Atypical HNPCC owing to MSH6 germline mutations: analysis of a large Dutch pedigree

Hereditary non-polyposis colorectal cancer (HNPCC) is the most common genetic susceptibility syndrome for colorectal cancer. HNPCC is most frequently caused by germline mutations in the DNA mismatch repair (MMR) genes MSH2 and MLH1. Recently, mutations in another MMR gene, MSH6 (also known as GTBP), have also been shown to result in HNPCC. Preliminary data indicate that the phenotype related to MSH6 mutations may differ from the classical HNPCC caused by defects in MSH2 and MLH1. Here, we describe an extended Dutch HNPCC family not fulfilling the Amsterdam criteria II and resulting from a MSH6 mutation. Overall, the penetrance of colorectal cancer appears to be significantly decreased (p<0.001) among the MSH6 mutation carriers in this family when compared with MSH2 and MLH1 carriers (32% by the age of 80 v >80%). Endometrial cancer is a frequent manifestation among female carriers (six out of 13 malignant tumours). Transitional cell carcinoma of the urinary tract is also relatively common in both male and female carriers (10% of the carriers). Moreover, the mean age of onset of both colorectal cancer (MSH6 v MSH2/MLH1 = 55 years v 44/41 years) and endometrial carcinomas (MSH6 v MSH2/MLH1 = 55 years v 49/48 years) is delayed. As previously reported, we confirm that the pattern of microsatellite instability, in combination with immunohistochemical analysis, can predict the presence of a MSH6 germline defect. The detailed characterisation of the clinical phenotype of this kindred contributes to the establishment of genotype-phenotype correlations in HNPCC owing to mutations in specific mismatch repair genes.

Evidence for subtelomeric exchange of 3.3 kb tandemly repeated units between chromosomes 4q35 and 10q26: implications for genetic counselling and etiology of FSHD1

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant myopathy, clinically characterized by asymmetric weakness of muscles in the face, shoulder girdle and upper arm. Deletion of an integral number of 3.3 kb repeated units within a highly polymorphic EcoRI fragment at chromosome 4q35, generating a relatively short EcoRI fragment (< 35 kb), has been shown to cause FSHD1. Probe p13E-11 detects these short fragments in FSHD1 patients, and has therefore been used for diagnostic DNA analysis. However, the reliability of this analysis has been hampered by cross-hybridization of p13E-11 to chromosome 10q26-linked EcoRI fragments of comparable size, which also contain a variable number of 3.3 kb repeated units. Recently, a BinI restriction site was identified within each of the repeated units derived from chromosome 10q26, which enables differentiation of the two polymorphic p13E-11 loci in most cases without haplotype analysis. Remarkably, applying the differential analysis to screen DNA of 160 Dutch cases referred to us for FSHD1 diagnosis, we obtained evidence for subtelomeric exchange of 3.3 kb repeated units between chromosomes 4q35 and 10q26 in affected and unaffected individuals. Subsequently, analysis of 50 unrelated control samples indicated such exchange between chromosomes 4q35 and 10q26 in at least 20% of the population. These subtelomeric rearrangements have generated a novel interchromosomal polymorphism, which has implications for the specificity and sensitivity of the differential restriction analysis for diagnostic purposes. Moreover, the high frequency of the interchromosomal exchanges of 3.3 kb repeated units suggests that they probably do not contain (part of) the FSHD1 gene, and supports position effect variegation as the most likely mechanism for FSHD1.

Fixed versus live endothelial cells: The effect of glutaraldehyde fixation manifested by characteristic bands on the Raman spectra of cells

This work shows an impact of glutaraldehyde (GA) fixation on endothelial cells. Raman spectroscopy imaging was used as a method to monitor biochemical content of the cells due to GA fixation since this is an approach frequently used for studying cells by means of Raman imaging. To get a deeper insight into the changes and to understand them better the measurements of live and fixed cells were performed using two lasers, i.e. 488 and 532 nm. It has been demonstrated that GA fixation affects lipids, proteins, nucleic acid and carbohydrates to small extent. The application of 488 nm laser line seems to be more efficient for live cells due to the small impact of cytochrome resonance on Raman spectra, however 532 nm line is more beneficial for fixed cells due to higher quantum efficiency of the detector, thus leading to higher intensity of Raman bands. Generally, the changes due to fixation are not pronounced but cannot be ignored and the knowledge about them can help in a proper interpretation of data collected for fixed versus live cells.

Chloroquine-Induced Accumulation of Autophagosomes and Lipids in the Endothelium

Chloroquine (CQ) is an antimalarial drug known to inhibit autophagy flux by impairing autophagosome–lysosome fusion. We hypothesized that autophagy flux altered by CQ has a considerable influence on the lipid composition of endothelial cells. Thus, we investigated endothelial responses induced by CQ on human microvascular endothelial cells (HMEC-1). HMEC-1 cells after CQ exposure were measured using a combined methodology based on label-free Raman and fluorescence imaging. Raman spectroscopy was applied to characterize subtle chemical changes in lipid contents and their distribution in the cells, while the fluorescence staining (LipidTox, LysoTracker and LC3) was used as a reference method. The results showed that CQ was not toxic to endothelial cells and did not result in the endothelial inflammation at concentrations of 1–30 µM. Notwithstanding, it yielded an increased intensity of LipidTox, LysoTracker, and LC3 staining, suggesting changes in the content of neutral lipids, lysosomotropism, and autophagy inhibition, respectively. The CQ-induced endothelial response was associated with lipid accumulation and was characterized by Raman spectroscopy. CQ-induced autophagosome accumulation in the endothelium is featured by a pronounced alteration in the lipid profile, but not in the endothelial inflammation. Raman-based assessment of CQ-induced biochemical changes offers a better understanding of the autophagy mechanism in the endothelial cells.

Menadione-induced endothelial inflammation detected by Raman spectroscopy

In this work, the effect of an early oxidative stress on human endothelial cells induced by menadione was studied using a combined methodology of label-free Raman imaging and fluorescence staining. Menadione-induced ROS-dependent endothelial inflammation in human aorta endothelial cells (HAEC) was studied with focus on changes in cytochrome, proteins, nucleic acids and lipids content and their distribution in cells. Fluorescence staining (ICAM-1, VCAM-1, vWF, LipidTox, MitoRos and DCF) was used to confirm endothelial inflammation and ROS generation. The results showed that short time, exposure to menadione did not cause their apoptosis or necrosis (Annexin V Apoptosis Detection Kit) within the 3 h timescale of measurement. On the other hand, 3 h of incubation, did result in endothelial inflammation (ICAM-1, VCAM-1, vWF) that was associated with an increased ROS formation (MitoRos and DCF) suggesting the oxidative stress-mediated inflammation. Chemometric analysis of spectral data enabled the determination of spectroscopic markers of menadione-induced oxidative stress-mediated endothelial inflammation including a decrease of the bands intensity of cytochrome (604, 750, 1128, 1315 and 1585 cm^-1), nucleic acids bands (785 cm^-1), proteins (1005 cm^-1) and increased intensity of lipid bands (722, 1085, 1265, 1303, 1445 and 1660 cm^-1), without changes in the spectroscopic signature of the cell nucleus. In conclusion, oxidative stress resulting in endothelial inflammation was featured by significant alterations in the number of biochemical changes in mitochondria and other cellular compartments detected by Raman spectroscopy. Most of these, coexisted with results from fluorescence imaging, and most importantly occurred earlier than the detection of increased ROS or markers of endothelial inflammation.

Tunicamycin induced endoplasmic reticulum changes in endothelial cells investigated in vitro by confocal Raman imaging

This paper describes how tunicamycin (Tu), the most widely used pharmacological agent for inducing endoplasmic reticulum (ER) stress, interacts with endothelial cells. Our results show that tunicamycin enters the cells and accumulates within the ER area. ER stress takes place when improperly folded or damaged proteins begin to accumulate; however, spectroscopic markers of these changes have not been identified as yet. In this work, Raman spectroscopy and scanning electron microscopy imaging of individual endothelial cells treated with Tu were performed. The changes in the biochemical composition of endothelial cells induced by Tu attributed to ER stress were studied in detail. A main feature of the Tu impact on the cells was a decrease of the phospholipid content in the area of ER, and the most abundant lipid with phosphorus groups found there, was identified as sphingomyelin.

Prognostic Factors and Outcomes of Patients After Liver Retransplantation

BACKGROUND

Despite great progress and improvement in results of orthotopic liver transplantation (OLTx), 10%-20% of patients still require retransplantation (re-OLTx). The aim of the study was to present long-term results of liver retransplantation and to determine the factors influencing outcomes.

PATIENTS AND METHODS

From December 1994 to July 2014, a total of 1461 liver transplantations were performed in the Department of General, Transplant and Liver Surgery of Medical University of Warsaw. There were 92 retransplantations (6.3%), including 40 early re-OLTx (up to 30 days). The most common indication for re-OLTx were vascular complications (41/92, 44.6%). Influence of clinical variables on short- and long-term outcomes was analyzed.

RESULTS

Postoperative mortality was 30.4% (28/92). One-year, 3-year and 5-year survival for all patients was 59.8%, 56.5% and 54.1%, respectively. The best results were achieved in patients undergoing retransplantation due to chronic rejection and biliary complications, whose 5-year survival rates were 75.0% and 72.9% respectively. There was no difference in long-term survival after early and late retransplantations (60.9% and 49.3%, respectively; P = .158). Multivariable analysis revealed factors associated with longer survival of patients, namely, higher preoperative hemoglobin concentration (P = .001), increased blood transfusions (P = .048), and decreased fresh frozen plasma transfusions (P = .004).

CONCLUSIONS

Liver retransplantation is a method providing satisfactory outcomes in selected patients. The perioperative period has a major impact on patient outcome.

Impact of Donor Risk Index on Risk of Hepatic Artery Thrombosis in Patients After Orthotopic Liver Transplantation

BACKGROUND

Hepatic artery thrombosis (HAT) is one of the most severe complications after liver transplantation (LT). HAT can lead to early graft loss and retransplantation or death of the recipient.

METHODS

This retrospective cohort study was conducted using data from patients treated between January 2008 and December 2013 in the Department of General, Transplant and Liver Surgery at the Medical University of Warsaw. A total of 750 patients underwent LT over this period.

RESULTS

HAT occurred in 27 patients (2.1%). The median DRI was 1.414 (IQR 1.103-1.578) points and median donor age was 47 (IQR 33-56) years. The optimal cut-off value of DRI in predicting HAT was ≥1.328 points. The cutoff point was characterized by sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 88.0%, 41.3%, 5.5% and 98.9%, respectively (AUC = 0.605, 95% CI 0.477-0.733). A DRI ≥1.328 was a significant risk factor for HAT (OR = 5.16, 95% confidence interval [CI] 1.529-17.48, P = .008). The optimal cutoff point for donor age was 50 years and was characterized by sensitivity, specificity, PPV, and NPV of 66.7%, 55.8%, 5.3%, and 97.8%, respectively. Donor age ≥50 years (OR = 2.53, 95% CI 1.123-5.714, P = .025) was a significant risk factor for HAT.

CONCLUSION

DRI is a clinically relevant factor that allows estimating the risk of HAT after liver transplantation from a deceased donor. To reduce the incidence of this complication, the allocation of organs taken from donors at DRI exceeding 1.328 for recipients without other HAT risk factors should be considered.

Outcomes of Patients With Poorly Differentiated Hepatocellular Carcinoma After Liver Transplantation

BACKGROUND

Liver transplantation (LT) outcomes for patients with poorly differentiated (G3) hepatocellular carcinoma (HCC) are unsatisfactory. The aim of this study was to evaluate outcomes in patients with poorly differentiated HCC undergoing LT.

PATIENTS AND METHODS

There were 192 HCC patients after LT in the Department of General, Transplant and Liver Surgery, Medical University of Warsaw, between January 2001 and April 2014. The study group comprised 24 patients with poorly differentiated tumors.

RESULTS

Disease-free survival (DFS) for all patients was 49.5% at 5 years. The 5-year DFS for patients who met the Milan criteria (n = 9, 88.9%) was significantly better compared to those who did not (n = 15, 28.0%, P = .025). Multivariable analysis revealed that only the largest tumor diameter (P = .014) and α-fetoprotein (AFP) concentration (P = .001) were independent risk factors for DFS. The optimal cut-off AFP and tumor size that could distinguish patients with the highest risk were ≥500 ng/mL and ≥3.5 cm, respectively. DFS for patients with AFP <500 ng/mL and tumor size <3.5 cm was 100% after 2.8 years, and for those with ≥500 ng/mL or tumor size ≥3.5 cm was 46.9% after 5 years. However, the DFS for patients with AFP ≥500 ng/mL and tumor size ≥3.5 cm was only 12.5% after 4.7 years (P = .002).

CONCLUSIONS

Outcomes of patients with poorly differentiated HCC treated with LT can be characterized with acceptable survival when applying criteria based on tumor size <3.5 cm and AFP <500 ng/mL.

Raman and fluorescence imaging of phospholipidosis induced by cationic amphiphilic drugs in endothelial cells

Cationic amphiphilic drugs (CADs) are known from lysosomotropism, drug-induced phospholipidosis (DIPL), activation of autophagy, and decreased cell viability, but the relationship between these events is not clear and little is known about DIPL in the endothelium. In this work, the effects of fluoxetine, amiodarone, clozapine, and risperidone on human microvascular endothelial cells (HMEC-1) were studied using a combined methodology of label-free Raman imaging and fluorescence staining. Raman spectroscopy was applied to characterize biochemical changes in lipid profile and their distribution in the cellular compartments, while fluorescence staining (LysoTracker, LipidTOX, LC3B, and JC-1) was used to analyze lysosome volume expansion, activation of autophagy, lipid accumulation, and mitochondrial membrane depolarization. We demonstrated that fluoxetine, amiodarone, and clozapine, but not risperidone, at non-toxic concentrations induced lipid accumulations in the perinuclear and cytoplasmic regions of endothelial cells. Spectroscopic markers of DIPL included a robust increase in the ratio (lipid/(protein + lipid)), an increase in choline-containing lipid, fatty acids, and the presence of cholesterol esters, while starvation-induced activated autophagy revealed a spectroscopic signature associated with subtle changes in the lipid profile only. Interestingly, lysosomal volume expansion, occurrence of DIPL, and activation of autophagy induced by selected CADs all depended on drug-accumulation in acidic pH of lysosome cellular compartments whereas reduced endothelial viability did not, and was attributed to mitochondrial mechanisms as evidenced by a decreased mitochondrial transmembrane potential. In conclusion, drug-induced phospholipidosis in the endothelium did not reduce endothelial viability per se and can be efficiently assayed by Raman imaging.

Raman microscopy allows to follow internalization, subcellular accumulation and fate of iron oxide nanoparticles in cells

An important issue in the context of both potenial toxicity of iron oxide nanoparticles (IONP) and their medical applications is tracking of the internalization process of these nanomaterials into living cells, as well as their localization and fate within them. The typical methods used for this purpose are transmission electron microscopy, confocal fluorescence microscopy as well as light-scattering techniques including dark-field microscopy and flow cytometry. All the techniques mentioned have their advantages and disadvantages. Among the problems it is necessary to mention complicated sample preparation, difficult interpretation of experimental data requiring qualified and experienced personnel, different behavior of fluorescently labeled IONP comparing to those label-free or finally the lack of possibility of chemical composition characteristics of nanomaterials. The purpose of the present investigation was the assessment of the usefulness of Raman microscopy for the tracking of the internalization of IONP into cells, as well as the optimization of this process. Moreover, the study focused on identification of the potential differences in the cellular fate of superparamagnetic nanoparticles having magnetite and maghemite core. The Raman spectra of U87MG cells which internalized IONP presented additional bands which position depended on the used laser wavelength. They occurred at the wavenumber range 1700-2400 cm-1 for laser 488 nm and below the wavenumber of 800 cm-1 in case of laser 532 nm. The intensity of the mentioned Raman bands was higher for the green laser (532 nm) and their position, was independent and not characteristic on the primary core material of IONP (magnetite, maghemite). The obtained results showed that Raman microscopy is an excellent, non-destructive and objective technique that allows monitoring the process of internalization of IONP into cells and visualizing such nanoparticles and/or their metabolism products within them at low exposure levels. What is more, the process of tracking IONP using the technique may be further improved by using appropriate wavelength and power of the laser source.

Mechanisms of mitotic inhibition in human aorta endothelial cells: Molecular and morphological in vitro spectroscopic studies

Mitotic inhibitors are drugs commonly used in chemotherapy, but their nonspecific and indiscriminate distribution throughout the body after intravenous administration can lead to serious side effects, particularly on the cardiovascular system. In this context, our investigation into the mechanism of the cytotoxic effects on endothelial cells of mitotic inhibitors widely used in cancer treatment, such as paclitaxel (also known as Taxol) and Vinca alkaloids, holds significant practical implications. Understanding these mechanisms can lead to more targeted and less harmful cancer treatments. Human aorta endothelial cells (HAECs) were incubated with selected mitotic inhibitors in a wide range of concentrations close to those in human plasma during anticancer therapy. The analysis of single cells imaged by Raman spectroscopy allowed for visualization of the nuclear, cytoplasmic, and perinuclear areas to assess biochemical changes induced by the drug's action. The results showed significant changes in the morphology and molecular composition of the nucleus. Moreover, an effect of a given drug on the cytoplasm was observed, which can be related to its mechanism of action (MoA). Raman data supported by fluorescence microscopy measurements identified unique changes in DNA form and proteins and revealed drug-induced inflammation of endothelial cells. The primary goal of mitotic inhibitors is based on the impairment of tubulin formation and the inhibition of the mitosis process. While all three drugs affect microtubules and disrupt cell division, they do so through different MoA, i.e., Vinca alkaloids inhibit microtubule formation, whereas paclitaxel stabilizes microtubules. To sum up, the work shows how a specific drug can interact with endothelial cells.

Raman microscopy reveals how cell inflammation activates glucose and lipid metabolism

Metabolism of endothelial cells (ECs) depends on the availability of the energy substrates. Since the endothelium is the first line of defence against inflammation in the cardiovascular system and its dysfunction can lead to the development of cardiovascular diseases, it is important to understand how glucose metabolism changes during inflammation. In this work, glucose uptake was studied in human microvascular endothelial cells (HMEC-1) in high glucose (HG), and additionally in an inflammatory state, using Raman imaging. HG state was induced by incubation of ECs with a deuterated glucose analogue, while the EC inflammation was caused by TNF-α pre-treatment. Spontaneous and stimulated Raman scattering spectroscopy provided comprehensive information on biochemical changes, including lipids and the extent of unsaturation induced by excess glucose in ECs., induced by excess glucose in ECs. In this work, we indicated spectroscopic markers of metabolic changes in ECs as a strong increase in the ratio of the intensity of lipids / (proteins + lipids) bands and an increase in the level of lipid unsaturation and mitochondrial changes. Inflamed ECs treated with HG, revealed enhanced glucose uptake, and intensified lipid production i.a. of unsaturated lipids. Additionally, increased cytochrome c signal in the mitochondrial region indicated higher mitochondrial activity and biogenesis. Raman spectroscopy is a powerful method for determining the metabolic markers of ED which will better inform understanding of disease onset, development, and treatment.