Signal pathways underlying homocysteine-induced production of MCP-1 and IL-8 in cultured human whole blood

Impact of Statin or Fibrate Therapy on Homocysteine Concentrations: A Systematic Review and Meta-analysis

INTRODUCTION

Statins and fibrates are two lipid-lowering drugs used in patients with dyslipidemia. This systematic review and meta-analysis were conducted to determine the magnitude of the effect of statin and fibrate therapy on serum homocysteine levels.

METHODS

A search was undertaken of the PubMed, Scopus, Web of Science, Embase, and Google Scholar electronic databases up to 15 July 2022. Primary endpoints focused on plasma homocysteine levels. Data were quantitatively analyzed using fixed or random- effect models, as appropriate. Subgroup analyses were conducted based on the drugs and hydrophilic-lipophilic balance of statins.

RESULTS

After screening 1134 papers, 52 studies with a total of 20651 participants were included in the meta-analysis. The analysis showed a significant decrease in plasma homocysteine levels after statin therapy (WMD: -1.388 μmol/L, 95% CI: [-2.184, -0.592], p = 0.001; I2 = 95%). However, fibrate therapy significantly increased plasma homocysteine levels (WMD: 3.459 μmol/L, 95% CI: [2.849, 4.069], p < 0.001; I2 = 98%). The effect of atorvastatin and simvastatin depended on the dose and duration of treatment (atorvastatin [coefficient: 0.075 [0.0132, 0.137]; p = 0.017, coefficient: 0.103 [0.004, 0.202]; p = 0.040, respectively] and simvastatin [coefficient: -0.047 [-0.063, -0.031]; p < 0.001, coefficient: 0.046 [0.016, 0.078]; p = 0.004]), whereas the effect of fenofibrate persisted over time (coefficient: 0.007 [-0.011, 0.026]; p = 0.442) and was not altered by a change in dosage (coefficient: -0.004 [-0.031, 0.024]; p = 0.798). In addition, the greater homocysteine- lowering effect of statins was associated with higher baseline plasma homocysteine concentrations (coefficient: -0.224 [-0.340, -0.109]; p < 0.001).

CONCLUSION

Fibrates significantly increased homocysteine levels, whereas statins significantly decreased them.

Serum Homocysteine Level Predictive Capability for Severity of Restenosis Post Percutaneous Coronary Intervention

Background: In stent restenosis (ISR) is one of the major complications after stent implantation. Thus, there is a growing interest in identifying a biomarker for the onset of ISR. High levels of serum homocysteine (Hcy) have been associated with the progression of cardiovascular disease. Therefore, the study was carried out to quantify the correlation between serum Hcy and ISR severity. Compared with coronary angiography (CAG), Hcy levels provided a significantly better clinical detection of ISR severity after PCI.

Methods: A total of 155 patients were recruited from Shanxi Bethune hospital, from 6 months to 2 years post PCI. Serum Hcy levels and postoperative angiography results were used to differentiate the patients into two experimental groups: ISR (>50% diametrical stenosis), and non-ISR. The non-ISR included two subgroups: intimal hyperplasia (10–50% diametrical stenosis), and recovery (<10% diametrical stenosis). In addition, a group of 80 healthy individuals was used as a negative control. The correlation between homocysteine level and ISR severity t was analyzed for all groups. In addition, the correlation between serum Hcy level and the severity of ISR in the experimental group was analyzed by the Pearson correlation test.

Results: The serum Hcy level in the experimental group and control group was determined to be (20.21 ± 11.42) μmol/L and (15.11 ± 10.25) μmol/L respectively. The level of serum Hcy in the experimental group was significantly higher than in the control group (t-value of 2.385; p-value of 0.019). The serum Hcy level in the restenosis and the intimal hyperplasia group was (25.72 ± 13.71) μmol/L and (17.35 ± 7.70) μmol/L respectively. The serum Hcy level in the restenosis group was significantly higher than in the intimal hyperplasia group (t-value of 2.215; p-value of 0.033). The level of serum Hcy in the group without a plaque in the stent was (16.30 ± 6.08) μmol/L, whereas in the control group was (15.11 ± 10.25) μmol/L. The no plaque group had a slightly higher serum Hcy level than the control group (t-value of 0.634; p-value of 0.528). All included patients were divided into four quartiles based on the serum Hcy concentration: quartile 1 (8.90–13.20 μmol/L), quartile 2 (13.30–16.45 μmol/L), quartile 3 (16.60–24.25 μmol/L) and quartile 4 (24.30-65.30 μ mol/L). The incidence of ISR was 5, 6.25, 7.5 and 15%, in the 1,2,3 and four quartiles respectively. The serum Hcy level in the experimental group was (20.21 ± 11.42) μmol/L, the severity of in-stent restenosis was (0.25 ± 0.31), (R-value was 0.234; p-value was 0.037), indicating a correlation between serum Hcy and the severity of restenosis (p < 0.05). Taking coronary angiography as the gold standard, a ROC curve analysis was performed on the serum Hcy levels for the experimental group. The area under the curve (AUC) was 0.718 (95% CI 0.585-0.854, p < 0.001), indicating that the serum Hcy concentration could predict ISR. On the ROC curve, the best critical value of serum Hcy concentration for predicting ISR was 20.05 μmol/L, with a sensitivity of 45% and specificity of 88.1%.

Conclusion: A positive correlation was observed between homocysteine and the severity of restenosis after PCI, The level of Hcy could serve as a predictive biomarker for the severity of ISR.

Value of neutrophil-to-lymphocyte ratio as a marker of renal damage in patients with H-type hypertension

Aim: To explore the relationship between the neutrophil-to-lymphocyte ratio (NLR) and renal damage in patients with H-type hypertension. Materials & methods: A total of 618 patients between 2017 and 2019 were analyzed retrospectively. Results: NLR was significantly correlated with renal damage in hypertension patients. Appropriate cut-off value for NLR (2.247) was determined by receiver operating characteristic curve; linear regression analysis showed that NLR and estimated glomerular filtration rate, blood urea nitrogen/creatinine has a significant negative correlation in H-type hypertension group (p < 0.05); logistic regression analysis showed that the risk of renal damage increased by 10% for each 1 umol/l increase of homocysteine, and 51% for each 1.0 increase of NLR in H-type hypertension patients. Conclusion: NLR worth popularizing in prediction of renal damage in patients with H-type hypertension.

Bakkenolide‑IIIa ameliorates lipopolysaccharide‑induced inflammatory injury in human umbilical vein endothelial cells by upregulating LINC00294

Inflammation, which causes injury to vascular endothelial cells, is one of the major factors associated with atherosclerosis (AS); therefore, inhibition of endothelial inflammation is a key step toward preventing AS. The present study aimed to investigate the effects of bakkenolide-IIIa (Bak-IIIa), an important active component of bakkenolides, on endothelial inflammation, as well as the mechanisms underlying such effects. Lipopolysaccharide (LPS)-damaged human umbilical vein endothelial cells (HUVECs) were treated with Bak-IIIa. The results of the MTT assay and enzyme-linked immunosorbent assay indicated that Bak-IIIa significantly alleviated survival inhibition, and decreased the levels of LPS-induced TNF-α, interleukin (IL)-1β, IL-8, and IL-6. Furthermore, long noncoding RNA (lncRNA) microarray analyses revealed 70 differentially expressed lncRNAs (DELs) in LPS-damaged HUVECs treated with Bak-IIIa. lncRNA target prediction results revealed that 44 DELs had 52 cis-targets, whereas 12 DELs covered 386 trans-targets. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses of the trans-targets indicated that three GO terms were associated with inflammation. Therefore, 17 targets involved in these GO terms and six relevant DELs were screened out. Validation via reverse transcription-quantitative PCR indicated that the fold change of NR_015451 (LINC00294) was the highest among the six candidates and that overexpression of LINC00294 significantly alleviated LPS-induced survival inhibition and inflammatory damage in HUVECs. In conclusion, Bak-IIIa ameliorated LPS-induced inflammatory damage in HUVECs by upregulating LINC00294. Thus, Bak-IIIa exhibited potential for preventing vascular inflammation.

Association of Elevated Plasma Homocysteine Level with Restenosis and Clinical Outcomes After Percutaneous Coronary Interventions: a Systemic Review and Meta-analysis

PURPOSE

We conducted this systemic review and meta-analysis to investigate the association between elevated plasma homocysteine (Hcy) levels and recurrent restenosis and clinical outcomes after percutaneous coronary intervention (PCI).

METHODS

PubMed, EMBASE, and Web of Science were systematically searched prior to May 2018. Studies evaluating the association between plasma Hcy levels and the occurrence of restenosis, major adverse cardiac events (MACE), all-cause mortality, cardiac death, non-fatal myocardial infarction (MI), and target lesion revascularization were identified.

RESULTS

A total of 19 articles with 4340 participants were identified. Higher Hcy levels were not associated with an increased risk of restenosis (relative risk (RR) = 1.10, 95% CI 0.90-1.33). Hcy levels in the restenosis group were not significantly higher than in the non-restenosis group (weighted mean difference = 0.70, 95% CI - 0.23-1.63). Subgroup analysis revealed that higher Hcy levels were not associated with restenosis after stenting but appeared to increase the risk of restenosis after angioplasty. Elevated Hcy levels increased the risk of all-cause mortality by an average of 3.19-fold (RR = 3.19, 95% CI 1.90-5.34, P = 0.000), the risk of MACE by 1.51-fold (RR = 1.51, 95% CI 1.23-1.85, P = 0.000), and the risk of cardiac death by 2.76-fold (RR = 2.76, 95% CI 1.44-5.32, P = 0.000) but appeared not to increase the risk of non-fatal MI (RR = 1.36, 95% CI 0.89-2.09).

CONCLUSIONS

Our meta-analysis suggests that although there is no clear association between higher Hcy levels and restenosis following stent implantation, higher Hcy levels appeared to increase the risk of restenosis after coronary angioplasty and also increased the risk of all-cause mortality, MACE, and cardiac death after PCI.

REGISTRATION DETAILS

The protocol of this meta-analysis was registered on PROSPERO (CRD42018096466). ( http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42018096466 ).

Association of MTHFR C677T polymorphism with elevated homocysteine level and disease development in vitiligo

Increasing evidence on the association of MTHFR gene polymorphism and serum homocysteine levels with autoimmune diseases such as vitiligo has made the MTHFR gene a very interesting candidate to be evaluated in different ethnicities and populations. We aimed to evaluate the levels of serum homocysteine and vitamin B12 and their associations with MTHFR C677T polymorphism in the Iranian population. This case-control study included 104 patients with vitiligo and 100 age- and sex-matched healthy control subjects. Serum vitamin B12 and homocysteine levels were measured by a chemiluminescence assay. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was used for genotyping the polymorphism. The mean serum homocysteine levels were significantly higher in cases than controls and associated with disease activity (p < .001). Furthermore, the homozygous MTHFR C677T variant genotype was associated with vitiligo development (adjusted OR: 3.52, 95% CI: 1.09-11.32, p = .02) and elevated homocysteine level (p < .001). There was no association between serum vitamin B12 levels and the MTHFR C677T genotype. The homozygous variant MTHFR C677T may be considered as a risk factor for both elevated homocysteine levels and the development of vitiligo in the Iranian population. Although these results are not conclusive, they could elucidate the contribution of genetic and immune-mediated inflammatory factors to the pathogenesis of vitiligo.

Saffron; An updated review on biological properties with special focus on cardiovascular effects

OBJECTIVE

Saffron as a natural product has long been used to impede and treat different disorders including cardiovascular disease (CVDs). Stigma is the most principal part of saffron. Various compounds such as carotenoids and flavonoids are the essential components of saffron stigma. The health benefits of saffron have been shown in previous studies; however, there is a lack of comprehensive data on the mechanistic aspects of its cardiovascular-health properties. This current comprehensive review focuses on the medicinal applications of saffron, and then the new findings regarding its cardiovascular-health effects and various cellular and molecular mechanisms of action will be debated.

METHODS

The literature search of MEDLINE, Embase, PubMed, Google Scholar and Cochrane Library was performed for all comparative studies since 2000-2018 with the limitations of the English language.

RESULTS

The results provided new evidence about antioxidant, anti-inflammatory, anti- atherogenic, anti- apoptotic, anti- hypertensive, and hypolipidemic effects of saffron. Pharmacological effects of saffron are due to a number of ingredients contained within this spice, including safranal, crocetin and crocins.

CONCLUSIONS

Our study concludes that saffron with wide range of usefulness in medicine may be the potent candidate in the process of new drug production for the treatment of CVDs.

Conditioned medium from contracting skeletal muscle cells reverses insulin resistance and dysfunction of endothelial cells

OBJECTIVE

Obese adipose tissue has been characterized with chronic inflammation associated with elevated secretion of inflammatory cytokines and declined secretion of anti-inflammatory cytokines which can impair endothelial function in an endocrine manner. Adipose tissue hypoxia plays a role in the changes of cytokines. Physical exercise/muscle contraction may help preventing cardiovascular disease through improving insulin resistance and endothelium function. However the mechanism is unclear. Skeletal muscle is an endocrine tissue. Contracting muscles secrete myokines which may play roles in the beneficial effect of exercise. In this study, the conditioned medium from electrical pulse stimulation (EPS) regulated skeletal muscle cells was used to explore the mechanism of contraction on endothelial dysfunction and insulin resistance induced by conditioned medium from hypoxic adipocytes.

METHODS

3T3-L1 adipocytes were incubated under normoxia or hypoxia condition, respectively. The supernatant was collected as adipocyte conditioned medium (CM-N and CM-H). C2C12 mouse skeletal muscle cells were stimulated with EPS for 12 h. The supernatant was collected as muscle cells conditioned medium (CM-EPS). Human umbilical vein endothelial cells (HUVECs) were incubated with adipocyte CM and muscle cells CM together. Macrophages migration to HUVECs was detected with transwell system. The mRNA expressions of E-selectin, ICAM-1, MCP-1 and IL-6 were measured by real-time PCR. The phosphorylation of IKKα/β, NF-κB, Akt, AMPK, eNOS and SOCS3 protein levels were detected by Western blot. Concentration of NO was measured by ELISA kit. HUVECs apoptosis was detected by flow cytometry.

RESULTS

CM-EPS reduced the increase of mRNA expressions of E-selectin, ICAM-1, MCP-1 and IL-6 in HUVECs induced by CN-H. The phosphorylations of IKKα/β and NF-κB, SOCS3 protein level and endothelial cells apoptosis, which were raised by CM-H, were significantly reduced by CM-EPS. CM-EPS reversed the effects of CM-H on Akt and eNOS phosphorylations and NO production in HUVECs. CM-EPS directly stimulated the phosphorylation of AMPK, which caused the following phosphorylation of eNOS in HUVECs.

CONCLUSION

In summary, CM-EPS reversed endothelial cells inflammation, apoptosis, insulin resistance and dysfunction induced by CM-H.

Sodium tanshinone IIA sulfonate prevents lipopolysaccharide-induced inflammation via suppressing nuclear factor-κB signaling pathway in human umbilical vein endothelial cells

Sodium tanshinone IIA sulfonate (STS), a water-soluble derivative of tanshinone IIA, has been demonstrated to have potent anti-inflammatory properties. However, the protective effects of STS on lipopolysaccharide (LPS)-induced inflammation in endothelial cells remain to be elucidated. In the present study, human umbilical vein endothelial cells (HUVECs) were used to explore the effects of STS on LPS-induced inflammation and the molecular mechanism involved. HUVECs were pretreated with STS for 2 h, followed by stimulation with LPS. Then expression and secretion of tumor necrosis factor (TNF)-α and interleukin (IL)-1β, and the activation of nuclear factor-κB (NF-κB) were assessed. The results demonstrated that STS significantly decreased LPS-induced TNF-α and IL-1β protein expression in HUVECs. Similarly, the increased levels of TNF-α and IL-1β in cell supernatants stimulated by LPS were also significantly inhibited by STS. Furthermore, STS inhibited LPS-induced NF-κB p65 phosphorylation and nuclear translocation. All the results suggest that STS prevents LPS-induced inflammation through suppressing NF-κB signaling pathway in endothelial cells, indicating the potential utility of STS for the treatment of inflammatory diseases.

Contributions of hyperhomocysteinemia to atherosclerosis: Causal relationship and potential mechanisms

Hyperhomocysteinemia (HHcy) is considered an independent risk factor for cardiovascular disease, including ischemic heart disease, stroke, and peripheral vascular disease. Mutations in the enzymes and/or nutritional deficiencies in B vitamins required for homocysteine metabolism can induce HHcy. Studies using genetic- or diet-induced animal models of HHcy have demonstrated a causal relationship between HHcy and accelerated atherosclerosis. Oxidative stress and activation of proinflammatory factors have been proposed to explain the atherogenic effects of HHcy. Recently, HHcy-induced endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) have been found to play a role in HHcy-induced atherogenesis. This review will focus on the cellular mechanisms of HHcy in atherosclerosis from both in vivo and in vitro studies. The contributions of ER stress and the UPR in atherogenesis will be emphasized. Results from recent clinical trials assessing the cardiovascular risk of lowering total plasma homocysteine levels and new findings examining the atherogenic role of HHcy in wild-type C57BL/6J mice will also be discussed. (c) 2009 International Union of Biochemistry and Molecular Biology, Inc.

Rosiglitazone attenuates NF-kappaB-dependent ICAM-1 and TNF-alpha production caused by homocysteine via inhibiting ERK1/2/p38MAPK activation

Previous studies demonstrated an important interaction between nuclear factor-kappaB (NF-kappaB) activation and homocysteine (Hcy)-induced cytokines expression in endothelial cells and vascular smooth muscle cells. However, the underlying mechanism remains illusive. In this study, we investigated the effects of Hcy on NF-kappaB-mediated sICAM-1, TNF-alpha production and the possible involvement of ERK(1/2)/p38MAPK pathway. The effects of rosiglitazone intervention were also examined. Our results show that Hcy increased the levels of sICAM-1 and TNF-alpha in cultured human umbilical vein endothelial cells (HUVECs) in a time- and concentration-dependent manner. This effect was significantly depressed by rosiglitazone and different inhibitors (PDTC, NF-kappaB inhibitor; PD98059, MEK inhibitor; SB203580, p38MAPK specific inhibitor; and staurosporine, PKC inhibitor). Next, we investigated the effect of Hcy on ERK(1/2)/p38MAPK pathway and NF-kappaB activity in HUVECs. The results show that Hcy activated both ERK(1/2)/p38MAPK pathway and NF-kappaB-DNA-binding activity. These effects were markedly inhibited by rosiglitazone as well as other inhibitors (SB203580, PD98059, and PDTC). Further, the pretreatment of staurosporine abrogated ERK(1/2)/p38MAPK phosphorylation, suggesting that Hcy-induced ERK(1/2)/p38MAPK activation is associated with PKC activity. Our results provide evidence that Hcy-induced NF-kappaB activation was mediated by activation of ERK(1/2)/p38MAPK pathway involving PKC activity. Rosiglitazone reduces the NF-kappaB-mediated sICAM-1 and TNF-alpha production induced by Hcy via inhibition of ERK(1/2)/p38MAPK pathway.

Toll-like receptor 2-dependent NF-kappaB activation is involved in nontypeable Haemophilus influenzae-induced monocyte chemotactic protein 1 up-regulation in the spiral ligament fibrocytes of the inner ear

Inner ear dysfunction secondary to chronic otitis media (OM), including high-frequency sensorineural hearing loss or vertigo, is not uncommon. Although chronic middle ear inflammation is believed to cause inner ear dysfunction by entry of OM pathogen components or cytokines from the middle ear into the inner ear, the underlying mechanisms are not well understood. Previously, we demonstrated that the spiral ligament fibrocyte (SLF) cell line up-regulates monocyte chemotactic protein 1 (MCP-1) expression after treatment with nontypeable Haemophilus influenzae (NTHI), one of the most common OM pathogens. We hypothesized that the SLF-derived MCP-1 plays a role in inner ear inflammation secondary to OM that is responsible for hearing loss and dizziness. The purpose of this study was to investigate the signaling pathway involved in NTHI-induced MCP-1 up-regulation in SLFs. Here we show for the first time that NTHI induces MCP-1 up-regulation in the SLFs via Toll-like receptor 2 (TLR2)-dependent activation of NF-kappaB. TLR2(-/-)- and MyD88(-/-)-derived SLFs revealed involvement of TLR2 and MyD88 in NTHI-induced MCP-1 up-regulation. Studies using chemical inhibitors and dominant-negative constructs demonstrated that it is mediated by the IkappaKbeta-dependent IkappaBalpha phosphorylation and NTHI-induced NF-kappaB nuclear translocation. Furthermore, we demonstrated that the binding of NF-kappaB to the enhancer region of MCP-1 is involved in this up-regulation. In addition, we have identified a potential NF-kappaB motif that is responsive and specific to certain NTHI molecules or ligands. Further studies are necessary to reveal specific ligands of NTHI that activate host receptors. These results may provide us with new therapeutic strategies for prevention of inner ear dysfunction secondary to chronic middle ear inflammation.

Regulation of UVB-Induced IL-8 and MCP-1 Production in Skin Keratinocytes by Increasing Vitamin C Uptake via the Redistribution of SVCT-1 from the Cytosol to the Membrane

It is well known that UVB (290-320 nm) induces inflammation in skin by the transcription and release of cytokines and chemokines from skin keratinocytes. In addition, it is considered that intracellular reactive oxygen species (ROS) plays an important role in UVB-induced inflammatory response in the skin. Therefore, we investigated the effect of vitamin C, a potent antioxidant, on the regulation of UVB-induced skin inflammation via the modulation of chemokines production. Vitamin C uptake into keratinocytes is increased by UVB irradiation in a time- and dose-dependent manner through the translocation of sodium-dependent vitamin C transporter-1 (SVCT-1), a vitamin C-specific transporter, from the cytosol to the membrane. To evaluate the effect of vitamin C on the chemokine mRNA expression, we performed RNase protection assay. As a result, there was a remarkable change in chemokine mRNA expression, especially IL-8 and monocyte chemoattractant protein (MCP)-1 expression. In addition, increased IL-8 and MCP-1 mRNA expressions were suppressed by vitamin C treatment. We also confirmed the results of protein levels measured by ELISA. Taken together, vitamin C uptake is increased in UVB-irradiated keratinocytes through the translocation of SVCT-1 and regulates inflammatory response in the skin via the downregulation of IL-8 and MCP-1 production.

ALTERED l-ARGININE/NITRIC OXIDE SYNTHASE/NITRIC OXIDE PATHWAY IN THE VASCULAR ADVENTITIA OF RATS WITH SEPSIS

1. In recent studies, the vascular adventitia has been established as an important source of inducible nitric oxide synthase (iNOS) and subsequent nitric oxide (NO) production, even more powerful than the media in response to certain inflammatory factors, such as lipopolysaccharide (LPS). The adventitia has an independent L-arginine (L-Arg)/NOS/NO pathway and is involved in the regulation of vascular function. In the present study, we explored the changes in and the pathophysiological significance of the L-Arg/NOS/NO pathway in the adventitia of rats with sepsis. 2. Sepsis was induced by caecal ligation and puncture in order to observe changes in L-Arg transport, NOS gene expression and activity and NO generation in the vascular adventitia to determine the mechanism of activation of the L-Arg/NOS/NO pathway. 3. Severe sepsis resulted in severe disturbance of haemodynamic features, with decreased mean arterial blood pressure, brachycardia and inhibited cardiac function (decreased left ventricular +/-dP/dt(max)). Left ventricular end-diastolic pressure was elevated threefold (P < 0.01) under anaesthesia. Rats with sepsis showed severe glucopenia and lacticaemia. Plasma levels of the inflammatory factors macrophage chemoattractant protein-1 and interleukin-8 were increased five- and 29-fold, respectively (P < 0.01). 4. In the adventitia of the thoracic and abdominal aortas, the L-Arg/NO pathway was similarly characterized: the uptake of [(3)H]-L-Arg was Na(+) independent, with the peak occurring at approximately 40 min incubation. Total NOS activity was largely calcium independent (> 90%). The V(max) of L-Arg transport in the sepsis group was increased by 83.5% (P < 0.01), but the K(m) value was not significantly different compared with controls. 5. The mRNA levels of cationic amino acid transporter (CAT)-1 and CAT-2B in the sepsis group were increased by 86 and 62%, respectively (both P < 0.01). Inducible NOS activity was increased 2.8-fold compared with controls (P < 0.01) and iNOS mRNA levels were elevated approximately sixfold (P < 0.01). The NO levels in the plasma and incubation media (incubation for 40 min) in the sepsis group were increased by 144 and 273%, respectively (both P < 0.01). 6. The Arg/NOS/NO pathway was activated in the vascular adventitia of rats with sepsis shock. The L-Arg/NOS/NO pathway in the aortic adventitia may play an important role in the pathogenesis of sepsis and septic shock.