The NRF2-CARM1 axis links glucose sensing to transcriptional and epigenetic regulation of the pentose phosphate pathway in gastric cancer.

Cancer cells autonomously alter metabolic pathways in response to dynamic nutrient conditions in the microenvironment to maintain cell survival and proliferation. A better understanding of these adaptive alterations may reveal the vulnerabilities of cancer cells. Here, we demonstrate that coactivator-associated arginine methyltransferase 1 (CARM1) is frequently overexpressed in gastric cancer and predicts poor prognosis of patients with this cancer. Gastric cancer cells sense a reduced extracellular glucose content, leading to activation of nuclear factor erythroid 2-related factor 2 (NRF2). Subsequently, NRF2 mediates the classic antioxidant pathway to eliminate the accumulation of reactive oxygen species induced by low glucose. We found that NRF2 binds to the CARM1 promoter, upregulating its expression and triggering CARM1-mediated hypermethylation of histone H3 methylated at R arginine 17 (H3R17me2) in the glucose-6-phosphate dehydrogenase gene body. The upregulation of this dehydrogenase, driven by the H3R17me2 modification, redirects glucose carbon flux toward the pentose phosphate pathway. This redirection contributes to nucleotide synthesis (yielding nucleotide precursors, such as ribose-5-phosphate) and redox homeostasis and ultimately facilitates cancer cell survival and growth. NRF2 or CARM1 knockdown results in decreased H3R17me2a accompanied by the reduction of glucose-6-phosphate dehydrogenase under low glucose conditions. Collectively, this study reveals a significant role of CARM1 in regulating the tumor metabolic switch and identifies CARM1 as a potential therapeutic target for gastric cancer treatment.

Comprehensive analysis of CPNE1 predicts prognosis and drug resistance in gastric adenocarcinoma.

BACKGROUND: Recent studies have confirmed that Copines-1 (CPNE1) is associated with many malignancies. However, the role of CPNE1 in stomach adenocarcinoma (STAD) is currently unclear. METHODS: TIMER2.0, TCGA, UALCAN databases were used to investigate the expression of CPNE1 in STAD and normal tissues. KM-plotter database was used to explore the relationship between CPNE1 expression and prognosis in STAD. Immunohistochemistry (IHC) was used to assess the protein levels of CPNE1 in both normal and cancer tissues, as well as to confirm the prognostic significance of CPNE1. In order to assess the viability of CPNE1 as a divider, the Recipient Operating Characteristics (ROC) curve was employed and the assessment based on the AUC score (below the curve). To investigate the potential function of CPNE1, correlation analysis and enrichment analysis were performed with the clusterProfiler package in R software. The CPNE1 binding protein network was constructed by STRING and GeneMANIA. The relationship between methylation and prognosis was explored by Methsurv database. The Genomics of Drug Sensitivity in Cancer (GDSC) was employed to predict drug responsiveness in STAD. Ultimately, CCK-8 assays and RT-qPCR were performed to confirm the correlation between CPNE1 expression and the IC50 of Axitinib in the AGS cell line. RESULT: CPNE1 is highly expressed in various cancers, including STAD. High expression of CPNE1 indicated poor overall survival (OS) of STAD (P < 0.05). The ROC curve suggested that CPNE1 was a potential diagnostic biomarker (AUC = 0.925). The functions of CPNE1 were enriched in DNA-acting catalytic activity, sulfur transferase activity, Ran GTPase binding, DNA helicase activity, helicase activity and eukaryotic ribosome biosynthesis. Hyper-methylated CPNE1 predicts better prognosis in STAD (P < 0.05). Additionally, STAD patients with high-expression CPNE1 seemed to be more resistant to the chemotherapeutic agents, including A-770041, WH-4-023, AZD-2281, AG-014699, AP-24534, Axitinib, AZD6244, RDEA119, AZD8055, Temsirolimus, Pazopanib and Roscovitine. In vitro experiments demonstrated the involvement of CPNE1 in Axitinib chemoresistance. CONCLUSION: CPNE1 could be a predictive biomarker and a potential target for biological therapy in STAD.

Delta opioid peptide [D-ala2, D-leu5]-Enkephalin's ability to enhance mitophagy via TRPV4 to relieve ischemia/reperfusion injury in brain microvascular endothelial cells.

BACKGROUND: Local brain tissue can suffer from ischaemia/reperfusion (I/R) injury, which lead to vascular endothelial damage. The peptide δ opioid receptor (δOR) agonist [D-ala2, D-leu5]-Enkephalin (DADLE) can reduce apoptosis caused by acute I/R injury in brain microvascular endothelial cells (BMECs). OBJECTIVE: This study aims to explore the mechanism by which DADLE enhances the level of mitophagy in BMECs by upregulating the expression of transient receptor potential vanilloid subtype 4 (TRPV4). METHODS: BMECs were extracted and made to undergo oxygen-glucose deprivation/reoxygenation (OGD/R) accompanied by DADLE. RNA-seq analysis revealed that DADLE induced increased TRPV4 expression. The CCK-8 method was used to assess the cellular viability; quantitative PCR (qPCR) was used to determine the mRNA expression of Drp1; western blot was used to determine the expression of TRPV4 and autophagy-related proteins; and calcium imaging was used to detect the calcium influx. Autophagosomes in in the cells' mitochondria were observed by using transmission electron microscopy. ELISA was used to measure ATP content, and a JC-1 fluorescent probe was used to detect mitochondrial membrane potential. RESULTS: When compared with the OGD/R group, OGD/R+DADLE group showed significantly enhanced cellular viability; increased expression of TRPV4, Beclin-1, LC3-II/I, PINK1 and Parkin; decreased p62 expression; a marked rise in calcium influx; further increases in mitophagy, an increase in ATP synthesis and an elevation of mitochondrial membrane potential. These protective effects of DADLE can be blocked by a TRPV4 inhibitor HC067047 or RNAi of TRPV4. CONCLUSION: DADLE can promote mitophagy in BMECs through TRPV4, improving mitochondrial function and relieving I/R injury.

SLAMF8 can predict prognosis of pan-cancer and the immunotherapy response effectivity of gastric cancer.

SLAMF8, the eighth member of the Signaling Lymphocytic Activation Molecule Family (SLAMF), functions in the regulation of the development and activity of diverse immune cells as a costimulatory receptor within the SLAMF family. Studies had revealed that SLAMF8 is expressed higher in several autoimmune inflammation diseases and tumors. Nevertheless, the connection between SLAMF8 and pan-cancer remains undisclosed. The research investigated the correlation between SLAMF8 and various factors including the immune microenvironment, microsatellite instability, immune novel antigen, gene mutation, immune regulatory factors, immune blockade TMB, and immune or molecular subtypes of SLAMF8 in verse cancer types. Immunohistochemistry was ultimately employed to validate the presence of the SLAMF8 gene in various tumor types including hepatocellular carcinoma, prostate adenocarcinoma, and kidney renal clear cell carcinoma. Furthermore, the relationship between SLAMF8 expression and the therapeutic efficacy of the PD1 blockade agent, Sintilimab, treatment in gastric cancer was validated. The result of differential analysis suggested that SLAMF8 was over-expressed in pan-cancer compared with paracancerous tissues. The analysis of survival indicated a connection between SLAMF8 and the overall prognosis in different types of cancers, where higher levels of SLAMF8 were found to be significantly linked to unfavorable outcomes in patients but favorable outcome of immunotherapy in gastric cancer. Significant correlations were observed between SLAMF8 levels and pan-cancer tumorigenesis, tumor metabolism, and immunity. As a result, SLAMF8 may become an important prognostic biomarker in the majority of tumors and a hopeful gene target for immunotherapy against gastric cancer.

Role of thrombospondin-1 in high-salt-induced mesenteric artery endothelial impairment in rats.

The matrix glycoprotein thrombospondin-1 (THBS1) modulates nitric oxide (NO) signaling in endothelial cells. A high-salt diet induces deficiencies of NO production and bioavailability, thereby leading to endothelial dysfunction. In this study we investigated the changes of THBS1 expression and its pathological role in the dysfunction of mesenteric artery endothelial cells (MAECs) induced by a high-salt diet. Wild-type rats, and wild-type and Thbs1-/- mice were fed chow containing 8% w/w NaCl for 4 weeks. We showed that a high salt diet significantly increased THBS1 expression and secretion in plasma and MAECs, and damaged endothelium-dependent vasodilation of mesenteric resistance arteries in wild-type animals, but not in Thbs1-/- mice. In rat MAECs, we demonstrated that a high salt environment (10-40 mM) dose-dependently increased THBS1 expression accompanied by suppressed endothelial nitric oxide synthase (eNOS) and phospho-eNOS S1177 production as well as NO release. Blockade of transforming growth factor-ß1 (TGF-ß1) activity by a TGF-ß1 inhibitor SB 431542 reversed THBS1 up-regulation, rescued the eNOS decrease, enhanced phospho-eNOS S1177 expression, and inhibited Smad4 translocation to the nucleus. By conducting dual-luciferase reporter experiments in HEK293T cells, we demonstrated that Smad4, a transcription promoter, upregulated Thbs1 transcription. We conclude that THBS1 contributes to endothelial dysfunction in a high-salt environment and may be a potential target for treatment of high-salt-induced endothelium dysfunction.

Enhanced Store-Operated Ca2+ Signal of Small Intestinal Smooth Muscle Cells Accelerates Small Bowel Transit Speed in Type 1 Diabetic Mouse.

Aims: The underlying mechanism of diabetic enteropathy, a common complication of type 1 diabetes, remains unclear. Store-operated Ca2+ entry (SOCE) is a ubiquitous type of Ca2+ influx involved in various cellular functions. Here, we show that SOCE-related stromal interaction molecule 1 (STIM1) and Orai1 participate in inappropriate cellular Ca2+ homeostasis, augmenting agonist-induced small intestinal smooth muscle contraction and small bowel transit speed in a mouse model of type 1 diabetes. Methods and Results: We used small interfering (si)RNA to suppress STIM1 and Orai1 proteins, and employed intracellular Ca2+, small intestinal contraction and intestinal transit speed measurement to investigate the functional change. We found that SOCE activity and Orai1 and STIM1 expression levels of small intestinal smooth muscle were significantly increased in cells cultured in high glucose medium or in diabetic mice. Gastrointestinal transit speed and SOCE-mediated contractions were markedly increased in diabetic mice; Knocking down Orai1 or STIM1 with siRNA rescued both alterations in diabetic mice. However, the Orai1-large conductance Ca2+-activated K+ (BKCa) channel interaction was decreased in diabetic mice, and suppressing Orai1 expression or inhibiting the BKCa channel increased agonist-induced small intestinal contractions in normal mice. Conclusion: We concluded that the increased SOCE caused by excessive STIM1 and Orai1 expression and decreased Orai1-BKCa interaction augmented small intestinal smooth muscle contraction and accelerated small bowel transit speed in diabetic mice. This finding demonstrates a pathological role for SOCE in diabetic enteropathy and provides a potential therapeutic target for diabetic enteropathy.

Physical interaction of tropomyosin 3 and STIM1 regulates vascular smooth muscle contractility and contributes to hypertension.

SCOPE: Tropomyosin (TPM), an actin-binding protein widely expressed across different cell types, is primarily involved in cellular contractile processes. We investigated whether TPM3 physically and functionally interacts with stromal interaction molecule 1 (STIM1) to contribute to vascular smooth muscle cell (VSMC) contraction, store-operated calcium entry (SOCE), and high-salt intake-induced hypertension in rats. METHODS AND RESULTS: Analysis of a rat RNA-seq data set of 80 samples showed that the STIM1 and Tpm3 transcriptome expression pattern is highly correlated, and co-immunoprecipitation results indicated that TPM3 and STIM1 proteins physically interacted in rat VSMCs. Immunohistochemical data displayed obvious co-localization of TPM3 and STIM1 in rat VSMCs. Knockdown of TPM3 or STIM1 in VSMCs with specific small interfering RNA significantly suppressed contractions in tension measurement assays and decreased SOCE in calcium assays. Rats fed a high-salt diet for 4 weeks had significantly higher systolic blood pressure than controls, with significantly increased contractility and markedly increased TPM3 and STIM1 expression levels in the mesenteric resistance artery (shown by tension measurements and immunoblotting, respectively). Additionally, high salt environment in vitro induced significant enhancement of TPM3 and STIM1 expression levels in VSMCs. CONCLUSIONS: We showed for the first time that TPM3 and STIM1 physically and functionally interact to contribute to VSMC contraction, SOCE, and high-salt intake-induced hypertension. Our findings provide mechanistic insights and offer a potential therapeutic target for high-salt intake-induced hypertension.

TRPP2 and STIM1 form a microdomain to regulate store-operated Ca2+ entry and blood vessel tone.

BACKGROUND: Polycystin-2 (TRPP2) is a Ca2+ permeable nonselective cationic channel essential for maintaining physiological function in live cells. Stromal interaction molecule 1 (STIM1) is an important Ca2+ sensor in store-operated Ca2+ entry (SOCE). Both TRPP2 and STIM1 are expressed in endoplasmic reticular membrane and participate in Ca2+ signaling, suggesting a physical interaction and functional synergism. METHODS: We performed co-localization, co-immunoprecipitation, and fluorescence resonance energy transfer assay to identify the interactions of TRPP2 and STIM1 in transfected HEK293 cells and native vascular smooth muscle cells (VSMCs). The function of the TRPP2-STIM1 complex in thapsigargin (TG) or adenosine triphosphate (ATP)-induced SOCE was explored using specific small interfering RNA (siRNA). Further, we created TRPP2 conditional knockout (CKO) mouse to investigate the functional role of TRPP2 in agonist-induced vessel contraction. RESULTS: TRPP2 and STIM1 form a complex in transfected HEK293 cells and native VSMCs. Genetic manipulations with TRPP2 siRNA, dominant negative TRPP2 or STIM1 siRNA significantly suppressed ATP and TG-induced intracellular Ca2+ release and SOCE in HEK293 cells. Inositol triphosphate receptor inhibitor 2-aminoethyl diphenylborinate (2APB) abolished ATP-induced Ca2+ release and SOCE in HEK293 cells. In addition, TRPP2 and STIM1 knockdown significantly inhibited ATP- and TG-induced STIM1 puncta formation and SOCE in VSMCs. Importantly, knockdown of TRPP2 and STIM1 or conditional knockout TRPP2 markedly suppressed agonist-induced mouse aorta contraction. CONCLUSIONS: Our data indicate that TRPP2 and STIM1 are physically associated and form a functional complex to regulate agonist-induced intracellular Ca2+ mobilization, SOCE and blood vessel tone. Video abstract.

Arginine methylation of ribose-5-phosphate isomerase A senses glucose to promote human colorectal cancer cell survival.

Cancer cells remodel their metabolic network to adapt to variable nutrient availability. Pentose phosphate pathway (PPP) plays protective and biosynthetic roles by oxidizing glucose to generate reducing power and ribose. How cancer cells modulate PPP activity in response to glucose supply remains unclear. Here we show that ribose-5-phosphate isomerase A (RPIA), an enzyme in PPP, directly interacts with co-activator associated arginine methyltransferase 1 (CARM1) and is methylated at arginine 42 (R42). R42 methylation up-regulates the catalytic activity of RPIA. Furthermore, glucose deprivation strengthens the binding of CARM1 with RPIA to induce R42 hypermethylation. Insufficient glucose supply links to RPIA hypermethylation at R42, which increases oxidative PPP flux. RPIA methylation supports ROS clearance by enhancing NADPH production and fuels nucleic acid synthesis by increasing ribose supply. Importantly, RPIA methylation at R42 significantly potentiates colorectal cancer cell survival under glucose starvation. Collectively, RPIA methylation connects glucose availability to nucleotide synthesis and redox homeostasis.

Transient Receptor Potential Canonical 5-Scramblase Signaling Complex Mediates Neuronal Phosphatidylserine Externalization and Apoptosis.

Phospholipid scramblase 1 (PLSCR1), a lipid-binding and Ca2+-sensitive protein located on plasma membranes, is critically involved in phosphatidylserine (PS) externalization, an important process in cell apoptosis. Transient receptor potential canonical 5 (TRPC5), is a nonselective Ca2+ channel in neurons that interacts with many downstream molecules, participating in diverse physiological functions including temperature or mechanical sensation. The interaction between TRPC5 and PLSCR1 has never been reported. Here, we showed that PLSCR1 interacts with TRPC5 through their C-termini in HEK293 cells and mouse cortical neurons. Formation of TRPC5-PLSCR1 complex stimulates PS externalization and promotes cell apoptosis in HEK293 cells and mouse cerebral neurons. Furthermore, in vivo studies showed that PS externalization in cortical neurons induced by artificial cerebral ischemia-reperfusion was reduced in TRPC5 knockout mice compared to wild-type mice, and that the percentage of apoptotic neurons was also lower in TRPC5 knockout mice than in wild-type mice. Collectively, the present study suggested that TRPC5-PLSCR1 is a signaling complex mediating PS externalization and apoptosis in neurons and that TRPC5 plays a pathological role in cerebral-ischemia reperfusion injury.

Nuclear lactate dehydrogenase A senses ROS to produce α-hydroxybutyrate for HPV-induced cervical tumor growth.

It is well known that high-risk human papilloma virus (HR-HPV) infection is strongly associated with cervical cancer and E7 was identified as one of the key initiators in HPV-mediated carcinogenesis. Here we show that lactate dehydrogenase A (LDHA) preferably locates in the nucleus in HPV16-positive cervical tumors due to E7-induced intracellular reactive oxygen species (ROS) accumulation. Surprisingly, nuclear LDHA gains a non-canonical enzyme activity to produce α-hydroxybutyrate and triggers DOT1L (disruptor of telomeric silencing 1-like)-mediated histone H3K79 hypermethylation, resulting in the activation of antioxidant responses and Wnt signaling pathway. Furthermore, HPV16 E7 knocking-out reduces LDHA nuclear translocation and H3K79 tri-methylation in K14-HPV16 transgenic mouse model. HPV16 E7 level is significantly positively correlated with nuclear LDHA and H3K79 tri-methylation in cervical cancer. Collectively, our findings uncover a non-canonical enzyme activity of nuclear LDHA to epigenetically control cellular redox balance and cell proliferation facilitating HPV-induced cervical cancer development.

Tumor necrosis factor α accelerates Hep-2 cells proliferation by suppressing TRPP2 expression.

TRPP2, a Ca2+-permeable non-selective cation channel, has been shown to negatively regulate cell cycle, but the mechanism underlying this regulation is unknown. Tumor necrosis factor α (TNF-α) is a proinflammatory cytokine extensively involved in immune system regulation, cell proliferation and cell survival. However, the effects and mechanisms for the role of TNF-α in laryngeal cancer remain unclear. Here, we demonstrated using western blot analyses and intracellular Ca2+ concentration measurements that TNF-α treatment suppressed both TRPP2 expression and ATP-induced Ca2+ release in a laryngeal cancer cell line (Hep-2). Knockdown of TRPP2 by a specific siRNA significantly decreased ATP-induced Ca2+ release and abolished the effect of TNF-α on the ATP-induced Ca2+ release. TNF-α treatment also enhanced Hep-2 cell proliferation and growth, as determined using cell counting and flow cytometry cell cycle assays. Moreover, TNF-α treatment down-regulated phosphorylated protein kinase R-like endoplasmic reticulum kinase (p-PERK) and phosphorylated eukaryotic translation initiation factor (p-eIF2α) expression levels, without affecting PERK and eIF2α expression levels in Hep-2 cells. We concluded that suppressing TRPP2 expression and TRPP2-mediated Ca2+ signaling may be one mechanism underlying TNF-α-enhanced Hep-2 cell proliferation. These results offer new insights into the mechanisms of TNF-α-mediated laryngeal cancer cell proliferation, and provide evidences showing a potential role of TNF-α in the development of laryngeal cancer.

TRPP2 Enhances Metastasis by Regulating Epithelial-Mesenchymal Transition in Laryngeal Squamous Cell Carcinoma.

BACKGROUND/AIM: Surgery and chemotherapy treatments of human laryngeal squamous cell carcinoma (HLSCC) may fail due to metastasis, in which epithelial-mesenchymal transition (EMT) plays an important role. TRPP2, a nonselective cation channel, is expressed in various cell types and participates in many biological processes. Here, we show that TRPP2 enhanced metastasis by regulating EMT. METHODS: We used immunohistochemistry, western blotting, Ca2+ imaging, transwell and wound healing assays to investigate TRPP2 expression levels in HLSCC tissue, and the role of TRPP2 in invasion and metastasis of a human laryngocarcinoma cell line (Hep2 cell). RESULTS: We found that TRPP2 protein expression levels were significantly increased in HLSCC tissue; higher TRPP2 levels were associated with decreased patient survival time and degree of differentiation and advanced clinical stage. Knockdown of TRPP2 by transfection with TRPP2 siRNA markedly suppressed ATP-induced Ca2+ release, wound healing, and cell invasion in Hep2 cells. Moreover, TRPP2 siRNA significantly decreased vimentin expression but increased E-cadherin expression in Hep2 cells. In the EMT signalling pathway, TRPP2 siRNA significantly decreased Smad4, STAT3, SNAIL, SLUG and TWIST expression in Hep2 cells. CONCLUSION: We revealed a previously unknown function of TRPP2 in cancer development and a TRPP2-dependent mechanism underlying laryngocarcinoma cell invasion and metastasis. Our results suggest that TRPP2 may be used as a biomarker for evaluating patient prognosis and as a novel therapeutic target in HLSCC.

Increasing TRPV4 expression restores flow-induced dilation impaired in mesenteric arteries with aging.

The flow-stimulated intracellular Ca(2+) concentration ([Ca(2+)]i) rise in endothelial cells is an important early event leading to flow-induced blood vessel dilation. Transient receptor potential vanilloid subtype 4 (TRPV4), a Ca(2+)-permeable cation channel, facilitates the flow-stimulated [Ca(2+)]i rise. To determine whether TRPV4 is involved in age-related flow-induced blood vessel dilation impairment, we measured blood vessel diameter and nitric oxide (NO) levels and performed Ca(2+) imaging, immunoblotting, and immunostaining assays in rats. We found that the flow-induced and TRPV4 activator 4α-PDD-induced dilation of mesenteric arteries from aged rats were significantly decreased compared with those from young rats. The flow- or 4α-PDD-induced [Ca(2+)]i rise was also markedly reduced in primary cultured mesenteric artery endothelial cells (MAECs) from aged rats. Immunoblotting and immunostaining results showed an age-related decrease of TRPV4 expression levels in MAECs. Additionally, the 4α-PDD-induced NO production was significantly reduced in aged MAECs. Compared with lentiviral GFP-treated aged rats, lentiviral vector delivery of TRPV4 increased TRPV4 expression level in aged MAECs and restored the flow- and 4α-PDD-induced vessel dilation in aged mesenteric arteries. We concluded that impaired TRPV4-mediated Ca(2+) signaling causes endothelial dysfunction and that TRPV4 is a potential target for clinical treatment of age-related vascular system diseases.

Role of Na+-K+-2Cl- Cotransporter 1 in Phenylephrine-Induced Rhythmic Contraction in the Mouse Aorta: Regulation of Na+-K+-2Cl- Cotransporter 1 by Ca2+ Sparks and KCa Channels.

BACKGROUND/AIMS: Vasoconstrictor-induced rhythmic contraction of arteries or veins has been observed both in vivo and in vitro. Many studies have reported that gap junctions, ryanodine receptors, Na+, K+-ATPase and other factors are involved in vasoconstrictor-induced rhythmic contraction in vascular smooth muscle. However, the mechanism is still not completely understood. METHODS: We used vessel tension measurements, intracellular recordings and intracellular Cl- concentration ([Cl-]i) measurements to investigate the mechanism underlying phenylephrine (PE)-induced rhythmic contraction in the mouse aorta. RESULTS: We found that Na+-K+-2Cl- cotransporter 1 (NKCC1) inhibitor bumetanide abolished PE-induced rhythmic contraction. The Cl- channel blockers DIDS and niflumic acid initially augmented the amplitude of PE-induced rhythmic contraction but later inhibited the rhythmic contraction. The large Ca2+-activated K+ channel blocker TEA and iberiotoxin increased the amplitude of PE-induced rhythmic contraction. The voltage-dependent Ca2+ channel blocker, nifedipine, and a Ca2+-free solution abolished PE-induced rhythmic contraction. The inhibitor of ryanodine receptors in the sarcoplasmic reticulum, ryanodine, inhibited PE-induced rhythmic contraction. Moreover, bumetanide hyperpolarized the membrane potential of vascular smooth muscle cells in a resting state or after PE pre-treatment. Bumetanide, niflumic acid, ryanodine, iberiotoxin, nifedipine and Ca2+-free buffer significantly suppressed the PE-induced [Cl-]i increase. CONCLUSION: These data indicate that NKCC1 is involved in the formation of PE-induced rhythmic contraction, and we also provide a method with which to indirectly observe the NKCC1 activity in isolated intact mouse thoracic aortas.

[A clinical intervention study among 463 essential hypertensive patients with metabolic syndrome].

OBJECTIVE: To study the role of baseline risk factors in predicting the onset of diabetes among essential hypertensive patients with metabolic syndrome (MS) and to evaluate an ideal therapeutic regime that could reduce the risk factors and risk of onset of diabetes. METHODS: A randomized parallel clinical trial in essential hypertensive patients of grade 1 or 2 was conducted. Two of the three components (1) increased waist circumference and/or BMI; (2) increased triglycerides (TG) and/or decreased high-density lipoprotein cholesterol; (3) impaired glucose tolerance (IGT) were present define the MS. The three intervention therapy groups were: indapamide + fosinopril (I + F, n = 151); atenolol + nitrendipine (A + N, n = 160); atenolol + nitrendipine + metformin (A + N + M, n = 152). Each case was followed-up monthly and the dosage of medicine taken be adjusted according to their BP level. The plasma glucose during fasting and two hours after taking 75 g glucose orally was also measured every six months. The new onset of diabetes was diagnosed according to the criteria. OGTT, insulin release test, lipid analysis, body weight and waist circumference were measured again at the last follow-up. RESULTS: (1) The lowering of BP was similar among the three groups (P > 0.05). 23 new diabetes onsets occurred, being 10 in group I + F and 8 in group A + N and 5 in group A + N + M, respectively (P > 0.05); (2) Proportions of patients' risk factors decreased significantly in group A + N or A + N + M, e.g. the proportions of high TG in each group reduced by 14.7% and 9.3% respectively (P < 0.05), the central fat distribution reduced by 16.7% and 15.9% respectively (P < 0.05) and the IGT reduced by 6.6% and 29.6% respectively (P < 0.05). However no changes were found in group I + F; (3) After 1 year and 5 months' follow-up, the proportions of main risk factors (high TG, central fat distribution and IGT) in the three groups were 91%, 96%, 83% and 90%, 88%, 47%, respectively. The difference of IGT was significant between two groups (P < 0.01) and the proportions of having three risk factors were 70% and 31% in the two groups (P < 0.01); (4) I + F group was better than A + N group in reduction of TG and central fat distribution. And A + N + M group improved in all risk factors. CONCLUSIONS: IGT alone or combined with increased TG plus abdominal obesity are the most important risk factors in predicting a new onset of diabetes among essential hypertensive patients with MS. Metformin in combination with atenolol plus nitrendipine can significantly prevent the onset of diabetes as well as improve patients' metabolic abnormality.