Vitamin C in chronic kidney disease and hemodialysis patients

Severe Acute Malnutrition Presenting With Scurvy: A Case Report

Scurvy is a disease caused by a lack of vitamin C. It is a nutritional deficiency that is associated with multiple severe conditions. Although developed countries report these cases rarely now due to advancements in food and nutritional supplements, they are still prevalent in developing countries, albeit rare, because of poor nutritional status. Due to the lower prevalence of scurvy, diagnosis is delayed in the majority of cases and sometimes missed completely, which results in serious complications and unnecessary workups. Here, we present a rare case of a four-year-old female child with severe acute malnutrition (SAM) presenting with scurvy. The initial clinical signs showed SAM. X-ray and MRI of the left femur and knee were done to further evaluate the orthopedic parameters. Clinical presentation and radiographic imaging confirmed all the signs of scurvy. The patient was started on the Formula 75 (F-75) diet to address the severe malnutrition, and steady weight gain was observed.

Lessons learned from "the great mimicker disease": A retrospective study of 18 patients with scurvy

Purpose

Scurvy is an uncommon medical condition that affects children and is caused by an inadequate intake of vitamin C. This study presents the characteristics of patients with scurvy to raise awareness of the diagnostic process in developing countries where laboratory testing for vitamin C levels is often not available.

Methods

A retrospective study was performed from period of 2018 to 2023. Data extraction includes patient age, sex, body mass index, constitutional symptoms, musculoskeletal, mucosal, cutaneous symptoms, other accompanying disorders, anemia, erythrocyte sedimentation rate, C-reactive protein, radiographic examination, vitamin C dose, and duration of treatment. Descriptive statistical analysis was performed in this study.

Results

Eighteen cases (17 males, 1 female) of scurvy were referred to our institution. Thirteen of 18 patients were misdiagnosed before referral. The median age at presentation was 4.5 (range, 2-11) years. The average body mass index was 13.93 ± 0.63 kg/m2. Half of patients had healthy weight. All patients presented with lower limb pain and 17 of 18 with refusal to walk. The median onset of diagnosis was 11 (range 4-48) weeks. White line of Frankel was described in all patients. Seven had anemia and 6 of 18 had increase in erythrocyte sedimentation rate and/or C-reactive protein levels. Only one patient had ascorbic acid levels evaluation before treatment since it was not readily available in our country. Treatment length varied from 2 weeks to 6 months.

Conclusion

The diagnosis of scurvy is frequently delayed due to its extreme rarity in modern society and its ability to mimic numerous other conditions. In children presenting with limb pain and/or reluctance to walk and pathognomonic radiological findings, physicians must prioritize scurvy as a differential diagnosis. In scurvy, vitamin C supplementation is curative.

Pseudoparalysis Secondary to Vitamin C Deficiency: A Rare Presentation in a Toddler

CASE

We present a 17-month-old girl with postencephalitic sequelae only on high-calorie cereal milk through a nasogastric tube. She presented with a 3-week history of swelling and decreased lower limb movements. Synovial fluid analysis ruled out septic arthritis. Plain radiograph and magnetic resonance imaging (MRI) were suggestive of scurvy. She was diagnosed to have pseudoparalysis secondary to scurvy. She was started on vitamin C supplements, after which she showed good clinical improvement.

CONCLUSION

This case report is to re-emphasize the need for awareness of the possibility of scurvy in children with poor nutritional status due to feeding difficulties.

Does Vitamin Supplementation Play a Role in Chronic Kidney Disease?

Although the role of vitamins in the human body is proven, guidelines for patients with chronic kidney disease (CKD) remain unclear. This narrative review summarizes the findings of 98 studies of CKD and the effects of vitamin D, B, C, A, E, and K supplementation on patients on dialysis for CKD, with the aim of summarizing the existing guidelines. The findings are promising, showing the potential effectiveness of vitamin supplementation with, for example, vitamins B, D, or C. However, recommendations are still ambiguous, especially in the case of vitamins A and K, due to the potential toxicity associated with higher doses for patients. Continued research is needed to rigorously evaluate the effectiveness and carefully consider the potential risks of some vitamin supplementation for patients with CKD.

Vitamin C supplementation for diabetes management: A comprehensive narrative review

Growing evidence suggests that vitamin C supplementation may be an effective adjunct therapy in the management of people with diabetes. This paper critically reviews the current evidence on effects of vitamin C supplementation and its potential mechanisms in diabetes management. Evidence from meta-analyses of randomized controlled trials (RCTs) show favourable effects of vitamin C on glycaemic control and blood pressure that may be clinically meaningful, and mixed effects on blood lipids and endothelial function. However, evidence is mostly of low evidence certainty. Emerging evidence is promising for effects of vitamin C supplementation on some diabetes complications, particularly diabetic foot ulcers. However, there is a notable lack of robust and well-designed studies exploring effects of vitamin C as a single compound supplement on diabetes prevention and patient-important outcomes (i.e. prevention and amelioration of diabetes complications). RCTs are also required to investigate potential preventative or ameliorative effects of vitamin C on gestational diabetes outcomes. Oral vitamin C doses of 500-1000 mg per day are potentially effective, safe, and affordable for many individuals with diabetes. However, personalisation of supplementation regimens that consider factors such as vitamin C status, disease status, current glycaemic control, vitamin C intake, redox status, and genotype is important to optimize vitamin C's therapeutic effects safely. Finally, given a high prevalence of vitamin C deficiency in patients with complications, it is recommended that plasma vitamin C concentration be measured and monitored in the clinic setting.

Protection of Vitamin C on Oxidative Damage Caused by Long-Term Excess Iodine Exposure in Wistar Rats

Vitamin C was reported to be able to protect against oxidative damage due to its reducibility. 120 Wistar rats were randomly divided into 4 × 2 groups, including normal iodine (NI), high iodine (HI), low vitamin C (HI + LC), and high vitamin C (HI + HC); potassium iodide (KI) and potassium iodate (KIO₃) were commonly used as additives for iodized salt, so every group was also divided into KI and KIO₃ groups. After 6 months' feed, the activities of antioxidant enzymes and Lipid Peroxide (MDA) content in serum, liver, kidney, brain, thyroid and lens were determined. In serum, for males, long-term excess iodine intake caused oxidative damage; in the liver, male rats in the HI + LC group had the highest MDA content, which showed that low-dose vitamin C might promote oxidative damage; in kidneys, the MDA content in the HI and HI + LC groups of females was higher; in the brain, high-dose vitamin C could increase the activity of superoxide dismutase (SOD), which was decreased by high iodine intake, and it also decreased MDA content; in the thyroid, for KIO₃, the activity of SOD in the HI group was lower than NI and HI + LC; in the lens, the MDA content in females was lower than males. Long-term excess iodine exposure caused oxidative damage and showed sex difference, and vitamin C had a protective effect on it, especially for high-dose vitamin C.

Evaluation of the combination effect of rutin and vitamin C supplementation on the oxidative stress and inflammation in hemodialysis patients

Background: Hemodialysis (HD) patients are at risk of malnutrition, cardiovascular complications, and all-cause mortality due to oxidative stress and inflammation. Some studies have demonstrated that rutin attenuates oxidative stress and inflammation in CKD rats, but its effects in HD patients are unknown to date. Aim: The aim of this study was to evaluate the effect of rutin and vitamin C versus vitamin C alone on oxidative stress and inflammation in HD patients. Methods: A prospective randomized, open-label, controlled trial enrolled on hundred and five HD patients divided into three groups as follows: patients in group 1 were given a rutin/vitamin C combination (Ruta C group as the combination trade name is known as Ruta C 60 tablets), patients in group 2 were given vitamin C (1 g) (vitamin C group), and group 3 was the control group; the study period was 16 weeks. The following were assessed at baseline and at the end of the study: serum malondialdehyde (MDA), glutathione peroxidase (GPx), high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), lipid profile levels, and erythrocyte sedimentation rate. Results: It was found that vitamin C significantly increased serum GPx in group 2 (p = 0.001) compared to a non-significant result in both group 1 and 3; in addition, serum MDA and TNF-α values had decreased significantly in the three groups compared to their baselines; however, a non-significant difference was seen among the studied groups at the end of the study. On the other hand, MDA levels were reduced by 50% in interventional groups compared to 28% in the control group, while the Ruta C group showed an 80% reduction in the level of TNF α compared to the 78% reduction observed in the vitamin C group, and finally, the interventional drugs showed a significant improvement in the lipid profile. Conclusion: Vitamin C supplementation alone for 16 weeks had a potential effect on the antioxidant's GPx activity. Moreover, it was reported that both vitamin C alone or the rutin/vitamin C combination (Ruta C) showed a protective role against lipid peroxidation, evidenced by the reduced levels of MDA. Finally, rutin had a favorable synergistic effect with vitamin C in reducing TG and TNF-α levels and increasing HDL-C level.

Dietary and Antioxidant Vitamins Limit the DNA Damage Mediated by Oxidative Stress in the Mother-Newborn Binomial

During pregnancy, appropriate nutritional support is necessary for the development of the foetus. Maternal nutrition might protect the foetus from toxic agents such as free radicals due to its antioxidant content. In this study, 90 mothers and their children were recruited. DNA damage mediated by oxidative stress (OS) was determined by the levels of 8-hidroxy-2′-deoxyguanosine (8-OHdG) in the plasma of women and umbilical cord blood. The mothers and newborns were categorised into tertiles according to their 8-OHdG levels for further comparison. No relevant clinical differences were observed in each group. A strong correlation was observed in the mother−newborn binomial for 8-OHdG levels (Rho = 0.694, p < 0.001). In the binomial, a lower level of 8-OHdG was associated with higher consumption of calories, carbohydrates, lipids, and vitamin A (p < 0.05). In addition, the levels of 8-OHdG were only significantly lower in newborns from mothers with a higher consumption of vitamin A and E (p < 0.01). These findings were confirmed by a significant negative correlation between the 8-OHdG levels of newborns and the maternal consumption of vitamins A and E, but not C (Rho = −0.445 (p < 0.001), −0.281 (p = 0.007), and −0.120 (p = 0.257), respectively). Multiple regression analysis showed that the 8-OHdG levels in mothers and newborns inversely correlated with vitamin A (β = −1.26 (p = 0.016) and −2.17 (p < 0.001), respectively) and pregestational body mass index (β = −1.04 (p = 0.007) and −0.977 (p = 0.008), respectively). In conclusion, maternal consumption of vitamins A and E, but not C, might protect newborns from DNA damage mediated by OS.

Albumin at the intersection between antioxidant and pro-oxidant in patients on peritoneal dialysis

Albumin (HSA) is a multifunctional protein and due to its free Cys34 thiol group, represents a main source of free thiols in the circulation. This property of HSA, combined with its ability to sequester redox active Cu(II) ions, makes HSA a dominant circulatory antioxidant. End stage kidney disease (ESRD) is a condition accompanied by elevated oxidative stress. The aim of the present study was to examine changes in the antioxidative capacity of HSA and Cu(II) binding affinity in patients on peritoneal dialysis (PD), and relate it to the Cys34 thiol group content and other structural changes of this molecule. HSA molecules are modified in ESRD patients subjected to PD, having significantly lower thiol group and bound Cu(II) content, reduced antioxidant capacity, an increased content of advanced glycation end-products and altered conformation. Also, Cu(II) binding capacity of HSA in these patients is impaired, since a significant portion of the high-affinity metal-binding site is unable to interact with Cu(II). Taking into account that the concentration of Cu(II) in the circulation of ESRD patients is much higher than in healthy persons and that Cu(II) binding capacity of HSA in these patients is significantly impaired, HSA may be considered as a novel circulatory pro-oxidant, thus exacerbating oxidative stress.

A Comparison of Dietary Intake Between Individuals Undergoing Maintenance Hemodialysis in the United Kingdom and China

OBJECTIVE

Protein-energy wasting is highly prevalent in people with end-stage kidney disease receiving regular hemodialysis. Currently, it is unclear what the optimal nutritional recommendations are, which is further complicated by differences in dietary patterns between countries. The aim of the study was to understand and compare dietary intake between individuals receiving hemodialysis in Leicester, UK and Nantong, China.

METHODS

The study assessed 40 UK and 44 Chinese participants' dietary intake over a period of 14 days using 24-hour diet recall interviews. Nutritional blood parameters were obtained from medical records. Food consumed by participants in the UK and China was analyzed using the Nutritics and Nutrition calculator to quantify nutritional intake.

RESULTS

Energy and protein intake were comparable between UK and Chinese participants, but with both below the recommended daily intake. Potassium intake was higher in UK participants compared to Chinese participants (2,115 [888] versus 1,159 [861] mg/d; P < .001), as was calcium (618 [257] versus 360 [312] mg/d; P < .001) and phosphate intake (927 [485] versus 697 [434] mg/d; P = .007). Vitamin C intake was lower in UK participants compared to their Chinese counterparts (39 [51] versus 64 [42] mg/d; P = .024). Data are reported here as median (interquartile range).

CONCLUSION

Both UK and Chinese hemodialysis participants have insufficient protein and energy in their diet. New strategies are required to increase protein and energy intakes. All participants had inadequate daily intake of vitamins C and D; there may well be a role in the oral supplementation of these vitamins, and further studies are urgently needed.

Impact of Physical Activity and Natural Bioactive Compounds on Endothelial Dysfunction in Chronic Kidney Disease

Chronic kidney disease (CKD) represents a world-wide public health problem. Inflammation, endothelial dysfunction (ED) and vascular calcifications are clinical features of CKD patients that increase cardiovascular (CV) mortality. CKD-related CV disease pathogenic mechanisms are not only associated with traditional factors such as arterial hypertension and dyslipidemia, but also with ED, oxidative stress and low-grade inflammation. The typical comorbidities of CKD contribute to reduce the performance and the levels of the physical activity in nephropathic patients compared to healthy subjects. Currently, the effective role of physical activity on ED is still debated, but the available few literature data suggest its positive contribution. Another possible adjuvant treatment of ED in CKD patients is represented by natural bioactive compounds (NBCs). Among these, minor polar compounds of extra virgin olive oil (hydroxytyrosol, tyrosol and oleocanthal), polyphenols, and vitamin D seem to exert a beneficial role on ED in CKD patients. The objective of the review is to evaluate the effectiveness of physical exercise protocols and/or NBCs on ED in CKD patients.

Implications of oxidative stress in chronic kidney disease: a review on current concepts and therapies

Moderate levels of endogenous reactive oxygen species (ROS) are important for various cellular activities, but high levels lead to toxicity and are associated with various diseases. Levels of ROS are maintained as a balance between oxidants and antioxidants. Accumulating data suggest that oxidative stress is a major factor in deterioration of renal function. In this review, we highlight the possible mechanism by which oxidative stress can lead to chronic kidney disease (CKD). This review also describes therapies that counter the effect of oxidative stress in CKD patients. Numerous factors such as upregulation of genes involved in oxidative phosphorylation and ROS generation, chronic inflammation, vitamin D deficiency, and a compromised antioxidant defense mechanism system cause progressive detrimental effects on renal function that eventually lead to loss of kidney function. Patients with renal dysfunction are highly susceptible to oxidative stress, as risk factors such as diabetes, renal hypertension, dietary restrictions, hemodialysis, and old age predispose them to increased levels of ROS. Biomolecular adducts (DNA, proteins, and lipids) formed due to reaction with ROS can be used to determine oxidative stress levels. Based on the strong correlation between oxidative stress and CKD, reversal of oxidative stress is being explored as a major therapeutic option. Xanthine oxidase inhibitors, dietary antioxidants, and other agents that scavenge free radicals are gaining interest as treatment modalities in CKD patients.

Vitamin C deficiency and impact of vitamin C administration among pediatric patients with advanced chronic kidney disease

BACKGROUND

Vitamin C deficiency is common in chronic kidney disease (CKD) due to losses through dialysis and dietary intake below requirement. We investigated prevalence of vitamin C deficiency and impact of vitamin C treatment in deficient/insufficient patients.

METHODS

A prospective cohort study in patients aged 1-18 years with CKD stages 4 and 5D collected demographic data including underlying disease, treatment, and anthropometric assessment. Vitamin C intake was assessed using 24-h dietary recall. Hemoglobin, iron status, serum vitamin C, and serum oxalate were measured at baseline and after treatment. Vitamin C (250 mg/day) was given orally for 3 months to deficient/insufficient patients.

RESULTS

Nineteen patients (mean age 12.00 ± 4.1 years) showed prevalence of 10.6% vitamin C insufficiency and 78.9% deficiency. There were no associations between vitamin C level and daily vitamin C intake (p = 0.64) or nutritional status (p = 0.87). Median serum vitamin C was 1.51 (0.30-1.90) mg/L. In 16 patients receiving treatment, median serum vitamin C increased from 1.30 (0.23-1.78) to 3.22 (1.77-5.96) mg/L (p = 0.008) without increasing serum oxalate (79.92 (56.6-106.84) vs. 80.47 (56.88-102.95) μmol/L, p = 0.82). However, 62.5% failed to achieve normal vitamin C levels. Ordinal regression analysis revealed patients with non-oligoanuric CKD were less likely to achieve normal vitamin C levels (β = - 3.41, p = 0.03).

CONCLUSION

We describe high prevalence of vitamin C insufficiency/deficiency among pediatric CKD patients. Vitamin C levels could not be solely predicted by nutritional status or daily intake. The treatment regimen raised serum vitamin C without increasing serum oxalate; however, it was largely insufficient to normalize levels, particularly in non-oligoanuric CKD. Graphical abstract .

Importance of micronutrients in the oral cavity

Introduction: Micronutrients play a potent role in the functioning of the different systems of the organism. It is necessary to sustain an adequate status of the micronutrients for maintaining the optimal condition of the oral cavity. The aim: Toemphasize the importance of different micronutrients for the normal functioning of the oral cavity, as well as their influence on the occurrence of various diseases of the soft and hard tissues of the oral cavity. Conclusion: Micronutrients such as vitamin C, B9 and E, calcium, zinc, copper and iron have a role in development so as anti-inflammatory and antioxidants properties Deficiency of certain micronutrients plays an important role in the development of periodontitis and caries. People with chronic inflammatory bowel disease, as well as children, pregnant and breastfeeding women, are usually deficient in these vitamins and therefore often susceptible to the development of inflammatory changes in soft tissues of oral cavity , periodontitis and caries.

Hemodialysis-Nutritional Flaws in Diagnosis and Prescriptions. Could Amino Acid Losses be the Sharpest "Sword of Damocles"?

This review aims to highlight the strengths and weaknesses emerging from diagnostic evaluations and prescriptions in an intent to prevent progression over time of malnutrition and/or protein-energy wasting (PEW) in hemodialysis (HD) patients. In particular, indications of the most effective pathway to follow in diagnosing a state of malnutrition are provided based on a range of appropriate chemical-clinical, anthropometric and instrumental analyses and monitoring of the nutritional status of HD patients. Finally, based on the findings of recent studies, therapeutic options to be adopted for the purpose of preventing or slowing down malnutrition have been reviewed, with particular focus on protein-calorie intake, the role of oral and/or intravenous supplements and efficacy of some classes of amino acids. A new determining factor that may lead inexorably to PEW in hemodialysis patients is represented by severe amino acid loss during hemodialysis sessions, for which mandatory compensation should be introduced.

Protective effect of vitamin C on chronic carbamazepine-induced reproductive toxicity in male wistar rats

The aim of this study was to evaluate the protective effect of vitamin C on chronic carbamazepine-induced reproductive toxicity in male Wistar rats. Four groups of 10 rats were respectively exposed to distilled water (2 ml/kg), vitamin C (100 mg/kg), carbamazepine (20 mg/kg) and vitamin C followed by CBZ, after 30 min.. The regimens were given by gavage once daily for 15 weeks. The pituitary glands and testicular tissues were assayed for oxidative stress parameters, sperm characteristics, relative weight and histological changes. Sera samples were also assayed for concentration of sex hormones. The results showed that treatment with vitamin C protected against the alteration in parameters measuring oxidative changes, sex hormones, sperm characteristics, relative pituitary and testicular weight and histological changes. The study concluded that protection against CBZ-induced alteration in reproductive parameters by vitamin C was partly due to its antioxidant effect.

Oxidative Stress in Hemodialysis Pediatric Patients

BACKGROUND:

Oxidative stress may play a role in complications of hemodialysis patients as atherosclerosis, thrombosis, and inflammation.

AIM:

The aim of the study was to evaluate the oxidative stress in hemodialysis pediatric patients through measurement of oxidative stress enzymes as paraoxanase activity (PON), arylesterase activity (ASA), superoxide dismutase (SOD) and also non-enzymatic antioxidant vitamins as vitamins A, C and E levels.

METHODS:

The study included 50 hemodialysis pediatric patients with mean age 11.4 ± 5.4 years and 30 normal children of matched sex and age as a control group. Assessment of oxidative stresses was done using ELIZA technique.

RESULTS:

SOD, ASA, and vitamin C were significantly lower among hemodialysis patients in comparison to control group (p = 0.004, 0.004, > 0.001 respectively).

CONCLUSION:

The study concluded that oxidative stress was common finding in hemodialysis pediatric patients which may play a role in complications encountered among these patients.

Uremic leontiasis ossea due to secondary hyperparathyroidism complicated by vitamin C deficiency in a non-adherent chronic hemodialysis patient: A case report

Non-adherence to medical therapy in patients with end-stage kidney disease (ESKD) can lead to severe metabolic derangements rarely seen in the current medical era. Such complications may take the form of secondary hyperparathyroidism (HPT) leading to rare manifestations of bone mineral disease, and profound vitamin C deficiency from poor nutrition combined with removal of water-soluble vitamins during dialysis. Secondary HPT causes renal osteodystrophy which can lead to diffuse enlargement of the facial skeleton and morphological changes suggestive of leontiasis ossea. We report a 36-year-old, non-adherent woman on chronic dialysis for over 10 years who developed progressive, diffuse facial bone enlargement in the context of years of extreme HPT and newly diagnosed severe vitamin C deficiency. Imaging revealed diffuse hypertrophy of the maxillary and mandibular bones. Histopathology showed extensive fibro-osseous proliferation without evidence of Brown tumor, suggestive of uremic leontiasis ossea. In this report, we discuss the orofacial manifestations of secondary HPT and the possible potentiating role of vitamin C deficiency on the development of renal osteodystrophy through altered vitamin D metabolism. Non-adherent patients on chronic dialysis should be evaluated for vitamin C deficiency, and the development of uremic leontiasis ossea should be considered when such patients present with distortion of facial features in the context of severe secondary HPT.

Plasma Vitamin C Concentrations and Cognitive Function: A Cross-Sectional Study

Vitamin-C is a water soluble molecule that humans have lost the ability to produce. Vitamin-C plays a role in CNS functions such as neuronal differentiation, maturation, myelin formation and modulation of the catecholaminergic systems. A recent systematic review by our team indicated the need for further research into the relationship between plasma vitamin C and cognition in cognitively intact participants using plasma vitamin C concentrations instead of estimates derived from food-frequency-questionnaires (FFQ), and more sensitive cognitive assessments suitable for cognitive abilities vulnerable to aging. It was hypothesized that higher plasma vitamin C concentrations would be linked with higher cognitive performance. This cross-sectional trial was conducted on healthy adults (n = 80, Female = 52, Male = 28, 24-96 years) with a range of plasma Vitamin C concentrations. Cognitive assessments included The Swinburne-University-Computerized-Cognitive-Assessment-Battery (SUCCAB) and two pen and paper tests, the Symbol-Digits-Modalities-Test (SDMT) and Hopkins-Verbal-Learning-Test-Revised (HVLT-R). The pen and paper assessments were conducted to establish whether their scores would correlate with the computerized tasks. Plasma-Vitamin C concentrations were measured using two biochemical analyses. Participants were grouped into those with plasma vitamin-C concentrations of adequate level (≥28 μmol/L) and deficient level (<28 μmol/L). The SUCCAB identified a significantly higher performance ratio (accuracy/reaction-time) in the group with adequate vitamin-C levels vs. deficient vitamin-C on the choice reaction time (M = 188 ± 4 vs. 167 ± 9, p = 0.039), immediate recognition memory (M = 81 ± 3 vs. 68 ± 6, p = 0.03), congruent Stroop (M = 134 ± 3 vs. 116 ± 7, p = 0.024), and delayed recognition tasks (M = 72 ± 2 vs. 62 ± 4, p = 0.049), after adjusting for age (p < 0.05). Significantly higher scores in immediate recall on the HVLT-R (M = 10.64 ± 0.16 vs. 9.17 ± 0.37, p = 0.001), delayed recall (M = 9.74 ± 0.22 vs. 7.64 ± 0.51, p < 0.001), total recall (M = 27.93 ± 0.48 vs. 24.19 ± 1.11, p = 0.003) were shown in participants with adequate plasma Vitamin-C concentrations, after adjusting for vitamin-C supplementation dose (p < 0.05). Similarly, higher SDMT scores were observed in participants with adequate plasma Vitamin-C concentrations (M = 49.73 ± 10.34 vs. 41.38 ± 5.06, p = 0.039), after adjusting for age (p < 0.05). In conclusion there was a significant association between vitamin-C plasma concentrations and performance on tasks involving attention, focus, working memory, decision speed, delayed and total recall, and recognition. Plasma vitamin C concentrations obtained through vitamin C supplementation did not affect cognitive performance differently to adequate concentrations obtained through dietary intake. Clinicaltrials.gov Unique Identifier: ACTRN 12615001140549, URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=369440.

Status of antioxidant and homocysteine-lowering vitamins related to cardiovascular diseases in hemodialysis patients

Background and aim

Cardiovascular disease is the major cause of mortality in hemodialysis patients. Oxidative stress and hyperhomocysteinemia may contribute to an increased risk of CVD. Therefore, we assessed the status of antioxidant and homocysteine-lowering vitamins related to cardiovascular disease in hemodialysis patients at Vasei hospital in Sabzevar.

Methods

In this cross-sectional study, we enrolled 75 hemodialysis patients by using census method at Vasei Hospital in Sabzevar (Iran) in 2014. After measuring height and body weight, food intake was assessed by a 24-hour dietary recall questionnaire for at least two days (a non-dialysis and dialysis day), and food frequency was recorded with Nutritionist IV software. Data were analyzed by SPSS version 16, using descriptive statistical tests, one sample t-test and independent samples t-test and p<0.05 was considered statistically significant.

Results

This study was carried out on 75 patients. Mean age and BMI of patients were 49.95±17.22 years and 20.04±3.38 kg/m², respectively. Intake of all vitamins with the exception of vitamin B12 in hemodialysis patients studied, were less than the recommended dietary allowance (RDA) (p<0.05).

Conclusion

According to the survey, consumption of antioxidants and B-vitamins related to cardiovascular disease was less than RDA in hemodialysis patients.

Naturally Occurring Compounds: New Potential Weapons against Oxidative Stress in Chronic Kidney Disease

Oxidative stress is a well-described imbalance between the production of reactive oxygen species (ROS) and the antioxidant defense system of cells and tissues. The overproduction of free radicals damages all components of the cell (proteins, lipids, nucleic acids) and modifies their physiological functions. As widely described, this condition is a biochemical hallmark of chronic kidney disease (CKD) and may dramatically influence the progression of renal impairment and the onset/development of major systemic comorbidities including cardiovascular diseases. This state is exacerbated by exposure of the body to uremic toxins and dialysis, a treatment that, although necessary to ensure patients' survival, exposes cells to non-physiological contact with extracorporeal circuits and membranes with consequent mitochondrial and anti-redox cellular system alterations. Therefore, it is undeniable that counteracting oxidative stress machinery is a major pharmacological target in medicine/nephrology. As a consequence, in recent years several new naturally occurring compounds, administered alone or integrated with classical therapies and an appropriate lifestyle, have been proposed as therapeutic tools for CKD patients. In this paper, we reviewed the recent literature regarding the "pioneering" in vivo testing of these agents and their inclusion in small clinical trials performed in patients affected by CKD.

Dietary vitamin C deficiency depressed the gill physical barriers and immune barriers referring to Nrf2, apoptosis, MLCK, NF-κB and TOR signaling in grass carp (Ctenopharyngodon idella) under infection of Flavobacterium columnare

This study explored the effects of vitamin C on the physical barriers and immune barriers, and relative mRNA levels of signaling molecules in the gill of grass carp (Ctenopharyngodon idella) under infection of Flavobacterium columnare. The results indicated that compared with optimal vitamin C supplementation, vitamin C deficiency (2.9 mg/kg diet) (1) increased reactive oxygen species, malondialdehyde and protein carbonyl (PC) contents (P < 0.05), decreased the copper/zinc superoxide dismutase, manganese superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase activities and mRNA levels (P < 0.05), and glutathione and vitamin C contents (P < 0.05), down-regulated NF-E2-related factor 2 mRNA level (P < 0.05), and up-regulated Kelch-like ECH-associating protein (Keap) 1a (rather than Keap1b) mRNA level (P < 0.05) in the gill of grass carp under infection of F. columnare, suggesting that vitamin C deficiency induced oxidative injury in fish gill; (2) up-regulated caspase-3, -7, -8, -9, Fas ligand, B-cell lymphoma protein 2 associated X protein, apoptotic protease activating factor-1 mRNA levels (P < 0.05), and down-regulated inhibitor of apoptosis protein and B-cell lymphoma-2 (rather than myeloid cell leukemia-1) mRNA level (P < 0.05) in the gill of grass carp under infection of F. columnare, suggesting that vitamin C deficiency aggravated cell apoptosis in fish gill; (3) up-regulated pore-forming TJs Claudin-12, 15a, -15b, and related signaling molecules myosin light chain kinase, p38 mitogen-activated protein kinase (rather than c-Jun N-terminal kinases) mRNA levels (P < 0.05), and down-regulated barrier-forming TJs Occludin, zonula occludens (ZO) 1, ZO-2, Claudin-c, -3c, -7a, -7b mRNA levels (P < 0.05) in the gill of grass carp under infection of F. columnare, suggesting that vitamin C deficiency disrupted tight junctional complexes in fish gill; (4) decreased lysozyme and acid phosphatase (ACP) activities, and complement 3 (C3), C4 and IgM contents (P < 0.05), down-regulated the mRNA levels of antimicrobial peptides liver expressed antimicrobial peptide (LEAP) 2A, LEAP-2B, Hepcidin, β-defensin mRNA levels (P < 0.05) in the gill of grass carp under infection of F. columnare, suggesting that vitamin C deficiency decrease fish gill immune function; (5) down-regulated the mRNA levels of anti-inflammatory cytokines-related factors interleukin 10 (IL-10), IL-11, transforming growth factor (TGF) β1, TGF-β2, inhibitor of κBa and eIF4E-binding protein 1 (4E-BP1) (rather than 4E-BP2) (P < 0.05), and up-regulated pro-inflammatory cytokines-related factors interferon γ2, IL-1β, IL-6, IL-8, IL-12 P35, IL-12 P40, nuclear factor κB (NF-κB) p65 (rather than NF-κB p52), IκB kinases (IKK) (only IKKα and IKKγ), target of rapamycin and ribosomal protein S6 kinase 1 mRNA levels (P < 0.05) in the gill of grass carp under infection of F. columnare, suggesting that vitamin C deficiency aggravated fish gill inflammation. In conclusion, vitamin C deficiency disrupted physical barriers and immune barriers, and regulated relative mRNA levels of signaling molecules in fish gill. The vitamin C requirement for against gill rot morbidity of grass carp (264-1031 g) was estimated to be 156.0 mg/kg diet. In addition, based on the gill biochemical indices (antioxidant indices MDA, PC and vitamin C contents, and immune indices LA and ACP activity) the vitamin C requirements for grass carp (264-1031 g) were estimated to be 116.8, 156.6, 110.8, 57.8 and 134.9 mg/kg diet, respectively.

Systemic Redox Imbalance in Chronic Kidney Disease: A Systematic Review

Patients with chronic kidney disease (CKD) experience imbalance between oxygen reactive species (ROS) production and antioxidant defenses leading to cell and tissue damage. However, it remains unclear at which stage of renal insufficiency the redox imbalance becomes more profound. The aim of this systematic review was to provide an update on recent advances in our understanding of how the redox status changes in the progression of renal disease from predialysis stages 1 to 4 to end stage 5 and whether the various treatments and dialysis modalities influence the redox balance. A systematic review was conducted searching PubMed and Scopus by using the Cochrane and PRISMA guidelines. In total, thirty-nine studies met the inclusion criteria and were reviewed. Even from an early stage, imbalance in redox status is evident and as the kidney function worsens it becomes more profound. Hemodialysis therapy per se seems to negatively influence the redox status by the elevation of lipid peroxidation markers, protein carbonylation, and impairing erythrocyte antioxidant defense. However, other dialysis modalities do not so far appear to confer advantages. Supplementation with antioxidants might assist and should be considered as an early intervention to halt premature atherogenesis development at an early stage of CKD.

Association of GSTO1 and GSTO2 Polymorphism with Risk of End-Stage Renal Disease Development and Patient Survival

Background

Oxidative stress in patients with end-stage renal disease (ESRD) is associated with long-term cardiovascular complications. The cytosolic family of glutathione S-transferases (GSTs) is involved in the detoxication of various toxic compounds and antioxidant protection. GST omega class members, GSTO1 and GSTO2 possess, unlike other GSTs, dehydroascorbate reductase and deglutathionylation activities. The aim of this study was to clarify the role of genetic polymorphisms of GSTO1 (rs4925) and GSTO2 (rs156697) as risk determinants for ESRD development, as well as in the survival of these patients.

Methods

A total of 199 patients and 199 healthy subjects were included in the study and genotyped for both GSTO1 and GSTO2 polymorphism. Protein thiol and carbonyl groups as markers of protein oxidative damage were determined spectrophotometrically. Cox proportional hazard model and Kaplan-Meier analysis were performed to investigate the role of GSTO1 and GSTO2 genetic polymorphism on mortality of ESRD patients during the follow-up period (36 month).

Results

Individuals carrying the variant GSTO2 GG genotype were at 2.45-fold higher risk of ESRD development compared to the wild type GSTO2 AA genotype (OR=2.45; 95%CI=1.18–5.07; p=0.016). The results of GSTO1/GSTO2 haplotype analysis showed that the haplotype combination of GSTO1 (*A)/GSTO2 (*A) (GSTO1 variant/GSTO2 wild type allele) was protective for ESRD (OR=0.23 95%CI=0.12-0.44, p=0.001). Patients carrying at least one GSTO1 reference allele have shorter mean overall (Log rank=2.844, p =0.241) and cardiovascular survival probability (Log rank=4.211, p=0.122).

Conclusions

GSTO polymorphisms have been shown to act as significant markers in assessing the risk of ESRD development and patients’ survival.

Dietary vitamin C deficiency depresses the growth, head kidney and spleen immunity and structural integrity by regulating NF-κB, TOR, Nrf2, apoptosis and MLCK signaling in young grass carp (Ctenopharyngodon idella)

This study investigated the effects of dietary vitamin C on the growth, and head kidney, spleen and skin immunity, structural integrity and related signaling molecules mRNA expression levels of young grass carp (Ctenopharyngodon idella). A total of 540 grass carp (264.37 ± 0.66 g) were fed six diets with graded levels of vitamin C (2.9, 44.2, 89.1, 133.8, 179.4 and 224.5 mg/kg diet) for 10 weeks. Subsequently, a challenge test was conducted by injection of Aeromonas hydrophila and the survival rate recorded for 14 days. The results indicated that compared with optimal vitamin C supplementation, vitamin C deficiency (2.9 mg/kg diet) decreased lysozyme (LA) and acid phosphatase (ACP) activities, and complement 3 and complement 4 (C4) contents (P < 0.05), down-regulated the mRNA levels of antimicrobial peptides [liver expressed antimicrobial peptide (LEAP) 2A, LEAP-2B, hepcidin, β-defensin] and anti-inflammatory cytokines-related factors, interleukin (IL) 4/13A, IL-4/13B (only in head kidney), IL-10, IL-11, transforming growth factor (TGF) β1, TGF-β2, inhibitor of κBα and eIF4E-binding protein 1 (P < 0.05), and up-regulated pro-inflammatory cytokines-related factors, tumor necrosis factor α, interferon γ2, IL-1β, IL-6, IL-8, IL-12 P35 (only in spleen), IL-12 P40, IL-15, IL-17D, nuclear factor κB p65, IκB kinases (IKKα, IKKβ, IKKγ), target of rapamycin and ribosomal protein S6 kinase 1 mRNA levels (P < 0.05) in the head kidney and spleen under injection fish of A. hydrophila, suggesting that vitamin C deficiency could decrease fish head kidney and spleen immunity and cause inflammation. Meanwhile, compared with optimal vitamin C supplementation, vitamin C deficiency decreased the activities and mRNA levels of copper/zinc superoxide dismutase, manganese superoxide dismutase (MnSOD), catalase, glutathione peroxidase, glutathione S-transferases and glutathione reductase (P < 0.05), and down-regulated zonula occludens (ZO) 1, ZO-2, Claudin-b, -c, -3c, -7a, -7b, B-cell lymphoma-2, inhibitor of apoptosis protein, NF-E2-related factor 2 mRNA levels (P < 0.05), increased reactive oxygen species (ROS), malondialdehyde (MDA) and protein carbonyl contents (P < 0.05), and up-regulated Claudin-12, 15a, -15b, Fas ligand, mitogen-activated protein kinase kinase 6, p38 mitogen-activated protein kinase, B-cell lymphoma protein 2 associated X protein, apoptotic protease activating factor-1, caspase-3, -7, -8, -9, Kelch-like ECH-associating protein (Keap) 1a and Keap 1b mRNA levels (P < 0.05) in the head kidney and spleen under injection fish of A. hydrophila, suggesting that vitamin C deficiency could decrease fish head kidney and spleen structural integrity through depression of antioxidative ability, induction of apoptosis and disruption of tight junctional complexes. In addition, except the activities of ACP and MnSOD, and mRNA expression levels of TGF-β1, Occludin and MnSOD, the effect of vitamin C on fish head kidney, spleen and skin immunity and structural integrity other indicators model are similar under infection of A. hydrophila. Finally, the vitamin C requirement for the growth performance (PWG) of young grass carp was estimated to be 92.8 mg/kg diet. Meanwhile, the vitamin C requirement for against skin lesion morbidity of young grass carp was estimated to be 122.9 mg/kg diet. In addition, based on the biochemical indices [immune indices (LA activity in the head kidney and C4 content in the spleen) and antioxidant indices (MDA content in the head kidney and ROS content in the spleen)] the vitamin C requirements for young grass carp were estimated to be 131.2, 137.5, 135.8 and 129.8 mg/kg diet, respectively.

Gingival Bleeding and Bloody Dialysate: A Case Report of Scurvy in a Child With End-Stage Renal Disease Receiving Peritoneal Dialysis

Patients with chronic kidney disease (CKD) or end-stage renal disease are at risk for vitamin C deficiency and scurvy due to diet restriction, increased urinary loss of the water-soluble vitamin C with diuretics, and in case of patients who are on dialysis, through dialysates. The condition may be overlooked as the clinical manifestation of scurvy may be subtle, and some presentations may mimic clinical signs in CKD. We reported a case of scurvy presenting with gingival bleeding and blood dialysate in a 6-year-old girl with end-stage renal disease who was on continuous ambulatory peritoneal dialysis. Physical examination showed gingival hyperplasia and bleeding, and the pathognomonic bleeding of perifollicular hemorrhage. The typical radiographic changes were present. The clinical signs and symptoms resolved after ascorbic acid treatment. This case underscores the importance of awareness of the increased risk for vitamin C deficiency in patients with CKD and receiving dialysis.

The epigenetic role of vitamin C in health and disease

Recent advances have uncovered a previously unknown function of vitamin C in epigenetic regulation. Vitamin C exists predominantly as an ascorbate anion under physiological pH conditions. Ascorbate was discovered as a cofactor for methylcytosine dioxygenases that are responsible for DNA demethylation, and also as a likely cofactor for some JmjC domain-containing histone demethylases that catalyze histone demethylation. Variation in ascorbate bioavailability thus can influence the demethylation of both DNA and histone, further leading to different phenotypic presentations. Ascorbate deficiency can be presented systematically, spatially and temporally in different tissues at the different stages of development and aging. Here, we review how ascorbate deficiency could potentially be involved in embryonic and postnatal development, and plays a role in various diseases such as neurodegeneration and cancer through epigenetic dysregulation.

Oxidative stress during erythropoietin hyporesponsiveness anemia at end stage renal disease: Molecular and biochemical studies

Inflammation and oxidative stress are two faces of one coin in end stage renal disease patients (ESRD) on maintenance hemodialysis. Their interconnection induces anemia complicated with erythropoietin hyporesponsiveness. The biochemical bases behind the resistance to erythropoietin therapy with frequent hemoglobinemia, oxidative stress and iron status have not been fully understood. Here two equal groups (40 patients each) of responders and non-responders to recombinant human erythropoietin therapy (higher than 300 IU/kg/wk of epoetin) were investigated. Hematological and biochemical analyses of collected blood and serum samples were performed along with serum electrophoretic protein footprinting. The leukocytic DNA fragmentation was used to evaluate the degree of oxidative insult. The good responders showed lower erythrocyte malondialdehyde (E-MDA) level and less DNA fragmentation of circulating leukocytes than poor responders with elevated hemoglobin, albumin, A/G ratio, total iron, and ferritin levels. Contrariwise, lower erythrocyte superoxide dismutase (E-SOD) and catalase activities in EPO poor responder group were noticed. Neither other serum constituents nor electrophoretic protein pattern showed any difference between the two groups. There were higher levels of inflammatory markers, interleukin-6 (IL6) and C-reactive protein (CRP) in EPO poor responder than good responder. The negative correlations between Hb and both IL6 and CRP levels in the present data remotely indicate a positive correlation between inflammatory markers and severity of anemia. A direct correlation between Hb and antioxidant enzymes (E-SOD and catalase) was noticed, while inverse correlation with E-MDA was recorded. The study proved that oral supplementation of vitamin C to ESRD patients might mitigate the previously elevated serum MDA level in these patients.

Plasma protein thiolation index (PTI) as a biomarker of thiol-specific oxidative stress in haemodialyzed patients

The role of oxidative stress in patients with end stage renal disease (ESRD), which occurs at significantly higher levels than in the general population, is often underestimated in clinical practice. Emerging evidence highlights the strong correlation of oxidative stress with chronic inflammation and cardiovascular disease, which are highly prevalent in most patients on maintenance haemodialysis (HD) and are a major risk factor for mortality in this population. In this study, total plasma thiols and plasma S-thiolated proteins were measured in patients with ESRD, before and after a regular HD session, and compared to age-matched healthy subjects. We found a significant decrease in the level of total plasma thiols and, conversely, a significant increase in the level of S-thiolated proteins in these patients. In most patients, post-HD plasma level of total thiols did not differ from the one in healthy subjects, whereas plasma level of S-thiolated proteins was lower in HD patients than in age-matched healthy controls. This suggests that a single HD session restores plasma thiol redox status and re-establishes the antioxidant capacity of plasma thiols. Additionally, we determined protein thiolation index (PTI), i.e., the molar ratio between the sum of all low molecular mass thiols bound to S-thiolated plasma proteins and protein free cysteinyl residues. Patients with ESRD had a significantly higher PTI compared to age-matched healthy subjects and HD was associated with a decrease in PTI to normal, or lower than normal, levels. Although this study is limited in size, our results suggest that PTI is a useful indicator of thiol-specific oxidative stress in patients with ESRD on maintenance HD. This study also emphasizes that PTI determination is a cheap and simple tool suitable for large-scale clinical studies that could be used for routine screening of thiol-specific oxidative stress.

Mitochondria: a new therapeutic target in chronic kidney disease

Cellular metabolic changes during chronic kidney disease (CKD) may induce higher production of oxygen radicals that play a significant role in the progression of renal damage and in the onset of important comorbidities. This condition seems to be in part related to dysfunctional mitochondria that cause an increased electron "leakage" from the respiratory chain during oxidative phosphorylation with a consequent generation of reactive oxygen species (ROS). ROS are highly active molecules that may oxidize proteins, lipids and nucleic acids with a consequent damage of cells and tissues. To mitigate this mitochondria-related functional impairment, a variety of agents (including endogenous and food derived antioxidants, natural plants extracts, mitochondria-targeted molecules) combined with conventional therapies could be employed. However, although the anti-oxidant properties of these substances are well known, their use in clinical practice has been only partially investigated. Additionally, for their correct utilization is extremely important to understand their effects, to identify the correct target of intervention and to minimize adverse effects. Therefore, in this manuscript, we reviewed the characteristics of the available mitochondria-targeted anti-oxidant compounds that could be employed routinely in our nephrology, internal medicine and renal transplant centers. Nevertheless, large clinical trials are needed to provide more definitive information about their use and to assess their overall efficacy or toxicity.

Scurvy in pediatric age group - A disease often forgotten?

Scurvy is caused by prolonged severe dietary deficiency of vitamin C. Being rare as compared to other nutritional deficiencies, it is seldom suspected and this frequently leads to delayed recognition of this disorder. Children with abnormal dietary habits, mental illness or physical disabilities are prone to develop this disease. The disease spectrum of scurvy is quite varied and includes dermatological, dental, bone and systemic manifestations. Subperiosteal hematoma, ring epiphysis, metaphyseal white line and rarefaction zone along with epiphyseal slips are common radiological findings. High index of suspicion, detailed history and bilateral limb radiographs aids physician in diagnosing this eternal masquerader. We searched Pubmed for recent literature (2009-2014) with search terms "scurvy" "vitamin C deficiency" "ascorbic acid deficiency" "scurvy and children" "scurvy and pediatric age group". There were a total of 36 articles relevant to pediatric scurvy in children (7 reviews and 29 case reports) which were retrieved. The review briefly recapitulates the role of vitamin C, the various disease manifestations and the treatment of scurvy to create awareness of the disease which still is reported from our country, although sporadically. The recent advances related to scurvy and its management in pediatric age group are also incorporated.

Plasma ascorbic acid concentrations in prevalent patients with end-stage renal disease on hemodialysis

OBJECTIVE

To determine the prevalence of vitamin C (ascorbic acid [AA]) deficiency in patients with end-stage renal disease, the effect of supplemental AA on plasma AA concentrations, and the extrinsic and intrinsic factors that affect plasma AA concentrations in this patient population.

DESIGN

In study 1, we compared the effect of hemodialysis (HD) on plasma AA concentrations between patients with low and high pre-HD AA concentrations. In study 2, we analyzed kinetic and nonkinetic factors for their association with increased plasma AA concentrations in patients on maintenance HD. Study 1 was performed in a single outpatient HD clinic in Cherry Hill, New Jersey. Study 2 was performed in 4 outpatient HD clinics in Southern New Jersey.

SUBJECTS AND INTERVENTION

In study 1, we collected plasma samples from 8 adult patients on maintenance HD at various time points around their HD treatment and assayed them for AA concentration. In study 2, we enrolled 203 adult patients and measured pre-HD plasma AA concentrations. We ascertained supplemental AA use and assessed dietary AA intake.

MAIN OUTCOME MEASURE

In study 1, plasma AA concentrations were compared during the intradialytic and interdialytic period. In study 2, pre-HD plasma AA concentrations were correlated with supplement use and demographic factors.

RESULTS

Study 1 showed that over the course of a single HD treatment, the plasma AA concentration decreased by a mean (±standard deviation) of 60% (±6.6). In study 2, the median pre-HD plasma AA concentration was 15.7 μM (interquartile range, 8.7-66.8) in patients who did not take a supplement and 50.6 μM (interquartile range, 25.1-88.8) in patients who did take a supplement (P < .001). Supplement use, increasing age, and diabetes mellitus were associated with a pre-HD plasma AA concentration ≥30 μM.

CONCLUSION

HD depletes plasma AA concentrations, and AA supplementation allows patients to achieve higher plasma AA concentrations.

Oxalate at physiological urine concentrations induces oxidative injury in renal epithelial cells: effect of α-tocopherol and ascorbic acid

OBJECTIVES

To test our hypothesis that physiological levels of urinary oxalate induce oxidative renal cell injury, as studies to date have shown that oxalate causes oxidative injury only at supra-physiological levels. To study the combined effect of α-tocopherol and ascorbic acid against oxalate-induced oxidative injury, as oxalate-induced oxidative cell injury is known to promote initial attachment of calcium oxalate crystals to injured renal tubules and subsequent development of kidney stones.

MATERIALS AND METHODS

Cultures of normal (antioxidant-undepleted) and antioxidant-depleted LLC-PK1 cells were exposed to oxalate at human physiological urine concentrations. After exposure, markers of oxidative stress and cell injury were measured in the cells and media, respectively. In addition, we also evaluated the combined effects of α-tocopherol and ascorbic acid on oxalate-induced oxidative cell injury.

RESULTS

Exposure of renal cells to oxalate at urinary physiological levels increased the oxidative cell injury as assessed by increased lactate dehydrogenase (LDH) leakage and increased lipid hydroperoxide in the renal cells; however, this effect was not seen until 24 h after oxalate exposure, at which point the injury was milder. On the other hand, when cellular reduced glutathione (GSH) and catalase were depleted in renal epithelial cells with pharmacological inhibitors, the physiological levels of urinary oxalate caused significant oxidative cell injury at 24 h, and remarkably, when additional endogenous antioxidants were depleted, the oxalate at the upper limit of normal 24 h urine caused a significant amount of cell injury in a shorter period of time, which was comparable to that seen in cells exposed to higher levels of oxalate. Exposure of LLC-PK1 cells to oxalate resulted in increased levels of H2 O2 and lipid hydroperoxide, correlating with increased release of cell injury markers, including LDH, alkaline phosphate, and γ-glutamyl transpeptidase from renal tubular epithelial cells. Oxalate exposure decreased the activity and protein expression of superoxide dismutase and glutathione peroxidase in a time-dependent manner. LLC-PK1 cells treated with oxalate and either α-tocopherol or ascorbic acid alone exhibited a significant decrease in oxidative cell injury and restored endogenous renal antioxidants towards normal levels, and interestingly, combined treatment with α-tocopherol and ascorbic was more efficient at preventing oxalate-induced toxicity than treatment with either agent alone.

CONCLUSION

To our knowledge this is the first study to show that oxalate alone at human physiological urine concentrations (in the absence of calcium oxalate crystal formation), induced oxidative renal injury in renal epithelial cells when endogenous antioxidants are depleted. Our data further suggests that a combination of α-tocopherol and ascorbic acid may be more effective than each individual agent in reducing oxalate-induced oxidative renal injury and subsequent calcium oxalate crystal deposition in recurrent stone formers.

Kidney fibrosis is independent of the amount of ascorbic acid in mice with unilateral ureteral obstruction

In response to sustained damage to a kidney, fibrosis that can be characterized as the deposition of a collagenous matrix occurs and consequently causes chronic kidney failure. Because most animals used in experiments synthesize ascorbic acid (AsA) from glucose, the roles of AsA in fibrotic kidney diseases are largely unknown. Unilateral ureteric obstruction (UUO) mimics the complex pathophysiology of chronic obstructive nephropathy and is an ideal model for the investigation of the roles of AsA in kidney failure. We examined the impact of a deficiency of Akr1a, a gene that encodes aldehyde reductase and is responsible for the production of AsA, on fibrotic damage caused by UUO in mice. Oxidatively modified DNA was elevated in wild-type and Akr1a-deficient kidneys as a result of UUO to a similar extent, and was only slightly suppressed by the administration of AsA. Even though Akrla-deficient mice could produce only about 10% of the AsA produced by wild-type mice, no difference was observed in collagen I synthesis under pathological conditions. The data implied either a low demand for AsA or the presence of another electron donor for collagen I production in the mouse kidney. Next, we attempted to elucidate the potential causes for oxidative damage in kidney cells during the fibrotic change. We found decreases in mitochondrial proteins, particularly in electron transport complexes, at the initial stage of the kidney fibrosis. The data imply that a dysfunction of the mitochondria leads to an elevation of ROS, which results in kidney fibrosis by stimulating cellular transformation to myofibroblasts.

Decreased plasma level of vitamin C in chronic kidney disease: comparison between diabetic and non-diabetic patients

BACKGROUND

A decreased plasma level of vitamin C has been reported to be associated with an increased risk of cardiovascular morbidity and mortality. Here, we sought to determine the vitamin C status of patients with chronic kidney disease and the pathophysiological role of vitamin C in these patients.

METHODS

We studied 58 patients and evaluated the relationship between renal function and plasma vitamin C concentration, as well as the effect of diabetes on this relationship. Endothelium-dependent flow-mediated dilation of brachial artery was measured to assess the endothelial function. Serum malondialdehyde low-density lipoprotein was measured as a marker for oxidative stress.

RESULTS

Plasma vitamin C concentration had a positive linear relationship with eGFR in both diabetic and non-diabetic patients (P = 0.006 and P = 0.004, respectively). When vitamin C concentration and eGFR relationships were compared in the two groups, vitamin C concentration was significantly lower in diabetic patients at every eGFR (P = 0.006). Flow-mediated vasodilatation of the brachial artery was positively correlated with vitamin C concentration in non-diabetic patients (P = 0.047) but not in diabetic patients. There was a negative correlation between serum malondialdehyde low-density lipoprotein and vitamin C concentration in non-diabetic patients (P = 0.044) but not in diabetic patients.

CONCLUSIONS

Renal dysfunction was associated with a decrease in plasma vitamin C level. Moreover, decreased vitamin C may cause endothelial dysfunction via an increase in oxidative stress in non-diabetic chronic kidney disease patients.

Determination of Vitamin C (Ascorbic Acid) Using High Performance Liquid Chromatography Coupled with Electrochemical Detection

Vitamin C (ascorbic acid, ascorbate, AA) is a water soluble organic compound that participates in many biological processes. The main aim of this paper was to utilize two electrochemical detectors (amperometric - Coulouchem III and coulometric - CoulArray) coupled with flow injection analysis for the detection of ascorbic acid. Primarily, we optimized the experimental conditions. The optimized conditions were as follows: detector potential 100 mV, temperature 25 °C, mobile phase 0.09% TFA:ACN, 3:97 (v/v) and flow rate 0.13 mL·min-1. The tangents of the calibration curves were 0.3788 for the coulometric method and 0.0136 for the amperometric one. The tangent of the calibration curve measured by the coulometric detector was almost 30 times higher than the tangent measured by the amperometric detector. Consequently, we coupled a CoulArray electrochemical detector with high performance liquid chromatography and estimated the detection limit for AA as 90 nM (450 fmol per 5 μL injection). The method was used for the determination of vitamin C in a pharmaceutical preparations (98 ± 2 mg per tablet), in oranges (Citrus aurantium) (varied from 30 to 56 mg/100 g fresh weight), in apples (Malus sp.) (varied from 11 to 19 mg/100 g fresh weight), and in human blood serum (varied from 38 to 78 μM). The recoveries were also determined.

Lipoperoxidation and hemodialysis

It has been suggested that hemodialysis patients may be under increased oxidative stress and may therefore benefit from the long-term use of antioxidants (particularly for the reduction of the risk of heart disease). The aim of this study was, first, to evaluate the effect of hemodialysis by itself on lipid and lipoprotein oxidation profiles and, second, to analyze the effect of vitamin C supplementation in patients with end-stage renal disease starting hemodialysis. Forty-one patients with end-stage renal disease were enrolled and randomized to receive 1000 mg/d vitamin C or matching placebo before starting hemodialysis. We measured lipid profile and the susceptibility of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) to oxidation using copper ions at the moment of inclusion and after 1 year. All lipoperoxidation parameters were included. Hemodialysis by itself improved the lipid profile, lowering total cholesterol (176.4 +/- 48.4 to 154.2 +/- 28.8 mg/dL, P < .01), LDL cholesterol (94.1 +/- 39.6 to 76.1 +/- 26.6 mg/dL LDL, P < .03), and phospholipids levels (196.5 +/- 36.7 to 182.9 +/- 36.1 mg/dL, P < .05) in all patients on maintenance hemodialysis. The HDL cholesterol was also decreased (49.4 +/- 19.8 to 43.4 +/- 24.1 mg/dL HDL, P < .03). No significant differences were detected between patients receiving vitamin C and those receiving placebo. Thiobarbituric acid reactive substances (TBARS) and lipoperoxides increased in patients after a year of hemodialysis, but the difference was lower in those administered vitamin C for a year-TBARS LDL (in nanograms per gram LDL): 0.25 +/- 0.20 to 0.38 +/- 0.2 in vitamin C-treated subjects and 0.28 +/- 0.17 to 0.46 +/- 0.21 in those treated with placebo (P < .007); TBARS HDL (in nanograms per gram HDL): 0.22 +/- 0.12 to 0.34 +/- 0.30 in patients receiving vitamin C and 0.20 +/- 0.18 to 0.28 +/- 0.19 in those receiving placebo (P = .071). Hemodialysis by itself seems to improve the lipid profile in patients with a previous prooxidative state such as uremia. Although our results failed to demonstrate significant differences between vitamin C-treated and untreated patients, and despite the small number of patients, the trend toward a decrease in oxidation products due to vitamin C supplementation may be beneficial for oxidation parameters. This area remains controversial and under active investigation. Further research is necessary before a firm conclusion can be reached.

Concentrations of vitamin C, vitamin B12 and folic acid in patients treated with hemodialysis and on-line hemodiafiltration or hemofiltration

OBJECTIVE

Uncertainty has arisen as to whether vitamin supplements are needed by dialysis patients, in particular those treated by means of hemofiltration or hemodiafiltration using highly permeable (high-flux) filters. We therefore measured the concentrations of vitamin C, cobalamin (vitamin B12) and folic acid in conventional (low-flux) dialysis patients and in those receiving on-line treatment (hemofiltration or hemodiafiltration).

MATERIAL AND METHODS

Plasma (P-)ascorbate, serum (S-)cobalamin and S-folate concentrations were measured before and after a treatment session in 15 patients treated with low-flux hemodialysis and in 14 treated with on-line hemofiltration or hemodiafiltration. The patients' vitamin supplementations were also recorded.

RESULTS

P-ascorbate concentrations were lowered by 51% and 53% in the hemodialysis and on-line groups, respectively after treatment and this reduction was significant (p<0.001). Concentrations below the reference values were found in 12/14 patients not receiving vitamin C supplementation. S-cobalamin did not decrease in the hemodialysis or on-line groups. S-folates did not change significantly in the hemodialysis or filtration groups. Patients without folacin supplementation had low values.

CONCLUSIONS

P-ascorbate was reduced by both dialysis and filtration treatments. Neither S-cobalamin nor S-folate were reduced by dialysis or filtration treatments.

Oxidative Stress in Children on Peritoneal Dialysis

Objectives

Enhanced oxidative stress has been observed in dialysis and predialysis adult patients with chronic kidney disease (CKD), which resulted in increased mortality and morbidity within this population. Not much attention in the literature has been paid to nonenzymatic antioxidant defense in children with CKD on peritoneal dialysis (PD). The aim of the present study was to describe the plasma, erythrocyte, and dialysate concentrations of oxidized (GSSG) and reduced glutathione (GSH) and vitamins A, E, and C in a pediatric PD population.

Patients

10 children on PD and 27 age-matched healthy subjects were enrolled in the study.

Results

Erythrocyte and plasma GSH concentrations were lower in PD patients, erythrocyte concentration of GSSG remained unchanged, and plasma GSSG was significantly higher in children on PD. Children on PD exhibited decreased plasma concentrations of antioxidant vitamins compared to healthy subjects. Moreover, we documented loss of vitamins A, E, and C into ultrafiltrate.

Conclusion

Such low plasma levels of vitamins A, E, and C and simultaneously decreased activity of erythrocyte GSH may be responsible for the increased oxidative stress occurring in children with CKD on PD.

The effect of intravenous iron on oxidative stress in hemodialysis patients at various levels of vitamin C

BACKGROUND/AIMS

Vitamin C levels decrease during hemodialysis (HD), which deteriorates antioxidant defense. Vitamin C may also act pro-oxidatively, via reduction in Fe(III). We sought to determine whether intravenous iron (Fe(iv))-induced oxidative stress differs in HD patients with low and physiological vitamin C levels and whether intravenous vitamin C (C(iv)) administration during HD would change the response to Fe(iv).

PATIENTS AND METHODS

Twenty patients with vitamin C deficiency (median 15.7 micromol/l, range 8.0-22.7) received Fe(iv) (100 mg iron sucrose between 150 and 180 min of HD). After 4 weeks of oral supplementation, the levels of vitamin C were comparable with those of controls (60.1 micromol/l, range 47.4-70.9). Patients were subsequently treated with (1) Fe(iv), (2) Fe(iv) and continuous 2 mg/min C(iv) throughout HD, (3) saline (S), and (4) S+C(iv). Plasma thiobarbituric acid reacting substances (TBARS) and vitamin C were assessed before, during and after FE(iv)(S), and 15, 30 and 60 min after infusion.

RESULTS

Fe(iv) induced a comparable rise in TBARS in patients with vitamin C deficiency (before Fe(iv), 1.9 micromol/l, range 1.4-1.9; after Fe(iv), 2.6 micromol/l, range 2.3-2.9; p < 0.01) and in those with normal vitamin C (before Fe(iv), 1.9 micromol/l, range 1.7-2.1; after Fe(iv), 2.6 micromol/l, range 2.5-2.9; p < 0.01). Fe(iv)+C(iv) resulted in a greater increase in TBARS (after Fe(iv), 3.1 micromol/l, range 2.8-3.2) compared with Fe(iv) (p < 0.01).

CONCLUSION

Iron sucrose-induced oxidative stress is comparable in HD patients with vitamin C deficiency and in those with normal vitamin C. We documented a pro-oxidative effect of vitamin C during Fe(iv)+C(iv) administration.

Lipid peroxidation and antioxidant enzymes in children on maintenance dialysis

End-stage renal disease (ESRD) is associated with numerous complications, which may partly result from excessive amounts of reactive oxygen species and/or decreased antioxidant activity. The aim of the study was to evaluate lipid peroxidation (LP) in plasma and erythrocytes, erythrocyte antioxidant enzyme activity (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GSH-Px), and concentrations of Cu and Zn as cofactors of SOD and Se as a cofactor of GSH-Px in erythrocytes, plasma and in dialysis fluid in children with ESRD. In particular, we analyzed whether the modality of dialysis could modify oxidative stress parameters in children. To determine the influence of hemodialysis (HD) on oxidative stress, the measurements were also performed on HD children 20 min after the beginning of the dialysis session. Thirty-one patients participated in the study: group I with 10 children on continuous ambulatory peritoneal dialysis (CAPD), and group II with 21 on HD. The erythrocyte malondialdehyde concentrations (E-MDA), plasma MDA (P-MDA) and plasma organic hydroperoxide (OHP) in children from both groups were higher than in controls. E-MDA and P-MDA in HD before the session was lower compared to the values after 20 min of HD session (time T20). The activity of SOD, GSH-Px, CAT, concentrations of erythrocyte and plasma Se, Cu, Zn were lower in children with ESRD than in controls. In the HD group, the activity of GSH-Px, CAT, and levels of trace elements in erythrocytes and in plasma were diminished at time T20. In conclusion, increased oxidative stress occurs in children on maintenance dialysis, independent of dialysis modality. The activity of the enzymatic antioxidant defence system is highly reduced in red blood cells of pediatric dialysis patients. Children with ESRD exhibit lower trace element (Se, Cu, Zn) levels in plasma and erythrocytes as compared to healthy subjects. Oxidative stress is aggravated during every single HD session in children.

Vitamins A, E and C as non-enzymatic antioxidants and their relation to lipid peroxidation in children with chronic renal failure

BACKGROUND

Increased lipid peroxidation (LP) and reduced enzymatic antioxidant defense have been observed in predialysis patients with advanced chronic renal failure (CRF) and in patients on maintenance hemodialysis (HD). To extend these observations, we evaluated the plasma, erythrocyte and dialysate levels of vitamins A and E and the plasma and dialysate levels of vitamin C as exogenous non-enzymatic antioxidants in children with CRF treated conservatively and on HD. The data obtained were related to LP monitored by erythrocyte malonyldialdehyde (E-MDA) and plasma organic hydroperoxide (OHP) concentrations.

PATIENTS

Forty-six predialysis children were enrolled in the study and divided into 2 groups: group I = moderate CRF (plasma creatinine < 265.3 micromol/l), and group II = plasma creatinine > or = 265.3 micromol/l. Group III consisted of 21 HD children. 27 age-matched healthy subjects served as a control group.

RESULTS

The plasma levels of vitamin A and vitamin C were significantly reduced in all CRF patients when compared to the controls, with the lowest values observed in children on maintenance HD (group III). Significant differences were also noted between the moderate CRF (group I) and HD (group III). Plasma levels of vitamin E were significantly decreased in moderate CRF (group I) and HD (group III) as compared to controls. In contrast, the erythrocyte vitamin A and vitamin E levels of predialysis children and HD patients were not different from the controls. The E-MDA and OHP concentrations in the 3 groups of CRF children were significantly higher than in healthy subjects. The concentration of plasma vitamin C was significantly inversely correlated with E-MDA, plasma OHP and creatinine in group I. In group II we found a significant correlation of plasma vitamin E levels with creatinine and E-MDA and a correlation of the plasma vitamin C concentration with E-MDA.

CONCLUSION

CRF in children is associated with decreased concentrations of plasma antioxidant vitamins. This reduction is most expressed in children on maintenance HD and particularly concerns plasma vitamin C and erythrocyte vitamin E concentrations. The low levels of plasma vitamin A, E and C might result in reduced activity of the non-enzymatic antioxidant defense system and might be responsible for increased oxidative stress occurring in children with CRF.

Long-term, low-dose, intravenous vitamin C leads to plasma calcium oxalate supersaturation in hemodialysis patients

BACKGROUND

Ascorbate supplementation for patients on regular dialysis treatment (RDT) is advised to obviate deficiency and improve epoetin response in those with functional iron deficiency. However, clear-cut safety concerns regarding hyperoxalemia are still poorly understood. This study tries to establish safety/efficacy profiles of ascorbate and oxalate during long-term intravenous ascorbate supplementation.

METHODS

A prospective study was performed in 30 patients on RDT showing ascorbate deficiency (plasma ascorbate < 2.6 mg/L [<15 micromol/L]): 18 patients were administered intravenous ascorbate during 18 months (250 mg/wk, subsequently increased to 500 mg), and 12 patients were taken as reference untreated cases. Plasma ascorbate and oxalate assays and dialytic balance determinations were performed (ion chromatography and reverse-phase high-performance liquid chromatography, respectively) at baseline, during treatment, and 12 months after withdrawal.

RESULTS

Plasma ascorbate levels increased dose dependently with supplementation (1.6 +/- 0.8 mg/L [9.1 +/- 4.6 mumol/L] at baseline, 2.8 +/- 1.8 mg/L [15.9 +/- 10.1 micromol/L]) with 250 mg of ascorbate, and 6.6 +/- 2.8 mg/L [37.5 +/- 16.0 micromol/L] with 500 mg/wk of ascorbate), but only normalized with greater dosages for several months in 94% of patients. Baseline plasma oxalate levels increased from 3.2 +/- 0.8 mg/L (35.8 +/- 8.8 micromol/L) to 3.6 +/- 0.8 mg/L (39.5 +/- 9.1 micromol/L) and 4.5 +/- 0.9 mg/L (50.3 +/- 10.4 micromol/L) with 250 and 500 mg, respectively ( P < 0.001). The calcium oxalate saturation threshold was exceeded by 7 of 18 patients (40%) during 6 months therapy with 500 mg/wk. Ascorbate dialysis removal increased from 37.8 +/- 23.2 mg (215 +/- 132 micromol) to 99.6 +/- 51.7 mg (566 +/- 294 micromol) during supplementation (P < 0.001), with corresponding increases in oxalate removal from 82.5 +/- 33.2 mg (917 +/- 369 micromol) to 111.2 +/- 32.6 mg/L (1,236 +/- 362 micromol; P < 0.01). Withdrawal reverted plasma levels and dialysis removal to initial values. Values for untreated patients did not change during 1 year of follow-up.

CONCLUSION

Patients on RDT may resolve ascorbate deficiency with intravenous supplementation of 500 mg/wk, but this implies a significant risk for oxalate supersaturation. Oxalate measurements are strongly recommended during long-term ascorbate therapy.

Efficacy and safety of oral versus intravenous ascorbic acid for anaemia in haemodialysis patients

BACKGROUND

Intravenous (i.v.) ascorbic acid (AA) improves anaemia in iron-overloaded, erythropoietin (rEPO) hyporesponsive haemodialysis patients. While oral AA is readily attainable, the efficacy and safety of oral versus i.v. AA has not been examined.

METHODS

We conducted an open-label randomised parallel study on the effects of 8 weeks of 250 mg oral AA (n=10) compared with 250 mg i.v. AA (n=11) 3x/week on haemoglobin (Hb), ferritin and rEPO dose in 21 iron-overloaded haemodialysis patients. We also examined the effect of 3 months of 500 mg oral AA 3x/week (n=70) compared with no treatment (n=83) on Hb, ferritin and rEPO dose in 153 haemodialysis patients.

RESULTS

Patients had severe AA deficiency (mean 2.2+/-SE 0.4 mg/L; normal range, 4.0-14.0). Following treatment, the plasma AA level increased (P<0.001), but was not significantly different between the groups. There was no change in Hb, iron availability and rEPO dose with oral or i.v. AA. There was a significant increase in serum oxalate but no significant changes in left ventricular function or renal calculi formation. In the second study, oral AA had no effect on Hb, rEPO dose and ferritin in the whole group and a subgroup of 30 with anaemia.

CONCLUSION

Haemoglobin and iron availability did not improve following oral or i.v. AA in this select small group of iron-overloaded haemodialysis patients or in a larger population of haemodialysis patients given oral AA at a higher dose and for a longer duration. AA supplementation may still be warranted in view of severe AA deficiency in haemodialysis patients.

Effects of oral vitamin C supplementation on oxidative stress and inflammation status in haemodialysis patients

BACKGROUND

There is increasing evidence for the presence of oxidative stress and vitamin C deficiency in dialysis patients. Limited data, however, are available regarding the effects of vitamin C supplementation on oxidative stress and inflammation markers in such patients.

METHODS

We ran a prospective, randomized, open-label trial to assess the effects of oral vitamin C supplementation (250 mg three times per week) for 2 months on well-defined oxidative and inflammatory markers in 33 chronic haemodialysis (HD) patients.

RESULTS

Normalization of plasma total vitamin C and ascorbate levels by oral vitamin C supplementation did not modify plasma levels of carbonyls, C-reactive protein and albumin, or erythrocyte concentrations of reduced and oxidized glutathione.

CONCLUSION

Short-term oral vitamin C supplementation did not modify well-defined oxidative/antioxidative stress and inflammation markers in HD patients. Whether a higher oral dose or the intravenous route can modify these markers remains to be determined.

Low total vitamin C plasma level is a risk factor for cardiovascular morbidity and mortality in hemodialysis patients

Hemodialysis patients are prone to deficiency of vitamin C, which constitutes the most abundant nonenzymatic antioxidant in blood. Because antioxidants are involved in the pathogenesis of atherosclerosis, the authors examined the association of total vitamin C plasma level with cardiovascular outcomes in such patients. One hundred thirty-eight consecutive maintenance hemodialysis patients (median age 61 yr, 90 males) were enrolled in a single-center study. At baseline, routine laboratory parameters were recorded, and predialysis total vitamin C plasma levels were measured by high-pressure liquid chromatography. Patients were prospectively followed-up for the occurrence of a primary composite endpoint consisting of fatal and nonfatal major adverse cardiovascular events (MACE) and for all-cause and cardiovascular mortality. MACE occurred in 35 patients (25%) over a period of median 30 mo, and 42 patients (30%) died [29 cardiovascular deaths (21% of total)]. Using Cox proportional hazards modeling, adjusted hazard ratios for the occurrence of MACE were 3.90 (95% confidence interval [CI]: 1.42 to 10.67; P = 0.008) and 3.03 (95% CI: 1.03 to 8.92; P = 0.044) for patients in the lower (<32 micromol/L) and middle (32 to 60 micromol/L) tertile of total vitamin C levels, compared with patients in the upper tertile (>60 micromol/L). Hazard ratios for cardiovascular death were 3.79 (95% CI: 1.23 to 11.66; P = 0.020) and 2.89 (95% CI: 0.89 to 9.37; P = 0.076). Total vitamin C levels were not independently associated with all-cause mortality. This study concludes that low total vitamin C plasma levels predict adverse cardiovascular outcomes among maintenance hemodialysis patients. Future studies should address the potential protective effect of an adequate vitamin C supplementation.

Intravenous iron preparations and ascorbic acid: Effects on chelatable and bioavailable iron

BACKGROUND

There is growing interest to use ascorbic acid as adjuvant therapy for patients with recombinant human erythropoietin-hyporesponsiveness (rHuEpo). Several clinical studies showed the beneficial effect of ascorbic acid treatment on hematologic parameters in rHuEpo-treated hemodialysis patients with elevated or even normal iron stores. However, whether ascorbic acid directly affects stability and cellular metabolism of intravenous iron preparations (IVI) is not well understood.

METHODS

The preparations for testing were iron sucrose (Venofer), ferric gluconate (Ferrlecit), and iron dextran (INFeD). HepG2-cells were used to investigate effects of ascorbic acid on iron bioavailability for the intracellular labile iron pool (LIP) from IVI by using the fluorescent calcein-assay, and cellular ferritin content was measured by enzyme-linked immunosorbent assay (ELISA). Transferrin-chelatable iron was assessed by fluorescent-apotransferrin, and cell toxicity was assayed by neutral red cytotoxicity test.

RESULTS

The effects of vitamin C on different preparations do not reflect their known chemical stability (i.e., iron dextran >iron sucrose >ferric gluconate). Effects of ascorbic acid on the increase of the intracellular LIP, as well as on increasing mobilization to transferrin in serum, were limited to iron sucrose. Ascorbic acid did not increase cell toxicity and the amount of low molecular weight iron in serum.

CONCLUSION

We conclude that corrected ascorbic acid levels in hemodialysis (HD) patients could increase the amount of bioavailable iron from iron sucrose, but not from other classes of IVI. Vitamin C administration could therefore result in a lower need of iron sucrose to correct anemia.