AIM: To describe the way stations of high-density lipoprotein(HDL) uptake and its lipid exchange in endothelial cells in vitro and in vivo. METHODS: A combination of fluorescence microscopy using ...novel fluorescent cholesterol surrogates and electron microscopy was used to analyze HDL endocytosis in great detail in primary human endothelial cells. Further, HDL uptake was quantified using radio-labeled HDL particles. To validate the in vitro findings mice were injected with fluorescently labeled HDL and particle uptake in the liver was analyzed using fluorescencemicroscopy. RESULTS: HDL uptake occurred via clathrin-coated pits, tubular endosomes and multivesicular bodies in human umbilical vein endothelial cells. During uptake and resecretion, HDL-derived cholesterol was exchanged at a faster rate than cholesteryl oleate, resembling the HDL particle pathway seen in hepatic cells. In addition, lysosomes were not involved in this process and thus HDL degradation was not detectable. In vivo, we found HDL mainly localized in mouse hepatic endothelial cells. HDL was not detected in parenchymal liver cells, indicating that lipid transfer from HDL to hepatocytes occurs primarily via scavenger receptor, class B, type Ⅰ mediated selective uptake without concomitant HDL endocytosis. CONCLUSION: HDL endocytosis occurs via clathrincoated pits, tubular endosomes and multivesicular bodies in human endothelial cells. Mouse endothelial cells showed a similar HDL uptake pattern in vivo indicating that the endothelium is one major site of HDL endocytosis and transcytosis.
Patients with preclinical left ventricular (LV) diastolic dysfunction (DD) are prone to develop heart failure with preserved ejection fraction. Although left atrial (LA) enlargement and deterioration ...of LA function in apparent DD and heart failure with preserved ejection fraction have been previously described, data regarding phasic LA strain (LAS) in preclinical DD are scarce.
In a cross-sectional trial, echocardiographic parameters of DD, LA volume index, and global LA reservoir, conduit, and pump function were prospectively analyzed in 473 women from the general population in Berlin, Germany (BErlin Female RIsk evaluation (BEFRI) study), using standard and two-dimensional speckle-tracking echocardiography.
One hundred thirty-one women (29.7%) showed early-stage DD (impaired relaxation DD1) and 22 (5.0%) showed an echocardiographically more advanced stage of DD (pseudonormal filling DD2). Compared with women with normal diastolic function (DD0), those with DD1 displayed lower LA reservoir and conduit function (DD0, 43.2 ± 8.5% and 27.2 ± 8.0%; DD1, 33.3 ± 8.0% and 16.1 ± 7.1%; P < .001) but significantly higher LA pump function (DD0, 17.6 ± 5.4%; DD1, 18.9 ± 5.5%; P < .05). In patients with DD2, all three phases of LAS were markedly impaired compared with those with DD0 (reservoir, conduit, and pump function, 29.0 ± 6.3%, 15.1 ± 5.4% P < .001, and 14.9 ± 4.1% P < .05, respectively). LA reservoir and conduit function was significantly associated with DD; in receiver operating characteristic curve analysis, these parameters showed higher diagnostic accuracy in detecting early DD compared with LA volume index. In multivariate analysis, LA reservoir strain remained significantly associated with DD.
All three components of LAS showed specific alterations in different stages of DD. LA reservoir and conduit function was markedly reduced before symptoms, LA enlargement, and elevations of noninvasively estimated LV filling pressures occurred. Analysis of LA function featured higher discriminative strength in diagnosing early-stage DD compared with the well-established parameter LA volume index. Assessment of LAS allows diagnosis of impaired LA function and DD in a subclinical stage and might enable timely preventive and therapeutic interventions.
The aim of our study was to compare the impact of implantation of a balloon-expandable transcatheter valve into the inferior vena cava (CAVI) on exercise capacity with optimal medical therapy (OMT) ...in patients with severe tricuspid regurgitation (TR) and high surgical risk.
Twenty-eight patients were randomised to OMT (n=14) or CAVI (n=14). The primary endpoint was maximal oxygen uptake at the three-month follow-up. Secondary endpoints included six-minute walk test, NYHA class, NT-proBNP levels, right heart function, unscheduled heart failure hospitalisation, and quality of life as assessed by the Minnesota Living with Heart Failure Questionnaire (MLHFQ). Patients underwent follow-up examinations one, three, six, and twelve months after randomisation. Maximal oxygen uptake did not change significantly in either group after three months and there was no difference between the OMT and CAVI groups (-0.1±1.8 ml∙kg-1∙min-1 vs -1.0±1.6 ml∙kg-1∙min-1, p=0.4995). Compared to baseline, CAVI improved NYHA class, dyspnoea, and quality of life after three months. However, there were no statistically significant differences in the secondary endpoints between the groups. Four periprocedural complications occurred after CAVI, resulting in open heart surgery. Four patients in the OMT group and eight patients (including four after conversion to surgery) in the CAVI group died from right heart failure, sepsis or haemorrhage.
CAVI did not result in a superior functional outcome compared to OMT. Due to an unexpectedly high rate of valve dislocations, the study was stopped for safety reasons.
Aim
We aim to determine normative reference data of phasic right atrial (RA) strain and to investigate determinants, possible clinical implications as well as feasibility and reproducibility of RA ...strain analysis.
Methods and Results
Right atrial strain was analyzed in 266 participants of the cross‐sectional Berlin Female Risk Evaluation (BEFRI) study using 2D speckle‐tracking echocardiography (2D STE). To determine reference values, phasic RA strain was determined in a subgroup of 123 individuals without known cardiovascular diseases or risk factors. Mean RA reservoir strain (RAS), RA conduit, and contraction strain in this reference group were 44.9 ± 11.6%, 27.1 ± 9.5%, and 17.0 ± 5.9%, respectively. Regarding possible clinical implications, RAS was significantly reduced in women with a BMI ≥ 25, compared with women with a BMI < 25 (35.5 ± 11.1% vs 43.4 ± 11.6%, P < 0.0001). RA strain analysis showed a good feasibility (92.7%); intra‐ and inter‐observer variability was low (<5%). BMI, global longitudinal peak systolic LV strain (LVGLS%), RA area, TAPSE, and early diastolic myocardial relaxation velocity of the RV (RV‐e′) were significantly associated with RA mechanics in a multivariate logistic regression analysis.
Conclusion
In this cross‐sectional trial, we determined reference values, feasibility and reproducibility, clinical and echocardiographic determinants, and possible clinical implications of RA strain analysis. Our data may help to introduce the analysis of RA mechanics into future echocardiographic routine use.
We previously reported that mutations in the anillin (
) gene cause familial forms of FSGS. ANLN is an F-actin binding protein that modulates podocyte cell motility and interacts with the ...phosphoinositide 3-kinase (PI3K) pathway through the slit diaphragm adaptor protein CD2-associated protein (CD2AP). However, it is unclear how the
mutations cause the FSGS phenotype. We hypothesized that the R431C mutation exerts its pathogenic effects by uncoupling ANLN from CD2AP.
We conducted
complementation assays in zebrafish to determine the effect of the previously identified missense
variants,
and
during development. We also performed
functional assays using human podocyte cell lines stably expressing wild-type ANLN (
) or
.
Experiments in
-deficient zebrafish embryos showed a loss-of-function effect for each
variant. In human podocyte lines, expression of
increased cell migration, proliferation, and apoptosis. Biochemical characterization of
-expressing podocytes revealed hyperactivation of the PI3K/AKT/mTOR/p70S6K/Rac1 signaling axis and activation of mTOR-driven endoplasmic reticulum stress in
-expressing podocytes. Inhibition of mTOR, GSK-3
, Rac1, or calcineurin ameliorated the effects of
. Additionally, inhibition of the calcineurin/NFAT pathway reduced the expression of endogenous ANLN and mTOR.
The
mutation causes multiple derangements in podocyte function through hyperactivation of PI3K/AKT/mTOR/p70S6K/Rac1 signaling. Our findings suggest that the benefits of calcineurin inhibition in FSGS may be due, in part, to the suppression of ANLN and mTOR. Moreover, these studies illustrate that rational therapeutic targets for familial FSGS can be identified through biochemical characterization of dysregulated podocyte phenotypes.
Genomic rearrangements that give rise to oncogenic gene fusions can offer actionable targets for cancer therapy. Here we present a systematic analysis of oncogenic gene fusions among a clinically ...well-characterized, prospectively collected set of 278 primary colon cancers spanning diverse tumor stages and clinical outcomes. Gene fusions and somatic genetic variations were identified in fresh frozen clinical specimens by Illumina RNA-sequencing, the STAR fusion gene detection pipeline, and GATK RNA-seq variant calling. We considered gene fusions to be pathogenically relevant when recurrent, producing divergent gene expression (outlier analysis), or as functionally important (e.g., kinase fusions). Overall, 2.5% of all specimens were defined as harboring a relevant gene fusion (kinase fusions 1.8%). Novel configurations of
, and
gene fusions resulting from chromosomal translocations were identified. An R-spondin fusion was found in only one tumor (0.35%), much less than an earlier reported frequency of 10% in colorectal cancers. We also found a novel fusion involving USP9X-ERAS formed by chromothripsis and leading to high expression of ERAS, a constitutively active RAS protein normally expressed only in embryonic stem cells. This USP9X-ERAS fusion appeared highly oncogenic on the basis of its ability to activate AKT signaling. Oncogenic fusions were identified only in lymph node-negative tumors that lacked BRAF or KRAS mutations. In summary, we identified several novel oncogenic gene fusions in colorectal cancer that may drive malignant development and offer new targets for personalized therapy.
.
Physicians need both medical expertise and diverse skills for effective patient care. Adaptability is also key in embracing advances in technology and new techniques. We outline six thought-provoking ...points to guide the new generation of urologists.
Aortic stenosis (AS) leads to remodeling of the left heart. Strain measurements enable the assessment of left atrial (LA) mechanics. The goal of this study was to evaluate the short-term effects of ...transcatheter aortic valve implantation (TAVI) on LA myocardial deformation as well as left ventricular (LV) diastolic function.
Thirty-two patients with severe AS were prospectively enrolled and examined before and 8.2 ± 3.3 days after TAVI. Speckle-tracking echocardiography of the basal septal and lateral segments of the left atrium was performed to determine peak positive strain (R(LA)), strain during early diastole (E(LA)), and, if feasible, strain during atrial contraction (A(LA)). Assessment of LV diastolic function included standard indices, the atrial fraction, and LA volumes.
Compared with baseline, the mean atrial reservoir (R(LA)) (24.0 ± 11.2% vs 32.2 ± 14.0%, P < .001) and conduit function (R(LA) - E(LA)) (13.9 ± 5.5% vs 20.8 ± 8.1%, P < .001) improved significantly after TAVI. There was a significant reduction in deceleration time (242 ± 56 vs 195 ± 65 msec, P < .001) and an improvement of pulsed-wave tissue Doppler-derived E' (5.5 ± 1.8 vs 7.3 ± 2.3 cm/sec, P = .01). Regarding LA volumes, only the minimal LA volume index changed significantly. In contrast, there was no improvement in atrial contraction, that is, contractile function (E(LA) - A(LA)) and atrial fraction. Moreover, the E/E' ratio remained unchanged.
8.2 ± 3.3 days after TAVI, only the reservoir and conduit function of the left atrium improved, whereas LA contraction and LA volumes, except for the systolic volume index, remained unchanged. This was accompanied by improvement of early LV diastolic function, indicating acute recovery of LV relaxation and LA function.
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