Analgesic effect of intrathecal bumetanide is accompanied by changes in spinal sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 expression in a rat model of incisional pain

Accumulating evidence has demonstrated that the sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 have a role in the modulation of pain transmission at the spinal level through chloride regulation in the pain pathway and by effecting neuronal excitability and pain sensitization. The present study aimed to investigate the analgesic effect of the speciifc sodium-potassium-chloride co-transporter 1 inhibitor bumetanide, and the change in spinal sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 expression in a rat model of incisional pain. Results showed that intrathecal bumetanide could decrease cumulative pain scores, and could increase thermal and mechanical pain thresholds in a rat model of incisional pain. Sodium-potassium-chloride co-transporter 1 expression in-creased in neurons from dorsal root ganglion and the deep laminae of the ipsilateral dorsal horn following incision. By contrast, potassium-chloride co-transporter 2 expression decreased in neurons of the deep laminae from the ipsilateral dorsal horn. These ifndings suggest that spinal sodium-potassium-chloride co-transporter 1 expression was up-regulated and spinal potassi-um-chloride co-transporter 2 expression was down-regulated following incision. Intrathecal bumetanide has analgesic effects on incisional pain through inhibition of sodium-potassi-um-chloride co-transporter 1.

Analysis of hepatitis B virus preS1 variability and prevalence of the rs2296651 polymorphism in a Spanish population

AIM To determine the variability/conservation of the domain of hepatitis B virus(HBV) pre S1 region that interacts with sodium-taurocholate cotransporting polypeptide(hereafter, NTCP-interacting domain) and the prevalence of the rs2296651 polymorphism(S267 F, NTCP variant) in a Spanish population. METHODS Serum samples from 246 individuals were included and divided into 3 groups: patients with chronic HBV infection(CHB)(n = 41, 73% Caucasians), patients with resolved HBV infection(n = 100, 100% Caucasians) and an HBV-uninfected control group(n = 105, 100% Caucasians). Variability/conservation of the amino acid(aa) sequences of the NTCPinteracting domain,(aa 2-48 in viral genotype D) and a highly conserved pre S1 domain associated with virion morphogenesis(aa 92-103 in viral genotype D) were analyzed by next-generation sequencing and compared in 18 CHB patients with viremia > 4 log IU/mL. The rs2296651 polymorphism was determined in all individuals in all 3 groups using an in-house real-time PCR melting curve analysis.RESULTS The HBV pre S1 NTCP-interacting domain showed a high degree of conservation among the examined viral genomes especially between aa 9 and 21(in the genotype D consensus sequence). As compared with the virion morphogenesis domain, the NTCPinteracting domain had a smaller proportion of HBV genotype-unrelated changes comprising > 1% of the quasispecies(25.5% vs 31.8%), but a larger proportion of genotype-associated viral polymorphisms(34% vs 27.3%), according to consensus sequences from Gen Bank patterns of HBV genotypes A to H. Variation/conservation in both domains depended on viral genotype, with genotype C being the most highly conserved and genotype E the most variable(limited finding, only 2 genotype E included). Of note, proline residues were highly conserved in both domains, and serine residues showed changes only to threonine or tyrosine in the virion morphogenesis domain. The rs2296651 polymorphism was not detected in any participant.CONCLUSION In our CHB population, the NTCP-interacting domain was highly conserved, particularly the proline residues and essential amino acids related with the NTCP interaction, and the prevalence of rs2296651 was low/null.

Efficacy and Safety of SGLT2 Inhibitors in Patients with Type 1 Diabetes:A Meta-analysis of Randomized Controlled Trials

Objective To assess the efficiency and safety of a novel sodium-glucose co-transporter 2(SGLT2) inhibitor—SGLT2 inhibitors,in combination with insulin for type 1 diabetes mellitus(T1DM). Methods We searched Medline,Embase,and the Cochrane Collaboration Library to identify the eligible studies published between January 2010 and July 2016 without restriction of language. The Food and Drug Administration(FDA) data and Clinical Trials(http://www.clinicaltrials.gov) were also searched. The included studies met the following criteria:randomized controlled trials; T1DM patients aged between 18 and 65 years old; patients were treated with insulin plus SGLT2 inhibitors for more than 2 weeks; patients' glycosylated hemoglobin(HbA1c) levels were between 7% and 12%. The SGLT2 inhibitors group was treated with SGLT2 inhibitors plus insulin,and the placebo group received placebo plus insulin treatment. The outcomes should include one of the following items:fasting blood glucose,HbA1c,glycosuria,or adverse effects. Data were analyzed by two physicians independently. The risk of bias was evaluated by using the Cochrane Collaboration's Risk of Bias tool and heterogeneity among studies was assessed using Chi-square test. Random effect model was used to analyze the treatment effects with Revman 5.3. Results Three trials including 178 patients were enrolled. As compared to the placebo group,SGLT2 inhibitor absolutely decreased fasting blood glucose [mean differences(MD)-2.47 mmol/L,95% confidence interval(CI)-3.65 to-1.28,P<0.001] and insulin dosage(standardized MD-0.75 U,95%CI-1.17 to-0.33,P<0.001). SGLT2 inhibitors could also increase the excretion of urine glucose(MD 131.09 g/24 h,95%CI 91.79 to 170.39,P<0.001). There were no significant differences in the incidences of hyperglycemia [odds ratio(OR) 1.82,95%CI 0.63 to 5.29,P=0.27],urinary tract infection(OR 0.95,95%CI 0.19 to 4.85,P=0.95),genital tract infection(OR 0.27,95%CI 0.01 to 7.19,P=0.43),and diabetic ketoacidosis(OR 6.03,95%CI 0.27 to 135.99,P=0.26) between the two groups. Conclusion SGLT2 inhibitors combined with insulin might be an efficient and safe treatment modality for T1DM patients.

Perspective of future drugs targeting sterile 20/SPS1-related proline/alanine-rich kinase for blood pressure control

According to a genome-wide association study,intronic SNPs within the human sterile 20/SPS1-related proline/alanine-rich kinase(SPAK) gene was linked to 20% of the general population and may be associated with elevated blood pressure. As cell volume changes,mammalian SPAK kinases respond to phosphorylate and regulate cation-coupled chloride co-transporter activity. To our knowledge,phosphorylation of upstream with-no-lysine(K)(WNK) kinases would activate SPAK kinases. The activation of WNK-OSR1/SPAK cascade on the kidneys and aortic tissue is related to the development of hypertension. Several regulators of the WNK pathway such as the Kelch kinase protein 3-Cullin 3 E3 ligase,hyperinsulinemia,and low potassium intake to mediate hypertension have been identified. In addition,the SPAK kinases may affect the action of renin-angiotensin-aldosterone system on blood pressure as well. In 2010,two SPAK knock-in and knock-out mouse models have clarified the pathogenesis of lowering blood pressure by influencing the receptors on the kidneys and aortic smooth muscle. More recently,two novel SPAK inhibitors for mice,Stock 1S-14279 and Closantel were discovered in 2014. Targeting of SPAK seems to be promising for future antihypertensive therapy. Therefore we raised some viewpoints for the issue for the antihypertensive therapy on the SPAK(gene or kinase).

Recent advances in new-onset diabetes mellitus after kidney transplantation

A common challenge in managing kidney transplant recipients(KTR)is posttransplant diabetes mellitus(PTDM)or diabetes mellitus(DM)newly diagnosed after transplantation,in addition to known pre-existing DM.PTDM is an important risk factor for post-transplant cardiovascular(CV)disease,which adversely affects patient survival and quality of life.CV disease in KTR may manifest as ischemic heart disease,heart failure,and/or left ventricular hypertrophy.Available therapies for PTDM include most agents currently used to treat type 2 diabetes.More recently,the use of sodium glucose co-transporter 2 inhibitors(SGLT2i),glucagon-like peptide-1 receptor agonists(GLP-1 RA),and dipeptidyl peptidase 4 inhibitors(DPP4i)has cautiously extended to KTR with PTDM,even though KTR are typically excluded from large general population clinical trials.Initial evidence from observational studies seems to indicate that SGLT2i,GLP-1 RA,and DPP4i may be safe and effective for glycemic control in KTR,but their benefit in reducing CV events in this otherwise high-risk population remains unproven.These newer drugs must still be used with care due to the increased propensity of KTR for intravascular volume depletion and acute kidney injury due to diarrhea and their single-kidney status,pre-existing burden of peripheral vascular disease,urinary tract infections due to immunosuppression and a surgically altered urinary tract,erythrocytosis from calcineurin inhibitors,and reduced kidney function from acute or chronic rejection.

Novel and emerging diabetes mellitus drug therapies for the type 2 diabetes patient

Type 2 diabetes mellitus is a metabolic disorder of deranged fat, protein and carbohydrate metabolism resulting in hyperglycemia as a result of insulin resistance and inadequate insulin secretion. Although a wide variety of diabetes therapies is available, yet limited efficacy, adverse effects, cost, contraindications, renal dosage adjustments, inflexible dosing schedules and weight gain significantly limit their use. In addition, many patients in the United States fail to meet the therapeutic HbA1c goal of 【 7% set by the American Diabetes Association. As such new and emerging diabetes therapies with different mechanisms of action hope to address some of these drawbacks to improve the patient with type 2 diabetes. This article reviews new and emerging classes, including the sodium-glucosecotransporter-2 inhibitors, 11β-Hydroxysteroid dehydrogenase type 1 inhibitors, glycogen phosphorylase inhibitors; protein tyrosine phosphatase 1B inhibitors, G Protein-Coupled receptor agonists and glucokinase activators. These emerging diabetes agents hold the promise of providing benefit of glucose lowering, weight reduction, low hypoglycemia risk, improve insulin sensitivity, pancreatic β cell preservation, and oral formulation availability. However, further studies are needed to evaluate their safety profile, cardiovascular effects, and efficacy durability in order to determine their role in type 2 diabetes management.

Changes in urinary excretion of water and sodium transporters during amiloride and bendroflumethiazide treatment

AIM： To quantify changes in urinary excretion of aquaporin2 water channels （u-AQP2）, the sodium-potassium-chloride co-transporter （u-NKCC2） and the epithelial sodium channels （u-ENaC） during treatment with bendrofumethiazide （BFTZ）, amiloride and placebo.METHODS： In a randomized, double-blinded, placebo-controlled, 3-way crossover study we examined 23 healthy subjects on a standardized diet and fuid intake. The subjects were treated with amiloride 5 mg, BFTZ 1.25 mg or placebo twice a day for 4.5 d before each examination day. On the examination day, glomerular filtration rate was measured by the constant infusion clearance technique with 51Cr-EDTA as reference substance. To estimate the changes in water transport via AQP2 and sodium transport via NKCC2 and ENaC, u-NKCC2, the gamma fraction of ENaC （u-ENaCγ）, and u-AQP2 were measured at baseline and after infusion with 3% hypertonic saline. U-NKCC2, u-ENaCγ, u-AQP2 and plasma concentrations of vasopressin （p-AVP）, renin （PRC）, angiotensin Ⅱ （p-ANG Ⅱ） and aldosterone （p-Aldo） were measured, by radioimmunoassay. Central blood pressure was estimated by applanation tonometry and body fuid volumes were estimated by bio-impedance spectroscopy. General linear model with repeated measures or related samples Friedman’s two-way analysis was used to compare differences. Post hoc Bonferroni correction was used for multiple comparisons of post infusion periods to baseline within each treatment group.RESULTS： At baseline there were no differences in u-NKCC2, u-ENaCγ and u-AQP2. PRC, p-Ang Ⅱ and p-Aldo were increased during active treatments （P 〈 0.001）. After hypertonic saline, u-NKCC2 increased during amiloride （6% ± 34%; P = 0.081） and increased significantly during placebo （17% ± 24%; P = 0.010）. U-AQP2 increased signifcantly during amiloride （31% ± 22%; P 〈 0.001） and placebo （34% ± 27%; P 〈 0.001）, while u-NKCC2 and u-AQP2 did not change signifcantly during BFTZ （-7% ± 28%; P = 0.257 and 5% ± 16%; P = 0.261）. U- ENaCγ increased in all three groups （ P 〈 0.050）. PRC, AngⅡ and p-Aldo decreased to the same extent, while AVP increased, but to a smaller degree during BFTZ （ P = 0.048）. cDBP decreased significantly during BFTZ （P 〈 0.001）, but not during amiloride or placebo. There were no significant differences in body fuid volumes.CONCLUSION： After hypertonic saline, u-NKCC2 and u-AQP2 increased during amiloride, but not during BFTZ. Lower p-AVP during BFTZ potentially caused less stimulation of NKCC2 and AQP2 and subsequent lower reabsorption of water and sodium.

Advances in reducing cardiovascular risk in the management of patients with type 2 diabetes mellitus

Treatment intended to lower cardiovascular (CV) risk in patients with diabetes has always been a primary goal of diabetes treatment. Due to the subdued effects of reducing hemoglobin A1c (HbA1c) on macrovascular complications, controlling other CV risk factors such as hypertension and hyperlipidemia instead of hyperglycemia has been the mainstay treatment to improve CV outcome in patients with type 2 diabetes mellitus (T2DM) until recent years. This review is intended to summarize and compare the results from the available cardiovascular outcome trials (CVOTs) for the two classes of glucose lowering drug: sodium-glucose cotransporter 2 inhibitor (SGLT2i) and glucagon-like peptide-1 receptor agonist (GLP-1 RA). The results including the EMPA-REG, CANVAS program and DECLARE-TIMI 58 trials for SGLT2i, and the ELIXA, LEADER, SUSTAIN-6, EXSCEL and HARMONY trials for GLP-1 RA were summarized. The potential mechanisms of these CV beneficial effects and the optimal CV risk reduction treatment in patients with T2DM based on patient risk stratification and evidence from these CVOTs in real-world setting were discussed.