Esophageal cooling for protection during left atrial ablation: a systematic review and meta-analysis.

PURPOSE: Thermal damage to the esophagus is a risk from radiofrequency (RF) ablation of the left atrium for the treatment of atrial fibrillation (AF). The most extreme type of thermal injury results in atrio-esophageal fistula (AEF) and a correspondingly high mortality rate. Various strategies for reducing esophageal injury have been developed, including power reduction, esophageal deviation, and esophageal cooling. One method of esophageal cooling involves the direct instillation of cold water or saline into the esophagus during RF ablation. Although this method provides limited heat-extraction capacity, studies of it have suggested potential benefit. We sought to perform a meta-analysis of published studies evaluating the use of esophageal cooling via direct liquid instillation for the reduction of thermal injury during RF ablation. METHODS: We searched PubMed for studies that used esophageal cooling to protect the esophagus from thermal injury during RF ablation. We then performed a meta-analysis using a random effects model to calculate estimated effect size with 95% confidence intervals, with an outcome of esophageal lesions stratified by severity, as determined by post-procedure endoscopy. RESULTS: A total of 9 studies were identified and reviewed. After excluding preclinical and mathematical model studies, 3 were included in the meta-analysis, totaling 494 patients. Esophageal cooling showed a tendency to shift lesion severity downward, such that total lesions did not show a statistically significant change (OR 0.6, 95% CI 0.15 to 2.38). For high-grade lesions, a significant OR of 0.39 (95% CI 0.17 to 0.89) in favor of esophageal cooling was found, suggesting that esophageal cooling, even with a low-capacity thermal extraction technique, reduces the severity of lesions resulting from RF ablation. CONCLUSIONS: Esophageal cooling reduces the severity of the lesions that may result from RF ablation, even when relatively low heat extraction methods are used, such as the direct instillation of small volumes of cold liquid. Further investigation of this approach is warranted, particularly with higher heat extraction capacity techniques

Chemokine receptor CXCR4 expression in hepatocellular carcinoma patients increases the risk of bone metastases and poor survival

Abstract Background The chemokine and bone marrow-homing receptor CXCR4 is implicated in metastases of various cancers. This study was conducted to analyze the association of CXCR4 expression with hepatocellular carcinoma (HCC) bone metastasis and patient survival. Methods Tumor tissue from HCC patients with (n = 43) and without (n = 138) bone metastasis was subjected to immunohistochemical staining for CXCR4 using tissue microarrays. Immunoreactivity was evaluated semi-quantitatively. A receiver-operating characteristic-based approach and logistical regression analysis were used to determine the predictive value of clinicopathologic factors, including CXCR4 expression, in bone metastasis. Patient survival was analyzed by Kaplan-Meier curves and log-rank tests. Results CXCR4 overexpression was detected in 34 of 43 (79.1%) patients with bone metastases and in 57 of 138 (41.3%) without bone metastases. CXCR4 expression correlated with (correlation coefficient: 0.551, P predictive of HCC bone metastases (AUC: 0.689; 95%CI: 0.601 – 0.776; P ). CXCR4 staining intensity correlated with the bone metastasis-free survival (correlation coefficient: -0.359; P = 0.018). CXCR4 overexpression in primary tumors (n = 91) decreased overall median survival (18.0 months vs. 36.0 months, P 0.001). Multivariable analysis identified CXCR4 as a strong, independent risk factor for reduced disease-free survival (relative risk [RR]: 5.440; P = 0.023) and overall survival (RR: 7.082; P = 0.001). Conclusion CXCR4 expression in primary HCCs may be an independent risk factor for bone metastasis and may be associated with poor clinical outcome.</p

The role of a new CD44st in increasing the invasion capability of the human breast cancer cell line MCF-7

<p>Abstract</p> <p>Background</p> <p>CD44, a hyaluronan (HA) receptor, is a multistructural and multifunctional cell surface molecule involved in cell proliferation, cell differentiation, cell migration, angiogenesis, presentation of cytokines, chemokines and growth factors to the corresponding receptors, and docking of proteases at the cell membrane, as well as in signaling for cell survival. The CD44 gene contains 20 exons that are alternatively spliced, giving rise to many CD44 isoforms, perhaps including tumor-specific sequences.</p> <p>Methods</p> <p>Reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting were used to detect CD44st mRNA and CD44 protein in sensitive MCF-7, Lovo, K562 and HL-60 cell lines as well as their parental counterparts, respectively. The full length cDNA encoding CD44st was obtained from the total RNA isolated from MCF-7/Adr cells by RT-PCR, and subcloned into the pMD19-T vector. The CD44st gene sequence and open reading frame were confirmed by restriction enzyme analysis and nucleotide sequencing, and then inserted into the eukaryotic expression vector pcDNA3.1. The pcDNA3.1-CD44st was transfected into MCF-7 cells using Lipofectamine. After transfection, the positive clones were obtained by G418 screening. The changes of the MMP-2 and MMP-9 genes and protein levels were detected by RT-PCR and gelatin zymography, respectively. The number of the cells penetrating through the artificial matrix membrane in each group (MCF-7, MCF-7+HA, MCF-7/neo, MCF-7/neo+HA, MCF-7/CD44st, MCF-7/CD44st+HA and MCF-7/CD44st+Anti-CD44+HA) was counted to compare the change of the invasion capability regulated by the CD44st. Erk and P-Erk were investigated by Western blotting to approach the molecular mechanisms of MMP-2 and MMP-9 expression regulated by the CD44st.</p> <p>Results</p> <p>Sensitive MCF-7, Lovo, K562 and HL-60 cells did not contain CD44st mRNA and CD44 protein. In contrast, the multidrug resistance MCF-7/Adr, Lovo/Adr, K562/Adr and HL-60/Adr cells expressed CD44st mRNA and CD44 protein. The CD44st mRNA gene sequence was successfully cloned into the recombinant vector pcDNA3.1 and identified by the two restriction enzymes. It was confirmed that the reconstructed plasmid contained the gene sequence of CD44st that was composed of exons 1 to 4, 16 to 17, and 1 to 205 bases of exons 18. The new gene sequence was sent to NCBI for publication, and obtained the registration number FJ216964. The up-regulated level of the mRNA of the CD44 gene and the CD44 protein were detected, respectively, by RT-PCR and flow cytometry in MCF-7 cells transfected with pcDNA3.1-CD44st. The invasiveness of the cells and the activity of MMP-2 and MMP-9 were clearly activated by HA treatment, and blocked by CD44 neutralizing antibody. MCF-7/CD44st cells pretreated with the neutralizing antibody against CD44, and the inhibitor of MAPKs signaling pathway, could strongly block the expression of P-Erk.</p> <p>Conclusions</p> <p>A new CD44st was expressed in multidrug resistant MCF-7/Adr, Lovo/Adr, K562/Adr and HL-60/Adr cells. The expression vector pcDNA3.1-CD44st was cloned and constructed successfully, and stably transfected into MCF-7 cells. HA could interact with the new CD44st and regulate the expression of MMP-2 and MMP-9, which could increase the invasion capability of MCF-7 cells through the Ras/MAPK signaling pathway.</p

Employment of gene expression profiling to identify transcriptional regulators of hepatic stellate cells

Activated hepatic stellate cells (HSC) play a central role in scar formation that leads to liver fibrosis. The molecular mechanisms underlying this process are not fully understood. Microarray and bioinformatics analyses have proven to be useful in identifying transcription factors that regulate cellular processes such as cell differentiation. Using oligonucleotide microarrays, we performed transcriptional analyses of activated human HSC cultured on Matrigel-coated tissue culture dishes. Examination of microarray data following Matrigel-induced deactivation of HSC revealed a significant down-regulation of myocardin, an important transcriptional regulator in smooth and cardiac muscle development. Thus, gene expression profiling as well as functional assays of activated HSC have provided the first evidence of the involvement of myocardin in HSC activation

Aldosterone does not require angiotensin II to activate NCC through a WNK4–SPAK–dependent pathway

We and others have recently shown that angiotensin II can activate the sodium chloride cotransporter (NCC) through a WNK4–SPAK-dependent pathway. Because WNK4 was previously shown to be a negative regulator of NCC, it has been postulated that angiotensin II converts WNK4 to a positive regulator. Here, we ask whether aldosterone requires angiotensin II to activate NCC and if their effects are additive. To do so, we infused vehicle or aldosterone in adrenalectomized rats that also received the angiotensin receptor blocker losartan. In the presence of losartan, aldosterone was still capable of increasing total and phosphorylated NCC twofold to threefold. The kinases WNK4 and SPAK also increased with aldosterone and losartan. A dose-dependent relationship between aldosterone and NCC, SPAK, and WNK4 was identified, suggesting that these are aldosterone-sensitive proteins. As more functional evidence of increased NCC activity, we showed that rats receiving aldosterone and losartan had a significantly greater natriuretic response to hydrochlorothiazide than rats receiving losartan only. To study whether angiotensin II could have an additive effect, rats receiving aldosterone with losartan were compared with rats receiving aldosterone only. Rats receiving aldosterone only retained more sodium and had twofold to fourfold increase in phosphorylated NCC. Together, our results demonstrate that aldosterone does not require angiotensin II to activate NCC and that WNK4 appears to act as a positive regulator in this pathway. The additive effect of angiotensin II may favor electroneutral sodium reabsorption during hypovolemia and may contribute to hypertension in diseases with an activated renin–angiotensin–aldosterone system

Differential baseline and response profile to IFN-γ gene transduction of IL-6/IL-6 receptor-α secretion discriminate primary tumors versus bone marrow metastases of nasopharyngeal carcinomas in culture

<p>Abstract</p> <p>Background</p> <p>Understanding of immunobiology of bone marrow metastases (designated BM-NPC) <it>versus </it>primary tumors (P-NPC) of the nasopharynx is far from complete. The aim of this study was to determine if there would be differences between cultured P-NPCs and BM-NPCs with respect to (i) constitutive IL-6 and the IL-6 receptor gp80 subunit (IL-6Rα) levels in the spent media of nontransduced cells, and (ii) IL-6 and IL-6Rα levels in the spent media of cells transduced with a retroviral vector containing the <it>IFN-γ </it>gene.</p> <p>Methods</p> <p>A panel of NPC cell lines were transduced with the <it>IFN-γ </it>gene through a retroviral vector. Four clonal sublines were isolated <it>via </it>limiting dilution methods. Cytofluorometric analysis was performed for the detection of cell surface antigens of HLA class I, HLA class II and ICAM-1. ELISA was used to assay for IFN-γ, IL-6 and IL-6Rα in the spent media of cultured cell lines.</p> <p>Results</p> <p>Our results showed that in day 3 culture supernatants, low levels of soluble IL-6 were detected in 5/5 cultured tumors derived from P-NPCs, while much higher constitutive levels of IL-6 were detected in 3/3 metastasis-derived NPC cell lines including one originated from ascites; the difference was significant (<it>p </it>= 0.025). An inverse relationship was found between IL-6Rα and IL-6 in their release levels in cultured P-NPCs and metastasis-derived NPCs. In <it>IFN-γ</it>-transduced-P-NPCs, IL-6 production increased and yet IL-6Rα decreased substantially, as compared to nontransduced counterparts. At variance with P-NPC cells, the respective ongoing IL-6 and IL-6Rα release patterns of BM-NPC cells were not impeded as much following <it>IFN-γ </it>transduction. These observations were confirmed by extended kinetic studies with representative NPC cell lines and clonal sublines. The latter observation with the clonal sublines also indicates that selection for high IL-6 or low IL-6Rα producing subpopulations did not occur as a result of <it>IFN-γ</it>-transduction process. P-NPCs, which secreted constitutively only marginal levels of IFN-γ (8.4 ~ 10.5 pg/ml), could be enhanced to produce higher levels of IFN-γ (6.8- to 10.3-fold increase) after <it>IFN-γ </it>transduction. Unlike P-NPCs, BM-NPCs spontaneously released IFN-γ at moderate levels (83.8 ~ 100.7 pg/ml), which were enhanced by 1.3- to 2.2-fold in the spent media of their <it>IFN-γ</it>-transduced counterparts.</p> <p>Conclusion</p> <p>Our results showed that cultured P-NPCs and BM-NPCs could be distinguished from one another on the basis of their differential baseline secretion pattern of IFN-γ, IL-6 and IL-6Rα, and their differential response profiles to <it>IFN-γ </it>gene transfer of the production of these three soluble molecules. These results suggest that the IL-6 and IFN-γ pathways in a background of genetic instability be involved in the acquisition of metastatic behaviour in BM-NPCs.</p

2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

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Localization and trafficking of aquaporin 2 in the kidney

Aquaporins (AQPs) are membrane proteins serving in the transfer of water and small solutes across cellular membranes. AQPs play a variety of roles in the body such as urine formation, prevention from dehydration in covering epithelia, water handling in the blood–brain barrier, secretion, conditioning of the sensory system, cell motility and metastasis, formation of cell junctions, and fat metabolism. The kidney plays a central role in water homeostasis in the body. At least seven isoforms, namely AQP1, AQP2, AQP3, AQP4, AQP6, AQP7, and AQP11, are expressed. Among them, AQP2, the anti-diuretic hormone (ADH)-regulated water channel, plays a critical role in water reabsorption. AQP2 is expressed in principal cells of connecting tubules and collecting ducts, where it is stored in Rab11-positive storage vesicles in the basal state. Upon ADH stimulation, AQP2 is translocated to the apical plasma membrane, where it serves in the influx of water. The translocation process is regulated through the phosphorylation of AQP2 by protein kinase A. As soon as the stimulation is terminated, AQP2 is retrieved to early endosomes, and then transferred back to the Rab 11-positive storage compartment. Some AQP2 is secreted via multivesicular bodies into the urine as exosomes. Actin plays an important role in the intracellular trafficking of AQP2. Recent findings have shed light on the molecular basis that controls the trafficking of AQP2