Left Ventricular Strain Rate for Intraoperative Evaluation of Cardiac Diastolic Function by Transesophageal Echocardiography: The Correlation Between Late Diastolic Peak Longitudinal Strain Rate and the Severity of Diastolic Dysfunction.

OBJECTIVES: Speckle-tracking echocardiography is a promising tool for evaluating cardiac diastolic dysfunction. A correlation between left atrial strain rate during atrial contraction and the severity of diastolic dysfunction previously has been demonstrated. Because visualization of the left atrial walls is difficult with transesophageal echocardiography, the authors evaluated the use of left ventricular strain rate during atrial contraction as a substitute for left atrial strain rate to intraoperatively measure the extent of cardiac diastolic dysfunction. DESIGN: Retrospective clinical study. SETTING: Single institutional study. PARTICIPANTS: Sixty-six patients who underwent cardiac surgery between January 2018 and January 2021. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Preoperative echocardiographic reports and intraoperative echocardiographic images of the participants were studied. The correlation of cardiac diastolic dysfunction stage with the peak longitudinal strain rate during late diastole and the time to peak value were evaluated. The late diastolic peak longitudinal strain rate was correlated significantly with the stage of diastolic dysfunction (r = -0.64, p < 0.0001). There was no significant correlation between the stage of diastolic dysfunction and the time to peak value (r = -0.17, p = 0.18). A late diastolic peak longitudinal strain rate <0.68 1/s had a sensitivity of 80% and specificity of 81% for predicting grade 2 or 3 diastolic dysfunction. CONCLUSIONS: The late diastolic peak longitudinal strain rate correlates with the severity of diastolic dysfunction in patients undergoing cardiac surgery.

Speckle- Tracking Echocardiography for the Staging of Diastolic Dysfunction: The Correlation Between Strain-Based Indices and the Severity of Left Ventricular Diastolic Dysfunction.

OBJECTIVES: Left ventricular diastolic function can be assessed by various methods. Tissue Doppler imaging is among the most commonly used techniques. However, this imaging is angle- dependent, affected by loading conditions, and susceptible to myocardial tethering. Speckle- tracking echocardiography also can measure strain-based indices to assess diastolic function, and it has fewer limitations than tissue Doppler imaging. Using speckle- tracking echocardiography, the authors evaluated the correlation between the stage of diastolic dysfunction and strain-based indices in patients undergoing cardiac surgery to determine whether strain-based indices can be used intraoperatively to identify the extent of left ventricular diastolic dysfunction. DESIGN: Retrospective clinical study. SETTING: Single university hospital. PARTICIPANTS: Fifty-eight patients undergoing cardiac surgery (December 2017 to December 2019). INTERVENTIONS: None. Measurement and Main Result: Preoperative echocardiographic reports and intraoperative echocardiographic images of the participants were studied. The correlation between the stage of left ventricular diastolic dysfunction and strain-based indices (including early diastolic peak longitudinal strain and tissue deceleration time) were evaluated. Early diastolic peak longitudinal strain rate significantly correlated with the stage of diastolic dysfunction (r = -0.7 and p < 0.0001). Tissue deceleration time significantly correlated with the stage of diastolic dysfunction in patients with diastolic abnormality (r = -0.4 and p = 0.02). When patients with normal diastolic function were included, this correlation was not significant (r= -0.25 and p = 0.05). CONCLUSIONS: Intraoperatively measured early diastolic peak longitudinal strain rate and tissue deceleration time correlated with the severity of diastolic dysfunction in patients undergoing cardiac surgery.

ß-Catenin induces T-cell transformation by promoting genomic instability.

Deregulated activation of ß-catenin in cancer has been correlated with genomic instability. During thymocyte development, ß-catenin activates transcription in partnership with T-cell-specific transcription factor 1 (Tcf-1). We previously reported that targeted activation of ß-catenin in thymocytes (CAT mice) induces lymphomas that depend on recombination activating gene (RAG) and myelocytomatosis oncogene (Myc) activities. Here we show that these lymphomas have recurring Tcra/Myc translocations that resulted from illegitimate RAG recombination events and resembled oncogenic translocations previously described in human T-ALL. We therefore used the CAT animal model to obtain mechanistic insights into the transformation process. ChIP-seq analysis uncovered a link between Tcf-1 and RAG2 showing that the two proteins shared binding sites marked by trimethylated histone-3 lysine-4 (H3K4me3) throughout the genome, including near the translocation sites. Pretransformed CAT thymocytes had increased DNA damage at the translocating loci and showed altered repair of RAG-induced DNA double strand breaks. These cells were able to survive despite DNA damage because activated ß-catenin promoted an antiapoptosis gene expression profile. Thus, activated ß-catenin promotes genomic instability that leads to T-cell lymphomas as a consequence of altered double strand break repair and increased survival of thymocytes with damaged DNA.

Generation of CD4CreER(T²) transgenic mice to study development of peripheral CD4-T-cells.

After thymic emigration CD4-T-cells continue to differentiate into multiple effector and suppressor sublineages in peripheral lymphoid organs. In vivo analysis of peripheral CD4-T-cell differentiation has relied on animal models with targeted gene mutations. These are expressed either constitutively or conditionally after Cre mediated recombination. Available Cre transgenic strains to specifically target T-cells act at stages of thymocyte development that precede thymic selection. Tracing gene functions in CD4-T-cell development after thymic exit becomes complicated when the targeted gene is essential during thymic development. Other approaches to conditionally modify gene functions in peripheral T-cells involve infection of in vitro activated cells with Cre expressing lenti-, retro-, or adenoviruses, which precludes in vivo analyses. To study molecular mechanisms of peripheral CD4-T-cell differentiation in vivo and in vitro we generated transgenic mice expressing a tamoxifen inducible Cre recombinase (CreER(T2) ) under the control of the CD4 gene promoter. We show here that in CD4CreER(T2) mice Cre is inducibly and selectively activated in CD4-T-cells. Tamoxifen treatment both in vivo and in vitro results in efficient recombination of loci marked by LoxP sites. Moreover, this strain shows no abnormalities related to transgene insertion. Therefore it provides a valuable tool for studying gene function during differentiation of naïve peripheral CD4-T-cells into effector or suppressor sub-lineages.

Beta-catenin/Tcf determines the outcome of thymic selection in response to alphabetaTCR signaling.

Thymic maturation of T cells depends on the intracellular interpretation of alphabetaTCR signals by processes that are poorly understood. In this study, we report that beta-catenin/Tcf signaling was activated in double-positive thymocytes in response to alphabetaTCR engagement and impacted thymocyte selection. TCR engagement combined with activation of beta-catenin signaled thymocyte deletion, whereas Tcf-1 deficiency rescued from negative selection. Survival/apoptotis mediators including Bim, Bcl-2, and Bcl-x(L) were alternatively influenced by stabilization of beta-catenin or ablation of Tcf-1, and Bim-mediated beta-catenin induced thymocyte deletion. TCR activation in double-positive cells with stabilized beta-catenin triggered signaling associated with negative selection, including sustained overactivation of Lat and Jnk and a transient activation of Erk. These observations are consistent with beta-catenin/Tcf signaling acting as a switch that determines the outcome of thymic selection downstream the alphabetaTCR cascade.

Four novel germline mutations in the MLH1 and PMS2 mismatch repair genes in patients with hereditary nonpolyposis colorectal cancer.

BACKGROUND: Hereditary nonpolyposis colorectal cancer (HNPCC) is the most common cause of early onset hereditary colorectal cancer. In the majority of HNPCC families, microsatellite instability (MSI) and germline mutation in one of the DNA mismatch repair (MMR) genes are found. MATERIALS AND METHODS: The entire coding sequence of MMR genes (MLH1, MLH2, MLH6, and PMS2) was analyzed using direct sequencing. Also, tumor tests were done as MSI and immunohistochemistry testing. RESULTS: We were able to find three novel MLH1 and one novel PMS2 germline mutations in three Iranian HNPCC patients. The first was a transversion mutation c.346A>C (T116P) and happened in the highly conserved HATPase-c region of MLH1 protein. The second was a transversion mutation c.736A>T (I246L), which caused an amino acid change of isoleucine to leucine. The third mutation (c.2145,6 delTG) was frameshift and resulted in an immature stop codon in five codons downstream. All of these three mutations were detected in the MLH1 gene. The other mutation was a transition mutation, c.676G>A (G207E), which has been found in exon six of the PMS2 gene and caused an amino acid change of glycine to glutamic acid. MSI assay revealed high instability in microsatellite for two patients and microsatellite stable for one patient. CONCLUSION: In all patients, an abnormal expression of the MMR proteins in HNPCC was related to the above novel mutations.

ß-Catenin promotes colitis and colon cancer through imprinting of proinflammatory properties in T cells.

The density and type of lymphocytes that infiltrate colon tumors are predictive of the clinical outcome of colon cancer. High densities of T helper 17 (T(H)17) cells and inflammation predict poor outcome, whereas infiltration by T regulatory cells (Tregs) that naturally suppress inflammation is associated with longer patient survival. However, the role of Tregs in cancer remains controversial. We recently reported that Tregs in colon cancer patients can become proinflammatory and tumor-promoting. These properties were directly linked with their expression of RORγt (retinoic acid-related orphan receptor-γt), the signature transcription factor of T(H)17 cells. We report that Wnt/ß-catenin signaling in T cells promotes expression of RORγt. Expression of ß-catenin was elevated in T cells, including Tregs, of patients with colon cancer. Genetically engineered activation of ß-catenin in mouse T cells resulted in enhanced chromatin accessibility in the proximity of T cell factor-1 (Tcf-1) binding sites genome-wide, induced expression of T(H)17 signature genes including RORγt, and promoted T(H)17-mediated inflammation. Strikingly, the mice had inflammation of small intestine and colon and developed lesions indistinguishable from colitis-induced cancer. Activation of ß-catenin only in Tregs was sufficient to produce inflammation and initiate cancer. On the basis of these findings, we conclude that activation of Wnt/ß-catenin signaling in effector T cells and/or Tregs is causatively linked with the imprinting of proinflammatory properties and the promotion of colon cancer.

Improvement of liver function in liver cirrhosis patients after autologous mesenchymal stem cell injection: a phase I-II clinical trial.

BACKGROUND: End-stage liver disease is a medical problem with high morbidity and mortality. We have investigated the feasibility, safety, and efficacy of using autologous mesenchymal stem cells (MSCs) as a treatment. METHODS: Eight patients (four hepatitis B, one hepatitis C, one alcoholic, and two cryptogenic) with end-stage liver disease having Model for End-Stage Liver Disease score > or =10 were included. Autologous MSCs were taken from iliac crest. Approximately, 30-50 million MSCs were proliferated and injected into peripheral or the portal vein. Liver function and clinical features were evaluated at baseline and 1, 2, 4, 8, and 24 weeks after injection. RESULTS: Treatment was well tolerated by all patients. Liver function improved as verified by the Model for End-Stage Liver Disease score, which decreased from 17.9+/-5.6 to 10.7+/-6.3 (P<0.05) and prothrombin complex from international normalized ratio 1.9+/-0.4 to 1.4+/-0.5 (P<0.05). Serum creatinine decreased from 114+/-35 to 80+/-18 micromol/l (P<0.05). Serum albumin changed from 30+/-5 to 33+/-5 g/l and bilirubin from 46+/-29 to 41+/-31 micromol/l. No adverse effects were noted. CONCLUSION: Our data show that MSCs injection can be used for the treatment of end-stage liver disease with satisfactory tolerability. Furthermore, this treatment may improve clinical indices of liver function in end-stage liver disease.