The proficiency (pMMR) or deficiency (dMMR) of mismatch repair was determined by immunohistochemistry. Cases were analyzed for tumor BRAFV600E mutation, and BRAF mutated tumors were further analyzed for hypermethylation status in the promoter region of MLH1 to distinguish between sporadic and hereditary cases. Swedish and Finish patients were matched with their respective National Cancer Registries. For the Czech cohort, thorough scrutiny of medical files was performed to identify any non-colorectal malignancy within 20 years before or after the diagnosis of CRC. Poisson regression analysis was performed to identify the incidence rates of non-colorectal malignancies. For validation purposes, standardized incidence ratios were calculated for the Swedish cases adjusted for age, year, and sex. RESULTS: Of the 1706 CRC patients included in the analysis, 819 were female [48%], median age at surgery was 67 years [interquartile range: 60-75], and sporadic dMMR was found in 188 patients (11%). Patients with sporadic dMMR CRC had a higher incidence rate ratio (IRR) for non-colorectal malignancy before and after diagnosis compared to patients with a pMMR tumor, in both uni- (IRR = 2.49, 95% confidence interval [CI] = 1.89-3.31, p = 0.003) and multivariable analysis (IRR = 2.24, 95% CI = 1.67-3.01, p = 0.004). This association applied whether or not the non-colorectal tumor developed before or after the diagnosis of CRC in both uni- (IRR = 1.91, 95% CI = 1.28-2.98, p = 0.004), (IRR = 2.45, 95% CI = 1.72-3.49, p = 0.004) and multivariable analysis (IRR = 1.67,95% CI = 1.05-2.65, p = 0.029), (IRR = 2.35, 95% CI = 1.63-3.42, p = 0.005), respectively. CONCLUSION: In this retrospective European multicenter cohort study, patients with sporadic dMMR CRC had a higher risk for non-colorectal malignancy than those with pMMR CRC. These findings indicate the need for further studies to establish the need for and design of surveillance strategies for patients with dMMR CRC.

Microfluidic Single-Cell Study on Arabidopsis thaliana Protoplast Fusion-New Insights on Timescales and Reversibilities.

Plant cells are omnipotent and breeding of new varieties can be achieved by protoplast fusion. Such fusions can be achieved by treatment with poly(ethylene glycol) or by applying an electric field. Microfluidic devices allow for controlled conditions and targeted manipulation of small batches of cells down to single-cell analysis. To provide controlled conditions for protoplast fusions and achieve high reproducibility, we developed and characterized a microfluidic device to reliably trap some Arabidopsis thaliana protoplasts and induced cell fusion by controlled addition of poly(ethylene glycol) (PEG, with a molecular weight of 6000). Experiments were conducted to determine the survival rate of isolated protoplasts in our microfluidic system. Afterward, PEG-induced fusion was studied. Our results indicate that the following fusion parameters had a significant impact on the fusion efficiency and duration: PEG concentration, osmolality of solution and flow velocity. A PEG concentration below 10% led to only partial fusion. The osmolality of the PEG fusion solution was found to strongly impact the fusion process; complete fusion of two source cells sufficiently took part in slightly hyper-osmotic solutions, whereas iso-osmotic solutions led to only partial fusion at a 20% PEG concentration. We observed accelerated fusion for higher fluid velocities. Until this study, it was common sense that fusion is one-directional, i.e., once two cells are fused into one cell, they stay fused. Here, we present for the first time the reversible fusion of protoplasts. Our microfluidic device paves the way to a deeper understanding of the kinetics and processes of cell fusion.

Intranuclear inclusions of polyQ-expanded ATXN1 sequester RNA molecules.

Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disease caused by a trinucleotide (CAG) repeat expansion in the ATXN1 gene. It is characterized by the presence of polyglutamine (polyQ) intranuclear inclusion bodies (IIBs) within affected neurons. In order to investigate the impact of polyQ IIBs in SCA1 pathogenesis, we generated a novel protein aggregation model by inducible overexpression of the mutant ATXN1(Q82) isoform in human neuroblastoma SH-SY5Y cells. Moreover, we developed a simple and reproducible protocol for the efficient isolation of insoluble IIBs. Biophysical characterization showed that polyQ IIBs are enriched in RNA molecules which were further identified by next-generation sequencing. Finally, a protein interaction network analysis indicated that sequestration of essential RNA transcripts within ATXN1(Q82) IIBs may affect the ribosome resulting in error-prone protein synthesis and global proteome instability. These findings provide novel insights into the molecular pathogenesis of SCA1, highlighting the role of polyQ IIBs and their impact on critical cellular processes.

Fabrication and Optimization of 3D-Printed Silica Scaffolds for Neural Precursor Cell Cultivation.

The latest developments in tissue engineering scaffolds have sparked a growing interest in the creation of controlled 3D cellular structures that emulate the intricate biophysical and biochemical elements found within versatile in vivo microenvironments. The objective of this study was to 3D-print a monolithic silica scaffold specifically designed for the cultivation of neural precursor cells. Initially, a preliminary investigation was conducted to identify the critical parameters pertaining to calcination. This investigation aimed to produce sturdy and uniform scaffolds with a minimal wall-thickness of 0.5 mm in order to mitigate the formation of cracks. Four cubic specimens, with different wall-thicknesses of 0.5, 1, 2, and 4 mm, were 3D-printed and subjected to two distinct calcination profiles. Thermogravimetric analysis was employed to examine the freshly printed material, revealing critical temperatures associated with increased mass loss. Isothermal steps were subsequently introduced to facilitate controlled phase transitions and reduce crack formation even at the minimum wall thickness of 0.5 mm. The optimized structure stability was obtained for the slow calcination profile (160 min) then the fast calcination profile (60 min) for temperatures up to 900 °C. In situ X-ray diffraction analysis was also employed to assess the crystal phases of the silicate based material throughout various temperature profiles up to 1200 °C, while scanning electron microscopy was utilized to observe micro-scale crack formation. Then, ceramic scaffolds were 3D-printed, adopting a hexagonal and spherical channel structures with channel opening of 2 mm, and subsequently calcined using the optimized slow profile. Finally, the scaffolds were evaluated in terms of biocompatibility, cell proliferation, and differentiation using neural precursor cells (NPCs). These experiments indicated proliferation of NPCs (for 13 days) and differentiation into neurons which remained viable (up to 50 days in culture). In parallel, functionality was verified by expression of pre- (SYN1) and post-synaptic (GRIP1) markers, suggesting that 3D-printed scaffolds are a promising system for biotechnological applications using NPCs.

Omics Analyses in a Neural Stem Cell Model of Familial Parkinson's Disease.

Parkinson's disease (PD) is the second most common neurodegenerative disorder, affecting millions of people worldwide. Despite considerable efforts, the underlying pathological mechanisms remain elusive, and yet, no treatment has been developed to efficiently reverse or modify disease progression. Thus, new experimental models are required to provide insights into the pathology of PD. Small-molecule neural precursor cells (smNPCs) are ideal for the study of neurodegenerative disorders due to their neural identity and stem cell properties. Cytoplasmic aggregates of α-synuclein (αSyn) are considered a hallmark of PD and a point mutation in the gene encoding p.A53T is responsible for a familial PD form with earlier and robust symptom onset. In order to study the cellular pathology of PD, we genetically modified smNPCs to inducibly overexpress EYFP-SNCA A53T. This cellular model was biochemically characterized, while dysregulated biological pathways and key regulators of PD pathology were identified by computational analyses. Our study indicates three novel genes, UBA52, PIP5K1A, and RPS2, which may mediate PD cellular pathology.

Oxidative Stress and Neurodegeneration: Interconnected Processes in PolyQ Diseases.

Neurodegenerative polyglutamine (polyQ) disorders are caused by trinucleotide repeat expansions within the coding region of disease-causing genes. PolyQ-expanded proteins undergo conformational changes leading to the formation of protein inclusions which are associated with selective neuronal degeneration. Several lines of evidence indicate that these mutant proteins are associated with oxidative stress, proteasome impairment and microglia activation. These events may correlate with the induction of inflammation in the nervous system and disease progression. Here, we review the effect of polyQ-induced oxidative stress in cellular and animal models of polyQ diseases. Furthermore, we discuss the interplay between oxidative stress, neurodegeneration and neuroinflammation using as an example the well-known neuroinflammatory disease, Multiple Sclerosis. Finally, we review some of the pharmaceutical interventions which may delay the onset and progression of polyQ disorders by targeting disease-associated mechanisms.

Colon cancer patients with mismatch repair deficiency are more likely to present as acute surgical cases.

BACKGROUND: The effect of the genetic imprint on the emergency presentation of colon cancer remains unclear. The disparity between tumours evolving along different carcinogenetic pathways has not been studied systematically. This retrospective multicenter cohort study evaluates the association between mismatch repair status and the risk for acute surgery of colon cancer. PATIENTS AND METHODS: A retrospective multicenter cohort study including in total 870 patients from three different countries. Scandinavian cohort (Finland and Sweden), including a total of 412 patients operated between January 1, 1995 and December 31, 2010, was validated against a cohort from the Czech Republic, including a total of 458 patients, operated between January 1, 2018 and December 31, 2019. The proficiency or deficiency of mismatch repair was determined by immunohistochemistry. Primary outcome was the risk for acute colon cancer surgery given as the Odds Ratio (OR) in the univariable and multivariable analyses. Acute colon cancer surgery was defined as surgery performed during the same hospital admission as when the diagnosis of colon cancer was made. RESULTS: Of the 870 patients (399 females [46%]) included in the analyses, median age at surgery was 69 [interquartile range, 61-76] years, deficient Mismatch Repair (dMMR) status was found in 190 patients (22%), and 179 patients (21%) underwent acute surgery during the same hospital admission as when the diagnosis of colon cancer was made. In the Scandinavian cohort, a significant association between dMMR status and acute surgery was seen in both the univariable (OR 1.82, 95% CI 1.11-3.02, P = 0.017) and the multivariable (OR = 2.21, 95% CI 1.28-3.95, P = 0.005) analyses. This was confirmed in the Czech validation cohort in both the univariable (OR = 1.94, 95% CI 1.09-3.26, P = 0.022) and the multivariable (OR = 1.77, 95% CI 1.15-3.18, P = 0.021) analyses. CONCLUSION: This multicenter study reveals a strong association between acute colon cancer surgery and dMMR tumour status.

[Digital assisted laparoscopy with adhesiolysis in mechanical intestinal obstruction]. / Digitalt assisterad laparoskopisk bridlösning ­ ett finger med i spelet.

Mechanical intestinal obstruction is an important diagnosis and a common cause of acute abdominal pain. Adhesions and scar tissue in the abdomen after previ-ous surgery is a frequent source. Small bowel obstruction caused by adhesions can be treated conservatively, but surgery may be needed. Laparotomy is usually the approach for adhesiolysis, but laparoscopy is an option. This case rapport describes a man in his 50s being admitted with severe abdominal pain and vomiting. Further investigation showed a small bowel obstruction caused by adhesions. After two days expectation, surgery be-came necessary. During laparoscopy, the surgeon's finger was introduced intraabdominally and used to release the adhesion.  We here present a possible approach to a situation encountered during laparoscopic adhesiolysis and encourage creativity and laparoscopy in selected patients with mechanical small bowel obstruction.

Biocompatibility of α-Al2O3 Ceramic Substrates with Human Neural Precursor Cells.

BACKGROUND: Biocompatible materials-topography could be used for the construction of scaffolds allowing the three-dimensional (3D) organization of human stem cells into functional tissue-like structures with a defined architecture. METHODS: Structural characterization of an alumina-based substrate was performed through XRD, Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), and wettability measurements. Biocompatibility of the substrate was assessed by measuring the proliferation and differentiation of human neural precursor stem cells (NPCs). RESULTS: α-Al2O3 is a ceramic material with crystallite size of 40 nm; its surface consists of aggregates in the range of 8-22 µm which forms a rough surface in the microscale with 1-8 µm cavities. The non-calcined material has a surface area of 5.5 m2/gr and pore size distribution of 20 nm, which is eliminated in the calcined structure. Thus, the pore network on the surface and the body of the ceramic becomes more water proof, as indicated by wettability measurements. The alumina-based substrate supported the proliferation of human NPCs and their differentiation into functional neurons. CONCLUSIONS: Our work indicates the potential use of alumina for the construction of 3D engineered biosystems utilizing human neurons. Such systems may be useful for diagnostic purposes, drug testing, or biotechnological applications.

Association between local immune cell infiltration, mismatch repair status and systemic inflammatory response in colorectal cancer.

BACKGROUND: Systemic inflammatory response in colorectal cancer (CRC) has been established as a prognostic factor for impaired cancer-specific survival, predominantly in patients with right-sided tumors. On the other hand, defective mismatch repair (dMMR) tumors, primarily located in the right colon, are known to have favorable survival and dense local immune infiltration. The aim of this study was to see if there is any form of relationship between these seemingly diverse entities. METHODS: Complete clinical and long-term survival data were retrieved for 316 CRC patients operated at Helsinki University Hospital between the years 1998 and 2003. Tissue microarrays were prepared from surgical specimens and further processed and analyzed for local immune cell infiltration using multispectral imaging with a Vectra quantitative pathology imaging system and Inform software. Multiplex immunohistochemistry was applied using antibodies against CD66b, CD8, CD20, FoxP3, CD68 and pan-Cytokeratin. After exclusions, data on immune infiltration were available for 275 patients. Mismatch repair status was determined by immunohistochemistry. RESULTS: CRP was seen to be an independent predictor of cancer-specific survival but not overall survival in uni- and multivariable (HR 1.01 (1.00-1.02); p = 0.028) analyses of non-irradiated patients. There was no significant difference in CRP according to mismatch repair status, but all cases (n = 10) with CRP ≥ 75 mg/l had proficient mismatch repair (pMMR). There was a significant negative correlation between intratumor stromal infiltration by T-regulatory FOXP3+ cells and CRP (p = 0.006). There was significantly lower intratumor stromal infiltration by FOXP3+ cells (p = 0.043) in the right colon compared to the rectum, but no significant difference in CRP (p = 0.44). CRP was not a predictor of overall survival (HR 0.99, 95% CI 0.98-1.01) nor cancer-specific survival in irradiated patients (HR 0.94, 95% CI 0.94-1.02). CONCLUSIONS: There was a significant negative relationship between SIR, defined as an elevated CRP, and intratumor stromal infiltration by T-regulatory FOXP3+ cells. This and the fact that all cases with a CRP > 75 mg/l had pMMR suggests that SIR and dMMR are independent entities in CRC. Indeed, the general lack of difference in CRP between cases with dMMR and pMMR may be evidence of overlap in cases with a less pronounced SIR.

Deficient mismatch repair as a prognostic marker in stage II colon cancer patients.

BACKGROUND: A number of reports have evaluated the relationship between deficient DNA mismatch repair (dMMR) and colorectal cancer prognosis. Unfortunately, the exact prognostic role of dMMR has not been clearly established due to contradictory results. This study aims to determine the prognostic impact of dMRR in stage II colon cancer patients only. The appropriate identification of high-risk stage II colon cancers is of paramount importance in the selection of patients who may benefit from adjuvant treatment after surgery. METHODS: Four hundred and fifty-two patients with curative resection of stage II colon cancer were included. Hospital records were used as data source, providing clinical, surgical, pathology, oncology and follow-up information for statistical analysis focusing on overall survival (OS) and time to progression (TTP). Mismatch repair status was determined by immunohistochemistry. Patient survival was followed-up for a mean of 77·35 months. RESULTS: dMMR was detected in 93 of 452 patients (20·6%). No impact on overall survival (Log-Rank, p = 0·583, 95% CI 0·76-1·67). However, the hazard ratio 0·50 for TTP was highly significant (Log-Rank, p = 0·012, 95% CI 0·28-0·87) in patients with dMMR compared with those with mismatch repair proficient tumours (pMMR). CONCLUSIONS: Patients with dMMR tumours have a lower risk for recurrence compared to those with pMMR tumours, but this finding did not correlate to better overall survival.

[Torsion of wandering spleen - unusual cause to acute abdominal pain in pediatric patients]. / Vandrande mjälte ­ ovanlig men viktig differentialdiagnos vid akut buksmärta hos barn.

Wandering spleen is a rare reason for acute abdominal pain in pediatric patients caused by laxity of the splenic ligaments. It can be complicated by torsion of the pedicle, leading to ischemia, a situation that in most cases results in acute abdominal surgery. To prevent ischemia of a mobile spleen caused by a total occlusion of the pedicle, splenopexy can be considered. We present an unusual case where changes in the position of the operating table during diagnostic laparoscopy might have caused a total occlusion of the pedicle.

Microsatellite Instability as a Prognostic Factor in Stage II Colon Cancer Patients, a Meta-Analysis of Published Literature.

BACKGROUND/AIM: The prognostic role of microsatellite instability (MSI) in stage II colon cancer patients remains controversial despite the fact that it has been investigated in a number of studies. Hazard ratios differ considerably among these studies. We performed a meta-analysis to define the significance of MSI in this group of patients. MATERIALS AND METHODS: Studies indexed in PubMed presenting separate data on MSI status and survival outcomes for stage II colon cancer patients have been analyzed using fixed-effect meta-analysis of hazard ratio (HR) according to the method of Peto. RESULTS: Analysis was performed on 19 studies including 5,998 patients. A 47.3% of patients received postoperative chemotherapy and included 52.8% males and 47.2% females. Eight studies included some rectal cancer patients although this cohort was not clearly defined in 3 of these. MSI observed in 20.8% (mean) of patients (median 19.9%). HR for overall survival (OS) of MSI vs. microsatellite stable (MSS) tumors for the entire population: 0.73 (95% confidence interval (CI)=0.33-1.65); HR for disease-free survival (DFS):0.60 (95%CI=0.27-1.32). No statistical significant difference was found when studies analyzing MSI with genotyping (MG) and immunohistochemistry (IHC) were compared separately (MG vs. IHC: HR OS 0.45, 95%CI=0.10-2.05 vs. 0.95, 95%CI=0.57-1.58; HR DFS 0.51, 95%CI=0.14-1.85 vs. 0.67, 95%CI=0.26-1.70). However, numerically MSI determination with genotyping shows significantly lower hazard ratios for both DFS and OS. Separate analysis of studies describing colon cancer patients only showed HR OS 0.72 (95%CI=0.31-1.71); HR DFS 0.60 (95%CI=0.27-1.31). CONCLUSION: No significant relation was found between MSI status and OS or DFS. Routine determination of MSI status to guide postoperative management of stage II colon cancer patients cannot be recommended. New large scale high quality studies are needed to answer this question definitively, since currently analyzed studies vary considerably.