Development and validation of a nomogram to predict the risk of peripheral artery disease in patients with type 2 diabetes mellitus.

Objective: To develop and validate a nomogram for predicting the risk of peripheral artery disease (PAD) in patients with type 2 diabetes mellitus (T2DM) and assess its clinical application value. Methods: Clinical data were retrospectively collected from 474 patients with T2DM at the Air Force Medical Center between January 2019 and April 2022. The patients were divided into training and validation sets using the random number table method in a ratio of 7:3. Multivariate logistic regression analysis was performed to identify the independent risk factors for PAD in patients with T2DM. A nomogram prediction model was developed based on the independent risk factors. The predictive efficacy of the prediction model was evaluated using the consistency index (C-index), area under the curve (AUC), receiver operating characteristic (ROC) curve, Hosmer-Lemeshow (HL) test, and calibration curve analysis. Additionally, decision curve analysis (DCA) was performed to evaluate the prediction model's performance during clinical application. Results: Age, disease duration, blood urea nitrogen (BUN), and hemoglobin (P<0.05) were observed as independent risk factors for PAD in patients with T2DM. The C-index and the AUC were 0.765 (95% CI: 0.711-0.819) and 0.716 (95% CI: 0.619-0.813) for the training and validation sets, respectively, indicating that the model had good discriminatory power. The calibration curves showed good agreement between the predicted and actual probabilities for both the training and validation sets. In addition, the P-values of the HL test for the training and validation sets were 0.205 and 0.414, respectively, indicating that the model was well-calibrated. Finally, the DCA curve indicated that the model had good clinical utility. Conclusion: A simple nomogram based on three independent factors-duration of diabetes, BUN, and hemoglobin levels-may help clinicians predict the risk of developing PAD in patients with T2DM.

Effect of high-dose clopidogrel according to CYP2C19*2 genotype in patients undergoing percutaneous coronary intervention- a systematic review and meta-analysis.

INTRODUCTION: High-dose clopidogrel has been recommended to overcome clopidogrel non-responsiveness in patients undergoing percutaneous coronary intervention (PCI), especially those with CYP2C19 loss-of-function genotypes. However, there is controversy over the pharmacodynamics and clinical effects of the strategy. This meta-analysis was conducted to evaluate the antiplatelet effects of high-dose clopidogrel according to CYP2C19*2 alleles in patients undergoing PCI. METHODS: Based on PubMed, Cochrane, and EMBASE prior to June 1st, 2014, a systematic review and meta-analysis was conducted to evaluate the antiplatelet effects of high-dose clopidogrel on platelet reactivity and clinical outcomes in PCI treated patients according to CYP2C19*2 genotypes. The reported outcomes including on-treatment platelet reactivity (OTPR), high on-treatment platelet reactivity (HTPR), major adverse cardiovascular events (MACE), stent thrombosis and composite cardiovascular events. RESULTS: Nineteen studies involving 10,960 patients were included. After high-dose clopidogrel administration (600/900 mg loading dose and/or 150 mg/day maintenance dose), compared with non-carriers, carriers of CYP2C19*2 genotype had significantly increased OTPR (SMD for VASP assay: 0.69, 95% CI: 0.48-0.90, p = 4 × 10(-4); for VerifyNow P2Y12 assay: 0.70, 95% CI: 0.54-0.85, p < 10(-5); for LTA assay:0.58, 95% CI: 0.48-0.69, p = 4 × 10(-4)). The incidence rate of HTPR was higher in CYP2C19*2 carriers after high-dose clopidogrel treatment (RR: 1.21, 95% CI:1.05-1.39, p = 0.008 for cutoff PRI > 50% by VASP assay; RR: 1.69, 95% CI: 1.44-1.98, p < 1 × 10(-4) for cutoff PRU > 230 by VerifyNow P2Y12 assay). As for clinical outcomes, CYP2C19*2 was associated with higher risk for MACE (RR: 1.68, 95% CI: 1.19- 2.37, p = 0.003), stent thrombosis (RR: 1.75, 95% CI: 1.31-2.34, p = 0.0001), as well as composite cardiovascular events (RR: 1.82, 95% CI: 1.42- 2.34, p < 10(-5)) after treated by high-dose clopidogrel. CONCLUSION: High-dose clopidogrel could not overcome the variability of clopidogrel antiplatelet effects between the CYP2C19 *2 carriers and non-carriers in patients treated with PCI.

Mitochondrial regulation of NADPH oxidase in hindlimb unweighting rat cerebral arteries.

Exposure to microgravity results in post-flight cardiovascular deconditioning and orthostatic intolerance in astronauts. Vascular oxidative stress injury and mitochondrial dysfunction have been indicated in this process. To elucidate the mechanism for this condition, we investigated whether mitochondria regulated NADPH oxidase in hindlimb unweighting (HU) rat cerebral and mesenteric arteries. Four-week HU was used to simulate microgravity in rats. Vascular superoxide generation, protein and mRNA levels of Nox2/Nox4, and the activity of NADPH oxidase were examined in the present study. Compared with control rats, the levels of superoxide increased in cerebral (P<0.001) but not in mesenteric vascular smooth muscle cells. The protein and mRNA levels of Nox2 and Nox4 were upregulated significantly (P<0.001 and P<0.001 for Nox2, respectively; P<0.001 and P<0.001 for Nox4, respectively) in HU rat cerebral arteries but not in mesenteric arteries. NADPH oxidases were activated significantly by HU (P<0.001) in cerebral arteries but not in mesenteric arteries. Chronic treatment with mitochondria-targeted antioxidant mitoTEMPO attenuated superoxide levels (P<0.001), decreased the protein and mRNA expression levels of Nox2/Nox4 (P<0.01 and P<0.05 for Nox2, respectively; P<0.001 and P<0.001 for Nox4, respectively) and the activity of NADPH oxidase (P<0.001) in HU rat cerebral arteries, but exerted no effects on HU rat mesenteric arteries. Therefore, mitochondria regulated the expression and activity of NADPH oxidases during simulated microgravity. Both mitochondria and NADPH oxidase participated in vascular redox status regulation.

Simulated microgravity-induced mitochondrial dysfunction in rat cerebral arteries.

Exposure to microgravity results in cardiovascular deconditioning, and cerebrovascular oxidative stress injury has been suggested to occur. To elucidate the mechanism for this condition, we investigated whether simulated microgravity induces mitochondrial dysfunction in rat arteries. Four-week hindlimb unweighting (HU) was used to simulate microgravity in rats. Mitochondrial reactive oxygen species (ROS), mitochondrial membrane potential (Δψm), mitochondrial permeability transition pore (mPTP) opening, mitochondrial respiratory control ratio (RCR), MnSOD/GPx activity and expression, and mitochondrial malondialdehyde (MDA) were examined in rat cerebral and mesenteric VSMCs. Compared with the control rats, mitochondrial ROS levels, mPTP opening, and MDA content increased significantly (P<0.001, P<0.01, and P<0.01, respectively), Δψm, RCR, MnSOD/GPx activity (P<0.001 for Δψm and RCR; P<0.05 for MnSOD; and P<0.001 for GPx activity) and protein abundance of mitochondrial MnSOD/GPx-1 decreased (P<0.001 for MnSOD and GPx-1) in HU rat cerebral but not mesenteric arteries. Chronic treatment with NADPH oxidase inhibitor apocynin and mitochondria-targeted antioxidant mitoTempol promoted recovery of mitochondrial function in HU rat cerebral arteries, but exerted no effects on HU rat mesenteric arteries. Therefore, simulated microgravity resulted in cerebrovascular mitochondrial dysfunction, and crosstalk between NADPH oxidase and mitochondria participated in the process.

PON1 Q192R genotype influences clopidogrel responsiveness by relative platelet inhibition instead of on-treatment platelet reactivity.

BACKGROUND: paraoxonase-1 (PON1) was recently identified as the crucial enzyme for clopidogrel bioactivation, with PON1 Q192R (rs662) polymorphism determining the clopidogel antiplatelet efficacy. However, subsequent studies showed controversies over the findings. This study aimed to evaluate the impact of PON1 Q192R in parallel to that of CYP2C19*2 (rs4244285) on clopidogrel responsiveness in a cohort of Chinese patients with unstable angina pectoris. MATERIAL AND METHODS: One hundred and eighty Chinese-Han patients diagnosed with unstable angina pectoris and treated with clopidogrel were consecutively recruited. Clopidogrel responsiveness, measured by relative platelet inhibition {RI=[(pretreatment aggregation-posttreatment aggregation at 5days)/(pretreatment aggregation)] x100%}, was assessed in relation to PON1 Q192R and CYP2C19*2 genotypes. RI values were stratified into four quartiles, with patients in quartile 1 defined as individuals of clopidogrel non-responsiveness. The contributions of PON1 Q192R and CYP2C19*2 to on-treatment platelet reactivity (OTPR) at 5days maintenance dose of clopidogrel were also evaluated. RESULTS: For PON1 Q192R genotypes, RI values were significantly lower in patients with QR and RR alleles than in patients with QQ alleles (p=0.01). OTPR values at 5days maintenance dose of clopidogrel were similar across all the PON1 Q192R genotypes (p=0.41). PON1 192 QR and RR conferred increased risks for clopidogrel non-responsiveness [OR 3.64; 95% CI (1.21-10.92), p=0.02]. For CYP2C19*2 genotypes, compared to CYP2C19*1/*1 wild type carriers, CYP2C19*2 carriers showed a significantly higher OTPR (p=0.009), and a trend for lower RI values (p=0.06). An increased risk for clopidogrel non-responsiveness was found in patients with CYP2C19*2 genotype [OR 2.02; 95% CI (1.03-3.96), p=0.04]. CONCLUSIONS: Both PON1 Q192R and CYP2C19*2 genotypes influence clopidogrel responsiveness, with the impact of PON1 Q192R mainly on relative platelet inhibition instead of OTPR of clopidogrel.

Influence of CYP2C9 and VKORC1 genotypes on the risk of hemorrhagic complications in warfarin-treated patients: a systematic review and meta-analysis.

BACKGROUND: The main challenge for warfarin anticoagulation is the risk for hemorrhagic complications. Although certain pharmacogenetic factors may explain the individual variabilities about the therapeutic warfarin dose requirement, the genetic factors to warfarin hemorrhagic complications due to over-anticoagulation are largely unknown. To interpret the potential role of warfarin-related genotypes on over-anticoagulation and hemorrhagic complications, we conducted a meta-analysis based on 22 published studies. METHODS: A comprehensive search was applied to the reports on over-anticoagulation and hemorrhagic complications published prior to December 31, 2012 in PubMed and EMBASE. References were identified by strict inclusion and exclusion criteria, with additional information obtained by consulting with the authors of primary studies. The roles of genotypes in CYP2C9 and VKORC1 on over-anticoagulation (INR > 4) and hemorrhagic complications were analyzed by Revman 5.0.2 software. RESULTS: A total of 6272 patients in 22 reports were included in the meta-analysis, including studies of 18 from Caucasians (3 from both Caucasian and African-American), 3 from Asians, and 1 from Brazilians. Compared to CYP2C9 wild genotype (CYP2C9*1), both CYP2C9*2 (rs 1799853, c. 430 C > T, p. Arg144Cys) and *3 (rs 1057910, c. 1075 A >C, p. Ile359Leu) confer significantly higher risk for warfarin over-anticoagulation and hemorrhagic complications. After stratification by CYP2C9 allele status, significantly higher risk for hemorrhagic complications was found only in carriers of at least 1 copy of CYP2C9*3 [For total hemorrhages: *1/*3 HR: 2.05 (1.36-3.10), p < 0.001; *3/*3 HR: 4.87 (1.38-17.14), p = 0.01; For major hemorrhages: *1/*3 HR: 2.43 (1.17-5.06), p = 0.02; *3/*3 HR: 4.81 (0.95-24.22), p = 0.06]. Furthermore, similar susceptibility of total hemorrhage by CYP2C9 genotypes was observed in Caucasians and Asians. After stratification by the occurrence time, both CYP2C9*2 and *3 are risk factors for over-anticoagulation within 30 days of warfarin treatment [*2 HR: 1.64 (1.11-2.43), p = 0.01; *3 HR: 2.48 (1.56-3.96), p < 0.001], and only CYP2C9*3 showed higher risk for over-anticoagulation after 30 days [HR: 1.86 (1.08-3.20), P = 0.03]. For VKORC1 c. -1639G > A (rs 9923231) genotypes, GA and AA contributed significantly higher risk for over-anticoagulation within 30 days [HR: 2.14 (1.75-2.62), p < 0.001], but not for over-anticoagulation after 30 days [HR:0.78 (0.46-1.33), p = 0.36]. No significant association was found between VKORC1 genotypes and hemorrhagic complications. CONCLUSIONS: Both CYP2C9 and VKORC1 genotypes are associated with an increased risk for warfarin over-anticoagulation, with VKORC1 c. -1639G > A more sensitive early in the course of anticoagulation. CYP2C9*3 is the main genetic risk factor for warfarin hemorrhagic complications.

Genetic determinants of high on-treatment platelet reactivity in clopidogrel treated Chinese patients.

INTRODUCTION: Cytochrome P450 (CYP), ATP-binding cassette transporters (ABCB1), and paraoxonase-1 (PON1) play crucial roles in clopidogel absorption and bioactivation. Genetic polymorphisms in these genes have been associated with the variability of the response to clopidogrel, however their contribution to high on-treatment platelet reactivity (HPR) in clopidogrel treated Chinese patients is less known. MATERIALS AND METHODS: Five-hundred Chinese-Han patients treated with clopidogrel for acute coronary syndrome (ACS) were consecutively recruited from the Department of Geriatric Cardiology, General Hospital of Chinese People's Liberation Army, from September 2010 to September 2012. We assessed the relations of CYP2C19*2 (rs4244285), CYP2C19*3 (rs4986893), CYP2C19*17 (rs12248560), PON1Q129R (rs662) and ABCB1C3435T (rs1045642) to the platelet aggregation after 5 days maintenance dose of clopidogrel administration, and the risk for HPR. The cutoff of HPR was defined as 20 µmol/L adenosine diphosphate (ADP)-induced platelet aggregation>50%. RESULTS: Both CYP2C19*2 and *3 alleles were significantly associated with higher platelet aggregation after 5 days maintenance dose of clopidogrel administration (P<0.00001 and P=0.042, respectively). The platelet aggregation in carriers of at least one CYP2C19 loss-of-function allele (*2 or *3, accounted for 58% of the study population) was obviously higher than that in non-carriers (P<0.00001). Patients with the CYP2C19*2 allele had a higher risk of HPR than those with the CYP2C19 wild-type genotype [adjusted hazard ratio (HR), 1.56; 95% confidence interval(CI), 1.04-2.33, P=0.03]. The carriers of at least one CYP2C19 loss-of-function allele could also predict significantly greater risk of HPR compared with non-carriers (adjusted HR1.79,95% CI: 1.33-2.4,P=0.003). However, the carriage of CYP2C19*3 alone could not predict the risk of HPR significantly (adjusted HR, 1.5; 95% CI: 0.83-3, P=0.16). Significant relation of CYP2C19*17, PON1Q129R and ABCB1C3435T to the platelet aggregation was not found. CONCLUSION: In clopidogrel treated Chinese patients with ACS, carriers of at least one CYP2C19 loss-of-function allele could predict greater risk of HPR, with the impact mainly attributing to CYP2C19*2. Neither ABCB1 nor PON1 genotype could influence the antiplatelet response of clopidogrel in the cohort of Chinese patients.

Nuclear translocation of calpain-2 regulates propensity toward apoptosis in cardiomyocytes of tail-suspended rats.

The compensatory increase in catecholamine release does not reverse orthostatic intolerance after returning from a long-term spaceflight, but it is unclear whether high dose of catecholamine induces cardiac damage. The tail-suspended rat model was used to simulate the effects of weightlessness on the heart. Apoptotic rates in the left ventricular myocardium did not increase in 4-week of tail-suspended rats compared with the synchronous control. On the contrary, isoproterenol (intraperitoneal injection) and 1-day recovery from the 4-week tail-suspension increased apoptotic rates in the myocardium. Propranolol and PD150606 inhibited cardiomyocyte apoptosis in the recovery group. PD150606 and calpain-2 knockdown also blocked isoproterenol-induced cardiomyocyte apoptosis in tail-suspended rats. The activity and nuclear translocation of calpain-2 increased, but the expression of calpain-1, calpain-2, and calpastatin was unchanged in the myocardium of tail-suspended rats. The Ser-16-phosphorylated phospholamban of the nuclear envelope was higher in tail-suspended rats than in the control rats under isoproterenol stimulation. Isoproterenol treatment also induced a large intranuclear Ca(2+) transient of cardiomyocytes in tail-suspended rats. These results suggest that high-dose isoproterenol phosphorylates phospholamban of the nuclear envelope and increases intranuclear Ca(2+) transient. Larger intranuclear Ca(2+) further activates nuclear calpain-2 and hence induces cardiomyocyte apoptosis.

[Cardiac hypertrophy and changes in contractile function of cardiomyocyte].

To investigate the cellular mechanisms of pressure-overload cardiac hypertrophy transition to heart failure, we observed time course of changes in morphology and contractile function of cardiomyocytes in transverse abdominal aortic constriction (TAC) rats. Since TAC rats suffered higher stress, body weight had a slower growth rate compared with that of synchronous control rats. Therefore, the left ventricular to body weight ratio produced experimental bias to evaluate the degree of cardiac hypertrophy. Length and width of collagenase-isolated cardiomyocyte were directly measured. Length, width and calculated surface area of cardiomyocyte showed a progressive increase in 8-, 16-, and 20-week TAC rats. The increasing rate of surface area in cardiomyocytes was higher at the middle stage of TAC (from the eighth to sixteenth week). Due to the constraint of fibrosis formation, the increasing rate of surface area in cardiomyocytes was slower at the late stage of TAC (from the sixteenth to twentieth week). The sarcomere length of cardiomyocytes was unchanged, whereas sarcomere numbers were significantly increased in 8-, 16-, and 20-week TAC rats. Shortening amplitude of unloaded contraction in single cardiomyocyte was significantly enhanced in 1-week TAC rats, but not altered in 8-week TAC rats compared with that in the synchronous control rats. On the contrary, unloaded shortening amplitude of single cardiomyocyte was significantly reduced in 16- and 20-week TAC rats. The above results suggest that the reduced shortening amplitude may be associated with intrinsic molecular alterations in hypertrophied cardiomyocytes.