Antiretroviral therapy provided to HIV-infected Malawian women in a randomized trial diminishes the positive effects of lipid-based nutrient supplements on breast-milk B vitamins.

BACKGROUND: Little information is available on B vitamin concentrations in human milk or on how they are affected by maternal B vitamin deficiencies, antiretroviral therapy, or maternal supplementation. OBJECTIVE: The objective was to evaluate the effects of antiretroviral therapy and/or lipid-based nutrient supplements (LNSs) on B vitamin concentrations in breast milk from HIV-infected women in Malawi. DESIGN: Breast milk was collected from 537 women recruited within the Breastfeeding, Antiretrovirals, and Nutrition study at 2 or 6 wk and 24 wk postpartum. Women were assigned to receive antiretrovirals and LNSs, antiretrovirals only, LNSs only, or a control. Antiretrovirals and LNSs were given to the mothers from weeks 0 to 28. The antiretrovirals were zidovudine/lamivudine and nelfinavir or lopinavir/ritonavir. LNSs provided 93-118% of the Recommended Dietary Allowances of thiamin, riboflavin, niacin, pyridoxine, and vitamin B-12. Infants were exclusively breastfed. RESULTS: LNSs increased milk concentrations of all vitamins except thiamin, whereas antiretrovirals lowered concentrations of nicotinamide, pyridoxal, and vitamin B-12. Although antiretrovirals alone had no significant effect on riboflavin concentrations, they negatively affected the LNS-induced increase in this vitamin. Thiamin was not influenced by the study interventions. Concentrations of all B vitamins were much lower than usually accepted values. CONCLUSIONS: All B vitamins were low in milk, and all but thiamin were increased by maternal supplementation with LNSs. Antiretrovirals alone decreased concentrations of some B vitamins in milk. When LNS was given in addition to antiretrovirals, the negative effect of antiretrovirals offset the positive effect of LNSs for all vitamins except thiamin. This trial was registered at clinicaltrials.gov as NCT00164762.

Use of proton pump inhibitors is associated with anemia in cardiovascular outpatients.

BACKGROUND: Proton pump inhibitors (PPI) are frequently prescribed in combination with aspirin for preventing peptic ulcer in patients with atherosclerotic diseases. In contrast, long-term use of PPI has been suggested to be associated with iron or vitamin B12 deficiency. The effect of PPI on hemoglobin (Hb) concentration, however, has not been clarified in cardiovascular outpatients. METHODS AND RESULTS: We retrospectively investigated the clinical characteristics of 278 continuous outpatients who received blood test including complete blood count and serum creatinine concentration (mean age, 69.9 ± 10.8 years; male, 68.7%). The frequency of anemia was 51% in patients receiving PPI and 19% in those not receiving PPI (chi-squared test, P<0.001). On multivariate analysis female sex (P<0.001), peripheral artery disease (P=0.003), PPI (P=0.003), low white blood cell count (P=0.004), old age (P=0.007), and low estimated glomerular filtration rate (P=0.010) were independently associated with low Hb. Among these patients, we investigated the change in Hb after the initiation of PPI in 36 patients for whom data on Hb level within 1 year before and within 1 year after the initiation of PPI were available. Mean decrease in Hb after the initiation of PPI was 0.38 ± 0.87 g/dl (95% confidence interval: -0.67 to -0.09 g/dl). CONCLUSIONS: Use of PPI was associated with anemia in Japanese cardiovascular outpatients.

B-vitamin deficiency in patients treated with antiepileptic drugs.

Enzyme-inducing antiepileptic drugs (AEDs) produce many alterations in metabolism, including vitamin levels. Whether they produce clinically relevant deficiency of B vitamins has rarely been assessed. We obtained B-vitamin levels in patients who were being converted from an inducing AED (phenytoin or carbamazepine) to a non-inducing AED (levetiracetam, lamotrigine, or topiramate), with measurements both before and ≥ 6 weeks after the switch. A group of normal subjects underwent the same studies. Neither folate nor B12 deficiency was seen in any patient. Vitamin B6 deficiency was found in 16/33 patients (48%) taking inducers, compared to 1/11 controls (9%; p=0.031). After switch to non-inducers, only 7 patients (21%) were B6 deficient (p=0.027). The incidence of deficiency was similar regardless of which inducing or non-inducing AED was being taken. Our findings demonstrate that treatment with inducing AEDs commonly causes pyridoxine deficiency, often severe. This could conceivably contribute to the polyneuropathy sometimes attributed to older AEDs, as well as other chronic heath difficulties.

L-Carnitine attenuates ifosfamide-induced carnitine deficiency and decreased intramitochondrial CoA-SH in rat kidney tissues.

BACKGROUND: The effects of L-carnitine on ifosfamide (IFO)-induced Fanconi syndrome have not been studied to date. This study aimed to investigate, on a mechanism basis, whether L-carnitine could prevent the development of IFO-induced Fanconi syndrome in rats. METHODS: Adult male Wistar albino rats were assigned to 1 of 4 treatment groups: group 1 (control) rats were given daily intraperitoneal (i.p.) injections of normal saline for 10 consecutive days; group 2 (L-carnitine) rats were given L-carnitine (200 mg/kg per day, i.p.) for 10 consecutive days. Rats of group 3 (IFO) received normal saline for 5 days, followed by IFO (50 mg/kg per day, i.p.) for 5 consecutive days. Rats of group 4 (IFO plus L-carnitine) received L-carnitine for 5 days before and 5 days concomitant with IFO. RESULTS: Administration of IFO for 5 consecutive days significantly increased serum creatinine, blood urea nitrogen (BUN), urinary carnitine excretion, intramitochondrial acetyl-CoA and thiobarbituric acid reactive substances (TBARS), and significantly decreased total carnitine, intramitochondrial CoA-SH, ATP and ATP/ADP ratio, and reduced glutathione (GSH) in kidney tissues. Administration of L-carnitine to IFO-treated rats resulted in a complete reversal of the increase in serum creatinine, BUN, urinary carnitine excretion and intramitochondrial acetyl-CoA, and of the decrease in total carnitine, intramitochondrial CoA-SH, ATP and GSH, induced by IFO, to the control values. CONCLUSIONS: L-Carnitine prevents the development of IFO-induced Fanconi syndrome by increasing intracellular carnitine content and intramitochondrial CoA-SH, with the consequent improvement in mitochondrial oxidative phosphorylation and energy production, as well as its ability to decrease oxidative stress.

Proton pump inhibitor side effects and drug interactions: much ado about nothing?

Proton pump inhibitors (PPIs) are widely prescribed for acid-peptic disease. In general, the safety of this class of drugs has been excellent. However, in the past several years, epidemiologic studies have indicated possible risks that are biologically plausible.

The plasma carnitine concentration regulates renal OCTN2 expression and carnitine transport in rats.

Previous findings in rats and in human vegetarians suggest that the plasma carnitine concentration and/or carnitine ingestion may influence the renal reabsorption of carnitine. We tested this hypothesis in rats with secondary carnitine deficiency following treatment with N-trimethyl-hydrazine-3-propionate (THP) for 2 weeks and rats treated with excess L-carnitine for 2 weeks. Compared to untreated control rats, treatment with THP was associated with an approximately 70% decrease in plasma carnitine and with a 74% decrease in the skeletal muscle carnitine content. In contrast, treatment with L-carnitine increased plasma carnitine levels by 80% and the skeletal muscle carnitine content by 50%. Treatment with L-carnitine affected neither the activity of carnitine transport into isolated renal brush border membrane vesicles, nor renal mRNA expression of the carnitine transporter OCTN2. In contrast, in carnitine deficient rats, carnitine transport into isolated brush border membrane vesicles was increased 1.9-fold compared to untreated control rats. Similarly, renal mRNA expression of OCTN2 increased by a factor of 1.7 in carnitine deficient rats, whereas OCTN2 mRNA expression remained unchanged in gut, liver or skeletal muscle. Our study supports the hypothesis that a decrease in the carnitine plasma and/or glomerular filtrate concentration increases renal expression and activity of OCTN2.

Atherosclerotic risk among children taking antiepileptic drugs.

Epilepsy is a common chronic neurological disorder that requires long-term or sometimes lifetime therapy. Recent evidence indicates that prolonged use of antiepileptic drugs (AEDs) might modify some vascular risk factors; however, the influence of AED therapy on the development of atherosclerosis has been the subject of controversy. Some epidemiological studies have reported a higher prevalence of ischemic vascular disease among epileptic patients on AEDs, while in other studies the mortality due to atherosclerosis-related cardiovascular disease in treated epileptics has been observed to be lower than in the general population. The etiology of atherosclerosis-related vascular diseases in epileptic patients has not been fully clarified. Since atherosclerotic vascular alterations may start early in life, this review focuses on major atherogenic risk factors among epileptic children, including altered metabolism of homocysteine, disordered lipid profiles, and increased lipoprotein (a) serum levels, as well as thyroid hormone deficiency with special concern for clinical implications.

Drug-induced pertubation of the aminothiol redox-status in patients with epilepsy: improvement by B-vitamins.

OBJECTIVES: Patients with epilepsy have excess morbidity and mortality due to ischemic cardiovascular disease. Many of these patients have elevated concentrations of plasma total homocysteine (Hcy), which is an acknowledged risk factor for cardiovascular disease, venous thromboembolic disease, foetal malformations and dementia. Hyperhomocysteinemia may have negative effects through mechanisms involving oxidative damage. In the present study, we have investigated the aminothiol redox-status in patients on antiepileptic drugs. Thereafter, in a subset of patients with elevated total Hcy, we evaluated the effect of B-vitamin therapy. METHODS: In the first part of the study, 101 patients on antiepileptic drugs were compared with 101 matched healthy controls. The redox-species of Hcy, cysteine and cysteinylglycine, the major aminothiols in plasma, were analyzed by high-performance liquid chromatography (HPLC). Hyperhomocysteinemia was defined as fasting total Hcy above 12 micromol/L and/or post-methionine load concentrations above 38 micromol/L. In the second part of the study, 33 patients identified with hyperhomocysteinemia were supplemented with three B-vitamins for 30 days; folic acid (B9), pyridoxine (B6) and riboflavin (B2). RESULTS: All redox-species of Hcy were significantly elevated in the patients, except the fasting concentrations of reduced Hcy (p=0.09). The reduced/total ratio of cysteine in fasting plasma was lower in the patients than in the controls: 5.20% vs. 6.19%, respectively (p=0.006). After 30 days of B-vitamin supplementation, the plasma concentrations of reduced, oxidized and protein-bound Hcy species were significantly lowered by 17%, 22% and 28%, respectively. The reduced/total ratio of cysteine rose from 4.9% to 7.9% (p=0.007). CONCLUSIONS: Patients on antiepileptic drugs have abnormal aminothiol redox-status associated with hyperhomocysteinemia. This is similar to findings in patients with cardiovascular disease. B-vitamin supplementation partially corrects the abnormal aminothiol redox-status. Possibly, B-vitamin supplementation may be useful in drug-induced hyperhomocysteinemia.

Pivalate lowers litter sizes and weights in female rats independent of its effect on carnitine status.

The present study investigated whether treatment of female rats with pivalate affects their reproductive function. Therefore, two experiments with female rats were performed. The first experiment included two groups of rats which received drinking water without (control) or with 20 mmol pivalate/L. The second experiment included a control group (which received drinking water without pivalate and a diet without added carnitine) and four groups which received drinking water with 20 mmol/L pivalate and diets without or with 1, 3 or 5 g added carnitine/kg, respectively. In both experiments, rats treated with pivalate had a lower number of pups born alive and, as a consequence of this, lower litter weights than control rats (p<0.05); pup weights were not altered by pivalate treatment. Supplementation of dietary carnitine in Experiment 2 increased plasma and tissue carnitine concentration even in excess of those in control rats but did not restore normal litter sizes. This study shows for the first time that pivalate affects the reproductive function in female rats independent of its effect on the carnitine status.

Science review: carnitine in the treatment of valproic acid-induced toxicity - what is the evidence?

Valproic acid (VPA) is a broad-spectrum antiepileptic drug and is usually well tolerated, but rare serious complications may occur in some patients receiving VPA chronically, including haemorrhagic pancreatitis, bone marrow suppression, VPA-induced hepatotoxicity (VHT) and VPA-induced hyperammonaemic encephalopathy (VHE). Some data suggest that VHT and VHE may be promoted by carnitine deficiency. Acute VPA intoxication also occurs as a consequence of intentional or accidental overdose and its incidence is increasing, because of use of VPA in psychiatric disorders. Although it usually results in mild central nervous system depression, serious toxicity and even fatal cases have been reported. Several studies or isolated clinical observations have suggested the potential value of oral L-carnitine in reversing carnitine deficiency or preventing its development as well as some adverse effects due to VPA. Carnitine supplementation during VPA therapy in high-risk patients is now recommended by some scientific committees and textbooks, especially paediatricians. L-carnitine therapy could also be valuable in those patients who develop VHT or VHE. A few isolated observations also suggest that L-carnitine may be useful in patients with coma or in preventing hepatic dysfunction after acute VPA overdose. However, these issues deserve further investigation in controlled, randomized and probably multicentre trials to evaluate the clinical value and the appropriate dosage of L-carnitine in each of these conditions.

Sodium valproate -- induced skeletal myopathy.

The authors report a case of skeletal myopathy in a four-year-old boy on long-term sodium valproate therapy for secondary epilepsy due to neurocysticercosis. He presented with clinical features of limb girdle weakness. EMG revealed features of myopathy. Carnitine deficiency due to sodium valproate was suspected and plasma carnitine levels were found to be low. Sodium valproate was withdrawn. L-carnitine supplementation resulted in marked clinical recovery as well as rise in plasma carnitine levels.

Slow replenishment of carnitine deficiency after cessation of long-term treatment with pivaloyl-containing antibiotics.

Long-term treatment with pivampicillin and pivmecillinam for 6-24 months in five adults and one child reduced the total serum carnitine concentration to 3.7-14 mumol/l (reference value: 25-66 mumol/l). Muscle carnitine was reduced to 0.3-0.7 mumol/g wet weight (reference value: 3-5 mumol/g) in two cases. All patients had muscle symptoms with weakness, asthenia and pains. One showed signs of carnitine depletion in the liver with increased secretion of dicarboxylic acids (C6, C8, C10) in urine and limited ketone body formation during prolonged fasting. Serum carnitine increased slowly after cessation of therapy and reached normal concentrations after 6-12 months. All symptoms caused by carnitine depletion disappeared. This was achieved on a normal diet without carnitine supplementation.

[Drugs and vitamins]. / Arzneimittel und Vitaminversorgung.

Since most of the drugs are taken orally via the gastrointestinal tract, interactions with food ingredients may lead to alterations in the intake of essential dietary factors. With regard to vitamins the following effects have been demonstrated: early decomposition resp. inactivation, decreased absorption or a qualitatively and quantitatively modified metabolism. Examples of such changes are given with regard to water- and lipid-soluble vitamins.

Significance of vitamins in cancer.

The relationship of vitamins to cancer is very complex. Three types of interactions are possible: the effect of vitamins on tumor growth, the effect of tumors on vitamin metabolism, and the effect of vitamins on chemical carcinogens and anti-tumor chemotherapeutic agents. The significance of vitamins with particular references to vitamins A,B-complex and C, in cancer has been reviewed.