Optimization of folic acid, vitamin B(12), and vitamin B(6) supplements in pediatric patients with sickle cell disease

Vitamin B supplementation for sickle cell disease

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To assess the effectiveness of vitamin B supplementation in children and adults with sickle cell disease (SCD), compared to no intervention or an alternative vitamin B supplementation given as part of standard care.

Optimum dose of oral folic acid supplementation in transfusion-dependent thalassemia: a randomized controlled trial

AIM AND OBJECTIVES

We compared the effect of different doses of oral folic acid (FA) supplementation (5 mg/day vs. 2.5 mg/day vs. 5 mg/week) on the proportion of children with folate excess (serum folate >20 ng/ml) and plasma homocysteine (Hcys) excess (>15 µmol/l) in transfusion-dependent thalassemia (TDT).

MATERIALS AND METHODS

Children with TDT aged 5-18 years received oral FA in doses of 5 mg/day (Group 1), 2.5 mg/day (Group 2) and 5 mg/week (Group 3) for 9 months, after a wash-off period of 8 weeks. Folate levels (Serum and RBC) and plasma Hcys levels were measured after the therapy.

RESULTS

Ninety children were randomized to receive one of the three interventions (30 per group). After wash-off period, the median serum folate levels were significantly lower and five children developed folate deficiency; the median [interquartile range (IQR)] serum folate levels (ng/dl) were comparable in the three groups [Group 1: 6.5 (3.3-14.2), Group 2: 5.1 (2.6-10.5) and Group 3: 4.8 (3.4-10.0)]. After 9 months of intervention, the median (IQR) serum folate levels (ng/ml) were comparable in all participants [Group 1: 18.0 (6.5-28), Group 2: 13.5 (6.4-24.5) and Group 3: 9.7 (5.3-22.5); p = 0.11]. Proportion of children with serum folate excess was 40%, 26.7% and 26.7% in Group 1, Group 2 and Group 3 (p = 0.48). Proportion of children with RBC folate excess was 92%, 86.7% and 86.7% in Group 1, Group 2 and Group 3 (p = 0.79). Hyperhomocysteinemia was seen in eight children with no significant difference between median Hcys levels in the groups (p = 0.75).

CONCLUSION

Folic acid supplementation is recommended in TDT with 5 mg weekly dose being adequate.

Plasma Folate Levels in Acutely Ill and Steady State Pediatric Sickle Cell Disease Patients in Ghana

Background

Individuals with sickle cell disease (SCD) are susceptible to infective conditions that predispose them to hemolysis and anemia. Folic acid is recommended as a preventative measure against anemia in SCD patients; however, there is scarce literature on the implications of this practice.

Patients and Methods

Plasma concentrations of folate were measured in acutely ill pediatric SCD patients presenting with malaria or bacteremia and compared with those of SCD patients in steady state, or acutely ill non-SCD patients with confirmed malaria.

Results

The proportion of individuals with high (>45.3 nmol/L) folate concentrations was 29.5% (13/44), 18.2% (8/44), 33.3% (6/18), and 0% in the SCD-malaria, SCD steady state, SCD bacteremia, and the non-SCD malaria groups, respectively. The proportion of SCD patients with high folate levels did not vary significantly at steady state and during confirmed malaria (p = 0.216), and during acute bacteremia (p = 0.20). The median (interquartile range) plasma folate levels were 34.50 (24.40–52.00 nmol/L), 33.40 (15.83–60.85 nmol/L), 30.85 (24.68–39.65 nmol/L), and 13.30 (10.03–17.18 nmol/L), respectively, in the SCD malaria, SCD bacteremia, SCD steady state, and the non-SCD malaria sub-groups. The median folate levels of SCD steady state, SCD malaria, and SCD bacteremia sub-groups differed significantly (p < 0.0001) when compared with non-SCD patients, but the levels in the SCD bacteremia and malaria groups were not significantly different from the SCD steady state group.

Conclusion

Elevated levels of plasma folate were found in a high proportion of pediatric SCD patients. The implications of such elevated folate levels in pediatric SCD patients are unknown but may suggest a need for review of current recommendations for prophylactic doses of folic acid in SCD patients.

Homocysteine is associated with severity of microvasculopathy in sickle cell disease patients

The pathophysiology of sickle cell disease (SCD) includes vasculopathy as well as anaemia. Elevated plasma homocysteine is a risk factor for vascular disease and may be associated with increased risk of vascular complications in SCD patients. In the present study, microvascular characteristics were assessed in the bulbar conjunctiva of 18 paediatric and 18 adult SCD patients, using the non-invasive technique of computer-assisted intravital microscopy. A vasculopathy severity index (SI) was computed to quantify the degree of microvasculopathy in each patient. Plasma homocysteine and several of its determinants [serum folate and vitamin B12, plasma pyridoxal-5'-phosphate (vitamin B6 status) and creatinine (kidney function)] were measured. Age was strongly correlated with microvasculopathy in the SCD patients, with the SI increasing about 0·1 unit per one-year increase in age (P < 0·001). After adjusting for age, gender, B-vitamin status and creatinine, homocysteine concentration was directly correlated with severity index (P < 0·05). Age and homocysteine concentration were independent predictors of microvasculopathy in SCD patients. It remains to be determined whether lowering homocysteine concentrations using appropriate B-vitamin supplements (folate and vitamins B12 and B6) - particularly if started early in life - could ameliorate microvasculopathy and its associated complications in SCD patients.

Dietary intakes and nutritional status of children with sickle cell disease at the Princess Marie Louise Hospital, Accra - a survey

Background

Sickle cell disease (SCD) is a chronic genetic blood disorder common among people of African descent, which places nutritional burden among affected individuals. The aim of the study was to determine the dietary intake and nutritional status of children with SCD.

Method

This was a cross sectional study that involved 120 children with SCD aged 3-12 years at the paediatric outpatient department of Princess Marie Louise Hospital (PML) in Accra. A semi-structured questionnaire was used to take information on participant's demographic characteristics and clinical data were obtained from their medical records. Dietary data were obtained using 24-h dietary recall and food frequency questionnaire. Height and weight were measured for participants and their haemoglobin levels were determined to assess their anaemia status.

Results

Intakes of participants were below recommendations for most nutrients, particularly for calcium and antioxidant vitamins (vitamin C and E). Adequacy of nutrient intake declined with age and children with genotype HbSS had a lower tendency to meet dietary recommendations (aOR = 0.45, 95% CI: 0.18, 1.10; p = 0.084). More than a third of the study children (38%) were malnourished, with older children having a tendency to be malnourished compared to the younger ones. Children with the SS genotype were more likely to be stunted (aOR = 3.48, 95% CI: 1.10, 11.01), compared to other genotypes.

Conclusion

Malnutrition is prevalent among children with SCD and hence there is the need to develop comprehensive management coupling nutritional therapy to medical care to improve their nutritional status. Nutritional management should focus much on calcium-rich foods and antioxidants nutrients particularly vitamin C and E to reduce rapid erythrocyte haemolysis and chronic anaemia.

The role of nutrition in the pathophysiology and management of sickle cell disease among children: A review of literature

Sickle cell disease (SCD) is one of the common inherited blood disorders in humans and has been associated with decreased dietary intake which results in poor nutritional status and impaired growth. Nutrition is one of the most important but often forgotten aspect of care of patients with chronic disorders and there have been emerging concern in literature on increased nutritional needs of SCD patients. This paper sought to review the available literature on the roles of individual nutrients in the pathophysiology and management of SCD among children. Children with SCD have been shown to exhibit suboptimal status with respect to both macronutrients and micronutrients. Thus, nutrition could play an important role in the management of SCD. However, there is paucity of evidence coming from trials with large sample sizes to support the suggestion that supplementation with various nutrients that have been considered in this review will be helpful.

Nutrient Insufficiencies/Deficiencies in Children With Sickle Cell Disease and Its Association With Increased Disease Severity

BACKGROUND

Sickle cell disease (SCD) is characteristically described as a disease of hemolytic anemia and vaso-occlusive crises (VOCs). However, patients suffer from a multitude of other problems including impaired development, chronic pain, and increased susceptibility to infection. Nutritional deficiency has been implicated as a contributor to these issues.

PROCEDURE

We reported the nutrition status with respect to vitamin D, zinc, B6, B12, folate, and homocysteine serum levels in Canadian children with SCD (n = 91). We also tested for associations between nutrients and markers of disease severity and growth.

RESULTS

Almost half the sample (42%) had multiple nutrient insufficiencies/deficiencies, and a further 27% had a single insufficiency/deficiency. The most common insufficiency/deficiency was zinc in 57% followed by calcidiol (25 dihydroxyvitamin D (25(OH)D)) (52%). Sixteen percent of patients had low vitamin B6 levels, while folate, calcitriol (1,25(OH)D), and homocysteine levels were normal. Increased number of vitamin insufficiencies/deficiencies was associated with increasing disease severity (P = 0.018). Zinc insufficiency/deficiency was significantly associated with an increased number of home pain crises (P = 0.001) and an increased incidence of hospitalizations for VOCs (P = 0.01).

CONCLUSIONS

Our findings show that patients with SCD commonly have multiple nutrient insufficiencies/deficiencies and support the growing evidence for the link between low zinc and increased VOC. It also indicates that increased nutrient insufficiencies/deficiencies are associated with increased disease severity in SCD. Prospective studies with larger samples are needed to further elucidate the relationship between nutrient deficiencies and SCD, and to determine whether nutrient supplementation can improve the disease course.

An anthropometric and hematological comparison of sickle cell disease children from rural and urban areas

BACKGROUND:

Sickle cell disease (SCD) is a prevalent genetic disorder in India and the rural and urban areas experience distinctly different healthcare facilities. In view of this, a comparative study of SCD-SS pattern children of age 8–15 years from rural and urban areas of Wardha district of Central India was carried out using anthropometric and hematological parameters.

MATERIALS AND METHODS:

The data were collected using standard methods and the results showed a significant (P < 0.05) difference in the mean values for body weight, body mass index (BMI), hemoglobin, hematocrit, and white blood corpuscles (WBC). Statistical analysis of the data was done using SPSS 18.0 software. Individuals were screened by solubility test method. Sickle cell patterns (AS and SS) were determined by using electrophoresis technique.

RESULT:

The SCD-SS children from rural were significantly underweight than those from the urban area of Wardha district. BMI is a good indicator of nutritional status and BMI values of SCD children have less than desired.

CONCLUSION:

The study highlights an urgent need to conduct integrated investigations for SCD population of rural areas covering clinical, nutritional, and social aspects.

Growth and nutritional status of children with homozygous sickle cell disease

BACKGROUND

Poor growth and under-nutrition are common in children with sickle cell disease (SCD). This review summarises evidence of nutritional status in children with SCD in relation to anthropometric status, disease severity, body composition, energy metabolism, micronutrient deficiency and endocrine dysfunction.

METHODS

A literature search was conducted on the Medline/PUBMED, SCOPUS, SciELO and LILACS databases to July 2007 using the keywords sickle cell combined with nutrition, anthropometry, growth, height and weight, body mass index, and specific named micronutrients.

RESULTS

Forty-six studies (26 cross-sectional and 20 longitudinal) were included in the final anthropometric analysis. Fourteen of the longitudinal studies were conducted in North America, the Caribbean or Europe, representing 78.8% (2086/2645) of patients. Most studies were observational with wide variations in sample size and selection of reference growth data, which limited comparability. There was a paucity of studies from Africa and the Arabian Peninsula, highlighting a large knowledge gap for low-resource settings. There was a consistent pattern of growth failure among affected children from all geographic areas, with good evidence linking growth failure to endocrine dysfunction, metabolic derangement and specific nutrient deficiencies.

CONCLUSIONS

The monitoring of growth and nutritional status in children with SCD is an essential requirement for comprehensive care, facilitating early diagnosis of growth failure and nutritional intervention. Randomised controlled trials are necessary to assess the potential benefits of nutritional interventions in relation to growth, nutritional status and the pathophysiology of the disease.

Folate status in various pathophysiological conditions

Folate is the generic term for compounds that have vitamin activity similar to that of pteroylglutamic acid. Folate acts as a coenzyme in several single carbon transfers involved in biosynthesis of purine nucleotides and deoxythymidylic acid essential for DNA and RNA synthesis. In addition, folate provides one-carbon unit for methylation of a wide variety of biological substances including DNA, proteins, phospholipids, and neurotransmitters, thereby regulating their function. Recent epidemiological-clinical and experimental studies suggest the association of folate deficiency with the risk of various cancers, birth defects, and cardiovascular diseases. Thus, it is important to consider the conditions that are associated with altered folate status and their consequences. The impairment in folate status has been found in number of pathophysiological conditions like inflammatory bowel disease, cancer, alcoholism, pregnancy, neonatal growth, and during administration of some drugs. The recent advances dealing with mechanistic aspects of impaired folate status in these conditions have been discussed in this review.

Erythrocyte glutamine depletion, altered redox environment, and pulmonary hypertension in sickle cell disease

Erythrocyte glutathione depletion has been linked to hemolysis and oxidative stress. Glutamine plays an additional antioxidant role through preservation of intracellular nicotinamide adenine dinucleotide phosphate (NADPH) levels, required for glutathione recycling. Decreased nitric oxide (NO) bioavailability, which occurs in the setting of increased hemolysis and oxidative stress, contributes to the pathogenesis of pulmonary hypertension (PH) in sickle cell disease (SCD). We hypothesized that altered glutathione and glutamine metabolism play a role in this process. Total glutathione (and its precursors) and glutamine were assayed in plasma and erythrocytes of 40 SCD patients and 9 healthy volunteers. Erythrocyte total glutathione and glutamine levels were significantly lower in SCD patients than in healthy volunteers. Glutamine depletion was independently associated with PH, defined as a tricuspid regurgitant jet velocity (TRV) of at least 2.5 m/s. The ratio of erythrocyte glutamine:glutamate correlated inversely to TRV (r = -0.62, P < .001), plasma arginase concentration (r = -0.45, P = .002), and plasma-free hemoglobin level (r = -0.41, P = .01), linking erythrocyte glutamine depletion to dysregulation of the arginine-NO pathway and increased hemolytic rate. Decreased erythrocyte glutathione and glutamine levels contribute to alterations in the erythrocyte redox environment, which may compromise erythrocyte integrity, contribute to hemolysis, and play a role in the pathogenesis of PH of SCD.

Therapy Insight: stroke risk and its management in patients with sickle cell disease

Children with sickle cell disease, a chronic hemolytic anemia, present with a wide variety of neurological syndromes, including ischemic and hemorrhagic stroke, transient ischemic attacks, 'soft neurological signs', seizures, headache, coma, visual loss, altered mental status, cognitive difficulties, and covert or 'silent' infarction. Those with ischemic stroke usually have stenosis or occlusion of the distal internal carotid and proximal middle cerebral arteries. Indefinite transfusion prevents recurrence in most patients who have had a stroke, and can prevent first stroke in those with high transcranial Doppler velocities. High white cell count, low hemoglobin and oxyhemoglobin desaturation predict neurological complications. Other risk factors for overt ischemic stroke include hypertension, previous transient ischemic attack, covert infarction and chest crisis. For hemorrhagic stroke, aneurysms are common in adults but not children, who often present with hypertension after transfusion or corticosteroids. Seizures are particularly common in patients with cerebrovascular disease and covert infarction; the latter is also associated with hyposplenism and infrequent pain. Factors associated with cognitive difficulties include thrombocytosis, infarction, large-vessel disease, and perfusion abnormality on neuroimaging. As well as investigating the role of genes and the possibility that hydroxyurea or blood pressure control reduce neurological complications, we should explore the modifiable effects of poor nutrition, chronic infection, hemolysis and oxyhemoglobin desaturation on stroke risk.

Cyanocobalamin (vitamin B12) conjugates with enhanced solubility

Cyanocobalamin (vitamin B12) is an essential nutrient as well as a very useful carrier in drug delivery. Conjugates of vitamin B12 are investigated due to their wide range of therapeutic applications. We report the synthesis of six vitamin B12 conjugates, and the effect of conjugation on their solubilities and stabilities in various media. We reveal here that vitamin B12 can be released readily if a 2'-hydroxyl group is conjugated rather than the 5'-hydroxyl group, and the solubility (thus the equivalents of vitamin B12) could be enhanced as much as 19-fold, by simple conjugates such as glycolates. Findings disclosed here provide insights into the reactivities of vitamin B12 conjugates, the design of future prodrugs and similar conjugated moieties using vitamin B12.

Stroke in children with sickle cell disease

Children with sickle disease are at high risk for ischemic stroke and transient ischemic attacks, usually secondary to intracranial arteriopathy involving the terminal internal carotid and proximal middle cerebral and anterior cerebral arteries, which may be diagnosed using transcranial Doppler ultrasound or magnetic resonance angiography (MRA). Other central nervous system (CNS) complications include seizures and coma, which may be secondary to ischemic stroke, sinovenous thrombosis, reversible posterior leukoencephalopathy, or acute demyelination. The immediate priority after an acute CNS event is to improve cerebral oxygenation with oxygen supplementation to maintain peripheral saturation measured using pulse oximetry between 96% and 99%, and a simple transfusion of packed cells within an hour of presentation if the patient's hemoglobin is less than 10 g/dL. The patient then should have erythrocytapheresis or manual exchange to reduce the hemoglobin S percentage to below 30%. Computed tomography to exclude hemorrhage is mandatory and MR T2-weighted imaging with MRA, fat-saturated imaging of the neck (dissection), MR venography (sinovenous thrombosis), and diffusion-weighted imaging usually distinguishes between arterial ischemic stroke and the differential diagnoses. Comatose patients with widespread focal or global cerebral edema may have good functional outcome after surgical decompression. Anticoagulation may be indicated for dissection or sinovenous thrombosis and steroids for demyelination. Blood pressure should be reduced slowly if raised in patients with reversible posterior leukoencephalopathy. Seizures should be treated aggressively and electroencephalogram monitoring should be done to exclude subclinical seizures if the patient is unconscious. Hemorrhagic stroke may require craniectomy and drainage and/or management of vasospasm. Interventional neuroradiology with coils is an alternative to surgical clipping for aneurysms. For secondary prevention, regular blood transfusion to hemoglobin S of less than 30% reduces the risk of recurrent stroke from approximately 67% to approximately 10%. Hydroxyurea and phlebotomy may be used in patients who are alloimmunized. Moyamoya syndrome is a risk factor for recurrence despite prophylactic blood transfusion. Revascularization may prevent additional stroke. Bone marrow transplantation may be offered to patients with human leukocyte antigen-compatible siblings. Blood transfusion prevents stroke in patients with velocities greater than 200 cm per second on TCD; a phase III trial studying the prevention of the progression of silent infarction is being done. Emerging primary prophylaxis regimens being tested include citrulline and arginine, aspirin, and overnight oxygen supplementation. Physicians caring for children with sickle cell disease also should ensure adequate nutrition, including five servings of fruit and vegetables a day. The role of vitamin supplementation is controversial, particularly when patients must take daily penicillin prophylaxis.

Mild hyperhomocysteinemia in adult patients with sickle cell disease: a common finding unrelated to folate and cobalamin status

Homocysteine has associations with both vitamin insufficiency and vascular complications, and its status is therefore of interest in sickle cell disease (SCD). However, information is limited, especially in adults. We studied plasma total homocysteine (tHcy) and three of its major modifiers, cobalamin, folate, and creatinine, in 90 adult patients with SCD and 76 control subjects. The patients had higher tHcy levels than did controls (P = 0.03) and had elevated tHcy more often (20% vs. 3%, P = 0.0005). None of the hyperhomocysteinemic patients had low cobalamin or folate levels; on the contrary, patients with SCD had high folate levels more often than control subjects (32% vs. 7%; P < 0.0001). Although serum creatinine values were lower in SCD patients than in control subjects (P = 0.03), high levels also tended to occur more often (8% vs. 1%; P = 0.054). Most importantly, creatinine levels correlated significantly with tHcy (P < 0.0001) and logistic regression analyses showed creatinine to be the only significant predictor of high tHcy levels in SCD (P = 0.01). Our results show that hyperhomocysteinemia affects 20% of adults with SCD despite routine folate supplementation and is independent of folate and cobalamin status. Creatinine was the major identifiable influence on tHcy, but renal insufficiency explained only 4 of the 18 elevated tHcy levels. Longitudinal studies will be needed to determine whether the frequent hyperhomocysteinemia of SCD influences the vascular complications in SCD. If reducing tHcy becomes advisable, then interventions other than folate therapy will be needed.

Is there a genetic basis for pediatric stroke?

PURPOSE OF REVIEW Childhood: stroke is more common than brain tumor, but because there is a wide spectrum in terms of etiology and most centers see only a few cases every year, there have been few large studies of genetic and environmental risk factors until recently. This review focuses on the clinical and radiologic methodology required to distinguish phenotypes in patients, and it focuses on the available data on genetic predisposition.

RECENT FINDINGS

A number of conditions with Mendelian inheritance (eg, sickle cell disease) predispose to childhood stroke, but the search for epistatic polymorphisms that explain why some but not all of these patients are affected has been hampered by our poor understanding of the pathophysiology. Emergency vascular imaging, including arteriography and venography, will almost certainly assist with the description of stroke subtypes with different genetic predisposition in these patients and in the important group of children who were completely healthy before their stroke. Environmental exposure (eg, to infection, hypoxemia, and vitamins) may play a crucial role in modifying genetic expression and must be described carefully in prospective studies.

SUMMARY

Now that much of the work on classifying stroke subtypes in children has been undertaken, international collaboration is likely to lead to identification of the genetic and environmental risk factors, and thus to primary and secondary prevention.