A short-term increase in dietary cholesterol and fat intake affects high-density lipoprotein composition in healthy subjects.

BACKGROUND AND AIMS: High-cholesterol and high-fat diets alter biochemical composition and anti-oxidant properties of high-density lipoproteins (HDL) in animals. Whether this occurs in humans is unknown. Therefore, we examined the effect of a short-term elevation in dietary cholesterol and fat intake on HDL composition in healthy subjects. METHODS AND RESULTS: In a randomized, crossover clinical trial, 14 healthy young volunteers followed a 14-day low-cholesterol/low-fat diet (LChF) and a 14-day isocaloric high-cholesterol/high-fat diet (HChF) in a random order. After each diet, we measured HDL concentrations of hydroxyeicosatetraenoic acids (HETE), hydroxyoctadecadienoic acids (HODE), and haptoglobin, as well as serum amyloid A (SAA) and paroxonase-1 activity (PON-1). HDL concentrations of 15-HETE (+254%, p = 0.002), 5-HETE (+116%, p = 0.004), 13-HODE (+102%, p = 0.049), and SAA levels (+75%, p = 0.007) were significantly higher after the HChF than after the LChF. Furthermore, haptoglobin was marginally increased (+32%, p = 0.091) while PON-1 activity was unaffected (-16%, p = 0.366) by the HChF. CONCLUSION: In healthy subjects, a short-term elevation in dietary cholesterol and fat intake increases HDL lipid hydroperoxide content (15-HETE, 5-HETE, 13-HODE) and SAA levels, which are key features of dysfunctional HDL. This is the first study showing that a physiologic manipulation of dietary cholesterol and fat intake affects HDL lipidome and proteome in healthy subjects independently of weight changes. CLINICAL TRIAL REGISTRATION: NCT02549144.

[Plasma levels of homocysteine in patients on hemodiafiltration]. / Livelli plasmatici di omocisteina in pazienti in emodiafiltrazione.

BACKGROUND: Hyperhomocysteinemia is an independent risk factor for cardiovascular diseases, and is a common finding in patients on regular dialysis treatment. Hemodialysis lowers homocysteine plasma levels in variable amounts, and it was also suggested that folic acid and vitamin B12 supplements can reduce such levels. The purpose of the present study was to evaluate homocysteine plasma levels in patients on hemodiafiltration who received vit. B12 and folate supplements such as to keep their plasma levels in the normal range. METHODS: A retrospective study was carried out in a group of 36 patients on hemodiafiltration, who received routinely folate and vit. B12 supplements i.v. Pre-dialysis plasma levels of folate and vit. B12 and pre-postdialysis homocysteine concentration were evaluated. The latter was correlated with other parameters. RESULTS: The present study confirmed high homocysteine levels in patients on RDT and their reduction due to dialysis, demonstrated a weak negative correlation of pre-dialysis homocysteine with vit. B12 plasma level, but no correlation with folic acid. CONCLUSIONS: This study showed a good efficiency of hemodiafiltration using high permeability membranes on homocysteine removal, whereas the negative correlation between folate and homocysteine plasma level was not confirmed.

[C-reactive protein and homocysteinemia in patients undergoing on-line hemodiafiltration]. / Proteina C-reattiva e omocisteinemia in emodiafiltrazione on-line.

PURPOSE: In renal disease therapy (RDT) patients, high plasma homocysteine (tHcy) is common and high C-reactive protein(CRP) levels can be observed, attributed to the inflammatory process caused by the dialysis itself. Hyperhomocysteinemia and bioincompatibility are considered independent vascular risk factors. This study evaluated the behavior of these parameters in patients undergoing on-line hemodiafiltration (OL-HDF). METHODS: In 56 patients, HDF was performed using high permeability polyamide membranes, exchanging in the post-dilution mode 16-18 L/session of a reinfusate obtained by the on-line system (triple filtration AK200, Gambro). CRP was measured by an immunological method at the start and the end of the session in patients without comorbidities (group 1, n=30)and with inflammatory diseases (group 2, n=26). In 23 of the 56 patients, tHCY was measured (by high performance liquid chromatography (HPLC)) before and after the mid-week session on different schedule of folinic acid, vitamin B12 and vitamin B6. RESULTS: Pre-dialytic CRP was in the normal range in group 1 patients, whereas it was higher in group 2 patients; dialysis did not induce a significant change in either group. The intradialytic percentage tHcy decrease was approximately 50% regardless of the pre-dialytic value, which was significantly different according to the vitamin supplements administered. CONCLUSIONS: HDF, as performed in this study, demonstrated biocompatibility and efficient Hcy removal; therefore, it can prevent cardiovascular disease (CVD) in patients on regular extracorporeal dialysis.

Prolactin secretion in polycystic ovary syndrome: circadian rhythmicity and dynamic aspects.

The circadian rhythms of plasma prolactin (PRL) and cortisol and of oral temperature were simultaneously studied in 24 women with polycystic ovary syndrome (PCOS). The PRL response to thyrotropin-releasing hormone (TRH) and domperidone was also evaluated in some of these patients. The physiological circadian chrono-organization of prolactin and cortisol secretion and of oral temperature was maintained in PCOS. The PRL responsiveness to the specific stimulations fell within normal limits. These results do not support the hypothesis of an impaired central dopaminergic regulation of prolactin secretion in PCOS.