C-reactive protein decreases expression of thrombomodulin and endothelial protein C receptor in human endothelial cells

Targeting endothelial cells with golden spice curcumin: A promising therapy for cardiometabolic multimorbidity

Cardiometabolic multimorbidity (CMM) is an increasingly significant global public health concern. It encompasses the coexistence of multiple cardiometabolic diseases, including hypertension, stroke, heart disease, atherosclerosis, and T2DM. A crucial component to the development of CMM is the disruption of endothelial homeostasis. Therefore, therapies targeting endothelial cells through multi-targeted and multi-pathway approaches hold promise for preventing and treatment of CMM. Curcumin, a widely used dietary supplement derived from the golden spice Carcuma longa, has demonstrated remarkable potential in treatment of CMM through its interaction with endothelial cells. Numerous studies have identified various molecular targets of curcumin (such as NF-κB/PI3K/AKT, MAPK/NF-κB/IL-1β, HO-1, NOs, VEGF, ICAM-1 and ROS). These findings highlight the efficacy of curcumin as a therapeutic agent against CMM through the regulation of endothelial function. It is worth noting that there is a close relationship between the progression of CMM and endothelial damage, characterized by oxidative stress, inflammation, abnormal NO bioavailability and cell adhesion. This paper provides a comprehensive review of curcumin, including its availability, pharmacokinetics, pharmaceutics, and therapeutic application in treatment of CMM, as well as the challenges and future prospects for its clinical translation. In summary, curcumin shows promise as a potential treatment option for CMM, particularly due to its ability to target endothelial cells. It represents a novel and natural lead compound that may offer significant therapeutic benefits in the management of CMM.

Contraception for Adolescents and Young Women with Type 2 Diabetes-Specific Considerations

PURPOSE OF REVIEW

This article reviews how to address contraception in young women with type 2 diabetes (T2D). The presence of obesity and comorbidities associated with insulin resistance increases the risk of thromboembolic disease and adverse cardiovascular outcomes.

RECENT FINDINGS

Recent studies have shown that adolescents with T2D are at high risk of unintended pregnancy with poor outcomes for the mother and offspring. Adolescents with T2D without severe obesity, micro- or macrovascular disease, or other cardiovascular risk factors can use any contraceptive method. However, only nonhormonal or progestin-only methods may be used when morbid obesity, severe hypertension, micro- or macrovascular disease, or multiple cardiovascular risk factors are present. The medical team must provide preconceptional counseling and contraception to reduce adolescent pregnancies in young women with T2D. Progestin-only or nonhormonal long-acting reversible contraception (LARC) should be recommended for women with T2D with compliance issues or adverse cardiovascular risk profiles.

Inflammatory Mechanisms Contributing to Endothelial Dysfunction

Maintenance of endothelial cell integrity is an important component of human health and disease since the endothelium can perform various functions including regulation of vascular tone, control of hemostasis and thrombosis, cellular adhesion, smooth muscle cell proliferation, and vascular inflammation. Endothelial dysfunction is encompassed by complex pathophysiology that is based on endothelial nitric oxide synthase uncoupling and endothelial activation following stimulation from various inflammatory mediators (molecular patterns, oxidized lipoproteins, cytokines). The downstream signaling via nuclear factor-κB leads to overexpression of adhesion molecules, selectins, and chemokines that facilitate leukocyte adhesion, rolling, and transmigration to the subendothelial space. Moreover, oscillatory shear stress leads to pro-inflammatory endothelial activation with increased monocyte adhesion and endothelial cell apoptosis, an effect that is dependent on multiple pathways and flow-sensitive microRNA regulation. Moreover, the role of neutrophil extracellular traps and NLRP3 inflammasome as inflammatory mechanisms contributing to endothelial dysfunction has recently been unveiled and is under further investigation. Consequently, and following their activation, injured endothelial cells release inflammatory mediators and enter a pro-thrombotic state through activation of coagulation pathways, downregulation of thrombomodulin, and an increase in platelet adhesion and aggregation owing to the action of von-Willebrand factor, ultimately promoting atherosclerosis progression.

Stable expression of the human thrombomodulin transgene in pig endothelial cells is associated with a reduction in the inflammatory response

BACKGROUND

Xenotransplantation is associated with an inflammatory response. The proinflammatory cytokine, TNF-α, downregulates the expression of thrombomodulin (TBM), and induces coagulation dysfunction. Although human (h) TBM-transgenic pigs (p) have been developed to reduce coagulation dysfunction, the effect of TNF-α on the expression of hTBM and its functional activity has not been fully investigated. The aims of this study were to investigate (i) whether the expression of hTBM on pig (p) cells is down-regulated during TNF-α stimulation, and (ii) whether cells from hTBM pigs regulate the inflammatory response.

METHODS

TNF-α-producing T, B, and natural killer cells in blood from baboons with pig heart or kidney xenografts were investigated by flow cytometry. TNF-α staining in the grafts was detected by immunohistochemistry. Aortic endothelial cells (AECs) from GTKO/CD46 and GTKO/CD46/hTBM pigs were stimulated by hTNF-α, and the expression of the inflammatory/coagulation regulatory protein, TBM, was investigated.

RESULTS

After pig organ xenotransplantation, there was a trend to increases in TNF-α-producing T and natural killer cells in the blood of baboons. In vitro observations demonstrated that after hTNF-α stimulation, there was a significant reduction in the expression of endogenous pTBM on pAECs, and a significant increase in the expression of inflammatory molecules. Blocking of NF-κB signaling significantly up-regulated pTBM expression, and suppressed the inflammatory response induced by hTNF-α in pAECs. Whereas the expression of pTBM mRNA was significantly reduced by hTNF-α stimulation, hTBM expression on the GTKO/CD46/hTBM pAECs was not affected. Furthermore, after hTNF-α stimulation, there was significant suppression of expression of inflammatory molecules on GTKO/CD46/hTBM pAECs compared to GTKO/CD46 pAECs.

CONCLUSIONS

The stable expression of hTBM in pig cells may locally regulate the inflammatory response. This will help suppress the inflammatory response and prevent coagulation dysregulation after xenotransplantation.

Enoxaparin pretreatment effect on local and systemic inflammation biomarkers in the animal burn model

Low-molecular weight heparins (LMWH) are anticoagulants that have shown anti-inflammatory activity in several experimental models. Hot water burn inflammatory model accurately simulates human clinical situations allowing its use for nociception test and evaluation of anti-inflammatory drugs. The present study aims to evaluate the enoxaparin pretreatment on local and systemic inflammation biomarkers in the animal burn model. Inflammation was induced by submersing the rat left hind paw in water at 60^o C for 60 s. C-reactive protein (CRP) and thrombin-antithrombin complex (TAT) were estimated by immunosorbent assay, fibrinogen (Fg) by the gravimetric method and paw oedema by orthogonal digital photography. Highest values of paw oedema, CRP and TAT were observed at 4 h post-burn while Fg peak occurs at 12 h post-burn; enoxaparin pretreatment decreased oedema (- 32.1%), and concentration of TAT (- 66.7%), PCR (- 37.9%) and Fg (- 8%). This study shows that enoxaparin has local and systemic anti-inflammatory effects and should be considered as a potential adjuvant drug for the treatment of burns.

Effect of cigarette smoke extract and nicotine on the expression of thrombomodulin and endothelial protein C receptor in cultured human umbilical vein endothelial cells

The present study investigated the influence of cigarette smoke extract (CSE) and nicotine on the expression of thrombomodulin (TM) and endothelial protein C receptor (EPCR) in human umbilical vein endothelial cells (HUVECs). Smoking is associated with intravascular thrombosis. As a vital anticoagulation cofactor, TM is located on the endothelial cell surface and regulates intravascular coagulation by binding to thrombin, hence activating protein C. Activated protein C is a natural anticoagulant that interacts with EPCR to enhance the function of anticoagulation system. The effects of CSE (0.5–5%) and nicotine (10-3-10-9 mol/l) on the expression of TM and EPCR in HUVECs were observed. Reverse transcription-quantitative polymerase chain reaction and flow cytometric analysis techniques were used for detecting TM and EPCR mRNA and protein expression levels, respectively. After 6-h exposure, TM protein and mRNA expression levels decreased in a dose-dependent manner. Stimulation with 5% CSE for 0, 6, 10, 12 and 24 h led to a decrease in the levels of TM mRNA and protein over time, which reached a peak at 12 h. The levels were significantly reduced compared with the control group (P<0.001). However, CSE had no effect on EPCR. Furthermore, nicotine had no influence on TM and EPCR. In conclusion, the present study supports a novel molecular mechanism of cigarette smoking-associated thrombosis by the decreased expression of TM. Further studies are required to identify specific components in CSE responsible for decreasing TM expression and its associated consequences.

Association of gene polymorphisms with the risk of warfarin bleeding complications at therapeutic INR in patients with mechanical cardiac valves

WHAT IS KNOWN AND OBJECTIVE

Pharmacogenetic studies of the genetic regulation of warfarin dose requirement have been reported, but few have been on the bleeding complications at therapeutic international normalized ratio (INR). This study aimed to evaluate the effect of gene polymorphisms of CYP2C9, VKORC1, thrombomodulin (THBD) and C-reactive protein (CRP) on the risk of bleeding complications of warfarin at therapeutic INR in Korean patients with mechanical cardiac valves.

METHODS

A retrospective warfarin pharmacogenetic association study was performed. One hundred and forty-two patients with mechanical cardiac valves who were on warfarin anticoagulation therapy and maintained INR levels of 2·0-3·0 for 3 consecutive time intervals were followed up. CYP2C9 rs1057910, VKORC1 rs9934438, CRP rs1205, THBD rs1042580 and THBD rs3176123 were genotyped. The association between genotypes and warfarin bleeding complications was evaluated using logistic regression analysis, adjusted for demographic and clinical factors.

RESULTS AND DISCUSSION

Of 142 eligible patients, 21 patients (14·8%) had bleeding complications at therapeutic INR. Patients with the G allele in THBD rs1042580 (AG or GG) had a lower risk of bleeding than patients with the AA genotype (adjusted OR: 0·210, 95% CI: 0·050-0·875, P = 0·032). The THBD rs3176123 polymorphism did not show any association with bleeding. For CRP rs1205, patients with the A allele (GA or AA genotype) had a higher risk of bleeding than patients with the GG genotype (adjusted OR: 5·575, 95% CI: 1·409-22·058, P = 0·014). Variant VKORC1 and CYP2C9 genotypes did not confer a significant increase in the risk for bleeding complications.

WHAT IS NEW AND CONCLUSIONS

As expected, no association could be found between bleeding complications and two dose-related genes (CYP2C9*3 and VKORC1 rs9934438). In contrast, our results suggest that two genetic markers (THBD rs1042580 and CRP rs1205) could be predictors of bleeding complications of warfarin at normal INR. Given the retrospective study design and the relatively small sample size, our hypothesis requires further independent validation using more robust prospective designs. However, additional retrospective studies similar to ours but in populations with different genetic backgrounds should also be useful.

Melatonin protection against burn-induced liver injury. A review

Severe thermal injury may be complicated by dysfunction of organs distant from the original burn wound, including the liver, and represents a serious clinical problem. Although pathophysiology of burn-induced liver injury remains unclear, increasing evidence implicate activation of inflammatory response, oxidative stress, endothelial dysfunction and microcirculatory disorders as the main mechanisms of hepatic injury. Several studies suggest melatonin as a multifunctional indolamine that counteracts some of the pathophysiologic steps and displays significant beneficial effects against burn-induced cellular injury. This review summarizes the role of melatonin in restricting the burn-induced hepatic injury and focuses on its effects on oxidative stress, inflammatory response, endothelial dysfunction and microcirculatory disorders as well as on signaling pathways such as regulation of nuclear erythroid 2-related factor 2 (Nrf2) and nuclear factor-kappaB (NF-kB). Further studies are necessary to elucidate the modulating effect of melatonin on the transcription factor responsible for the regulation of the pro-inflammatory and antioxidant genes involved in burn injuries.

Thrombomodulin and the vascular endothelium: insights into functional, regulatory, and therapeutic aspects

Thrombomodulin (TM) is a 557-amino acid protein with a broad cell and tissue distribution consistent with its wide-ranging physiological roles. When expressed on the lumenal surface of vascular endothelial cells in both large vessels and capillaries, its primary function is to mediate endothelial thromboresistance. The complete integral membrane-bound protein form displays five distinct functional domains, although shorter soluble (functional) variants comprising the extracellular domains have also been reported in fluids such as serum and urine. TM-mediated binding of thrombin is known to enhance the specificity of the latter serine protease toward both protein C and thrombin activatable fibrinolysis inhibitor (TAFI), increasing their proteolytic activation rate by almost three orders of magnitude with concomitant anticoagulant, antifibrinolytic, and anti-inflammatory benefits to the vascular wall. Recent years have seen an abundance of research into the cellular mechanisms governing endothelial TM production, processing, and regulation (including flow-mediated mechanoregulation)--from transcriptional and posttranscriptional (miRNA) regulation of TM gene expression, to posttranslational processing and release of the expressed protein--facilitating greater exploitation of its therapeutic potential. The goal of the present paper is to comprehensively review the endothelial/TM system from these regulatory perspectives and draw some fresh conclusions. This paper will conclude with a timely examination of the current status of TM's growing therapeutic appeal, from novel strategies to improve the clinical efficacy of recombinant TM analogs for resolution of vascular disorders such as disseminated intravascular coagulation (DIC), to an examination of the complex pleiotropic relationship between statin treatment and TM expression.

Analysis of endothelial protein C receptor gene and metabolic profile in Prader-Willi syndrome and obese subjects

The endothelial protein C receptor (EPCR) has a critical role in the regulation of anticoagulant and anti-inflammatory functions of activated protein C (APC). Abnormalities in EPCR might be associated with an increased risk of thrombosis. In this respect, a 23 bp insertion in the exon 3 of the EPCR gene predicts a truncated protein which cannot bind APC. High levels of C-reactive protein (CRP), a strong predictor of cardiovascular events, are found both in the obese and in subjects with Prader-Willi syndrome (PWS). Several cardiovascular risk factors are already present in prepubertal PWS children, but it is uncertain which mechanism contributes to the increased risk of cardiovascular disease in PWS. We analyzed the distribution of 23 bp insertion in the EPCR gene in 81 overweight and obese PWS subjects, 52 adults and 29 children, and in 58 overweight and obese children and adolescents (controls). We found that 1/58 (1.7%) of the controls was heterozygous for the 23 bp insertion, while this mutation was never found in PWS subjects. Furthermore, we evaluated CRP levels, glucose, insulin, and lipid profile, and we found higher CRP values in PWS adults with respect to children with PWS and controls, and a better insulin sensitivity in all PWS subjects than in the controls. This study suggests that in PWS subjects there is no predisposition to develop thrombotic events in association with EPCR gene alteration and demonstrates substantial differences regarding metabolic and inflammatory profile between PWS and non-PWS obese children, with further impairment in adults with PWS.

Modulation of tissue factor and thrombomodulin expression in human aortic endothelial cells incubated with high glucose

Diabetes is often associated with atherothrombosis. It is unknown whether high glucose can modulate the expression of tissue factor (TF) and thrombomodulin (TM) in human aortic endothelial cells (HAECs). HAECs were treated with a lower-degree high glucose condition (LG, 11.2 mM) for 8 days and a higher-degree high glucose condition (HG, 30 mM) for 4-6 h. Methoxyphenyl tetrazolium inner salt assay, real-time polymerase chain reaction, western blot, and TF activity assay were performed. In HAECs, both LG and HG conditions were nontoxic. LG caused a 74 ± 20% decrease (P = 0.273) and HG caused a 57 ± 5% decrease in TF mRNA expression (P = 0.001). LG caused a 53 ± 13% decrease (P = 0.036) and HG caused a 75 ± 10% decrease in TF protein expression (P = 0.096). TF activity was not significantly changed by LG (127 ± 13%, P = 0.40) or HG treatments (120 ± 42%, P = 0.70). In contrast, LG caused a 153 ± 16% increase (P = 0.03) and HG caused a 211 ± 20% increase in TM mRNA expression (P = 0.005). LG caused a 131 ± 31% increase (P = 0.35) and HG caused a 140 ± 9% increase in TM protein expression (P = 0.006). Different high glucose conditions do not provide the sufficient stress required to induce TF expression in HAECs. In contrast, high glucose conditions can induce TM expression in HAECs.

The involvement of inflammatory cytokines in the pathogenesis of recurrent miscarriage

OBJECTIVE

To investigate the inflammatory cytokine expression pattern in trophoblastic tissue from women with unexplained recurrent miscarriage (RM).

STUDY DESIGN

Trophoblasts were obtained during uterine evacuation from 11 women with RM and from 20 healthy pregnant women undergoing elective termination of pregnancy, who served as controls. The array was performed using GEArray Q Series Human Inflammatory Cytokines & Receptors Gene Array HS-015 membranes. Data were confirmed by quantitative real-time PCR. The Mann-Whitney U test was performed for statistical analysis.

RESULTS

Microarray analysis identified three genes that were differentially expressed between RM patients and controls. We observed significant downregulation of Transforming Growth Factor beta 3 (TGF-β3) and Interleukin 25 (IL-25) (5-fold reduction and 2.5-fold reduction, respectively) and significant upregulation of CD-25, also known as Interleukin 2 receptor alpha (IL-2RA) (7-fold increase) in women with RM compared with controls. The median ΔC(t) of TGF-β3 was 8.2 (interquartile range, 7.67-8.9) in RM patients vs. 5.85 (interquartile range, 5.3-6.09) in controls; the median ΔC(t) of IL-25 was 5.18 (interquartile range, 4.46-5.76) in RM patients vs. 3.85 (interquartile range, 3.6-4.51) in controls, and the median ΔC(t) of CD-25 was 9.62 (interquartile range, 7.81-12.42) in RM patients vs. 12.44 (interquartile range, 11.02-13.86) in controls.

DISCUSSION

Our results suggest that the immunological and inflammatory regulation mechanisms of the placental environment play a key role in recurrent miscarriage. The observed trophoblast cytokine expression pattern at the maternal-fetal interface confirms the immunotrophic theory, as demonstrated by a switch from a T-helper-1 (Th1) profile to a T-helper-2 (Th2) profile in women who experience recurrent miscarriages.

Thrombomodulin and its role in inflammation

The goal is to provide an extensive review of the physiologic role of thrombomodulin (TM) in maintaining vascular homeostasis, with a focus on its anti-inflammatory properties. Data were collected from published research. TM is a transmembrane glycoprotein expressed on the surface of all vascular endothelial cells. Expression of TM is tightly regulated to maintain homeostasis and to ensure a rapid and localized hemostatic and inflammatory response to injury. By virtue of its strategic location, its multidomain structure and complex interactions with thrombin, protein C (PC), thrombin activatable fibrinolysis inhibitor (TAFI), complement components, the Lewis Y antigen, and the cytokine HMGB1, TM exhibits a range of physiologically important anti-inflammatory, anti-coagulant, and anti-fibrinolytic properties. TM is an essential cofactor that impacts on multiple biologic processes. Alterations in expression of TM and its partner proteins may be manifest by inflammatory and thrombotic disorders. Administration of soluble forms of TM holds promise as effective therapies for inflammatory diseases, and infections and malignancies that are complicated by disseminated intravascular coagulation.

The protein C pathway in tissue inflammation and injury: pathogenic role and therapeutic implications

Inflammation and coagulation are closely linked interdependent processes. Under physiologic conditions, the tissue microcirculation functions in anticoagulant and anti-inflammatory fashions. However, when inflammation occurs, coagulation is also set in motion and actively participates in enhancing inflammation. Recently, novel and unexpected roles of hemostasis in the humoral and cellular components of innate immunity have been described. In particular, the protein C system, besides its well-recognized role in anticoagulation, plays a crucial role in inflammation. Indeed, the protein C system is now emerging as a novel participant in the pathogenesis of acute and chronic inflammatory diseases, such as sepsis, asthma, inflammatory bowel disease, atherosclerosis, and lung and heart inflammation, and may emerge as unexpected therapeutic targets for intervention.

Placental thrombomodulin expression in recurrent miscarriage

BACKGROUND

Early pregnancy loss can be associated with trophoblast insufficiency and coagulation defects. Thrombomodulin is an endothelial-associated anticoagulant protein involved in the control of hemostasis and inflammation at the vascular beds and it's also a cofactor of the protein C anticoagulant pathway.

DISCUSSION

We evaluate the Thrombomodulin expression in placental tissue from spontaneous recurrent miscarriage and voluntary abortion as controls. Thrombomodulin mRNA was determined using real-time quantitative polymerase chain reaction. Reduced expression levels of thrombomodulin were found in recurrent miscarriage group compared to controls (1.82-fold of reduction), that corresponds to a reduction of 45% (from control group Delta CT) of thrombomodulin expression in spontaneous miscarriage group respect the control groups.

SUMMARY

We cannot state at present the exact meaning of a reduced expression of Thrombomodulin in placental tissue. Further studies are needed to elucidate the biological pathway of this important factor in the physiopathology of the trophoblast and in reproductive biology.

The protein C pathway in tissue inflammation and injury: pathogenic role and therapeutic implications

Inflammation and coagulation are closely linked interdependent processes. Under physiologic conditions, the tissue microcirculation functions in anticoagulant and anti-inflammatory fashions. However, when inflammation occurs, coagulation is also set in motion and actively participates in enhancing inflammation. Recently, novel and unexpected roles of hemostasis in the humoral and cellular components of innate immunity have been described. In particular, the protein C system, besides its well-recognized role in anticoagulation, plays a crucial role in inflammation. Indeed, the protein C system is now emerging as a novel participant in the pathogenesis of acute and chronic inflammatory diseases, such as sepsis, asthma, inflammatory bowel disease, atherosclerosis, and lung and heart inflammation, and may emerge as unexpected therapeutic targets for intervention.

Inadequate dietary magnesium intake increases atherosclerotic plaque development in rabbits

Epidemiological studies have shown dietary magnesium (Mg) intake and serum Mg levels to be inversely correlated with the development of atherosclerosis. We hypothesized that low levels of Mg would promote atherosclerotic plaque development in rabbits. New Zealand white rabbits (4 months old, n = 22) were fed an atherogenic diet containing 0.12% (-Mg), 0.27% (control), or 0.43% (+Mg) Mg for 8 weeks. Blood samples were obtained at baseline, 2, 4, 6, and 8 weeks and were assayed for total cholesterol, high-density lipoprotein (HDL), non-HDL, triglycerides (TG), C-reactive protein, serum Mg, and erythrocyte Mg. Aortas from -Mg had significantly more plaque, with an intima thickness 42% greater than control and 36% greater than +Mg. Serum cholesterol levels rose over time, and at 8 weeks, -Mg had the highest and +Mg the lowest total and non-HDL cholesterol and TG levels, although these results did not reach significance. Over time, serum Mg levels increased, and erythrocyte Mg levels decreased. C-reactive protein significantly increased in all groups at 4 and 6 weeks but returned to baseline levels by 8 weeks. This study supports the hypothesis that inadequate intake of Mg results in an increase in atherosclerotic plaque development in rabbits.

Regulation of endothelial protein C receptor shedding by cytokines is mediated through differential activation of MAP kinase signaling pathways

The endothelial protein C receptor (EPCR) plays a pivotal role in coagulation, inflammation, cell proliferation, and cancer, but its activity is markedly changed by ectodomain cleavage and release as the soluble protein (sEPCR). In this study we examined the mechanisms involved in the regulation of EPCR shedding in human umbilical endothelial cells (HUVEC). Interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), but not interferon-gamma and interleukin-6, suppressed EPCR mRNA transcription and cell-associated EPCR expression in HUVEC. The release of sEPCR induced by IL-1beta and TNF-alpha correlated with activation of p38 MAPK and c-Jun N-terminal kinase (JNK). EPCR shedding was also induced by phorbol 12-myristate 13-acetate, ionomycin, anisomycin, thiol oxidants or alkylators, thrombin, and disruptors of lipid rafts. Both basal and induced shedding of EPCR was blocked by the metalloproteinase inhibitors, TAPI-0 and GM6001, and by the reduced non-protein thiols, glutathione, dihydrolipoic acid, dithiothreitol, and N-acetyl-l-cysteine. Because other antioxidants and scavengers of reactive oxygen species failed to block the cleavage of EPCR, a direct suppression of metalloproteinase activity seems responsible for the observed effects of reduced thiols. In summary, the shedding of EPCR in HUVEC is effectively regulated by IL-1beta and TNF-alpha, and downstream by MAP kinase signaling pathways and metalloproteinases.

C-reactive protein increases plasminogen activator inhibitor-1 expression in human endothelial cells

C-reactive protein (CRP) is an inflammatory marker which predicts cardiovascular disease. However, it is not fully understood whether CRP has direct effects on endothelial functions and gene expression. The purpose of current study was to determine the effects and molecular mechanisms of CRP on the expression of plasminogen activator inhibitor-1 (PAI-1) in human endothelial cells. Human coronary artery endothelial cells (HCAEC) were treated with CRP at clinically relevant concentrations for different durations. PAI-1 mRNA, protein and enzyme activities were studied. The effects of CRP on MAPK p38 phosphorylation was also studied by Bio-Plex luminex immunoassay. In addition, other types of human endothelial cells isolated from umbilical vein, skin, and lung microvessels were tested. CRP significantly increased PAI-1 mRNA levels in a time- and concentration-dependent manner. The protein level and enzyme activity of PAI-1 in the supernatant of CRP-treated HCAEC cultures were significantly increased. Anti-CD32 antibody effectively blocked CRP-induced PAI-1 mRNA expression. In addition, CRP significantly increased CD32 mRNA levels and enhanced phosphorylation of MAPK p38. Furthermore, antioxidant curcumin dramatically inhibited CRP-induced PAI-1 mRNA expression. The effect of CRP on PAI-1 expression was also confirmed in other types of human endothelial cells. In conclusion, CRP significantly increased the expression of PAI-1 in HCAEC and other human endothelial cells. CRP also increased its receptor CD32 expression which may further enhance its action. CRP-induced PAI-1 expression may be mediated by oxidative stress and p38 signal pathway as antioxidant effectively blocks the effect of CRP on HCAEC.

Low testosterone and high C-reactive protein concentrations predict low hematocrit in type 2 diabetes

OBJECTIVE

After the demonstration that one-third of male patients with type 2 diabetes have hypogonadotrophic hypogonadism, we have shown that patients with hypogonadotrophic hypogonadism also have markedly elevated C-reactive protein (CRP) concentrations. We have now hypothesized that type 2 diabetic subjects with hypogonadotrophic hypogonadism may have a lower hematocrit because testosterone stimulates, whereas chronic inflammation suppresses, erythropoiesis.

RESEARCH DESIGN AND METHODS

Seventy patients with type 2 diabetes at a tertiary referral center were included in this study.

RESULTS

The mean hematocrit in patients with hypogonadotrophic hypogonadism (n = 37), defined as calculated free testosterone (cFT) of <6.5 ng/dl, was 40.6 +/- 1.1%, whereas that in eugonadal patients (n = 33) was 43.3 +/- 0.7% (P = 0.011). The hematocrit was related to cFT concentration (r = 0.46; P < 0.0001); it was inversely related to plasma CRP concentration (r = 0.41; P < 0.0004). Patients with CRP <3 mg/l had a higher hematocrit (42.7 +/- 0.7%) than those with CRP >3 mg/l (39.9 +/- 1.1%; P < 0.05). The prevalence of normocytic normochromic anemia (hemoglobin <13 g/dl) was 23% in the entire group, whereas it was 37.8% in the men with hypogonadotrophic hypogonadism and 3% in the eugonadal men (P < 0.01). Erythropoietin concentration was elevated or high normal in all 11 patients with anemia in whom it was tested.

CONCLUSIONS

We conclude that hypogonadotrophic hypogonadism in male type 2 diabetic subjects is associated with a lower hematocrit and a frequent occurrence of mild normocytic normochromic anemia with normal or high erythropoietin concentrations. In these patients, hematocrit is also inversely related to CRP concentration. Thus, low testosterone and chronic inflammatory mechanisms may contribute to mild anemia. Such patients may also have a high risk of atherosclerotic cardiovascular events in view of their markedly elevated CRP concentrations.