Plasma angiogenesis and oxidative stress markers in patients with diabetic retinopathy

Abstract

Background: Neovascularization in the retina and hyperglycaemia-induced oxidative stress are implicated in the pathogenesis of diabetic retinopathy (DR). In this study, we hypothesized that the plasma angiogenic and oxidative stress markers associated with these derangements could aid in the screening of diabetic patients who are at an increased risk of developing retinopathy.

Methods: This study included normal (n?=?148), type2 diabetes without retinopathy (DNR; n?=?148), proliferative DR (PDR; n?=?74) and non-PDR (NPDR; n?=?148) subjects. Plasma concentrations of vascular endothelial growth factor-A (VEGF-A), hypoxia-inducible factor-1α (HIF-1α), matrix metalloproteinase-9 (MMP-9), pigment epithelium-derived factor (PEDF), nitric oxide (NO), soluble receptors for advanced glycation end products (sRAGE), malondialdehyde (MDA) and protein thiols were estimated.

Results: A statistically significant increase was observed in the plasma concentrations of pro-angiogenic factors and markers of oxidative stress in both retinopathy groups. By contrast, the concentrations of anti-angiogenic factors and antioxidants were decreased significantly in these groups. Receiver operating characteristic analysis indicated that the plasma thresholds of HIF-1α and PEDF can be suitable markers in case of NPDR. However, in PDR, HIF-1α, NO, MMP-9 and PEDF showed high sensitivity and specificity.

Conclusions: The factors associated with hypoxia, matrix degradation and angiogenic inhibition play a crucial role in predicting DR.     

Urinary neutrophil gelatinase-associated lipocalin and L-type fatty acid binding protein as diagnostic markers of early acute kidney injury after liver transplantation

Objective: We examined the value of two potential novel urinary biomarkers, neutrophil gelatinase-associated lipocalin (NGAL) and L-type fatty acid binding protein (L-FABP), in diagnosing acute kidney injury (AKI) in liver transplant recipients.

Methods: NGAL and L-FABP in urinary sample from Twenty-five patients before surgery and at 2, 4, 6, 12, 24, 48, 72 and 120 h after the anhepatic phase were tested. Standard statistics were used along with receiver-operating characteristic (ROC) analysis to evaluate the diagnostic value of selected markers.

Results: Urinary NGAL was only slightly elevated at 2 h in the non-AKI group while rose and stayed high from 2–6 h in the AKI group. However, urinary L-FABP rose transiently in both groups 2–120 h following surgery. The level of urinary NGAL presented differences at 2–6 h (p < 0.05) and urinary L-FABP at 4 h (p < 0.05) between AKI and non-AKI groups. ROC analysis showed that area under the curves (AUCs) of NGAL were 0.766, 0.773, and 0.773 at 2, 4 and 6 h respectively while 0.760 of L-FABP at 4 h.

Conclusion: Urinary NGAL rather than L-FABP appeared to be a sensitive and specific marker of AKI in liver transplant recipients.     

Exposure of colonic epithelial cells to oxidative and endoplasmic reticulum stress causes rapid potassium efflux and calcium influx

Endoplasmic reticulum (ER) stress and oxidative stress have recently been linked to the pathogenesis of inflammatory bowel diseases. Under physiological conditions, intestinal epithelial cells are exposed to ER and oxidative stress affecting the cellular ionic homeostasis. However, these altered ion flux ‘signatures’ during these stress conditions are poorly characterized. We investigated the kinetics of K⁺, Ca²⁺ and H⁺ ion fluxes during ER and oxidative stress in a colonic epithelial cell line LS174T using a non‐invasive microelectrode ion flux estimation technique. ER and oxidative stress were induced by cell exposure to tunicamycin (TM) and copper ascorbate (CuAsc), respectively, from 1 to 24 h. Dramatic K⁺ efflux was observed following acute ER stress with peak K⁺ efflux being ?30·6 and ?138·7 nmolm^?2 s^?1 for 10 and 50 µg ml^?1, respectively (p < 0·01). TM‐dependent Ca²⁺ uptake was more prolonged with peak values of 0·85 and 2·68 nmol m^?2 s^?1 for 10 and 50 µg ml^?1 TM, respectively (p < 0·02). Ion homeostasis was also affected by the duration of ER stress. Increased duration of TM treatment from 0 to 18 h led to increases in both K⁺ efflux and Ca²⁺ uptake. While K⁺ changes were significantly higher at each time point tested, Ca²⁺ uptake was significantly higher only after prolonged treatment (18 h). CuAsc also led to an increased K⁺ efflux and Ca²⁺ uptake. Functional assays to investigate the effect of inhibiting K⁺ efflux with tetraethylammonium resulted in increased cell viability. We conclude that ER/oxidative stress in colonic epithelial cells cause dramatic K⁺, Ca²⁺ and H⁺ ion flux changes, which may predispose this lineage to poor stress recovery reminiscent of that seen in inflammatory bowel diseases. Copyright © 2012 John Wiley & Sons, Ltd.     

Systemic redox imbalance in stable chronic obstructive pulmonary disease

Context: Increased oxidative burden is found in chronic obstructive pulmonary disease (COPD).

Objective: To assess the association of ceruloplasmin, albumin, bilirubin, transferrin, thiols and malondialdehyde (MDA) with stable COPD.

Materials and methods: Oxidative stress markers measured in 106 COPD patients and 45 healthy subjects were evaluated.

Results: Higher ceruloplasmin and MDA, and lower albumin, transferrin and thiols in COPD patients were found. Ceruloplasmin was the strongest single predictor of COPD. The model combining ceruloplasmin, albumin and thiols improved their individual diagnostic performances.

Conclusions: Diagnostic characteristics of ceruloplasmin, albumin, transferrin, thiols and MDA suggest their potential value as additional tools in disease diagnosis.     

Circulating multimarker profile of patients with symptomatic heart failure supports enhanced fibrotic degradation and decreased angiogenesis

Background: Heart failure (HF) involves myocardial fibrosis and dysregulated angiogenesis.

Objective: We explored whether biomarkers of fibrosis and angiogenesis correlate with HF severity.

Methods: Biomarkers of fibrosis [procollagen types I and III (PIP and P3NP), carboxyterminal-telopeptide of type I collagen (ICTP), matrix metalloproteases (MMP2 and MMP9), tissue inhibitor of MMP1 (TIMP1)]; and angiogenesis [placental growth factor (PGF), vascular endothelial growth factor (VEGF), soluble Fms-like tyrosine kinase-1 (sFlt1)] were measured in 52 HF patients and 19 controls.

Results: P3NP, ICTP, MMP2, TIMP1, PGF, and sFlt1 levels were elevated in HF, while PIP/ICTP, PGF/sFlt1, and VEGF/sFlt1 ratios were reduced. PIP/ICTP, MMP-9/TIMP1, and VEGF/sFlt1 ratios were lowest among patients with severe HF.

Conclusions: Severe HF is associated with collagen breakdown and reduced angiogenesis. A multimarker approach may guide therapeutic targeting of fibrosis and angiogenesis in HF.     

Cystatin C,NT-proBNP,and inflammatory markers in acute heart failure: insights into the cardiorenal syndrome

Background: Inflammation is thought to be a mediator in the pathophysiology of the cardiorenal syndrome. We evaluated the interactions between kidney function, cardiac stress, and various inflammatory cytokines in patients with acute heart failure (AHF). The effect on 1-year mortality was also assessed.

Methods and results: Plasma levels of cystatin C, NT-proBNP, and inflammatory cytokines (interleukin [IL]-6, tumor necrosis factor-α [TNF-α], IL-10) were measured in consecutive patients (n?=?465) hospitalized for AHF. After adjustment for demographic characteristics and comorbidities, TNF-α had the strongest relation with renal function (β?=?0.39, P?<?0.0001). Elevated TNF-α levels were seen in patients with high cystatin C, irrespective of NT-proBNP. Levels of IL-6 (β?=?0.26, P?<?0.0001) and IL-10 (β?=?0.15, P?<?0.01), but not TNF-α, were associated with NT-proBNP. Moreover, the most elevated levels of IL-6 were seen in patients with combined high NT-proBNP and high cystatin C. Cox regression analysis found IL-6 above median to be independently predictive of mortality (hazard ratio 1.9; 95% CI 1.2–2.9, P?=?0.003). TNF-α was not significantly associated with prognosis in the overall population after adjustment for multiple covariates, but improved risk stratification in the subgroup with low cystatin C and NT-proBNP.

Conclusion: Levels of TNF-α in AHF are related to kidney function, but not to NT-proBNP. IL-6 seems to be more associated with cardiac stress. Patients with severe dual organ dysfunction have the highest levels of IL-6 and TNF-α. Different relations of inflammatory cytokines to renal function and cardiac stress need to be considered when evaluating heart–kidney interactions.     

Curcumin alleviates acute kidney injury in a dry‐heat environment by reducing oxidative stress and inflammation in a rat model

Curcumin exhibits anti‐inflammatory and antioxidant activities. We investigated the protective effects of curcumin in a renal injury rat model under dry‐heat conditions. We divided Sprague‐Dawley rats into four groups: dry‐heat 0‐ (normal temperature control group), 50‐, 100‐, and 150‐minute groups. Each group was divided into five subgroups (n = 10): normal saline (NS), sodium carboxymethylcellulose (CMCNa), and curcumin pretreated low, medium, and high‐dose (50, 100, and 200 mg/kg, respectively) groups. Compared to the normal temperature group, serum creatinine, blood urea nitrogen, urinary kidney injury molecule‐1, and neutrophil gelatinase‐associated load changes in lipoprotein (NGAL) levels were significantly increased in the dry‐heat environment group (P < .05); inducible nitric oxide synthase (iNOS) and cyclooxygenase‐2 (COX‐2) expression and malondialdehyde (MDA) and related inflammatory factor levels were increased in the kidney tissue. Superoxide dismutase (SOD) and catalase (CAT) levels were decreased. However, following all curcumin pretreatment, the serum levels of kidney injury indicators and NGAL were decreased in the urine compared to those in the NS and CMCNa groups (P < .05), whereas renal SOD and CAT activities were increased and MDA was decreased (P < .05). Renal tissues of the 150‐minute group showed obvious pathological changes. Compared to the NS group, pathological changes in the renal tissues of the 100‐ and 200‐mg/kg curcumin groups were significantly reduced. Furthermore, iNOS and COX‐2 expression and inflammatory factor levels were decreased after curcumin treatment. Curcumin exerted renoprotective effects that were likely mediated by its antioxidant and anti‐inflammatory effects in a dry‐heat environment rat model.     

Tryptophan metabolism and oxidative stress in patients with Huntington's disease

Abnormalities in the kynurenine pathway may play a role in Huntington's disease (HD). In this study, tryptophan depletion and loading were used to investigate changes in blood kynurenine pathway metabolites, as well as markers of inflammation and oxidative stress in HD patients and healthy controls. Results showed that the kynurenine : tryptophan ratio was greater in HD than controls in the baseline state and after tryptophan depletion, indicating increased indoleamine dioxygenase activity in HD. Evidence for persistent inflammation in HD was provided by elevated baseline levels of C-reactive protein, neopterin and lipid peroxidation products compared with controls. The kynurenate : kynurenine ratio suggested lower kynurenine aminotransferase activity in patients and the higher levels of kynurenine in patients at baseline, after depletion and loading, do not result in any differences in kynurenic acid levels, providing no supportive evidence for a compensatory neuroprotective role for kynurenic acid. Quinolinic acid showed wide variations in blood levels. The lipid peroxidation data indicate a high level of oxidative stress in HD patients many years after disease onset. Levels of the free radical generators 3-hydroxykynurenine and 3-hydroxyanthranilic acid were decreased in HD patients, and hence did not appear to contribute to the oxidative stress. It is concluded that patients with HD exhibit abnormal handling of tryptophan metabolism and increased oxidative stress, and that these factors could contribute to ongoing brain dysfunction.     

Hydroxytyrosol prevents dermal papilla cells inflammation under oxidative stress by inducing autophagy

Hydroxytyrosol (HT), a primary phenolic antioxidant in olive oil, can afford protection from oxidative stress (OS) in different cells, including skin cells. In particular, it regulates several inflammation‐associated processes as well as in improving the antioxidant defense system. However, there is no information about HT used in the treatment of hair loss. This work aimed at exploring the potential protective actions of HT against OS in rat dermal papilla cells. After treatment, the related expression of protein and messenger RNA were detected using morphological and molecular analyses. The results showed that HT significantly reduced intracellular reactive oxygen species level, apoptotic markers and inflammation induced by OS and enhanced cell survival by regulating autophagy. Furthermore, HT enhanced the secretion of hair growth factors in the anti‐inflammation process. These results suggest that HT has a significant protective ability against OS and encourage the use of this biological ingredient as a possible tool to prevent alopecia.     

Severe Vitamin E deficiency exacerbates acute hyperoxic lung injury associated with increased oxidative stress and inflammation

Hyperoxia causes acute lung injury along with an increase of oxidative stress and inflammation. It was hypothesized that vitamin E deficiency might exacerbate acute hyperoxic lung injury. This study used α-tocopherol transfer protein knockout (α-TTP KO) mice fed a vitamin E-deficient diet (KO E(-) mice) as a model of severe vitamin E deficiency. Compared with wild-type (WT) mice, KO E(-) mice showed a significantly lower survival rate during hyperoxia. After 72 h of hyperoxia, KO E(-) mice had more severe histologic lung damage and higher values of the total cell count and the protein content of bronchoalveolar lavage fluid (BALF) than WT mice. IL-6 mRNA expression in lung tissue and the levels of 8-iso-prostaglandin F_2α (8-iso-PGF_2α) in both lungs and BALF were higher in KO E(-) mice than in WT mice. It was concluded that severe vitamin E deficiency exacerbates acute hyperoxic lung injury associated with increased oxidative stress or inflammation.     

Functions and oxidative stress status of leukocytes in patients with nephrotic syndrome

This study was conducted to establish the functions and oxidative stress status in leukocytes of adult patients with nephrotic syndrome. Thirty adult patients with nephrotic syndrome and 32 controls were included. Phagocytosis ability, the killing ability of the micro-organism phagosited of polymorphonuclear leukocytes (PMNL) and monocytes, along with oxidative stress parameters of PMNLs were assessed. There was no statistically significant difference in phagocytosis function of PMNLs and monocytes of patients when compared to those of controls. PMNL burst activities of the patient and control groups also showed no difference; however, the monocyte burst activities of patients were significant (p = 0.012). The glutathione peroxidase (GSH-Px) activities in PMNLs of the patients with nephrotic syndrome were significantly higher (p = 0.026) when compared to those of controls. In comparison with those of the control subjects, the patients had also higher selenium levels in their PMNLs (p < 0.001). Although PMNL malonyldialdehyde (MDA) levels of the patients seem to be higher than those of controls, the difference had no statistical significance (p = 0.071). Conclusively, in the patients with nephrotic syndrome, PMNLs appear to be exposed to an oxidative stress as indicated by their increased GSH-Px activities and selenium content. However, PMNLs in nephrotic syndrome patients seem to be coping with the insulting oxidative stress, as suggested by their near-normal MDA productions. Furthermore, these data suggest that nephrotic syndrome appears not to have an influence on phagocytosis and killing abilities of granulocytes and monocytes as long as these cells can overcome the oxidative stress to which they are exposed in this disease.     

IP3R attenuates oxidative stress and inflammation damage in smoking-induced COPD by promoting autophagy

Tobacco smoking is one of the most important risk factors for chronic obstructive pulmonary disease (COPD). However, the most critical genes and proteins remain poorly understood. Therefore, we aimed to investigate these hub genes and proteins in tobacco smoke-induced COPD, together with the potential mechanism(s). Differentially expressed genes (DEGs) were analysed between smokers and patients with COPD. mRNA expression and protein expression of IP₃R were confirmed in patients with COPD and extracted smoke solution (ESS)-treated human bronchial epithelial (HBE) cells. Moreover, expression of oxidative stress, inflammatory cytokines and/or autophagy-related protein was tested when IP₃R was silenced or overexpressed in ESS-treated and/or 3-MA-treated cells. A total of 30 DEGs were obtained between patients with COPD and smoker samples. IP₃R was identified as one of the key targets in tobacco smoke-induced COPD. In addition, IP₃R was significantly decreased in patients with COPD and ESS-treated cells. Loss of IP₃R statistically increased expression of oxidative stress and inflammatory cytokines in ESS-treated HBE cells, and overexpression of IP₃R reversed the above functions. Furthermore, the autophagy-related proteins (Atg5, LC3 and Beclin1) were statistically decreased, and p62 was increased by silencing of IP₃R cells, while overexpression of IP₃R showed contrary results. Additionally, we detected that administration of 3-MA significantly reversed the protective effects of IP₃R overexpression on ESS-induced oxidative stress and inflammatory injury. Our results suggest that IP₃R might exert a protective role against ESS-induced oxidative stress and inflammation damage in HBE cells. These protective effects might be associated with promoting autophagy.     

Influence of metabolic syndrome on biomarkers of oxidative stress and inflammation in obese adults

Objective: Both obesity and the metabolic syndrome (MetS) have been independently linked with increased oxidative and inflammatory stress. This study tested the hypothesis that obesity with MetS is associated with greater oxidative and inflammatory burden compared with obesity alone. Research Methods and Procedures: Forty‐eight normal‐weight and 40 obese (20 without MetS; 20 with MetS) adults were studied. MetS was defined according to National Cholesterol Education Program Adult Treatment Panel III criteria. Plasma concentrations of oxidized low‐density lipoprotein, C‐reactive protein, tumor necrosis factor‐α, interleukin (IL)‐6, and IL‐18 were determined by enzyme immunoassay. Results: Plasma biomarkers of oxidative stress and inflammation were lowest in normal‐weight controls. Of note, obese MetS adults demonstrated significantly higher plasma concentrations of oxidized low‐density lipoprotein (62.3 ± 3.2 vs. 54.0 ± 4.0 U/L; p < 0.05), C‐reactive protein (3.0 ± 0.6 vs. 1.5 ± 0.3 mg/L; p < 0.01), tumor necrosis factor‐α (2.1 ± 0.1 vs. 1.6 ± 0.1 pg/mL; p < 0.05), IL‐6 (2.8 ± 0.4 vs. 1.4 ± 0.2 pg/mL; p < 0.01), and IL‐18 (253 ± 16 vs. 199 ± 16 pg/mL; p < 0.01), compared with obese adults without MetS. Discussion: These results suggest that MetS heightens oxidative stress and inflammatory burden in obese adults. Increased oxidative and inflammatory stress may contribute to the greater risk of coronary heart disease and cerebrovascular disease in obese adults with MetS.     

Evaluation of oxidative stress markers and cardiovascular risk factors in Fabry Disease patients

Fabry Disease, an X-linked inborn error of metabolism, is characterized by progressive renal insufficiency, with cardio and cerebrovascular involvement. Homocysteine (Hcy) is considered a risk factor for vascular diseases, but the mechanisms by which it produces cardiovascular damage are still poorly understood. Regarding the vascular involvement in FD patients, the analysis of factors related to thromboembolic events could be useful to improving our understanding of the disease. The aim of this study was to evaluate plasma Hcy and other parameters involved in the methionine cycle, as well as oxidative stress markers. The sample consisted of a group of 10 male FD patients and a control group of 8 healthy individuals, paired by age. Venous blood was collected for Hcy determination, molecular analysis, identification of thiobarbituric acid reactive substances, total glutathione and antioxidant enzymes activity, as well as vitamins quantification. Comparative analysis of FD patients versus the control group indicated hyperhomocysteinemia in 8 of the 10 FD patients, as well as a significant increase in overall glutathione levels and catalase activity. It is inferred that FD patients, apart from activation of the antioxidant system, present increased levels of plasma Hcy, although this is probably unrelated to common alterations in the methionine cycle.     

α-亚麻酸对糖尿病大鼠炎症介质和氧化应激的影响

目的:观察α-亚麻酸(ALA)对糖尿病大鼠体内炎症介质和氧化应激的影响,探讨ALA在糖尿病防治中的作用。方法:雄性SD大鼠高脂饮食喂养4周后,腹腔注射链脲佐菌素(STZ)30 mg/kg建立2型糖尿病(T2DM)模型。将大鼠随机分为3组(n=10):正常对照组、糖尿病模型组和ALA治疗组(500μg/kg.d)。4周后测定大鼠血清中肿瘤坏死因子(TNF-α)、可溶性P-选择素(sP-selectin)、可溶性细胞间黏附分子(sICAM-1)、一氧化氮(NO)、丙二醛(MDA)的含量以及超氧化物岐化酶(SOD)和过氧化氢酶(CAT)的活性。结果:与正常对照组相比,糖尿病大鼠血清中炎症介质TNF-α、sP-selectin和sICAM-1的含量增加,血清NO含量下降而MDA升高,同时抗氧化酶SOD和CAT的活性降低;ALA治疗可显著降低糖尿病大鼠血清中TNF-α、sP-selectin和sICAM-1的含量(与STZ+vehicle组相比,P<0.01),增加血清NO水平并减少MDA含量,升高抗氧化酶SOD和CAT的活性(与STZ+vehicle组相比,均P<0.05)。结论:ALA可显著降低糖尿病大鼠血清炎症介质的生成,减轻氧化应激水平,具有抗炎和抗氧化作用。提示ALA对糖尿病及糖尿病并发症的发生发展可能具有一定的防治作用。     

Peripheral biomarkers of oxidative stress and their limited potential in evaluation of clinical features of Huntington's patients

Abstract

Context: Peripheral oxidative biomarkers could be useful for monitoring clinical features of Huntington's disease (HD).

Materials and methods: Cu/Zn-superoxide dismutase (Cu/Zn-SOD), neuron-specific enolase (NSE) and 8-hydroxy-2′-deoxyguanosine (8-oxoGua) serum levels were analysed in 18 HD patients and 10 controls. Clinical measures were recorded from each HD patients.

Results: Cu/Zn-SOD, NSE and 8-oxoGua values were higher in HD patients than in controls. Cu/Zn-SOD and NSE correlated positively. No correlation was observed between the biomarkers analysed and the clinical measures assessed.

Discussion and conclusion: Serum oxidative biomarkers could express the neuronal oxidative processes going on in HD patients but are inadequate to evaluate clinical features of the disease.     

Soluble fms-like tyrosine kinase-1 (sFLT-1) predicts post-percutaneous coronary intervention (PCI) myocardial infarction (MI type 4a)

Context: Acute myocardial infarction (AMI) related to percutaneous coronary intervention (PCI) (MI type 4a) occurs in up to 26% of elective patients.

Objective: To evaluate if sFLT-1 helps to predict MI type 4a in troponin negative patients with elective PCI.

Materials and methods: We enrolled 135 patients, 106 had a PCI. sFLT-1 levels were assessed at five time points before and after PCI.

Results: MI type 4a occurred in 22.1% of patients. sFLT-1 levels at admission above 251 pg/mL indicated a significant relative risk for MI type 4a of 2.83.

Conclusion and discussion: Increased sFLT-1 levels at baseline might indicate unstable atherosclerosis and risk for microembolization and thus be predictive of MI type 4a.     

Boswellia serrata extract attenuates inflammatory mediators and oxidative stress in collagen induced arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease which leads to destruction of joints. Current treatment modalities for RA either produce symptomatic relief (NSAIDs) or modify the disease process (DMARDs). Though effective, their use is also limited by their side effects. As a result, the interest in alternative, well tolerated anti-inflammatory remedies has re-emerged. Our aim was to evaluate the antioxidant and antiarthritic activity of Boswellia serrata gum resin extract (BSE) in collagen induced arthritis. Arthritis was induced in male Wistar rats by collagen induced arthritis (CIA) method. BSE was administered at doses of 100 and 200 mg/kg body weight once daily for 21 days. The effects of treatment in the rats were assessed by biochemical (articular elastase, MPO, LPO, GSH, catalase, SOD and NO), inflammatory mediators (IL-1β, IL-6, TNF-α, IL-10, IFN-γ and PGE₂), and histological studies in joints. BSE was effective in bringing significant changes on all the parameters (articular elastase, MPO, LPO, GSH, catalase, SOD and NO) studied. Oral administration of BSE resulted in significantly reduced levels of inflammatory mediators (IL-1β, IL-6, TNF-α, IFN-γ and PGE₂), and increased level of IL-10. The protective effects of BSE against RA were also evident from the decrease in arthritis scoring and bone histology. The abilities to inhibit proinflammatory cytokines and modulation of antioxidant status suggest that the protective effect of Boswellia serrata extract on arthritis in rats might be mediated via the modulation of immune system.