Inflammation and Oxidative Stress Markers by Pentoxifylline Treatment in Rats with Chronic Renal Failure and High Sodium Intake

The Effect of High-Salt Diet on Oxidative Stress Production and Vascular Function in Tff3-/-/C57BL/6N Knockout and Wild Type (C57BL/6N) Mice

INTRODUCTION

It is well documented that high-salt (HS) diet increases systemic and vascular oxidative stress in various animal models and in humans, leading to impairment of vascular reactivity. The present study examined the interaction of genotype and HS diet intake and the potential effects of oxidative stress - antioxidative system balance on the flow-induced dilation (FID) in pressurized carotid arteries of normotensive Tff3-/-/C57BL/6N knockout mice and their wild-type (WT) controls.

METHODS

Male, ten-week-old transgenic Tff3-/-/C57BL/6N (Tff3-/-) knockout mice and WT/C57BL/6N (WT) (parental strain) healthy mice were divided in LS (0.4% NaCl in rodent chow) and HS (4% NaCl in rodent chow fed for 1 week) groups. Additionally, LS and HS groups were treated with 1 mmol/L 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPOL) dissolved in the drinking water. After anesthesia with ketamine chloride (100 mg/kg) and midazolam (5 mg/kg), blood pressure was measured, carotid arteries and aortas were isolated, and blood samples were collected.

RESULTS

FID was decreased in WT_HS mice and restored by superoxide scavenger TEMPOL in vivo. On the other hand, attenuated FID of Tff3-/- mice was not further affected by HS diet or TEMPOL in vivo treatment. Vascular superoxide/reactive oxygen species levels were increased with HS diet in both strains and restored by TEMPOL. HS upregulated glutathione peroxidase 1 (GPx1) gene expression in WT_HS and Tff3-/-_HS mice, while GPx activity was significantly decreased only in WT_HS group. Systemic (serum) markers of oxidative stress (oxLDL and AOPP) and arterial blood pressure were similar among groups.

CONCLUSION

HS diet increases vascular oxidative stress and impairs vasodilation in WT mice. Tff3 gene deficiency attenuates vasodilation per se, without further effects of HS intake. This can be attributed to vascular upregulation of antioxidative enzyme GPx1 in Tff3-/-/C57BL/6N mice conferring protection from oxidative stress.

Sodium chloride-induced changes in oxidative stress, inflammation, and dysbiosis in experimental multiple sclerosis

Objectives: The high-salt diet (HSD) has been associated with cognitive dysfunction by attacking the cerebral microvasculature, through an adaptive response, initiated in the intestine and mediated by Th17 cells. In the animal model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE), it has been described that NaCl causes an increase in T cell infiltration in the central nervous system. NaCl also promotes macrophage response and Th17 cell differentiation, worsening the course of the disease. HSD may trigger an activation of the immune system and enhance inflammation. However, certain studies not only do not support this possibility, but support the opposite, as the effect of salt on immune cells may not necessarily be pathogenic. Therefore, this study aimed to evaluate the effect of an over intake of salt in rats with EAE, based on the clinical course, oxidative stress, markers of inflammation and the gut dysbiosis.Methods: 15 Dark Agouti rats were used, which were divided into control group, EAE group and EAE + NaCl group. Daily 0.027 g of NaCl dissolved in 300 μl of H2O was administered through a nasogastric tube for 51 days.Results: NaCl administration produced an improvement in clinical status and a decrease in biomarkers of oxidative stress, inflammation, and dysbiosis.Conclusion: The underlying mechanism by which NaCl causes these effects could involve the renin-angiotensin-aldosterone system (RAAS), which is blocked by high doses of salt.

The association of carotid artery atherosclerosis with the estimated excretion levels of urinary sodium and potassium and their ratio in Chinese adults

Background

Arterial stiffness is an independent cardiovascular risk factor. However, the association between sodium/potassium intake and vascular stiffness was inconsistent. Therefore, a large community-based cross-sectional study was performed to try and achieve more definitive conclusion.

Methods

Urinary sodium, potassium, and creatinine levels were tested in spot urine samples during physical examinations of each recruited participant. The 24-h estimated urinary sodium excretion (eUNaE) and estimated urinary potassium excretion (eUKE) levels were determined using the Kawasaki formula (used as a surrogate for intake). Carotid intima-media thickness (IMT) and plaques were measured using ultrasound.

Results

In 13,523 subjects aged 18–80 years, the relationships between carotid plaques and IMT with eUNaE, eUKE and their ratios were analyzed. Overall, 30.2% of participants were diagnosed with carotid artery plaques. The ratio of estimated sodium vs. potassium excretion (Na/K ratio) of the individuals with carotid artery plaques was significantly higher than that of participants without plaque (2.14 ± 0.73 vs. 2.09 ± 0.61, P < 0.01). After adjusting for age, gender, and other lifestyle covariates, a significant positive relation was found between carotid plaque and Na/K ratios (OR = 1.06, P < 0.05). In participants without plaque, a similar positive association was observed between Na/K ratios and increased bifurcation carotid IMT (β = 0.008, P < 0.01), especially in the females (P_interaction < 0.01).

Conclusions

In this study, in which sodium intake was estimated on the basis of measured urinary excretion, high estimated excretion levels of urinary sodium and/or low estimated excretion levels of urinary potassium might be associated with an increased presence of carotid atherosclerosis in Chinese individuals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00710-8.

Urinary Sodium and Potassium Excretion and Carotid Atherosclerosis in Chinese Men and Women

Limited studies have examined the association between sodium (Na) and potassium (K) levels and the risk of atherosclerosis. This study examined whether higher Na and Na/K levels and low K levels were independent risk factors for atherosclerosis. This community-based cross-sectional study included 3290 subjects (1067 men and 2223 women) 40 to 75 years of age in Guangzhou, China, between 2011 and 2013. Urinary excretion of Na and K were measured from the first morning void, and creatinine-adjusted values were used. The intima-media thickness (IMT) of the carotid common artery and the carotid bifurcation was measured with high-resolution B-mode ultrasonography. Dietary K and Na intake and other covariates were obtained by face-to-face interviews. A significant positive association was seen between urinary Na excretion and carotid atherosclerosis after adjustment for age, sex, and other lifestyle covariates. The odds ratios (OR) and 95% confidence interval (CI) of the highest (vs. lowest) quartile of urinary Na were 1.32 (1.04-1.66) for carotid plaques, 1.48 (1.18-1.87) for increased common carotid artery IMT, and 1.55 (1.23-1.96) for increased carotid bifurcation IMT (all p-trend < 0.01). A similar positive association was observed between urinary Na/K levels and carotid plaque and increased IMT, and between dietary Na intake and increased bifurcation IMT. Regarding potassium data, we only found a significantly lower presence of carotid plaque (OR 0.72, 95% CI 0.57-0.91) for quartile 2 (vs. 1) of urinary K. Our findings suggest that higher levels of urinary excretion Na and Na/K are significantly associated with greater presence of carotid atherosclerosis in Chinese adults.

Association of Processed Meat Intake with Hypertension Risk in Hemodialysis Patients: A Cross-Sectional Study

In this cross-sectional study, we hypothesized that hemodialysis patients consuming greater processed meat is associated with hypertension risk, which can be partly explained by the high sodium content in processed meat. From September 2013 to May 2014, one hundred and four patients requiring chronic hemodialysis treatment were recruited from hemodialysis centers. Data on systolic blood pressure and diastolic blood pressure before receiving dialysis, and 3-day dietary records of the recruited patients were collected. HD patients with systolic and diastolic blood pressures greater than140 mmHg and higher than 90 mmHg, respectively, were considered hypertension risk. Protein foods were divided into 4 categories: red meat, white meat, soybeans, and processed meat (e.g., sausage and ham). In a model adjusted for energy intake and hypertension history, additional servings of processed meats was positively associated to systolic blood pressure >140 mmHg (odds ratio [95% confidence interval]: 2.1 [1.0–4.3]), and diastolic blood pressure > 90 mmHg (odds ratio: 2.5 [1.2–5.5]). After adjustment for dietary sodium contents or body mass index (BMI), most associations were substantially attenuated and were no longer significant. In systolic blood pressure greater than140 mmHg, one serving per day of red meats (β = -1.22, P < .05) and white meats (β = -0. 75, P = .05) was associated with a reduced risk compared with one serving per day of processed meats. Similarly, compared with one serving per day of processed meat, a reduced risk of diastolic blood pressure higher than 90 mmHg was associated with one serving per day of red meat (β = -1. 59, P < .05), white meat (β = -0. 62, P < .05). Thus, in these hemodialysis patients, intake of processed meat is significantly positively associated with higher blood pressure risk, and both sodium contents in processed meat and BMI significantly contributes to this association.

Pentoxifylline attenuates nitrogen mustard-induced acute lung injury, oxidative stress and inflammation

Nitrogen mustard (NM) is a toxic alkylating agent that causes damage to the respiratory tract. Evidence suggests that macrophages and inflammatory mediators including tumor necrosis factor (TNF)α contribute to pulmonary injury. Pentoxifylline is a TNFα inhibitor known to suppress inflammation. In these studies, we analyzed the ability of pentoxifylline to mitigate NM-induced lung injury and inflammation. Exposure of male Wistar rats (150-174 g; 8-10 weeks) to NM (0.125 mg/kg, i.t.) resulted in severe histopathological changes in the lung within 3d of exposure, along with increases in bronchoalveolar lavage (BAL) cell number and protein, indicating inflammation and alveolar-epithelial barrier dysfunction. This was associated with increases in oxidative stress proteins including lipocalin (Lcn)2 and heme oxygenase (HO)-1 in the lung, along with pro-inflammatory/cytotoxic (COX-2(+) and MMP-9(+)), and anti-inflammatory/wound repair (CD163+ and Gal-3(+)) macrophages. Treatment of rats with pentoxifylline (46.7 mg/kg, i.p.) daily for 3d beginning 15 min after NM significantly reduced NM-induced lung injury, inflammation, and oxidative stress, as measured histologically and by decreases in BAL cell and protein content, and levels of HO-1 and Lcn2. Macrophages expressing COX-2 and MMP-9 also decreased after pentoxifylline, while CD163+ and Gal-3(+) macrophages increased. This was correlated with persistent upregulation of markers of wound repair including pro-surfactant protein-C and proliferating nuclear cell antigen by Type II cells. NM-induced lung injury and inflammation were associated with alterations in the elastic properties of the lung, however these were largely unaltered by pentoxifylline. These data suggest that pentoxifylline may be useful in treating acute lung injury, inflammation and oxidative stress induced by vesicants.

Evaluation of nephrotoxic effects of mycotoxins, citrinin and patulin, on zebrafish (Danio rerio) embryos

Citrinin (CTN) and patulin (PAT) are fungal secondary metabolites which are found in food and feed and showed organotoxicity in mature animals. In this study zebrafish embryos were applied to investigate the developmental toxicity of CTN and PAT on embryonic kidney. In the presence of CTN and PAT, the gross morphology of kidneys from embryos with green fluorescent kidney (wt1b:GFP) was not apparently altered. Histological analysis of CTN-treated embryos indicated cystic glomerular and tubular lesions; a disorganized arrangement of renal cells was also found in the PAT-treated group. From the view point of renal function, dextran clearance abilities of embryos exposed to CTN and PAT were significantly reduced. The damaged renal function caused by CTN could be partially rescued by the administration of pentoxifylline, suggesting the reduction of glomerular blood flow contributes to CTN-induced renal dysfunction. Additionally, CTN induced the expression of proinflammation genes, including COX2a, TNF-α and IL-1β, but failed to modify the levels and distribution of wt1a transcript and Na(+)/K(+)-ATPase protein. In summary, CTN and PAT caused profound nephrotoxicity in histological structure and biological function of zebrafish embryos; the inflammatory pathway and blood rheology may involve in CTN-induced renal impairment.

Pentoxifylline decreases serum levels of tumor necrosis factor alpha, interleukin 6 and C-reactive protein in hemodialysis patients: results of a randomized double-blind, controlled clinical trial

AIM

The aim of this study was to compare the effect of pentoxifylline versus placebo on serum concentrations of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6) and C-reactive protein (CRP) of hemodialysis (HD) patients.

METHODS

This is a randomized double-blind, controlled clinical trial. HD patients without infection or drugs with anti-inflammatory effect were randomly allocated to a study (n = 18, pentoxifylline 400 mg/day) or control (n = 18, placebo) group; all patients had arteriovenous fistula. Besides clinical and laboratory monthly assessments, serum TNF-α and IL-6 (ELISA) and CRP (nephelometry) were measured at 0, 2 and 4 months.

RESULTS

All the inflammation markers significantly (P < 0.05) decreased in the pentoxifylline group: TNF-α [baseline 0.4 (0-2) versus final 0 (0-0) pg/mL], IL-6 [baseline 9.4 (5-14) versus final 2.9 (2-5) pg/mL] and CRP [baseline 7.1 (3-20) versus final 2.6 (1-8) mg/L], whereas no significant changes were observed in the placebo group: TNF-α [baseline 0 (0-0) versus final 1.2 (0-4) pg/mL], IL-6 [baseline 8.0 (5-11) versus final 8.7 (4-11) pg/mL] and CRP [baseline 4.5 (2-9) versus final 3.8 (3-23) mg/L].

CONCLUSIONS

Pentoxifylline significantly decreased serum concentrations of TNF-α, IL-6 and CRP compared to placebo. Pentoxifylline could be a promising and useful strategy to reduce the systemic inflammation frequently observed in patients on HD.

Pentoxifylline attenuates iminodipropionitrile-induced behavioral abnormalities in rats

This investigation was undertaken to study the effect of pentoxifylline (PTX) on iminodipropionitrile (IDPN)-induced behavioral abnormalities [excitation with choreiform and circling movements (ECC) syndrome] in rats. The animals were intraperitoneally injected with IDPN (100 mg/kg) daily for 7 days. PTX was administered daily 30 min before IDPN in the doses of 25, 50, and 100 mg/kg for 9 days. The animals were observed for neurobehavioral abnormalities including dyskinetic head movements, circling, tail hanging, air righting reflex, and contact inhibition of the righting reflex. The onset of ECC syndrome was observed on day 8 in the group treated with IDPN alone; all animals in this group became dyskinetic on day 10. Co-treatment with PTX dose dependently delayed the onset time and significantly reduced the incidence and severity of IDPN-induced ECC syndrome; high dose of PTX completely inhibited the abnormal behavioral signs in IDPN-treated rats. Administration of IDPN caused significant depletions in cerebral glutathione and vitamin E levels. Treatment with PTX dose dependently attenuated IDPN-induced oxidative stress in rats. The beneficial effects of PTX against IDPN toxicity may be attributed to its antioxidant and anti-inflammatory properties.

Effects of soy protein hydrolysate on blood pressure and angiotensin-converting enzyme activity in rats with chronic renal failure

We investigated the effects of soy protein and soy protein hydrolysate on blood pressure control, angiotensin-converting enzyme (ACE) activity, and renal function in a rat chronic renal failure model. Rats that had undergone a 5/6 nephrectomy were separated into three groups and fed different experimental diets for 14 weeks. At the end of the study, rats that fed a diet containing soy protein as the protein source had better blood pressure control and renal function, as well as lower circulating ACE activity and renal tumor-necrosis factor-alpha (TNF-alpha) concentration than rats fed a casein protein diet. Soy protein hydrolysate was shown to be as effective as soy protein in preventing the elevation of blood pressure, the progression of renal failure, and decreases in kidney TNF-alpha level, plasma ACE activity, and insulin concentration. In conclusion, the beneficial effects of consuming soy protein on blood pressure and renal function may be mediated mostly by its pepsin-digested hydrolysate through its ACE inhibitory activity.

Enhanced formation of advanced oxidation protein products in IBD

BACKGROUND

Advanced oxidation protein products (AOPPs) are new protein markers of oxidative stress with pro-inflammatory properties, accumulated in many pathological conditions. The issue of their enhanced formation in IBD has not been addressed yet.

METHODS

The concentration of relative AOPPs (rAOPP; concentration of AOPPs divided by albumin level) were measured in 68 subjects with ulcerative colitis (UC), 50 subjects with Crohn's disease (CD) and 45 healthy volunteers, and related to disease phenotype, clinical and biochemical activity, and therapeutic strategy. Diagnostic utility of rAOPP was evaluated by ROC analysis.

RESULTS

In comparison with controls (1.367 micromol/g), rAOPP were increased in inactive (1.778 micromol/g, P = 0.053) and active (1.895 micromol/g, P = 0.013) UC and in active (1.847 micromol/g, P = 0.003) CD. In CD, but not UC, rAOPP correlated with disease activity (r = 0.42, P = 0.013). Significant correlations with the inflammatory/malnutrition indices-erythrocyte sedimentation rate (ESR) (r = 0.53), leukocytes (r = 0.33), platelets (r = 0.38), IL-6 (r = 0.36), and transferrin (r = -0.35) were demonstrated in CD. In UC, rAOPP correlated only with ESR (r = 0.35) and IL-6 (r = 0.30). Instead, associations with antioxidant dismutase (r = 0.29) and catalase (r = 0.22) were observed. The diagnostic power of rAOPP in discriminating diseased from non-diseased subjects was less than that of C-reactive protein (CRP). Simultaneous determination of rAOPP and CRP did not significantly improve the power of single CRP determination.

CONCLUSIONS

IBD was associated with enhanced formation of AOPP, which differed between C and UC with respect to the relationship between rAOPP and disease activity, inflammatory and antioxidant response. These differences may reflect divergent ways that oxidative stress develops in CD and UC. The diagnostic power of rAOPP was insufficient for its clinical application.

Pentoxifylline ameliorates lithium-pilocarpine induced status epilepticus in young rats

The neuroprotective effects of pentoxifylline (PTX) against lithium-pilocarpine (Li-Pc)-induced status epilepticus (SE) in young rats are described. Animals treated with PTX (0, 20, 40, and 60 mg/kg) before induction of SE were examined for latency to and frequency of SE, behavioral changes, oxidative stress, neurochemical alterations in the hippocampus and striatum, and histological abnormalities in the hippocampus. Treatment with PTX significantly ameliorated the frequency and severity of epileptic seizures in a dose-dependent manner. Our behavioral studies using the elevated plus-maze, rotarod, and water maze tests suggested a significant reduction in anxiety, enhanced motor performance, and improved learning and memory in PTX-treated rats. Li-Pc-induced neuronal cell loss and sprouting of mossy fibers in the hippocampus were also attenuated by PTX. The neuroprotective activity of PTX was accompanied by reduction in oxidative stress and reversal of SE-induced depletion of dopamine and 5-hydroxytryptamine in hippocampus and striatum. The results of this study provide a good rationale to explore the prophylactic/therapeutic potential of PTX in SE.

Fluid dynamics of gingiva and gingival health in children with end stage renal failure

OBJECTIVES

Impaired homeostasis and fluid balance are important physiopathological alterations in patients with chronic renal failure which may adversely affect the fluid dynamics and health status of tissues and organs. There are insufficient data about this phenomenon in periodontal tissues. The aim of this study was to evaluate the fluid dynamics of gingiva in children with end stage renal failure (ESRF), correlating this entity with gingival health in the same patient group.

DESIGN

Fifteen paediatric ESRF patients undergoing peritoneal dialysis (test group) and 15 systemically healthy children (control group) who were without periodontitis participated in the study. Fluid dynamics of gingiva were assessed via the gingival crevicular fluid (GCF) volume and tissue osmotic pressure (GOP) levels in the groups. GCF volume was measured using a Periotron 8000, whereas GOP was measured using a digital osmometer. Silness and Löe Plaque index (PI) and, Löe and Silness gingival index (GI) scores were utilized to determine the gingival health status in the study population.

RESULTS

There were increases in the GCF volume and GOP of the test group compared to those of the control group (p<0.01). The PI and GI scores were higher in the test group than in the control group (p<0.01). Strong and positive correlations were found between GI and GCF volume, GI and GOP and, GCF volume and GOP in both groups (p<0.01).

CONCLUSIONS

Our findings suggest that the fluid dynamics of gingiva may alter in children with ESRF, and this phenomenon may consequently affect the gingival health of these patients.