Data are summarized about digestion and absorption of carbohydrates, lipids and proteins during mammalian perinatal development including human fetuses. Corresponding with the high fat intake in suckling rats, absorption of triglycerides was found to be approximately 2-3 times higher in suckling than in adult rats. Carnitine contents of the small intestinal mucosa of rats decrease postnatally, reaching adult levels at the time of weaning. Other studies suggested that gluconeogenesis may occur in the small intestine in the neonatal period. The intestinal mucosa of infant rats produces ketones; it was suggested that ketone production is to a large extent due to a breakdown of long-chain fatty acids. Studies dealing with the development of colonic sodium transport in rats are described. Other studies on the developing colon showed that the proximal colon resembles ileum during the early postnatal period. Developmental changes of the "specialization" of intestinal segments are reviewed. In all studies attention is given to the maturative effects of hormones of the adrenal cortex and thyroid gland (88 references).
It was confirmed that the main source of energy for growth and development in the neonatal period was fat. Considerable attention was paid to the development of both white adipose tissue (WAT) and brown adipose tissue (BAT) in the rat and human newborn. Cholesterol metabolism during development was studied in the liver, the small intestine and both WAT and BAT. Brown adipose tissue of rats and adipose tissue from human newborns require carnitine for optimum respiration and fatty acid oxidation. Surprisingly, carnitine enhanced lipolysis in human newborn adipose tissue, Intravenously-fed newborn patients exhibited a rapid decrease of plasma level of carnitine and its esters, indicating a greater requirement for exogenous carnitine than in adult subjects (52 references)
The objective of the study was to assess the association between plasma levels of lipoprotein(a) [Lp(a)] and the presence of angiographically defined coronary artery disease (aCAD). Patients (346 men and 184 women) undergoing selective coronary angiography (SCA) were classified into groups with positive [aCAD(+)] and negative [aCAD(–)] findings and their age, body mass index (BMI), waist circumference, blood pressure, smoking, plasma total, LDL-, HDL-cholesterol (TC, LDL-C, HDL-C), triglycerides (TG), apolipoprotein B (apoB), Log(TG/HDL-C) and TC/HDL-C were determined. Concentration of plasma Lp(a) was estimated using the commercial solid phase two-side immunoradiometric assay of apolipoprotein apo(a). The plasma Lp(a) was significantly higher in both women and men with aCAD(+) compared to those with aCAD(–). While there was no significant difference in the Lp(a) level between men and women with aCAD(–) (median 138 vs. 145 units/l), the women with aCAD(+) had almost twice as high Lp(a) levels as men (median 442 vs. 274 units/l, p<0.001). Women with aCAD(+) had also significantly lower HDL cholesterol levels (1.09 vs. 1.20 mmol/l, p<0.05), higher triglycerides (1.82 vs. 1.46 mmol/l, p<0.05) and Log(TG/HDL-C) than women with aCAD(–). The differences in Lp(a) between positive and negative findings remained highly significant (p<0.001 in women, p<0.05 in men) after the adjustment for age, plasma HDL- and LDL-cholesterol and triglycerides in logistic regression analyses. In logistic regression model the Lp(a) and Log(TG/HDL-C) and smoking in women but smoking and age in men were the most powerful predictors of positive aCAD findings. Our findings suggest that Lp(a) is more strongly associated with aCAD+ in women than in men.
The distribution of differently sized HDL particles in the plasma can be assessed by measurement of the fractional rate of cholesterol esterification (FERhdl). We have characterized the isotopic assay and compared it to the enzymatic measurement of the decrease in HDL free cholesterol (mass assay). The normal values of FERhdl were established in 116 apparently healthy individuals. The isotopic assay is particularly sensitive to changes in the incubation temperature above 37 °C. The reproducibility of the assay in aliquots of plasma stored at -20 °C and -70 °C for 3 months and even up to 2 years was high. Intraindividual variability of FERhdl is low. In the subjects in whom FERhdl was measured over a 3-month and 2-5 years’ period, FERhdl showed a low variability (97.5±2.6 % and 101+6.0 % respectively in a paired t-test). Comparison of the isotopic assay and the mass assay revealed that the isotopic assay was much more reproducible. Normal values of FERhdl and the HDL subspecies distribution (using gradient gel electrophoresis) were established in 63 men and 56 women. The average values of FERhdl were significantly higher in men (16.8±4.5 %/h) than in women (10.6±3.6 %/h) and correlated well with the distribution of the HDL subspecies. FERhdl radioassay as a highly reproducible method for the assessment of HDL subspecies distribution which may be suitable for both retrospective and prospective studies of diseases of atherogenous origin.
Particle size of low density (LDL) and high density (HDL) lipoproteins and cholesterol esterification rate in HDL plasma (FERHDL) are important independent predictors of coronary artery diseases (CAD). In this study we assessed the interrelations between these indicators and routinely examined plasma lipid parameters and plasma glucose concentrations. In 141 men, healthy volunteers, we examined plasma total cholesterol (TC), triglycerides (TG), HDL and LDL cholesterol (HDL-C, LDL-C) an
d HDL unesterified cholesterol (HDL-UC). Particle size distribution in HDL
and LDL was assessed by gradient gel electrophoresis and FERHDL was estimated by radioassay. An effect of particle size and FERHDL on atherogenic indexes as the Log(TG/HDL-C) and TC/HDL-C was evaluated. Subjects in the study had plasma concentrations (mean ± S.D.) of TC 5.2±0.9
mmol/l, HDL-C 1.2±0.3 mmol/l, TG 2.1±1.7 mmol/l, glucose 5±0.8 mmol/l. Relative concentration of HDL2b was 17.6±11.5 % and 14.6±11.8 % of HDL
3b,c. The mean diameter of LDL particles was 25.8±1.5 nm. The increase in FERHDL significantly correlated with the decrease in HDL2b and LDL
particle size (r = –0.537 and –0.583, respectively, P<0.01) and
the increase in HDL3b,c (0.473, P<0.01). Strong interrelations among TG and HDL-C or HDL-UC and FERHDL and particle size were found, but TC or LDL-C did not have such an effect. Atherogenic indexes Log(TG/HDL-C) and TC/HDL-C correlated with FERHDL (0.827 and 0.750, respectively, P<0.0001) and with HDL and LDL particle size.
Traditionally, lecithinxholesterol acyltransferase (LCAT) role in the reverse cholesterol transport (RCT) has been considered "antiatherogenic" as the cholesterol esterification is the prerequisite for the formation of mature high density lipoprotein (HDL) particles and may create a gradient necessary for the flow of unesterified cholesterol (UC) from tissues to plasma. However, newer data suggest that a higher esterification rate is not necessarily protective. Here we review the available data on the role of LCAT in RCT and propose that the LCAT-mediated esterification of plasma cholesterol promotes RCT only in the presence of sufficient concentrations of HDL2 while this reaction may be atherogenic in the presence of high concentration of plasma low density lipoprotein (LDL) cholesteroL Thus, the "protective" or potentially "atherogenic" role of LCAT depends on the quality of HDL and concentration of LDL. This hypothesis is consistent with the known high predictive value of LDL/HDL cholesterol ratio.