Empagliflozin ameliorates vascular calcification in diabetic mice through inhibiting Bhlhe40-dependent NLRP3 inflammasome activation

Type 2 diabetes mellitus (T2DM) patients exhibit greater susceptibility to vascular calcification (VC), which has a higher risk of death and disability. However, there is no specific drug for VC therapy. NLRP3 inflammasome activation as a hallmark event of medial calcification leads to arterial stiffness, causing vasoconstrictive dysfunction in T2DM. Empagliflozin (EMPA), a sodium-glucose co-transporter 2 inhibitor (SGLT2i), restrains hyperglycemia with definite cardiovascular benefits. Given the anti-inflammatory activity of EMPA, herein we investigated whether EMPA protected against VC in the aorta of T2DM mice by inhibiting NLRP3 inflammasome activation. Since db/db mice receiving a normal diet developed VC at the age of about 20 weeks, we administered EMPA (5, 10, 20 mg·kg-1·d-1, i.g) to 8 week-old db/db mice for 12 weeks. We showed that EMPA intervention dose-dependently ameliorated the calcium deposition, accompanied by reduced expression of RUNX2 and BMP2 proteins in the aortas. We found that EMPA (10 mg·kg-1·d-1 for 6 weeks) also protected against VC in vitamin D3-overloaded mice, suggesting the protective effects independent of metabolism. We showed that EMPA (10 mg·kg-1·d-1) inhibited the abnormal activation of NLRP3 inflammasome in aortic smooth muscle layer of db/db mice. Knockout (KO) of NLRP3 significantly alleviated VC in STZ-induced diabetic mice. The protective effects of EMPA were verified in high glucose (HG)-treated mouse aortic smooth muscle cells (MOVASs). In HG-treated NLRP3 KO MOVASs, EMPA (1 μM) did not cause further improvement. Bioinformatics and Western blot analysis revealed that EMPA significantly increased the expression levels of basic helix-loop-helix family transcription factor e40 (Bhlhe40) in HG-treated MOVASs, which served as a negative transcription factor directly binding to the promotor of Nlrp3. We conclude that EMPA ameliorates VC by inhibiting Bhlhe40-dpendent NLRP3 inflammasome activation. These results might provide potential significance for EMPA in VC therapy of T2DM patients.

Association of lipoprotein(a) with left ventricular hypertrophy in patients with new-onset acute myocardial infarction: A large cross-sectional study

BACKGROUND

The association of lipoprotein(a) [Lp(a)] with echocardiography-estimated left ventricular hypertrophy (LVH) in high-risk population remains uncertain, so we assessed the association between Lp(a) with echocardiography-derived LVH in patients with new-onset acute myocardial infarction (AMI).

METHODS

In this large, single-center, cross-sectional observational study, we enrolled 2,096 patients with new-onset AMI. Lp(a) was used as the independent variable and LVH was used as the dependent variable. Logistic regression, subgroup and sensitivity analysis were performed to test the association of Lp(a) with LVH.

RESULTS

The concentration of Lp(a) was higher in LVH group compared with the non-LVH group (P < 0.001). Multivariate logistic regression analysis showed that higher Lp(a) was strongly associated with higher risk of LVH, independently of traditional cardiovascular risk factors (Fully adjusted model, Q4 vs Q1, OR: 1.941, 95% CI: 1.343-2.803, P < 0.001). Subgroup analysis showed that the association of Lp(a) with LVH persisted in the subgroups of age (<60 and ≥60 years), sex (male and female), smoking (yes and no), diabetes (yes), hypertension (yes), hyperlipidemia (yes), and chronic kidney diseases (yes and no). Further sensitivity analysis indicated that Lp(a) remained significantly associated with LVH after further adjusting for high-sensitivity C-reactive protein or excluding patients with estimated glomerular filtration rate < 30 ml/min/1.73 m² or dividing Lp(a) into multiple dichotomous variables.

CONCLUSION

Lp(a) was closely associated with LVH in patients with new-onset AMI.

Association of lipoprotein(a) with all-cause and cause-specific mortality: A prospective cohort study

BACKGROUND

A growing number of studies have demonstrated a causal association between lipoprotein(a) [Lp(a)] and atherosclerotic cardiovascular diseases (ASCVDs), but its association with all-cause and cause-specific mortality remains unclear. Therefore, this study aimed to explore the association of Lp(a) with all-cause and cause-specific mortality.

METHODS

This prospective cohort study included 8,525 participants from the third National Health and Nutrition Examination Survey. Lp(a) was considered an exposure variable, all-cause and cause-specific mortality were used as outcome variables, and all participants were followed from the interview date until death or December 31, 2015. COX proportional hazards regression models, stratified analysis, sensitivity analysis, restricted cubic spline plots and Kaplan-Meier survival curves were used to analyze the association of Lp(a) with all-cause and cause-specific mortality.

RESULTS

After adjusting for traditional cardiovascular risk factors, Lp(a) remained strongly associated with all-cause and CVDs-related mortality (P for trend = 0.007 and < 0.001). Subgroup analyses showed that higher Lp(a) remained associated with higher risk of all-cause mortality in those > 60 years of age, with a BMI < 30 kg/m², and without diabetes, whereas the association between Lp(a) and CVDs-related mortality remained stable in participants ≤ 60 years of age, male, with a BMI < 30 kg/m², with hypertension, without diabetes, or without CVDs (P < 0.05). In sensitivity analyses, we found that the association of Lp(a) with all-cause and CVDs-related mortality remained robust after excluding individuals who died within one year of follow-up (P for trend = 0.041 and 0.002).

CONCLUSIONS

Lp(a) was associated with the risk of all-cause and CVDs-related mortality.

Factors predicting the occurrence of aortic valve calcification in patients with coronary artery calcification in China

OBJECTIVES

In patients with coronary artery calcification (CAC), a predictor of adverse cardiovascular events, coronary computed tomography angiography (CCTA) also shows valvular calcification. In this study, we evaluated common clinical indicators in CAC patients with aortic (AoVC) and mitral valve (MVC) calcification.

METHODS

CAC and valvular calcification were quantified using the Agatston score in 636 hospitalised patients with CAC who underwent CCTA.

RESULTS

Valvular calcification was found in 30.5% of patients, with 25.2% (160 patients) showing AoVC. Age was an independent predictor of AoVC in both men (odds ratio (OR), 1.086; 95% confidence interval (CI), [1.054-1.119]; p < 0.001) and women (OR, 1.109; CI, [1.066-1.154]; p < 0.001). In men, we also found that a history of cerebral infarction was an independent predictor of AoVC (OR, 2.402; CI, [1.177-4.902]; p < 0.05). The independent predictors of AoVC in the 60- to 69-years age group were BMI (OR, 1.181; CI, [1.061-1.316]; p < 0.01) and history of cerebral infarction (OR, 3.187; CI, [1.283-7.919]; p < 0.05).

CONCLUSIONS

Age is a key independent predictor of AoVC in CAC patients. History of cerebrovascular disease was also an independent predictor of AoVC, but only in men and patients aged 60-69 years. Our results indicate that a history of cerebral infarction may be used as a risk factor when identifying AoVC in patients with CAC.

Programmed cell death in atherosclerosis and vascular calcification

The concept of cell death has been expanded beyond apoptosis and necrosis to additional forms, including necroptosis, pyroptosis, autophagy, and ferroptosis. These cell death modalities play a critical role in all aspects of life, which are noteworthy for their diverse roles in diseases. Atherosclerosis (AS) and vascular calcification (VC) are major causes for the high morbidity and mortality of cardiovascular disease. Despite considerable advances in understanding the signaling pathways associated with AS and VC, the exact molecular basis remains obscure. In the article, we review the molecular mechanisms that mediate cell death and its implications for AS and VC. A better understanding of the mechanisms underlying cell death in AS and VC may drive the development of promising therapeutic strategies.

Correlation analysis of coronary artery tortuosity and calcification score

Background

Coronary artery tortuosity (CAT) is regarded as a variation of vascular anatomy, and its relationship with coronary artery calcification (CAC) score is still not well clarified. Studying the correlation between coronary artery calcification scores and CAT to determine specific prevention and intervention populations seems to have more meaningful.

Methods

The study is a cross-sectional retrospective study, including 1280 patients. CAT is defined as the presence of at least three consecutive curvatures of more than 45°measured during systole or diastole of a major epicardial coronary artery. Multivariable regression analysis was used to adjust the clinical parameters directly affecting CAT.

Results

Of these individuals, 445 (35%) were evaluated having CAT, of which females are higher than males (59.1% vs. 40.9%). Moderate CAC score (101–400) (odds ratio (OR) 1.49, 95% confidence interval [95%CI] 1.05–2.10, P = 0.025) revealed significantly associated with CAT on univariable analysis. However, multivariable analysis after adjusting for confounding factors only indicated that CAT was positively correlated with female (OR 1.68, 95%CI 1.30–2.17, P < 0.001), hypertension (OR 1.35, 95% CI 1.04–1.75, P = 0.024), and age (OR 1.02, 95% CI 1.01–1.03, P = 0.001), while was negatively associated with body mass index (BMI) 24–27.9(OR 0.76, 95% CI 0.58–1.00, P = 0.044), and BMI > 28 (OR 0.46, 95% CI 0.31–0.68, P < 0.001). Further analysis stratified by gender showed that compared with non-CAT, CAT was significantly linked with moderate CAC score (OR 1.79, 95% CI 1.00–3.20, P = 0.048), hypertension (OR 1.54, 95% CI 1.07–2.22, P = 0.021), and high-density lipoprotein (HDL) (OR 1.86, 95% CI 1.07–3.24, P = 0.028), while was negatively related to BMI > 28 (OR 0.51, 95% CI 0.31–0.84, P = 0.008) in female patients.

Conclusions

CAT is more likely to be found in females, connected with hypertension, age, and BMI. No significant correlation is found between the presence of tortuosity and calcium score or diameter stenosis on multivariable analysis. Whereas the CAT is associated with moderate CAC score in correlation analysis when women are selected as the main group.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-022-01470-w.

Association between hemoglobin glycation index and subclinical myocardial injury in the general population free from cardiovascular disease

BACKGROUND AND AIMS

The relationship between hemoglobin glycation index (HGI) and the diagnosis and prognosis of cardiovascular disease (CVD) has been verified by previous studies. However, it remains unknown whether HGI has a predictive effect on subclinical myocardial injury (SC-MI). The purpose of the present study was to explore the relationship between HGI and SC-MI in the general population free from CVD.

METHODS AND RESULTS

The present study included 6009 participants free of CVD from the third National Health and Nutrition Examination Survey. Binary Logistic regression analysis was used to tested the association between HGI and SC-MI. As results, the HGI was significantly higher in participants with SC-MI compared with those without, and the HGI was positively correlated with SC-MI and other metabolic disorder parameters. Each 1-unit increase of HGI and glycated hemoglobin A1c (HbA1c) was independently associated with higher risk of SC-MI (P < 0.05), while fasting plasma glucose (FPG) was no longer a predictive indicator of SC-MI with the increase of confounding factors [OR (95% CI): 1.001 (0.999-1.003), P = 0.305]. And in the subgroup analysis, HGI, only in participants without diabetes, was independently associated with higher risk of SC-MI, while HbA1c and FPG had no independent predictive role in both diabetic and non-diabetic participants.

CONCLUSIONS

HGI was a significant predictor of SC-MI in the general population free from CVD.

Diabetic mellitus, vascular calcification and hypoxia: A complex and neglected tripartite relationship

DM (diabetic mellitus) and its common vascular complications VC (vascular calcification), are increasingly harmful to human health. In recent years, the research on the relationship between DM and VC is also deepening. Hypoxia, as one of the pathogenic factors of many disease models, is also closely related to the occurrence of DM and VC. There are some studies on the role of hypoxia in the pathogenesis of DM and VC respectively, but no one has made an in-depth summary of the systematic connection between hypoxia, DM and VC. Therefore, what we want to review in this article are the relationship between DM, VC and hypoxia, respectively, as well as the role of hypoxia in the development of DM and VC, which has little concern but is a novel and potentially target that may provide some new ideas for the prevention and treatment of DM, VC, especially diabetic VC.

Mitochondria Homeostasis and Vascular Medial Calcification

Vascular calcification occurs highly prevalent, which commonly predicts adverse cardiovascular events. The pathogenesis of calcification, a complicated and multifactorial process, is incompletely characterized. Accumulating evidence shows that mitochondrial dysfunction may ultimately be more detrimental in the vascular smooth muscle cells (VSMCs) calcification. This review summarizes the role of mitochondrial dysfunction and metabolic reprogramming in vascular calcification, and indicates that metabolic regulation may be a therapeutic target in vascular calcification.

Lactate accelerates vascular calcification through NR4A1-regulated mitochondrial fission and BNIP3-related mitophagy

Arterial media calcification is related to mitochondrial dysfunction. Protective mitophagy delays the progression of vascular calcification. We previously reported that lactate accelerates osteoblastic phenotype transition of VSMC through BNIP3-mediated mitophagy suppression. In this study, we investigated the specific links between lactate, mitochondrial homeostasis, and vascular calcification. Ex vivo, alizarin S red and von Kossa staining in addition to measurement of calcium content, RUNX2, and BMP-2 protein levels revealed that lactate accelerated arterial media calcification. We demonstrated that lactate induced mitochondrial fission and apoptosis in aortas, whereas mitophagy was suppressed. In VSMCs, lactate increased NR4A1 expression, leading to activation of DNA-PKcs and p53. Lactate induced Drp1 migration to the mitochondria and enhanced mitochondrial fission through NR4A1. Western blot analysis of LC3-II and p62 and mRFP-GFP-LC3 adenovirus detection showed that NR4A1 knockdown was involved in enhanced autophagy flux. Furthermore, NR4A1 inhibited BNIP3-related mitophagy, which was confirmed by TOMM20 and BNIP3 protein levels, and LC3-II co-localization with TOMM20. The excessive fission and deficient mitophagy damaged mitochondrial structure and impaired respiratory function, determined by mPTP opening rate, mitochondrial membrane potential, mitochondrial morphology under TEM, ATP production, and OCR, which was reversed by NR4A1 silencing. Mechanistically, lactate enhanced fission but halted mitophagy via activation of the NR4A1/DNA-PKcs/p53 pathway, evoking apoptosis, finally accelerating osteoblastic phenotype transition of VSMC and calcium deposition. This study suggests that the NR4A1/DNA-PKcs/p53 pathway is involved in the mechanism by which lactate accelerates vascular calcification, partly through excessive Drp-mediated mitochondrial fission and BNIP3-related mitophagy deficiency.

Periostin promotes arterial calcification through PPARγ-related glucose metabolism reprogramming

Extracellular matrix (ECM) exerts a series of biological functions and contributes to almost 30% of the osteogenic process. Periostin is a secreted protein that can alter ECM remodeling in response to vascular injury. However, the role of periostin in vascular calcification has yet to be fully investigated. As found in this study, recombinant periostin accelerated the thoracic aortas calcification, increased the expression of glycolysis key enzymes, and disturbed the normal oxidative phosphorylation (OXPHOS) ex vivo, which could be alleviated by the peroxisome proliferation-activated receptor γ (PPARγ) agonist pioglitazone. In vascular smooth muscle cells (VSMCs), periostin promoted VSMC-osteoblastic phenotype transition and calcium deposition and suppressed PPARγ expression. Mechanistically, periostin caused overactivation of glycolysis and mitochondrial dysfunction in VSMCs as assessed by extracellular acidification rate, oxygen consumption rate, and mitochondrial respiratory chain complex activities. Targeted glycolysis inhibitors reduced mitochondrial calcium overload, apoptosis, and periostin-induced VSMCs calcification. PPARγ agonists preserved glycolysis and OXPHOS in the stimulated microenvironment and reversed periostin-promoted VSMC calcification. Furthermore, plasma periostin, lactate, and matrix Gla protein levels were measured in 274 patients undergoing computed tomography to determine coronary artery calcium score (Agatston score). Plasma periostin and lactate levels were both linked to an Agatston score in patients with coronary artery calcification (CAC). There was also a positive correlation between plasma periostin and lactate levels. This study suggests that downregulation of PPARγ is involved in the mechanism by which periostin accelerates arterial calcification partly through excessive glycolysis activation and unbalanced mitochondrial homeostasis.NEW & NOTEWORTHY Periostin caused arterial calcification, overactivated glycolysis, and damaged OXPHOS. PPARγ agonists alleviated periostin-promoted arterial calcification and corrected abnormal glycolysis and unbalanced mitochondrial homeostasis. There exists a relationship between periostin and lactate in patients with CAC.

POSTN promotes diabetic vascular calcification by interfering with autophagic flux

Autophagy is a lysosomal degradative process that is closely related to the pathogenesis of vascular calcification. Recent evidence suggests that periostin (POSTN) is a unique extracellular matrix protein that is associated with diabetic vascular complications. The aim of current study is to investigate the role of POSTN in diabetic vascular calcification and the underlying mechanisms. Results showed that POSTN was highly upregulated in both calcified arteries of diabetic rats and AGEs-BSA mediated vascular smooth muscle cell (VSMC) calcification. POSTN blocked autophagic flux during the diabetic calcification process, as evidenced by increased protein expression of Beclin1, LC3-II, and P62, as well as the co-localization of LC3-II and LAMP1. Inhibition of POSTN alleviated AGEs-BSA-induced autophagic flux blockade, thereby attenuating AGEs-BSA-induced VSMC calcification. Mechanistically, the upregulation of POSTN impaired the fusion of autophagosomes and lysosome and resulted in the autophagic flux blockade in AGEs-BSA-treated VSMC. Furthermore, this autophagic blockade was intracellular ROS-dependent. In summary, this study uncovered a novel mechanism of POSTN in autophagy regulation of diabetic vascular calcification.

Metformin attenuates hyperlipidaemia-associated vascular calcification through anti-ferroptotic effects

Ferroptosis is a form of regulated cell death that involves metabolic dysfunction resulting from iron-dependent excessive lipid peroxidation. Elevated plasma levels of free fatty acids are tightly associated with cardiometabolic risk factors in patients with obesity, diabetes mellitus, and metabolic syndrome. Metformin (Met) is an antidiabetic drug with beneficial cardiovascular disease effects. The aim of this study was to determine the effects of Met on ferroptosis induced by lipid overload and the effects of these changes on vascular smooth muscle cells (VSMCs) calcification. We developed a hyperlipidaemia-related vascular calcification in vivo model with rats fed a high-fat diet combined with vitamin D3 plus nicotine, and palmitic acid (PA), the most abundant long-chain saturated fatty acid in plasma, was used to induce lipid overload and develop an oxidative stress-related calcification model in vitro. The results showed that Met inhibits hyperlipidaemia-associated calcium deposition in the rat aortic tissue. In vitro, treatment of VSMCs with PA stimulates ferroptosis concomitant with increased calcium deposition in VSMCs, while pretreatment with Met attenuates these effects. Furthermore, PA also promotes the protein expression of the extracellular matrix protein periostin (POSTN) and its secretion into the extracellular environment. More importantly, upregulation of POSTN increased the sensitivity of cells to ferroptosis. Mechanistically, upregulation of POSTN suppresses SLC7A11 expression through the inhibition of p53 in VSMCs, which contributes to a decrease in glutathione synthesis and therefore triggers ferroptosis. Interestingly, overexpression of p53 attenuates the inhibitory effect of POSTN on SLC7A11 expression, accompanied by increased Gpx4 expression. Furthermore, p53 knockdown suppresses Met-mediated anti-ferroptosis effects in PA-treated VSMCs, which may be related to the downregulation of SLC7A11 expression. In addition, supplementation of VSMCs with Met enhances the antioxidative capacity of VSMCs through Nrf2 signalling activation. Collectively, targeting POSTN in VSMCs may provide a new strategy for vascular calcification prevention or treatment.

PDK4 promotes vascular calcification by interfering with autophagic activity and metabolic reprogramming

Pyruvate dehydrogenase kinase 4 (PDK4) is an important mitochondrial matrix enzyme in cellular energy regulation. Previous studies suggested that PDK4 is increased in the calcified vessels of patients with atherosclerosis and is closely associated with mitochondrial function, but the precise regulatory mechanisms remain largely unknown. This study aims to investigate the role of PDK4 in vascular calcification and the molecular mechanisms involved. Using a variety of complementary techniques, we found impaired autophagic activity in the process of vascular smooth muscle cells (VSMCs) calcification, whereas knocking down PDK4 had the opposite effect. PDK4 drives the metabolic reprogramming of VSMCs towards a Warburg effect, and the inhibition of PDK4 abrogates VSMCs calcification. Mechanistically, PDK4 disturbs the integrity of the mitochondria-associated endoplasmic reticulum membrane, concomitantly impairing mitochondrial respiratory capacity, which contributes to a decrease in lysosomal degradation by inhibiting the V-ATPase and lactate dehydrogenase B interaction. PDK4 also inhibits the nuclear translocation of the transcription factor EB, thus inhibiting lysosomal function. These changes result in the interruption of autophagic flux, which accelerates calcium deposition in VSMCs. In addition, glycolysis serves as a metabolic adaptation to improve VSMCs oxidative stress resistance, whereas inhibition of glycolysis by 2-deoxy-D-glucose induces the apoptosis of VSMCs and increases the calcium deposition in VSMCs. Our results suggest that PDK4 plays a key role in vascular calcification through autophagy inhibition and metabolic reprogramming.

LYMPHATIC SYSTEM MALFORMATIONS IN NOONAN SYNDROME: TWO CASE REPORTS AND IMAGING ANALYSIS

Lymphedema is a well-known complication of Noonan syndrome (NS) but the lymphatic malformations in NS are poorly understood. We report clinical, genetic, and imaging information about a boy and girl with NS and late-onset lower extremity lymphedema. A de novo mission mutation of RIT1 (NM_006912.5) c.246T&gt;A, p.Phe82Leu was identified in the girl, who also showed systemic lymphatic hyperplasia and dysfunction. Magnetic resonance lymphangio-graphy (MRL) of the boy clearly demonstrated segmental dilated and hyperplastic lymphatics with impaired transport function in an affected limb and pelvic region. Indocyanine green lymphography (ICGL) showed delayed and partial enhancement of the lymph vessels in the affected limb but no lymph reflux was detected. No causative mutation was identified in the second case. Lymphoscintigraphy (LSG) failed to show lymph vessels in either of the children. Our study showed that MRL is a reliable and accurate test that can be used to demonstrate morpho-logical and functional defects of the lymphatic system. Moreover, ICGL is sufficiently sensitive to determine the functional condition of peripheral lymph vessels. The combined use of imaging modalities can give an accurate diagnosis of complex lymphatic system anomalies in NS and other syndromic diseases.

Restoring mitochondrial biogenesis with metformin attenuates β-GP-induced phenotypic transformation of VSMCs into an osteogenic phenotype via inhibition of PDK4/oxidative stress-mediated apoptosis

Mitochondrial abnormalities have long been observed in the development of vascular calcification. Metformin, a member of the biguanide class of antidiabetic drugs, has recently received attention owing to new findings regarding its protective role in cardiovascular disease. Since the precise control of mitochondrial quantity and quality is critical for the survival and function of vascular smooth muscle cells (VSMCs), maintaining mitochondrial homeostasis may be a potential protective factor for VSMCs against osteoblast-like phenotypic transition. However, limited studies have been reported in this area. Here, we investigated the role of metformin in the phenotypic transformation of VSMCs, as well as its intracellular signal transduction pathways. We demonstrated that supplementation with metformin restored the β-glycerophosphate (β-GP)-mediated impairment of mitochondrial biogenesis in VSMCs, as evidenced by an increased mitochondrial DNA copy number, a restored mitochondrial membrane potential (MMP), and upregulated mitochondrial biogenesis-related gene expression, whereas the AMP-activated protein kinase (AMPK) inhibitor compound C suppressed these effects. We also observed that overexpression of pyruvate dehydrogenase kinase 4 (PDK4), an important mitochondrial matrix enzyme in cellular energy metabolism, exacerbated β-GP-induced oxidative stress and subsequent apoptosis in VSMCs but that these effects were suppressed by dichloroacetate, a widely reported PDK4 inhibitor. More importantly, enhanced mitochondrial biogenesis attenuated the β-GP-induced phenotypic transformation of VSMCs into an osteogenic phenotype through inhibition of the PDK4/oxidative stress-mediated apoptosis pathway, whereas disruption of mitochondrial biogenesis by zidovudine aggravated β-GP-induced apoptosis in VSMCs. In addition, inhibition of autophagy by small interfering RNA targeting Atg5 reduced mitochondrial biogenesis in VSMCs. In summary, we uncovered a novel mechanism by which metformin attenuates the phenotypic transformation of VSMCs into an osteogenic phenotype via inhibition of the PDK4/oxidative stress-mediated apoptosis pathway, and mitochondrial homeostasis is involved in this process.

Advanced glycation end products accelerate calcification in VSMCs through HIF-1α/PDK4 activation and suppress glucose metabolism

Arterial media calcification is associated with diabetes mellitus. Previous studies have shown that advanced glycation end products (AGEs) are responsible for vascular smooth muscle cell (VSMC) calcification, but the underlying mechanisms remain unclear. Hypoxia-inducible factor-1α (HIF-1α), one of the major factors during hypoxia, and pyruvate dehydrogenase kinase 4 (PDK4), an important mitochondrial matrix enzyme in cellular metabolism shift, have been reported in VSMC calcification. The potential link among HIF-1α, PDK4, and AGEs-induced vascular calcification was investigated in this study. We observed that AGEs elevated HIF-1α and PDK4 expression levels in a dose-dependent manner and that maximal stimulation was attained at 24 h. Two important HIF-1α-regulated genes, vascular endothelial growth factor A (VEGFA) and glucose transporter 1 (GLUT-1), were significantly increased after AGEs exposure. Stabilization or nuclear translocation of HIF-1α increased PDK4 expression. PDK4 inhibition attenuated AGEs-induced VSMC calcification, which was evaluated by measuring the calcium content, alkaline phosphatase (ALP) activity and runt-related transcription factor 2 (RUNX2) expression levels and by Alizarin red S staining. In addition, the glucose consumption, lactate production, key enzymes of glucose metabolism and oxygen consumption rate (OCR) were decreased during AGEs-induced VSMC calcification. In conclusion, this study suggests that AGEs accelerate vascular calcification partly through the HIF-1α/PDK4 pathway and suppress glucose metabolism.

Involvement of brain-derived neurotrophic factor in exercise‑induced cardioprotection of post-myocardial infarction rats

Exercise induces a number of benefits, including angiogenesis in post‑myocardial infarction (MI); however, the underlying mechanisms have not been fully clarified. Neurotrophic brain‑derived neurotrophic factor (BDNF) serves a protective role in certain adult cardiac diseases through its specific receptor, BDNF/NT‑3 growth factors receptor (TrkB). The present study explored the mechanisms by which exercise improves cardiac function, with a focus on the involvement of the BDNF/TrkB axis. MI rats were assigned to Sham, sedentary, exercise, exercise with K252a (a TrkB inhibitor), and exercise with NG‑nitro‑L‑arginine methyl ester (L‑NAME) groups. The exercise group was subjected to 8 weeks of treadmill running. The results demonstrated that the rats in the exercise group exhibited increased myocardial angiogenesis and improved cardiac function, which was attenuated by K252a. Exercise induced activation of the BDNF/TrkB axis in the ischaemic myocardium and increased serum BDNF levels were abated by exposure to L‑NAME. Improvements in angiogenesis and left ventricular function exhibited a positive association, with changes in serum BDNF. In the in vitro experiments, human umbilical vein endothelial cells were exposed to shear stress (SS) of 12 dyn/cm2 to mimic the effects of exercise training on vascular tissue. An increased tube‑forming capacity, and a nitric oxide (NO)‑dependent prolonged activation of the BDNF/TrkB‑full‑length axis over 12 h, but not the TrkB‑truncated axis, was observed. The SS‑related angiogenic response was attenuated by TrkB inhibition. Overall, these results demonstrate that exercise confers certain aspects of its cardioprotective effects through the activation of the BDNF/TrkB axis in an NO‑dependent manner, a process in which fluid‑induced SS may serve a crucial role.

A Folate-Conjugated Dual-Modal Fluorescent Magnetic Resonance Imaging Contrast Agent that Targets Activated Macrophages In Vitro and In Vivo

Mucin-1 (MUC1), a transmembrane glycoprotein is aberrantly expressed on ∼90% of breast cancer and is an excellent target for nanoparticulate targeted imaging. In this study, the development of a dye-doped NIR emitting mesoporous silica nanoparticles platform conjugated to tumor-specific MUC1 antibody (ab-tMUC1-NIR-MSN) for in vivo optical detection of breast adenocarcinoma tissue is reported. The structural properties, the in vitro and in vivo performance of this nanoparticle-based probe were evaluated. In vitro studies showed that the MSN-based optical imaging nanoprobe is non-cytotoxic and targets efficiently mammary cancer cells overexpressing human tMUC1 protein. In vivo experiments with female C57BL/6 mice indicated that this platform accumulates mainly in the liver and did not induce short-term toxicity. In addition, we demonstrated that the ab-tMUC1-NIR-MSN nanoprobe specifically detects mammary gland tumors overexpressing human tMUC1 in a human MUC1 transgenic mouse model.

Associations between LPL gene polymorphisms and coronary artery disease: evidence based on an updated and cumulative meta-analysis

Lipoprotein lipase (LPL) is widely linked to lipid and lipoprotein metabolism, but its effects on coronary artery disease (CAD) are not clearly elucidated. The aim of this study was to clarify the association between LPL gene polymorphisms and CAD susceptibility. The pooled odds ratio (OR) and 95% confidence interval (CI) were calculated to estimate the strength of the relationship between LPL gene polymorphisms and CAD risk. Comprehensive electronic databases, including PubMed, EMBASE, Web of Science, and the Cochrane Library, were systematically searched. A total of 45 records containing 80 eligible studies were analyzed. The results indicated an increased risk between the LPL D9N polymorphism and susceptibility to CAD in the dominant genetic model (AA + GA vs. GG: OR = 1.46, 95% CI = 1.14-1.87), whereas the LPL HindIII polymorphism showed a protective effect against CAD under all tested models (GG+GT vs. TT: OR = 0.85, 95% CI = 0.75-0.97; GG vs. TT + TG: OR = 0.62, 95% CI = 0.47-0.83; G vs. T: OR = 0.81, 95% CI = 0.71-0.92). No significant association was identified for the LPL N291S and PvuII polymorphisms. Stratification analysis by ethnicity suggested a significant correlation between the LPL S447X polymorphism and CAD susceptibility in Caucasians under the dominant and allele genetic models. In summary, our meta-analysis indicated that the LPL D9N polymorphism was associated with an increased risk of CAD, whereas the S447X and HindIII polymorphisms showed protective effects. There was no association observed between the N291S and PvuII polymorphisms and CAD risk.

Nε-carboxymethyl-lysine promotes calcium deposition in VSMCs via intracellular oxidative stress-induced PDK4 activation and alters glucose metabolism

Diabetes and vascular calcification are intrinsically linked. We previously reported that advanced glycation end products (AGEs) accelerate calcium deposition in vascular smooth muscle cells (VSMCs) via excessive oxidative stress. However, the underlying mechanism remains poorly understood. Pyruvate dehydrogenase kinase 4 (PDK4) is an important mitochondrial matrix enzyme in cellular energy metabolism. Since hyperactivation of PDK4 has been reported in calcified vessels and in patients with diabetes mellitus, inhibition of PDK4 expression may be a strategy for the prevention of diabetic vascular calcification. In this study, we used a rat VSMC model to investigate the role of PDK4 in diabetic vascular calcification and further explore the underlying mechanisms. We observed that Nε-carboxymethyl-lysine (CML), which is a major immunogen of AGEs, accelerated calcium deposition in VSMCs through PDK4 activation. An elevated level of reactive oxygen species (ROS) acted as a signal transduction intermediate to increase PDK4 expression. Either inhibition of PDK4 expression or RAGE (receptor for AGEs) blockade attenuated CML-induced VSMC calcification, as shown by decreased alkaline phosphatase (ALP) activity and runt-related transcription factor 2 (RUNX2) expression. Glucose consumption and lactate production were increased during CML-induced VSMC calcification. Importantly, CML accelerates glycolysis in VSMCs via a PDK4-dependent pathway. In conclusion, this study demonstrates a novel mechanism by which CML promotes VSMC calcification via PDK4 activation and alters glucose metabolism in VSMCs.

A LYVE-1/CRSBP-1 Mutation in Inherited Primary Lymphedema

Primary lymphedema is clinically and genetically heterogeneous with germline mutations identified in approximately 20 primary lymphedema genes. The lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) gene, also known as cell-surface retention sequence binding protein-1 (CRSBP-1), encodes the major hyaluronan receptor in lymphatic endothelia and is one of the most specific lymphatic vessel markers. However, the role of this lymphatic endothelial specific protein in the development of the lymphatic system and lymphatic diseases remains unclear. Here, we report a missense mutation c.18C>G (p.S6R) in exon 1 within the N-terminal extension domain (outside the hyaluronan binding region) of LYVE-1 in three generations of an inherited lymphedema family with or without clinical symptoms. Lymphatic imaging revealed a partial, weak and delayed enhancement of tortuous lymph collectors in the distal part of the lymphedematous lower limb. Our findings revealed that LYVE-1/CRSBP-1 mutation in primary lymphedema cases is connected with both structural and functional lymphatic defects.

Role and timing of second-line therapies for patients with recurrent platinum-resistant ovarian epithelial cancer

OBJECTIVE

To explore the regimens and prognoses of second-line therapies for recurrent platinum-resistant ovarian epithelial cancer (OEC).

MATERIALS AND METHODS

The clinical profiles and second-line regimens were retrospectively analyzed for 65 recurrent platinum-resistant OEC patients treated at Zhejiang Provincial Tumor Hospital during January 2003 to January 2013. In conjunction with literature reviews, the second-line therapies for platinum-resistant recurrent OEC were discussed.

RESULTS

Their average age was 55.2 years. The stages were I (n=4), II (n=3), III (n=45), and IV (n=13). The predominant type was serous adenocarcinoma (n=47, 72.3%). Chemotherapy was refused (n=14) and resistant (n=5 1). One case was lost to follow-up and another three withdrew early. An average of four chemotherapeutic courses were offered in 61 cases. Among them, five cases selected chemotherapy after a second operation. The average therapy-free interval (TFI) was 3.5 months. The efficacies were evaluated for 61 cases. CR (n=5) and partial remission (PR, n=22). The overall survival (OS) rate was 43.6% and average progression-free survival (PFS) was 15.44 months.

CONCLUSION

The efficacy of second-line therapy for recurrent platinum-resistant OEC is rather poor and the feasibility and efficacy of second operation are to be further explored.

Association of RAGE gene Gly82Ser polymorphism with coronary artery disease and ischemic stroke: A systematic review and meta-analysis

BACKGROUND

The receptor for advanced glycosylation end products (RAGE) has been widely linked to diabetic atherosclerosis, but its effects on coronary artery disease (CAD) and ischemic stroke (IS) remain controversial. The Gly82Ser polymorphism is located in the ligand-binding V domain of RAGE, suggesting a possible influence of this variant on RAGE function. The aim of the present study is to clarify the association between the RAGE Gly82Ser polymorphism and susceptibility to CAD and IS.

METHODS

Eligible studies were identified through a comprehensive literature search. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the association of Gly82Ser polymorphism with CAD and IS risk. Fixed- or random-effects model was used depending on the heterogeneity between studies. A funnel plot and Egger linear regression test were applied to assess publication bias. We also performed subgroup analyses to investigate potential sources of heterogeneity.

RESULTS

A total of 16 eligible articles containing 18 studies were analyzed. The pooled analysis indicated that the Gly82Ser polymorphism significantly increased CAD risk in recessive and homozygous genetic models (SS vs GS + GG: OR = 1.34, 95% CI = 1.09-1.64; SS vs GG: OR = 1.38, 95% CI = 1.12-1.71). A significant association between the Gly82Ser polymorphism and IS risk was observed in all tested models except the heterozygous genetic model (GS + SS vs GG: OR = 1.20, 95% CI = 1.04-1.38; SS vs GS + GG: OR = 2.20, 95% CI = 1.74-2.78; SS vs GG: OR = 2.23, 95% CI = 1.72-2.91; S vs G: OR = 1.32, 95% CI = 1.05-1.65). Subgroup analysis suggested an association between CAD and IS risk and the Gly82Ser polymorphism in the Chinese population, but not in the non-Chinese population.

CONCLUSIONS

The current meta-analysis suggests that the RAGE Gly82Ser polymorphism is associated with an increased risk of CAD and IS, especially in the Chinese population. However, better-designed studies with larger sample sizes are needed to validate the results.

Rare Variants in LAMA5 Gene associated with FLT4 and FOXC2 Mutations in Primary Lymphedema May Contribute to Severity

Mutations in the Fms-related tyrosine kinase 4 (FLT4) and forkhead box protein C2 (FOXC2) genes cause Milroy disease (MD) and lymphedema-distichiasis syndrome (LDS), respectively, but the mechanism underlying disease pathology remains unclear. Applying whole-exome sequencing to two families with MD, one LDS family, and one sporadic LDS case, we identified four rare variants in the laminin subunit alpha-5 gene (LAMA5) in subjects carrying novel and known missense FLT4 mutations and a 7-bp duplication and 1-bp insertion in FOXC2. Phenotyping was expanded in some individuals using magnetic resonance lymphangiography, indiocyanine green fluorescence lymphography, and immunofluorescent lymphatic staining of skin tissue. Skin lymphatic staining showed the existence of dermal lymphatic vasculature in the MD case. Significant lymphatic dysfunction was observed in both MD and LDS patients. In the MD patient, tortuous lymphatics in the dorsum of the foot were slowly enhanced on indocyanine green fluorescent lymphography (ICG) imaging. Dilated lymph collectors with disruption and lymph leakage were observed in the familial LDS case on magnetic resonance lymphangiography (MRL). Numerous tortuous lymph collectors were visualized along the entire length of affected lower limbs on MRL imaging, and retrograde lymph flow was observed in the lymph collectors during ICG lymphography in the isolated LDS case. The finding of rare LAMA5 variants together with FLT4 and FOXC2 mutations suggests that these mutations may be co-responsible for these disorders and most likely interfere with the function of lymphatics. Further, larger studies are needed to confirm these results.

Associations between XRCC1 Gene Polymorphisms and Coronary Artery Disease: A Meta-Analysis

Genetic variations that influence DNA repair efficiency may contribute to coronary artery disease (CAD) susceptibility. Previous studies have investigated whether there was evidence of an association between polymorphisms at the X-ray repair cross complementing 1 (XRCC1) gene and susceptibility to CAD, but findings have been inconclusive. We identified eligible studies through a comprehensive literature search to determine whether an association exists between XRCC1 gene polymorphisms and CAD susceptibility. Findings were assessed using the odds ratio (OR) and corresponding 95% confidence interval (CI), which were calculated using a fixed- or random-effects model, based on the heterogeneity of the studies. Ten eligible studies were finally included in this meta-analysis. Our pooled analysis found that XRCC1 polymorphisms were significantly associated with CAD susceptibility under recessive (Arg194Trp: OR = 1.47, 95% CI = 1.13–1.93; Arg399Gln: OR = 1.45, 95% CI = 1.12–1.89), homozygous (Arg194Trp: OR = 1.37, 95% CI = 1.03–1.81; Arg399Gln: OR = 1.56, 95% CI = 1.19–2.05), and allele (Arg399Gln: OR = 1.18, 95% CI = 1.06–1.32) genetic models. Following subgroup analysis by ethnicity, in Asian populations, we found evidence of associations between the XRCC1 Arg194Trp polymorphism and CAD under recessive and homozygous genetic models, and between the XRCC1 Arg399Gln polymorphism and CAD under recessive, homozygous, and allele genetic models. Subgroup analysis stratified by control source revealed associations between the Arg194Trp and Arg399Gln polymorphisms and susceptibility to CAD under recessive and homozygous modes of inheritance, respectively. In addition, subgroup analysis stratified by sample size found that findings of the Arg194Trp polymorphism in large sample sizes were comparable to those found using pooled eligible studies. Based on our meta-analysis, we concluded that the XRCC1 gene polymorphisms, Arg194Trp and Arg399Gln, are associated with CAD susceptibility, specifically in Asian populations. However, additional, comprehensive and well-designed studies are warranted to confirm these findings.

A NOVEL FLT4 GENE MUTATION AND MR LYMPHANGIOGRAPHY IN A CHINESE FAMILY WITH MILROY DISEASE

Milroy disease is a congenital onset lymphedema linked to FLT4 gene mutations in the tyrosine kinase domain. So far, a total of 59 different FLT4 variants have been identified. Here, we report a novel FLT4 gene mutation in a Chinese family with Milroy disease and present their clinical symptoms and MR lymphangiographic findings.

Which is the appropriate surgical procedure for Stage I endometrial carcinoma?

OBJECTIVE

To study the appropriate surgical procedure for Stage I endometrial carcinoma (EC), the clinical and pathological features and prognosis factors, as well as types were analyzed retrospectively.

MATERIALS AND METHODS

This is a retrospective study of 277 patients with early-stage EC in clinical Stages I that received surgery between January 2000 and March 2008. The appropriate surgical procedures were divided into three types (procedure I-III: hysterectomy with or without ovary preservation, subradical hysterectomy plus pelvic lymph node biopsy, and radical hysterectomy pelvic plus lymphadenectomy) according to the clinical stage.

RESULTS

Tumor invasion of the cervix and deep muscularis as well as the parametrium, EC Stage Ib, grade 3 and ascites had carcinoma cells, were high-risk factors of EC metastasis to the retroperitoneum (p < 0.05). The ovarian preservation of EC Stage Ia had no effect on overall survival. The three types of procedure for the EC Stage Ia were not correlated significantly to the three-year and five-year survival rates. The three-year and five-year survival rates of three surgical procedures for the EC Stage Ib were significantly correlated. The survival rates of surgical procedures II and III were significantly higher than that of procedure I (P < 0.05).

CONCLUSION

Subradical hysterectomy plus pelvic lymph node biopsy was recommended for EC Stage 1b with high-risk factors. There was no evidence of benefit in terms of overall or recurrence-free survival for radical hysterectomy plus pelvic lymphadenectomy in women with Stage I EC.

Magnetic resonance lymphography (MRL): point and counter-point

Two preeminent lymphologists debate the findings, implications, interpretations, and value of magnetic resonance lymphography (MRL) in the evaluation of peripheral lymphedema. Their contrasting views are discussed in the context of different lymphatic imaging modalities including MRL, lymphoscintigraphy, and microscopic anatomy.

Magnetic resonance lymphography at 3T: a promising noninvasive approach to characterise inguinal lymphatic vessel leakage

PURPOSE

To explore the feasibility of using 3T high-resolution MR lymphangiography to characterize inguinal lymphatic vessel leakage (LVL).

MATERIALS AND METHODS

Sixteen patients with known inguinal LVL underwent 3T MR lymphangiography and T(2)-weighted imaging. The presence or absence of inguinal LVL and the responsible lymphatic vessels were determined using the above imaging modalities and confirmed by surgical procedure. Afterwards, fifteen patients with recurring LVL following conservative treatment were referred to surgical intervention.

RESULTS

Specific inguinal LVL enhancement patterns and leaking lymphatic vessels were detected in 15 of 16 patients. Compared to the SNR of enhanced lymph nodes, that of the enhanced LVL was significantly greater (t = 7.149, p < 0.01), thereby making it possible to differentiate between LVL sites and enhancing inguinal lymph nodes. Furthermore, the steepest contrast enhancement curve slope of enhanced LVL was lower than that of enhanced lymph nodes (t = -2.860, p = 0.02). After MR diagnosis, 15 patients successfully underwent open exploration and ligation of the leaking lymphatic vessel. Clinical follow-up did not demonstrate recurrence of lymphatic fluid in the groin.

CONCLUSIONS

High-resolution MR lymphangiography combined with T(2)-weighted imaging is a promising approach to identifying specific features of lymphatic vessel leakage in the groin.

Effects of heme oxygenase-1 gene modulated mesenchymal stem cells on vasculogenesis in ischemic swine hearts

BACKGROUND

Mesenchymal stem cells (MSCs) transplantation may partially restore heart function in the treatment of acute myocardial infarction (AMI). The aim of this study was to explore the beneficial effects of MSCs modified with heme xygenase-1 (HO-1) on post-infarct swine hearts to determine whether the induction of therapeutic angiogenesis is modified by the angiogenic cytokines released from the implanted cells.

METHODS

In vitro, MSCs were divided into four groups: (1) non-transfected MSCs (MSCs group), (2) MSCs transfected with the pcDNA3.1-Lacz plasmid (Lacz-MSCs group), (3) MSCs transfected with pcDNA3.1-hHO-1 (HO-1-MSCs group), and (4) MSCs transfected with pcDNA3.1-hHO-1 and pretreatment with an HO inhibitor, tin protoporphyrin (SnPP) (HO-1-MSCs + SnPP group). Cells were cultured in an airtight incubation bottle for 24 hours, in which the oxygen concentration was maintained at < 1%, followed by 12 hours of reoxygenation. After hypoxia/reoxygen treatment, ELISA was used to measure transforming growth factor (TGF-β) and fibroblast growth factor (FGF-2) in the supernatant. In vivo, 28 Chinese mini-pigs were randomly allocated to the following treatment groups: (1) control group (saline), (2) Lacz-MSCs group, (3) HO-1-MSCs group, and (4) HO-1-MSCs + SnPP group. About 1 × 10(7) of autologous stem cells or an identical volume of saline was injected intracoronary into porcine hearts 1 hour after MI. Magnetic resonance imaging (MRI) assay and postmortem analysis were assessed four weeks after stem cell transplantation.

RESULTS

Post hypoxia/reoxygenation in vitro, TGF-β in the supernatant was significantly increased in the HO-1-MSCs ((874.88 ± 68.23) pg/ml) compared with Lacz-MSCs ((687.81 ± 57.64) pg/ml, P < 0.001). FGF-2 was also significantly increased in the HO-1-MSCs ((1106.48 ± 107.06) pg/ml) compared with the Lacz-MSCs ((853.85 ± 74.44) pg/ml, P < 0.001). In vivo, at four weeks after transplantation, HO-1 gene transfer increased the capillary density in the peri-infarct area compared with the Lacz-MSCs group (14.24 ± 1.66/HPFs vs. 11.51 ± 1.34/HPFs, P < 0.001). Arteriolar density was also significantly higher in HO-1-MSCs group than in the Lacz-MSCs group (7.86 ± 2.00/HPFs vs. 6.45 ± 1.74/HPFs, P = 0.001). At the same time, the cardiac function was significantly improved in the HO-1-MSCs group compared with the Lacz-MSCs group ((53.17 ± 3.55)% vs. (48.82 ± 2.98)%, P < 0.05). However, all these effects were significantly abrogated by SnPP.

CONCLUSION

MSCs provided a beneficial effect on cardiac function after ischemia/reperfusion by the induction of therapeutic angiogenesis, and this effect was amplified by HO-1 overexpression.

Fluvastatin attenuates myocardial interstitial fibrosis and cardiac dysfunction in diabetic rats by inhibiting over-expression of connective tissue growth factor

BACKGROUND

Diabetic myocardiopathy is characterized by myocardial interstitial fibrosis and cardiac dysfunction. Statins were found to exert protective effects on cardiovascular disease by suppressing activation of small G proteins, independently of their lipid-lowering effect. The study investigated the effect of fluvastatin on myocardial interstitial fibrosis, cardiac function and mechanism of its action in diabetic rats.

METHODS

Twenty-four male SD rats were randomly assigned to 3 groups: control rats (n = 8), streptozotocin (STZ)-induced diabetic rats (n = 8), and diabetic rats treated with fluvastatin (administered fluvastatin orally, 10 mg/kg body weight per day, n = 8). Twelve weeks later, miniature cardiac catheter was inserted into the left ventricle to conduct hemodynamic examination. Then myocardium tissues were collected, collagen content was detected by picro-sirius red staining, real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to detect the mRNA expression of connective tissue growth factor (CTGF), and Western blotting was used to detect the protein expression of CTGF. Rho activity was determined by pull-down assay.

RESULTS

After 12 weeks, the left ventricular systolic pressure (LVSP) and maximum rate of left ventricular (LV) pressure rise and fall (+dP/dt max and -dP/dt max) were significantly lower and left ventricular end diastolic pressure (LVEDP) was higher in the diabetic rats than those in the control rats (P < 0.01). Moreover, in LV myocardial tissue of diabetic rats the collagen content, fibronectin, mRNA and protein expression of CTGF and the activity of RhoA were all significantly increased compared with the control rats (P < 0.01). Administration of fluvastain obviously improved the cardiac function of diabetic rats, attenuated fibronectin expression, mRNA and protein expression of CTGF and the activity of RhoA in LV myocardium of diabetic rats.

CONCLUSIONS

Fluvastatin attenuates cardiac dysfunction and myocardial interstitial fibrosis of diabetic rat by inhibiting activity of RhoA to down-regulate the overexpression of CTGF, and Rho/Rho-kinase pathway may be an important target in the treatment of diabetic cardiomyopathy.

Influence of CYP2C9 and CYP2C19 genetic polymorphisms on pharmacokinetics and pharmacodynamics of gliclazide in healthy Chinese Han volunteers

BACKGROUND AND OBJECTIVE

CYP2C9 is the major contributor to gliclazide metabolic clearance in vitro, while the pharmacokinetics of gliclazide modified release are affected mainly by CYP2C19 genetic polymorphisms in vivo. This study aims to investigate the influence of CYP2C9 and CYP2C19 genetic polymorphisms on the pharmacokinetics and pharmacodynamics of gliclazide in healthy Chinese Han volunteers.

METHODS

Eighteen healthy Han subjects with various combinations of CYP2C9 and CYP2C19 genotypes received 80 mg gliclazide. Plasma gliclazide concentrations were measured by a liquid chromatography-tandem mass spectrometry method for 84 h and plasma glucose and insulin levels were measured up to 15 h post-dose.

RESULTS AND DISCUSSION

There was no difference in either pharmacokinetic and or pharmacodynamic parameters of gliclazide when group A (CYP2C9*1/*1, CYP2C19 extensive metabolizers) was compared with group B (CYP2C9*1/*3, CYP2C19 *1/*1). When group C (CYP2C9*1/*1 and CYP2C19 poor metabolizers) was compared with group A, the AUC(0-∞) and C(max) in group C were significantly higher [83.94 ± 40.41 vs. 16.39 ± 5.10 μg·h/mL (P = 0.000) and 1.50 ± 0.85 vs. 0.45 ± 0.18 μg/mL (P = 0.000)], and the oral clearance was significantly lower [1.17 ± 0.63 vs. 5.38 ± 1.86 L/h (P = 0.000)]. The half-life of gliclazide was also significantly prolonged in group C subjects when compared with that of group A (33.47 ± 12.39 vs. 19.34 ± 10.45 h), but the difference was not significant (P = 0.052). The increase in serum glucose level at 11 h after dosing (ΔC(glu11)) in group C was significantly higher than that of group A (-1.08 ± 0.42 vs. 0.22 ± 1.01 mmol/L, P = 0.022). The corresponding insulin levels showed no difference between the two groups.

CONCLUSION

CYP2C9*3 was not associated with any change in the disposition of gliclazide. CYP2C19 polymorphisms appear to exert the dominant influence on the pharmacokinetics of gliclazide in healthy Chinese Han subjects, and may also affect the observed pharmacodynamics of the drug as a result.

Effect of Rosiglitazone on Cardiac Fibroblast Proliferation, Nitric Oxide Production and Connective Tissue Growth Factor Expression Induced by Advanced Glycation End-products

This study investigated the effects of the peroxisome proliferator-activated receptor-γ agonist rosiglitazone (RGZ) on cardiac fibroblast proliferation, nitric oxide content and connective tissue growth factor (CTGF) expression following incubation with advanced glycation end-products (AGEs). Cultured neonatal rat cardiac fibroblasts were incubated with various concentrations of AGEs for 48 h. Cells were also incubated with 200 mg/l AGEs plus various concentrations of RGZ. Cardiac fibroblast proliferation and cell cycle status were detected using a 3-(4, 5dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and flow cytometry. Western blotting was used to measure the expression of CTGF and nitric oxide content was evaluated using a nitrate reductase assay. AGEs significantly accelerated proliferation, increased CTGF expression and decreased nitric oxide production in cardiac fibroblasts. These effects of AGEs were inhibited by RGZ in a dose-dependent manner. Treatment with RGZ could be a valuable therapeutic approach in diabetic patients with myocardial fibrosis.

Lymphedema in China--experiences and prospects

The history of prevention and treatment of lymphedema in China is long. Filarial lymphedema was the most common type of the disease in the past with 5 million patients countrywide in the 1950's. Great efforts have gone into controlling filariasis during the past 50 years, and China now has essentially eliminated filariasis. In contrast to the reduction in filarial lymphedema, there has been a trend of increase in secondary lymphedema cases after malignant tumor surgery. Although there are no precise figures on the incidence of lymphedema nationwide, physicians and therapists are in great clinical demand. Traditional Chinese medicine has shown effectiveness for prevention and treatment of inflammation and alleviating swelling. The combination with Western medicine may offer improved methods for lymphedema treatment.

Trafficking of hyaluronan in the interstitium and its possible implications

The mechanisms underlying the pathological changes in lymphedematous tissue are far from clear, and it is becoming apparent that plasma proteins may not be the only key factors responsible for holding water in the interstitium. This review focuses on an "old" macromolecule--hyaluronan (HA) which is one of the major components of the interstitium and has a close relationship with the lymphatic system. Growing recognition of the multiple functions of this macromolecule for important physiological and pathological events may be helpful in identifying the crucial changes in tissues subjected to lymphatic circulation insufficiency and ultimately in the search for rational therapeutic approaches to prevent or reverse these tissues changes.

Mechanisms of irbesartan in prevention of renal lesion in streptozotocin-induced diabetic rats

AIM

To investigate the mechanisms of angiotensin II receptor antagonist irbesartan (Irb) in prevention of renal lesion in streptozotocin (STZ)-induced diabetic rats.

METHODS

Sprague-Dawley (SD) rats were randomly divided into three groups: normal control (group N), diabetic nephropathy (group DN), and diabetic nephropathy treated with Irb (group DNI). Diabetes was induced by injection of STZ ip after rats had received uninephrectomy. Blood glucose (BG), body weight (BW), urinary albumin excretion (Ualb), and 24-h proteinuria (24hUpro) were observed in the rats at week 4, 8, and 12, respectively. Creatinine clearance (Ccr), the kidney weight (KW), profile of kidney hypertrophy (KW/BW), renal tissue protein contents (RTP), glomerular area (AG), glomerular volume (VG), and width of glomerular basement membrane (GBM) were determined after the rats were sacrificed at week 12. Renal expression of connective tissue growth factor (CTGF) and transforming growth factor-beta1 (TGF-beta1) were determined by immunohistochemistry.

RESULTS

There was no significant difference in BG between group DN and DNI (P >0.05). Irb prevented the increasing of Ualb excretion, 24 hUpro, and Ccr in diabetic rats ( P < 0.01). Furthermore, Irb markedly inhibited the increasing of KW, KW/BW, RTP, AG, and VG shown in diabetic rats (P <0.05, P <0.01, respectively). Irb prevented the thickening of GBM and immunostaining of CTGF (P <0.01). The extent of CTGF expression was positively correlated with the glomerular immunostaining for TGF-beta1 and size of VG (P <0.01).

CONCLUSION

Irb exerts an early renal protective role to diabetic nephropathy, possibly through inhibition of renal hypertrophy and expression of CTGF.

Effects of L-arginine on the proliferation of human renal mesangial cells and production of extracellular matrix

AIM

To investigate the effect of L-arginine (L-arg) on the proliferation of human mesangial cells and production of collagen.

METHODS

The influence of L-arg on the cell proliferation was determined by MTT assay, immunocytochemical detection of expression of proliferative cell nuclear antigen (PCNA), and flow cytometrical analysis of cell cycle. Procollagen III and total collagen level in the supernatant and expression of collagen IV mRNA in human mesangial cells were determined by radioimmunoassay, hydroxyproline colorimetric assay, and reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

L-Arg induced inhibition of human mesangial cell lines (HMCL) in a concentration- and time-dependent manner. Immunocytochemical study for PCNA showed the number of cells was decreased, though the percentage of PCNA positive cells was increased in L-arg-treated group. Flow cytometrical analysis showed that cells in S and G2/-M phases were markedly increased in L-arg-treated group compared with those in control group. Furthermore, L-arg significantly inhibited the production of procollagen III and total collagen in the supernatants determined by radioimmunoassay and hydroxyproline colorimetric assay (P < 0.05 and 0.01, respectively) and inhibited the expression of collagen IV mRNA determined by RT-PCR (P < 0.01).

CONCLUSION

L-arg could exert an inhibitory effect on the proliferation of human mesangial cells and production of extracellular components, which strongly suggested its potential therapeutic role in the chronic renal scarring.

Gene expression of monocyte chemoattractant protein-1 in human monocytes by exposure to advanced glycosylation end products

AIM

To explore the effects of advanced glycosylation end products (AGEP) on monocyte chemoattractant protein-1 (MCP-1) gene expression in human peripheral blood monocytes/macrophages (PBMC).

METHODS

Expression of MCP-1 mRNA in PBMC incubated with AGEP-bovine serum albumin (AGEP-BSA) was examined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) with beta-actin as an internal standard. Sequencing of RT-PCR products was performed to confirm the specificity of amplification for MCP-1 gene.

RESULTS

AGEP-BSA stimulated monocytes to express MCP-1 mRNA in a glucose-concentration-related fashion. The levels of MCP-1 mRNA were increased slightly when monocytes were exposed to AGEP-BSA 200 mg/L (glycosylated with glucose 20 mmol/L), and increased markedly when exposed to AGEP-BSA 200 mg/L (glycosylated with glucose 50 mmol/L), but decreased slightly when exposed to AGEP-BSA 200 mg/L (glycosylated with glucose 80 mmol/L). Expression of MCP-1 mRNA was undetectable in freshly isolated monocytes, but was induced at 12 h and reached a maximal level at 24 h and was almost undetectable at 36 h after the monocytes were incubated with AGEP-BSA 200 mg/L (P < 0.01).

CONCLUSION

AGEP enhanced MCP-1 mRNA expression in human PBMC.

Antagonistic effect of 3,6-dimethamidodibenzopyriodonium gluconate on lipid peroxidation in cerebral cortical neuronal cultures and rat brains during focal cerebral ischemia reperfusion

AIM

To study 3,6-dimethamidodibenzopyriodonium gluconate (I-93) antagonistic effects on lipid peroxidation in cerebral cortical neuronal cultures and rat brains during focal cerebral ischemia-reperfusion.

METHODS

Cerebral cortical neurons were cultured and rat focal cerebral ischemia-reperfusion model was established by reversible middle cerebral artery occlusion (MCAO) without craniectomy. The efflux of lactate dehydrogenase (LDH) from neurons, content of malondialdehyde (MDA) in neurons and brain homogenate, activity of superoxide dismutase (SOD) in brain homogenate, and index of cerebral edema as well as brain morphology were investigated.

RESULTS

I-93 10-40 mumol.L-1 concentration-dependently inhibited efflux of LDH and elevated levels of MDA induced by addition of H2O2(10 mumol.L-1) in vitro. I-93 0.5 mg.kg-1 improved the cerebral morphology, reduced brain edema, decreased MDA content, and enhanced SOD activity in brain homogenate.

CONCLUSION

I-93 protects neurons from H2O2-induced neurotoxicity and ischemia-reperfusion mediated damage by increasing the activity of antioxidant enzymes and suppressing the generation of lipid peroxides.

Clearance of increased serum advanced glycosylation end products in patients with end stage renal disease by hemodialysis

AIM

To study the effect of removal of hemodialysis using acetate membrane on serum advanced glycosylation end products (AGEP) in 36 patients (59.1 +/- 1.6) with end stage renal disease (ESRD).

METHODS

Serum AGEP levels were determined with quantitative fluorescence spectrometry, flow injection analysis (FIA), and competitive enzyme-linked immunosorbent assay (ELISA) using a polyclonal antibody directed against AGEP.

RESULTS

The serum AGEP levels in patients with ESRD quantified by fluorescence spectrometry, FIA, and ELISA were higher than those in controls [(25 +/- 5) vs (7.5 +/- 1.5), (6.1 +/- 1.8) vs (1.4 +/- 0.5), and (37 +/- 20) vs (9 +/- 10) kU/L, respectively] and markedly reduced to [(22 +/- 6), (4.2 +/- 1.4), and (19 +/- 14) kU/L, respectively] after hemodialysis.

CONCLUSION

Increased serum AGEP levels in the circulation of patients with ESRD were reduced effectively by hemodialysis.

[The pathogenic mechanism and prevention and treatment of muscle contracture after replantation of severed palm or wrist]

OBJECTIVE

To explore the pathogenic mechanism of intrinsic muscle contracture after replantation of severed palm or wrist, and put forward the prevention and treatment methods.

METHODS

From 1985 to 1997, 48 cases were received replantation of severed palm or wrist, among them, 9 cases with thumb adductor contracture and 6 cases with intrinsic muscle contracture were occurred in different degree. Two cases with mild thumb adductor contracture were received conservative treatment, and 7 cases with moderate thumb adductor contracture and 6 cases with intrinsic muscle contracture were received operative treatment. The pathogenic mechanism, clinical results, and prevention methods were studied in those 15 cases.

RESULTS

The postoperative function recovery was better in 4 cases, moderate in 5 cases with thumb adductor contracture, and better in 3 cases, moderate in 1 case with intrinsic muscle contracture, and moderate in 1 case, poor in 1 case with intrinsic muscle contracture of cord-like induration. Followed up 1 to 10 years, no recurrence was observed in all of 15 cases. The incidence and degree of thumb adductor contracture and intrinsic muscle contracture were closely related to the ischemia time of replanting graft.

CONCLUSION

Prevention of thumb adductor contracture and intrinsic muscle contracture is most important in severed palm or wrist replantation. When the ischemia time of replanting graft is longer than 12 hours, the effective decompression in myofascial compartment is performed in time to reach satisfactory result.

Effect of advanced glycosylation end products on diacylglycerol signaling pathway in cultured rat aortic smooth muscle cells

AIM

To investigate whether diacylglycerol (Dia) signaling pathway is stimulated by advanced glycosylation end products (AGEP) and to determine effect of vitamin E and aminoguanidine on Dia level induced by AGEP in cultured rat aortic vascular smooth muscle cells (VSMC).

METHODS

The effect of AGEP on Dia level in cultured VSMC was measured by radio-enzymatic assay. Quantitative measurements of [32P]phosphatidic acid were performed by thin-layer chromatography and autoradiography.

RESULTS

The Dia level in VSMC incubated with AGEP-BSA was markedly increased in a concentration-dependent, biphasic manner. The early phase was rapid and transient, peaking at 15 s. The late phase reached the maximal level at 10 min and decayed slowly. The Dia levels in VSMC exposed to different concentrations of AGEP-BSA and AGEP-BSA glycosylated for various periods were greatly increased compared with control group. Vitamin E 50, 100 nmol.L-1 prevented the AGEP-BSA-stimulated elevation of Dia level in VSMC, from (940 +/- 43) pmol.L-1 to (599 +/- 38), (290 +/- 21) pmol.L-1, respectively. In aminoguanidine-treated AGEP-BSA groups, Dia level in the cells incubated with the same concentration of AGEP-BSA (100, 200 mg.L-1) were decreased to (260 +/- 8) and (289 +/- 10) pmol.L-1, respectively. Early glycosylated low-density lipoproteins (LDL) did not affect Dia level.

CONCLUSION

AGEP causes a robust stimulation of Dia signaling pathway in VSMC. Vitamin E and aminoguanidine attenuate the production of Dia.

Changes of tissue fluid hyaluronan (hyaluronic acid) in peripheral lymphedema

Hyaluronan (hyaluronic acid or HA) is an important component of the extracellular matrix which is synthesized in the tissue, transported in lymph and catabolized mainly in lymph nodes and the liver. In 39 patients with chronic peripheral lymphedema, the HA content in lymphedematous interstitial fluid was measured using radioimmunoassay. For comparison, the concentration of HA in serum and normal tissue fluid were also determined. These samples were also tested for protein concentration. The results showed that the HA concentration in interstitial fluid of a lymphedema limb was 22 x 10(3) +/- 10(3) (aspiration) and 30 x 10(3) +/- 4 x 10(3) (wick) ng/ml which were significantly higher than that in interstitial fluid, serum and lymph of normal limbs (control) and interstitial fluid of limbs with venous edema (p < 0.001). The protein concentration in these fluids did not show significant differences between lymphedema and those with normal limbs. The findings suggest that HA stagnates in the limb with impaired lymph drainage which may exert a deleterious effect on the interstitium.

The role of magnetic resonance imaging in diagnosis of peripheral lymphatic disorders

Magnetic resonance imaging (MRI) was used in 13 patients with peripheral lymphedema and 2 patients with extensive cavernous lymphangioma of the limb for the purpose of evaluating its role in diagnosis of lymphatic disorders. In chronic lymphedema, MRI showed deformity of lymphatics at different tissue levels. In the subcutis, MRI characteristically displayed diffuse edema or a honeycombed pattern consistent with reticular lymphangiectasis and "lakes" with a marked increase in signal intensity with T2-weighted imaging. In lymphedema hyperplasia and chylous reflux, MRI depicted dilated retroperitoneal lymphatic collectors and lumbar trunks. In cavernous lymphangiomatosis, MRI demonstrated a prominent lattice-like pattern which had lower signal intensity on T1-weighted imaging and higher intensity on T2-weighted imaging. The findings of MRI are valuable not only for accurate assessment of lymphatic dysplasia syndromes but also provide a blueprint for treatment options.