Esther Granot

Plasma triglyceride determines structure-composition in low and high density lipoproteins.

Because the association of hypertriglyceridemia and premature atherosclerosis is not due to the direct effects of the triglyceride molecule itself, we studied the effects of increased plasma triglyceride-rich lipoproteins on the composition and structure of low density lipoprotein (LDL) and high density lipoprotein (HDL). We found profound changes in the core and surface domains of both lipoproteins with increasing triglyceridemia. Core cholesterol esters were progressively depleted and replaced by triglyceride molecules. Highly significant negative correlations were found between cholesterol ester/protein ratios (r = -0.64 for LDL and -0.58 for HDL (p less than 0.001); positive correlations were found for triglyceride/protein ratios (r = 0.62 for LDL and 0.58 for HDL) and for triglyceride/cholesterol ester ratios (r = 0.70 for LDL and 0.83 for HDL) when these variables were assayed as a function of plasma triglyceride concentrations. With severe hypertriglyceridemia, triglyceride/cholesterol ester ratios of more than 1.0 were consistently observed (normal, less than 0.02). This leads to an underestimation of LDL and HDL levels when cholesterol alone is measured. At the surface, LDL and HDL were depleted of phospholipid and free cholesterol, with a relative enrichment of protein. These changes can be explained on the basis of high levels of plasma triglyceride-rich lipoproteins serving as acceptors for cholesterol esters and other constituents from LDL and HDL. Concomitantly, triglycerides are transferred to LDL and HDL. These transfer processes are likely to be mediated by the activity of lipid transfer proteins present in human plasma.

Long-term assessment of combined vitamin A and E treatment for the prevention of retinal degeneration in abetalipoproteinaemia and hypobetalipo-proteinaemia patients

Purpose To assess the long-term efficacy of combined vitamin A and E treatment in preventing retinal degeneration in patients with abetalipoproteinaemia (ABL) or homozygous hypobetalipoproteinaemia (HBL).Methods Ten patients with ABL and 3 with homozygous HBL who were treated with oral supplements of vitamins A and E were studied. Systemic, ophthalmological and electroretinographic follow-up for a mean of 11.7 years (range 4-20 years) after onset of treatment was evaluated.Results Despite vitamin A and E treatment, 7 of 10 patients who began treatment prior to 2 years of age and all 3 patients who began treatment later in life manifested unusual fundoscopic pigmentary changes over time. At the end of follow-up, 11 of 13 patients had subnormal mixed cone-rod electroretinogram amplitudes. Seven of 10 patients for whom perimetry was available had mild to severe constriction of the visual fields.Conclusions Combined oral vitamin A and E supplementation that is initiated prior to 2 years of age can markedly attenuate the severe retinal degeneration that is associated with untreated ABL or homozygous HBL. Yet, fundoscopic and functional retinal changes do occur despite early initiation of vitamin treatment. Therefore, the adequacy of the present treatment protocol for ABL and homozygous HBL should be re-evaluated.

Tacrolimus immunosuppression - : An association with asymptomatic eosinophilia and elevated total and specific IgE levels

Abstract:  De novo development of food allergy is an infrequent but potentially serious complication of transplantation. An increased prevalence of food allergy noted specifically in children receiving tacrolimus immunosuppression supports the hypothesis that selective suppression of Th1 lymphocytes by the IL‐2 inhibitor immunosuppressants CsA, and the more potent drug, tacrolimus , promotes Th2 lymphocytes and an allergic immune response. This study was undertaken to characterize the IgE‐mediated immune response, in CsA and tacrolimus‐treated, post‐OLT children. Thirty children and adolescents aged 1.9–21 yr, mean: 10.6 yr, (6.4 yr post‐tx.) were studied. Immunosuppression‐CsA: 10 patients, tacrolimus; 20 patients. Blood eosinophils, total IgE levels and specific IgE antibodies (Immulite 2000 Allergy; Diagnostic Products Corp., Los Angeles, CA, USA) to a panel of food and inhaled allergens were measured and correlated with clinical symptoms of allergy. Eosinophilia (>500/mm3) range: 599–3125, mean: 1294, was present in 10/20 of patients treated with tacrolimus and 1/10 treated with CsA. IgE levels were elevated in eight of these 10 tacrolimus‐treated patients and in two CsA patients ; five were <3 yr of age and IgE levels ranged from 54 to 111 IU/mL (mean: 83), normal for age <45 IU/mL and five were ≥9 yr and IgE levels ranged from 134 to 1606 IU/mL (mean: 557), normal for age <87 IU/mL. Specific IgE levels to a wide panel of food allergens were positive in five tacrolimus‐treated patients and to both food and inhaled allergens in three patients (two tacrolimus‐treated, one CsA). Four children (tacrolimus‐treated) had symptoms of food allergy . None had a family history of allergy. Eosinophilia is present in up to 50% of children and adolescents receiving tacrolimus immunosuppression. The majority of these patients also have elevated levels of total and specific (mainly to food allergens) IgE antibodies. Most patients are asymptomatic and do not manifest food allergy or asthma.

Neutral lipid transfer protein does not regulate α-tocopherol transfer between human plasma lipoproteins

Vitamin E has no known plasma carrier protein and is transported by plasma lipoproteins. The site of association of vitamin E in the lipoprotein particle and the mode of transfer of vitamin E between plasma lipoproteins have not been ascertained. Since neutral lipids (triglycerides and cholesterol esters) exchange between plasma lipoproteins by processes mediated by neutral lipid transfer protein, we questioned that if vitamin E, a hydrophobic molecule, is carried in the core of the lipoprotein particle then its transfer between plasma lipoproteins may be mediated by neutral lipid transfer protein. Transfer of D-α(5-methyl-3H)tocopherol from in vitro-labeled human plasma lipoprotein fractions to other plasma lipoproteins was measured under incubation conditions that were designed to yield markedly differing degrees of neutral lipid exchange. Despite the presence of the d>1.21 g/ml lipoprotein-poor plasma fraction or purified lipid transfer protein that resulted in up to a 10-fold increase in neutral lipid transfer, vitamin E transfer between very low density lipoproteins, low density and high density lipoproteins remained constant. Even excess amounts of lipid transfer protein, which caused triglyceride transfer between very low density and high density lipoproteins to reach saturation, failed to affect significantly vitamin E transfer. Vitamin E distribution between lipoprotein fractions did correlate with lipoprotein mass ratios. Vitamin E transfer was higher as the protein ratio of acceptor lipoproteins to donor lipoproteins increased. We conclude that vitamin E transfer between lipoproteins is not dependent primarily on neutral lipid transfer protein and is not mediated via neutral lipid transfer.

An association between Helicobacter pylori infection and serum vitamin B12 levels in healthy adults.

Goals To determine whether serum vitamin B12 levels in non-vitamin B12 deficient healthy adults correlate with serological evidence of H. pylori infection. Background An association between H. pylori infection and vitamin B12 deficiency has been recently reported. Study 133 adults, presenting to a community based primary care clinic who met the following exclusion criteria; history of H. pylori eradication or antacid use, liver disease, inflammatory bowel disease, previous gastrointestinal surgery, a vegetarian diet or multivitamin supplementation were studied. Blood was drawn for a complete blood count, serum vitamin B12, gastrin, folic acid and H. pylori IgG antibodies. Subjects with vitamin B12 ≤ 145 ng/mL (deficient range) were excluded. Results Of 133 subjects 96 (72.2%) were seropositive for H. pylori IgG antibodies (HP+). Age of HP(+) subjects did not differ from that of seronegative subjects (HP−); 52.8 ± 1.6 mean ± SE versus 49.2 ± 2.9 (p = NS). Prevalence of HP seropositivity was significantly higher among subjects with borderline (>145–180 pg/mL) or low normal (>180–250 pg/mL) vitamin B12 levels than among those with vitamin B12 >250 pg/mL; among 25 subjects with vitamin B12 >145–180 pg/mL 92% were seropositive and among 47 subjects with vitamin B12 >180–250 pg/mL 89% were seropositive as compared with 31/61 (51%) of subjects with B12 >250 pg/mL, Fisher exact test p < 0.0001. Vitamin B12 levels did not correlate with age (r = −0.07). Gastrin levels (pg/mL) did not differ significantly between groups; 70.2 ± 5.8 in HP(+) versus 56.0 ± 12.4 in HP(−). Conclusions The higher prevalence of H. pylori infection among subjects with serum vitamin B12 levels that are within the lower end of the normal range suggests a causal relationship between H. pylori infection and vitamin B12 levels in healthy adults.

Histological comparison of suction capsule and endoscopic small intestinal mucosal biopsies in children

Small intestinal biopsies are part of the routine evaluation of children with chronic diarrhea and malabsorption, and are commonly performed via suction capsule. Because this technique entails x-ray exposure, longer procedure time, and technical failures, most small intestinal biopsies in adults are currently obtained via endoscopy. Endoscopy is believed to yield morphologically inferior specimens, and, therefore, its use for obtaining small intestinal biopsies in children has remained limited. The histological adequacy of biopsy specimens obtained in 30 children by endoscopy and in 30 children by suction capsule was compared. Biopsies were assessed for quality of orientation, size (length and depth), presence of Brunners glands and crush artifact, and for the ability to confirm or exclude a mucosal abnormality. Small intestinal biopsies obtained via endoscopy were shown to yield tissue specimens that are histologically comparable to those obtained by suction capsule, and that are equally suitable for interpretation.

OXIDATIVE STRESS IN HEALTHY BREAST FED VERSUS FORMULA FED INFANTS

Abstract Polyunsaturated fatty acids (PUFA), major substrates for lipid peroxidation, have been associated with enhanced oxidative injury. Infants fed solely on breast milk (BM) and infants fed cows milk modified formulas (F), differ in amount and composition of dietary fatty acids (FA). A major difference relates to breast milks content of long chain PUFA [C 20–22] which are highly susceptible to peroxidation. In healthy infants, 13 on BM and 13 on F, plasma lipid peroxidation products were determined using TBARs method and plasma antioxidant capacity evaluated by cyclic voltammetry (CV). Mean age, weight [expressed as % of 50th percentile for age] and hemoglobin levels did not differ between the two groups. Results of the TBARs assay were expressed as malondialdehyde equivalent content nmol MDA/ml plasma: in BM-fed infants 5.87±0.56 (mean ± s. error) vs. 2.34±0.11 in F-fed infants (p

Cardiac function in children post-orthotopic liver transplantation: Echocardiographic parameters and biochemical markers of subclinical cardiovascular damage

Abstract:  Tacrolimus and cyclosporin A (CsA), the mainstay of preventive therapy for solid organ rejection, may cause various side‐effects, such as hypertension and nephrotoxicity. Furthermore, tacrolimus is associated with cardiac hypertrophy. In the immediate post‐transplant period, both drugs raise the levels of Endothelin‐1 (ET), a potent vasoconstrictor; and of B‐type Natriuretic Peptide (BNP), a sensitive marker of left ventricular volume overload, which may precede echocardiographic changes of cardiac dysfunction. The aim of the study was to investigate the presence of cardiac damage, by echocardiography and by the biochemical markers BNP and ET, in post‐orthotopic liver transplantation (OLT) children, receiving long‐term immunosuppressive therapy. ET (ELISA) and BNP (RIA) were measured in plasma of 18 children, post‐OLT and 18 healthy controls. Children post‐OLT were echocardiographically assessed for left ventricular mass (interventricular septum and posterior wall dimensions), systolic function (ejection fraction, fractional shortening) and diastolic parameters (mitral valve E and A waves, deceleration time, isovolumic relaxation time). None of the post‐transplant recipients had a history or physical examination consistent with cardiac disease and all recipients were normotensive. Echocardiography revealed no systolic or diastolic dysfunction in any of the recipients. The mean ET and BNP levels tended to be higher among children post‐liver transplant, compared with healthy controls (ET: 4.22 ± 5.35 pg/mL vs. 2.1 ± 2.0 pg/mL; BNP: 7.05 ± 4.4 pg/mL vs. 5.87 ± 2.0 pg/mL, respectively, mean ± s.d.) although differences did not reach statistical significance. Three children (17%) had elevated BNP and/or ET levels. A strong correlation was observed between ET and BNP levels in post‐OLT children (r = 0.79, p ≤  0.05). No correlation was found between ET or BNP levels and echocardiographic findings. In children receiving long‐term immunosuppressive therapy post‐OLT, although cardiac function is grossly preserved, ET and BNP levels tend to be higher than in healthy, age‐matched children. Thus, elevated levels of BNP and/or ET may identify patients with early cardiac damage.

Helicobacter pylori infection in young children detected by a monoclonal stool antigen immunoassay.

The prevalence of Helicobacter pylori infection in young children attending day care facilities was studied using a monoclonal stool antigen test. Of 316 samples, 78 (24.7%) were positive. Only 7/98 (7.1%) of the 3- to 12-month-old infants tested positive compared with 71/218 (32.5%) of the 13- to 60-month-old group. We conclude that approximately 30% of infants may become infected with H. pylori after the first year of life.

Cell adhesion molecules and hyaluronic acid as markers of inflammation, fibrosis and response to antiviral therapy in chronic hepatitis C patients

OBJECTIVE: Cell adhesion molecules (intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1)) and hyaluronic acid, markers of inflammation and fibrosis were monitored in hepatitis C patients to determine whether changes in plasma levels, during antiviral treatment, can predict long-term response to therapy. METHODS: In 55 patients with chronic hepatitis C virus (HCV), 33 treated with interferon (IFN) and 22 treated with IFN + ribavirin, sera was collected prior to treatment, at 3 + 6 months of therapy and 6 months post-treatment. Levels of ICAM-1, VCAM-1 and hyaluronic acid were correlated with alanine aminotransferase levels, HCV-RNA-polymerase chain reaction status and histological fibrosis scoring. RESULTS: A decrease in ICAM-1 levels at 3 and 6 months of therapy, compared with pretreatment levels, was observed in responders to IFN + ribavirin therapy but this decrease in ICAM-1 levels was not evident following cessation of treatment. Hyaluronic acid levels, in both treatment groups, did not differ significantly between responders and non-responders. Hyaluronic acid levels did correlate, significantly, with degree of fibrosis whereas VCAM-1 levels were marginally increased only in patients with moderate (grade III) fibrosis. CONCLUSIONS: Monitoring of VCAM-1 and hyaluronic acid, during antiviral therapy, does not differentiate between responders and non-responders. A decrease in ICAM-1 levels during IFN + ribavirin treatment is associated with response to therapy, and its efficacy in predicting long-term response should be further substantiated.