Can curcumin supplementation break the vicious cycle of inflammation, oxidative stress, and uremia in patients undergoing peritoneal dialysis?

BACKGROUND & AIMS

Turmeric (a source of curcumin) is an excellent food to modulate oxidative stress, inflammation, and gut dysbiosis in patients with chronic kidney disease (CKD). However, no studies report the benefits of curcumin in patients undergoing peritoneal dialysis (PD). This study aims to evaluate the effects of curcuminoid supplementation on oxidative stress, inflammatory markers, and uremic toxins originating from gut microbiota in patients with CKD undergoing PD.

METHODS

This longitudinal, randomized, single-blind, placebo-controlled trial evaluated 48 patients who were randomized into two groups: Curcumin (three capsules of 500 mg of Curcuma longa extract, with 98.42 % total curcuminoids) or placebo (three capsules of 500 mg of starch) for twelve weeks. In the peripheral blood mononuclear cells (PBMCs), the transcriptional expression levels of Nrf2, HOX-1 and NF-κB were evaluated by quantitative real-time PCR. Oxidative stress was evaluated by malondialdehyde (MDA) and total Thiol (T-SH). TNF-α and IL-6 plasma levels were measured by ELISA. P-cresyl sulphate plasma level, a uremic toxin, was evaluated by high-performance liquid chromatography (HPLC) with fluorescent detection.

RESULTS

Twenty-four patients finished the study: 10 in the curcumin group (57.5 ± 11.6 years) and 14 in the placebo group (56.5 ± 10.0 years). The plasma levels of MDA were reduced after 12 weeks in the curcumin group (p = 0.01), while the placebo group remained unchanged. However, regarding the difference between the groups at the endpoint, no change was observed in MDA. Still, there was a trend to reduce the p-CS plasma levels in the curcumin group compared to the placebo group (p = 0.07). Likewise, the concentrations of protein thiols, mRNA expression of Nrf2, HOX-1, NF-κB, and cytokines plasma levels did not show significant changes.

CONCLUSION

Curcuminoid supplementation for twelve weeks attenuates lipid peroxidation and might reduce uremic toxin in patients with CKD undergoing PD. This study was registered on Clinicaltrials.gov as NCT04413266.

Sulforaphane Supplementation Did Not Modulate NRF2 and NF-kB mRNA Expressions in Hemodialysis Patients

BACKGROUND

Patients with chronic kidney disease (CKD) have reduced expression of erythroid nuclear factor-related factor 2 (NRF2) and increased nuclear factor κB (NF-κB). "Food as medicine" has been proposed as an adjuvant therapeutic alternative in modulating these factors. No studies have investigated the effects of sulforaphane (SFN) in cruciferous vegetables on the expression of these genes in patients with CKD.

OBJECTIVE

The study aimed to evaluate the effects of SFN on the expression of NRF2 and NF-κB in patients on hemodialysis (HD).

DESIGN AND METHODS

A randomized, double-blind, crossover study was performed on 30 patients on regular HD. Fourteen patients were randomly allocated to the intervention group (1 sachet/day of 2.5 g containing 1% SFN extract with 0.5% myrosinase) and 16 patients to the placebo group (1 sachet/day of 2.5 g containing corn starch colored with chlorophyll) for 2 months. After a washout period of 2 months, the groups were switched. NRF2 and NF-κB mRNA expression was evaluated by real-time quantitative polymerase chain reaction, and tumor necrosis factor alpha and interleukin-6 levels were quantified by enzyme-linked immunosorbent assay. Malondialdehyde was evaluated as a marker of lipid peroxidation.

RESULTS

Twenty-five patients (17 women, 55 [interquartile range = 19] years and 55 [interquartile range = 74] months on HD) completed the study. There was no significant difference concerning the expression of mRNA NRF2 (P = .915) and mRNA NF-κB (P = .806) after supplementation with SFN. There was no difference in pro-inflammatory and oxidative stress biomarkers.

CONCLUSION

150 μmol of SFN for 2 months had no antioxidant and anti-inflammatory effect in patients with CKD undergoing HD.

Evaluation of Bach1 mRNA expression in patients with chronic kidney disease: A preliminary study

INTRODUCTION

BTB and CNC homology 1 (Bach1) is a protein that antagonizes some actions of nuclear factor erythroid 2-related factor-2 (Nrf2), the master regulator of cytoprotective responses. Bach1 binds to genomic DNA and inhibits the synthesis of antioxidant enzymes, thereby increasing inflammation. Bach1 may be a therapeutic target for mitigating inflammation in chronic kidney disease (CKD) patients. However, no clinical study has been reported on Bach1 in this population. This study aimed to evaluate Bach1 mRNA expression with different treatments for CKD, including conservative treatment (nondialysis), hemodialysis (HD), and peritoneal dialysis (PD).

METHODS

Twenty patients undergoing HD (56.5 [19] years), 15 on PD (54 [24] years) and 13 nondialysis patients (63 [10] years, with an estimated glomerular filtration rate of 41 [14] mL/min/1.73 m² ) were enrolled in the study. The mRNA expression of Nrf2, NF-kB, heme oxygenase 1 (HO-1), and Bach1 was evaluated in peripheral blood mononuclear cells using quantitative real-time polymerase chain reaction. Malondialdehyde (MDA) was evaluated as a lipid peroxidation marker. Routine biochemical parameters were also evaluated.

FINDINGS

As expected, patients on dialysis were more inflamed. Bach1 mRNA expression was significantly higher in patients undergoing HD than in PD and nondialysis patients (p < 0.007). The mRNA expression of HO-1, NF-kB, and Nrf2 was not different in the groups.

CONCLUSION

In conclusion, CKD patients on HD exhibited an upregulation of Bach1 mRNA expression compared to patients on PD treatment and nondialysis CKD patients. The association between Nrf2 and Bach1 expression in these patients warrants further investigation.

Dark chocolate (70% cocoa) attenuates the inflammatory marker TNF-α in patients on hemodialysis

BACKGROUND

Inflammation and oxidative stress lead to a high risk of cardiovascular disease in patients with chronic kidney disease (CKD). Food rich in polyphenols such as dark chocolate may be an effective strategy to mitigate inflammation and delay CKD complications, outwith sensorial pleasure promotion. The aim of this study was to evaluate the effects of dark chocolate on inflammation and oxidative stress markers in patients with CKD on hemodialysis (HD).

METHODS

A clinical trial was carried out with 59 patients who were allocated into the chocolate group [40g of dark chocolate (70% cocoa) offered during HD sessions, 3×/week] or the control group with any intervention for two months. Plasma levels of the inflammatory cytokines TNF-α and IL-6 were evaluated by the ELISA method. Thiobarbituric acid reactive substances such as malondialdehyde (MDA) and LDLox levels were evaluated as lipid peroxidation markers. Routine biochemical parameters were analysed using commercial BioClin® kits.

RESULTS

Thirty-five patients completed the chocolate group (18 men, 53.0 (16) years and 31.0 (39) months on HD) and 11 in the control group (7 men, 48.0 (17.5) years and 44.0 (56.5) months on HD). Regarding the differences between the groups, the patients who received dark chocolate had reduced plasma levels of TNF-α compared to the control (p = 0.008). No significant changes were observed in the oxidative stress parameters evaluated in both groups. Routine biochemical (including phosphorus and potassium levels) and anthropometric parameters and food intake were not changed after the study period.

CONCLUSION

The intervention with dark chocolate (70% cocoa) for two months reduced the plasma levels of TNF-α in patients with CKD on HD. In addition, it is essential to emphasise that chocolate intake did not increase the plasma levels of phosphorus and potassium in these patients. This study was registered at clinicaltrials.gov as NCT04600258.

MO603: Effects of Intradialytic Bicycle Ergometer Exercise on Inflammation Transcription Factors in Patients with Chronic Kidney Disease

BACKGROUND AND AIMS

Oxidative stress and inflammation are involved in the pathophysiological mechanisms in patients with chronic kidney disease (CKD) on hemodialysis (HD). In this context, the therapeutic potential of targeting the gene transcription factors associated with these mechanisms has been studied; for instance, nuclear factor erythroid 2-related factor 2 (Nrf2), the master regulator of antioxidant responses and, nuclear factor κappa B (NF-κB) that promotes the inflammatory response. However, the effects of physical exercise on the modulation of these factors are under investigation in CKD patients. Therefore, the aim of the present study was to evaluate the effects of an intradialytic aerobic exercise training program on the expression of transcription factors (Nrf2 and NF-κB) in patients with CKD on HD.

METHODS

This is a longitudinal, randomized clinical trial with a washout period and crossover performed with 18 patients randomized into two groups: Exercise (individualized intradialytic aerobic exercise on an adapted stationary exercise bike) three times per week for 3 months and control (without exercise). After the washout period (1 month), the exercise group became the control, and the other group performed the exercises for another 3 months. Peripheral blood mononuclear cells (PBMCs) were isolated, and quantitative real-time PCR analysis was performed to evaluate Nrf2, NF-kB and NAD(P)H: quinone oxidoreductase-1 (NQO1) mRNA expression. The plasma levels of inflammatory cytokines, tumour necrosis factor-α (TNF-α), C-reactive protein (CRP) and interleukin-6 (IL-6) were evaluated by ELISA.

RESULTS

Eighteen patients [11 men, 44.1 ± 8.4 years, 17.3 (6.6–124) months on HD] completed all the study. The obtained data revealed that the intervention did not affect the mRNA expression of Nrf2, NQO1 and NF-κB (Table 1). Also, TNF-α levels were not changed. However, IL-6 showed a tendency to decrease after the exercise intervention (P = 0.054).

CONCLUSION

Three months of intradialytic aerobic exercise were insufficient for modulating the transcription factors associated with antioxidant activity (Nrf2 and NQO1) and inflammation (NF-κB) in patients with CKD.

MO570: Effects of Dark Chocolate on Inflammation and Oxidative Stress in Patients With Chronic Kidney Disease on Hemodialysis

BACKGROUND AND AIMS

Patients with chronic kidney disease (CKD), especially on hemodialysis (HD), have a high prevalence of cardiovascular mortality, with oxidative stress (OE) and inflammation as the main contributors. Persistent inflammation from the early stages of CKD is caused by several factors, including increased production of reactive oxygen species (ROS), leading to OE, which in turn induces inflammation by activating the nuclear factor-kB pathway, causing the overproduction of inflammatory cytokines such as tumour necrosis factor-alpha (TNF-α) and interleukins (IL). Dark chocolate is rich in polyphenols, which have antioxidant, anti-inflammatory and cardioprotective properties, and it could be an alternative nonpharmacological to mitigate inflammation and complications of CKD. Therefore, this study aimed to evaluate the effects of dark chocolate on oxidative stress and inflammation in patients with CKD on HD.

METHODS

This is a longitudinal clinical trial performed with 46 patients with CKD on a regular dialysis program (3 dialysis sessions per week). A group received 40 g of dark chocolate during HD sessions, totaling 120 g per week, for 2 months, and a group did not receive any intervention. Plasma levels of TNF-α and IL-6 were evaluated using the ELISA method. Thiobarbituric acid reactive substances were performed to evaluate lipid peroxidation as malondialdehyde (MDA). Routine parameters were also analyzed using commercial kits. Changes in parameters were evaluated between the pre- and post-treatment.

RESULTS

Thirty-five patients performed the chocolate group (18 men, 53.4 ± 12.9 years old and 43.2 ± 30 months on HD) and 11 patients (7 men, 46.7 ± 10.9 years old and 55.2 ± 18.7 months on HD) the control group. Although TNF-α plasma levels did not reduce significantly after chocolate, the levels were increased in the control group (Table 1 and Fig. 1). The potassium plasma levels were reduced (from 5.9 ± 0.8 to 5.5 ± 0.8 mg/dL, P &lt; 0.05) and phosphorus plasma levels did not change in the chocolate group (5.9 ± 1.7 to 5.8 ± 1.6 mg/dL). In the control group, both parameters did not change after 2 months.

CONCLUSION

Two months of dark chocolate intervention seem to modulate the TNF-α plasma levels (inflammation marker) in patients with CKD on hemodialysis. It is important to emphasize that dark intervention in this study did not increase the phosphorus plasma levels in patients with CKD on HD.

MO565: Evaluation of Bach1 Mrna Expression (Repressor of NRF2) in Patients With Chronic Kidney Disease

BACKGROUND AND AIMS

BTB and CNC homology 1 (Bach1) is a protein into the cells that antagonizes the actions of nuclear factor erythroid 2-related factor-2 (Nrf2), a master regulator of cytoprotective responses. Bach1 binds to genomic DNA and can inhibit the synthesis of antioxidant enzymes, increasing inflammation. Bach1 may be a therapeutic target to mitigate inflammation in patients with chronic kidney disease (CKD). However, no clinical study has been reported on Bach1 in patients with CKD. This study aimed to evaluate Bach1 mRNA expression in different treatments of CKD, including patients on conservative treatment (non-dialysis), hemodialysis (HD) and peritoneal dialysis (PD).

METHODS

Twenty patients on HD (54.3 ± 13.7 years old, nine men), fifteen on PD (51.4 ± 14.9 years old, eight men) and thirteen non-dialysis patients (61.0 ± 6.9 years old, seven men, estimated glomerular filtration rate of 39.2 ± 9.6 mL/min/1.73 m2) were enrolled in the study. The peripheral blood mononuclear cells were isolated and processed to evaluate the expression of nuclear factor-kB (NF-kB), Nrf2 and Bach1 by quantitative real-time polymerase chain reaction. Malondialdehyde (MDA), a lipid peroxidation marker, and C-reactive protein (CRP) plasma levels were also measured.

RESULTS

Bach1 mRNA expression was significantly higher in patients on hemodialysis (P &lt; 0.02) when compared with PD and non-dialysis patients (Table 1 and Fig. 1). Also, as expected, CRP plasma levels were higher in HD patients when compared with non-dialysis patients (P = 0.05). Bach1 mRNA expression was positively correlated with MDA plasma levels (r = 0.37, P = 0.01) in all patients.

CONCLUSION

Patients with CKD on HD patients seem to have upregulation of Bach1 mRNA expression compared to patients on conservative and DP treatment. The associations among Nrf2 and Bach1 expressions in these patients deserve further investigation.

MO585: Effects of EPP-AF® Green Propolis Extract Supplementation on Inflammatory Markers in Patients With chronic Kidney Disease on Peritoneal Dialysis

BACKGROUND AND AIMS

Inflammation and oxidative stress are involved in the mortality of patients with chronic kidney disease (CKD) on peritoneal dialysis (PD). In this context, propolis may mitigate inflammation, reducing mRNA expression of nuclear factor-kB (NF-kB) and levels of inflammatory markers as tumor necrosis factor-α (TNF-α). Several studies have been performed in vitro and in animals showing that propolis (a resin made by bees) has excellent anti-inflammatory properties. Only one study evaluated the effects of propolis in patients with CKD (stages 3 and 4) and showed a reduction in proteinuria and urinary MCP-1, but there is no study in patients with CKD on peritoneal dialysis (PD). The present study aimed to evaluate the effects of propolis supplementation on inflammatory markers in patients with CKD on PD.

METHODS

This is a longitudinal, randomized, double-blind, placebo-controlled trial with 19 patients randomized into two groups: propolis (4 capsules of 500 mg/day containing concentrated and standardized dry EPP-AF® green propolis extract) or placebo (4 capsules of 500 mg/day of magnesium stearate, silicon dioxide and microcrystalline cellulose as placebo) for 2 months. The inflammatory cytokines plasma levels such as TNF-α and interleukin-6 (IL-6) were evaluated by ELISA, and quantitative real-time PCR analyses were performed to evaluate the mRNA expression of NF-kB in peripheral blood mononuclear cells (PBMCs). Plasma malondialdehyde (MDA) levels, a peroxidation lipid marker, was measured as thiobarbituric acid reactive substances (TBARS). Routine parameters, including C-reactive protein (CRP), were analyzed using commercial kits.

RESULTS

All patients concluded the study: 10 patients in the propolis group [57.2 ± 13.7 years, five men, 6 (6–36) months on DP] and 9 in the placebo group [56.6 ± 14.7 years, two men, 6 (6–57) months on DP]. The obtained data revealed that the intervention did not affect the mRNA expression of NF-κB. However, the plasma levels of TNF-α reduced significantly after propolis supplementation (Table 1 and Fig. 1). There were no significant differences in the placebo group.

CONCLUSION

Short-term EPP-AF® propolis dry extract supplementation seems to mitigate inflammation, reducing the plasma levels of TNF-α in patients with CKD on PD.

Could resistant starch supplementation improve inflammatory and oxidative stress biomarkers and uremic toxins levels in hemodialysis patients? A pilot randomized controlled trial

An imbalance of gut microbiota is considered a new cardiovascular risk factor for chronic kidney disease (CKD) patients, since it is directly associated with increased uremic toxin production, inflammation and oxidative stress. Strategies such as prebiotic supplementation have been suggested to mitigate these complications. We hypothesized that prebiotic-resistant starch could ameliorate uremic toxins levels, oxidative stress, and inflammatory states in hemodialysis (HD) patients. This pilot study evaluated 31 HD patients assigned to either resistant starch (16 g of resistant starch Hi-Maize® 260) or placebo (manioc flour) supplementation, which they received for 4 weeks on alternate days through cookies on dialysis days and powder in a sachet on non-dialysis days. Levels of interleukin (IL)-6, high-sensitive C-reactive protein, thiobarbituric acid reactive substances plasma (TBARS), protein carbonylation, indoxyl sulfate (IS) and p-cresyl sulfate were measured. Anthropometric and biochemical parameters, as well as, food intake were also evaluated. As expected, resistant starch group increased fiber intake (p > 0.01), in addition the prebiotic supplementation reduced IL-6 (p = 0.01), TBARS (p > 0.01), and IS (p > 0.01) plasma levels. No significant differences were evident in the placebo group. Prebiotic-resistant starch supplementation seems to be a promising nutritional strategy to improve inflammation, oxidative stress and to reduce IS plasma levels in CKD patients on HD.

Detection and identification of Leishmania species in field-captured phlebotomine sandflies based on mini-exon gene PCR

Leishmaniasis is one of the most diverse and complex of all vector-borne diseases. Because it involves several overlapping species and sandfly vectors, the disease has a complex ecology and epidemiology. Adequate therapy and follow-up depend on parasitological diagnosis, but classical methods present several constraints when identifying species. We describe a polymerase chain reaction (PCR) which uses primers designed from mini-exon repetitive sequences that are specific for subgenus LeishmaniaViannia (PV), as well as sequences with specificity for genus (PG) that can distinguish between Leishmania species from other insect flagellates with minor differences in PCR products. For standardization, these PCR were tested in experimentally infected sandflies, and Leishmania infection in these insects was successfully confirmed. This methodology identified a 3.9% infection rate in field-captured phlebotomine sandflies from an endemic region in Brazil. Natural infection by Leishmania species was identified in three samples of Lutzomyia longipalpis, of which two were Leishmania (L.) chagasi and one Leishmania (L.) amazonensis. Irrespective of specific epidemiological conclusions, the method used in this study was able to identify Leishmania infections both in experimentally infected and field-captured phlebotomine sandflies, and could be a useful tool in epidemiological studies and strategic planning for the control of human leishmaniasis.