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α -Lactalbumin, an abundant protein present in the milk of most mammals, is associated with biological, nutritional and technological functionality. Its sequence presents N-glycosylation motifs, the occupancy of which is species-specific, ranging from no to full occupancy. Here, we investigated the N-glycosylation of bovine α-lactalbumin in colostrum and milk sampled from four individual cows, each at 9 time points starting from the day of calving up to 28.0 d post-partum. Using a glycopeptide-centric mass spectrometry-based glycoproteomics approach, we identified N-glycosylation at both Asn residues found in the canonical Asn-Xxx-Ser/Thr motif, i.e. Asn45 and Asn74 of the secreted protein. We found similar glycan profiles in all four cows, with partial site occupancies, averaging at 35% and 4% for Asn45 and Asn74, respectively. No substantial changes in occupancy occurred over lactation at either site. Fucosylation, sialylation, primarily with N-acetylneuraminic acid (Neu5Ac), and a high ratio of N,N'-diacetyllactosamine (LacdiNAc)/N-acetyllactosamine (LacNAc) motifs were characteristic features of the identified N-glycans. While no substantial changes occurred in site occupancy at either site during lactation, the glycoproteoform (i.e. glycosylated form of the protein) profile revealed dynamic changes; the maturation of the α-lactalbumin glycoproteoform repertoire from colostrum to mature milk was marked by substantial increases in neutral glycans and the number of LacNAc motifs per glycan, at the expense of LacdiNAc motifs. While the implications of α-lactalbumin N-glycosylation on functionality are still unclear, we speculate that N-glycosylation at Asn74 results in a structurally and functionally different protein, due to competition with the formation of its two intra-molecular disulphide bridges., (© The Author(s) 2024. Published by Oxford University Press.)

Immunoglobulins M (IgM) are key natural antibodies produced initially in humoral immune response. Due to their large molecular weights and extensive glycosylation loads, IgMs represent a challenging target for conventional mass analysis. Charge detection mass spectrometry (CDMS) may provide a unique approach to tackle heterogeneous IgM assemblies, although this technique can be quite laborious and technically challenging. Here, we describe the use of online size exclusion chromatography (SEC) to automate buffer exchange and sample introduction, and demonstrate its adaptability with Orbitrap-based CDMS. We discuss optimal experimental parameters for online SEC-CDMS experiments, including ion activation, choice of column, and resolution. Using this approach, CDMS histograms containing hundreds of individual ion signals can be obtained in as little as 5 min from single injections of <1 μg of sample. To demonstrate the unique utility of online SEC-CDMS, we performed real-time kinetic monitoring of pentameric IgM digestion by the protease IgMBRAZOR, which cleaves specifically in the hinge region of IgM. Several digestion intermediates corresponding to processive losses of F(ab') 2 subunits could be mass-resolved and identified by SEC-CDMS. Interestingly, we find that for the J-chain linked IgM pentamer, cleavage of one of the F(ab') 2 subunits is much slower than the other four F(ab') 2 subunits, which we attribute to the symmetry-breaking interactions of the J-chain within the pentameric IgM structure. The online SEC-CDMS methodologies described here open new avenues into the higher throughput automated analysis of heterogeneous, high-mass protein assemblies by CDMS.

We monitored longitudinal changes in bovine milk IgG in samples from four cows at 9 time points in between 0.5 and 28 days following calving. We used peptide-centric LC-MS/MS on proteolytic digests of whole bovine milk, resulting in the combined identification of 212 individual bovine milk protein sequences, with IgG making up >50 percent of the protein content of every 0.5 d colostrum sample, which reduced to ≤3 percent in mature milk. In parallel, we analyzed IgG captured from the bovine milk samples to characterize its N-glycosylation, using dedicated methods for bottom-up glycoproteomics employing product ion-triggered hybrid fragmentation; data are available via ProteomeXchange with identifier PXD037755. The bovine milk IgG N-glycosylation profile was revealed to be very heterogeneous, consisting of >40 glycoforms. Furthermore, these N-glycosylation profiles changed substantially over the period of lactation, but consistently across the four individual cows. We identified NeuAc sialylation as the key abundant characteristic of bovine colostrum IgG, significantly decreasing in the first days of lactation, and barely detectable in mature bovine milk IgG. We also report, for the first time to our knowledge, the identification of subtype IgG3 in bovine milk, alongside the better-documented IgG1 and IgG2. The detailed molecular characteristics we describe of the bovine milk IgG, and their dynamic changes during lactation, are important not only for the fundamental understanding of the calf's immune development, but also for understanding bovine milk and its bioactive components in the context of human nutrition., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Human milk is a vital biofluid containing a myriad of molecular components to ensure an infant's best start at a healthy life. One key component of human milk is β-casein, a protein which is not only a structural constituent of casein micelles but also a source of bioactive, often antimicrobial, peptides contributing to milk's endogenous peptidome. Importantly, post-translational modifications (PTMs) like phosphorylation and glycosylation typically affect the function of proteins and peptides; however, here our understanding of β-casein is critically limited. To uncover the scope of proteoforms and endogenous peptidoforms we utilized mass spectrometry (LC-MS/MS) to achieve in-depth longitudinal profiling of β-casein from human milk, studying two donors across 16 weeks of lactation. We not only observed changes in β-casein's known protein and endogenous peptide phosphorylation, but also in previously unexplored O -glycosylation. This newly discovered PTM of β-casein may be important as it resides on known β-casein-derived antimicrobial peptide sequences.

The objectives of this study were to evaluate the growth and survival of the model probiotic strain Lactobacillus plantarum WCFS1 in co-culture with traditional yoghurt starters and to investigate the impact of preculturing on their survival and metabolite formation in set-yoghurt. L. plantarum WCFS1 was precultured under sublethal stress conditions (combinations of elevated NaCl and low pH) in a batch fermentor before inoculation in milk. Adaptive responses of L. plantarum WCFS1 were evaluated by monitoring bacterial population dynamics, milk acidification and changes in volatile and non-volatile metabolite profiles of set-yoghurt. The results demonstrated that sublethal preculturing did not significantly affect survival of L. plantarum WCFS1. On the other hand, incorporation of sublethally precultured L. plantarum WCFS1 significantly impaired the survival of Lactobacillus delbrueckii subsp. bulgaricus which consequently reduced the post-acidification of yoghurt during refrigerated storage. A complementary metabolomics approach using headspace SPME-GC/MS and (1)H NMR combined with multivariate statistical analysis revealed substantial impact of sublethally precultured L. plantarum WCFS1 on the metabolite profiles of set-yoghurt. This study provides insight in the technological implications of non-dairy model probiotic strain L. plantarum WCFS1, such as its good stability in fermented milk and the inhibitory effect on post-acidification., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Lactose is the main carbohydrate in the milk of most species. It is present in virtually all dry dairy ingredients, with levels ranging from <2% (e.g., caseinates, milk protein isolates) to 100% in lactose powders. The presence of lactose has a strong effect on ingredient processing and stability. Lactose can negatively influence powder properties and lead to undesirable effects, such as the stickiness of powder resulting in fouling during drying, or caking and related phenomena during storage. In addition, being a reducing carbohydrate, lactose can also participate in the Maillard reaction with free amino groups of proteins, peptides, and free AA. In this review, the influence of the presence (or absence) of lactose on physiochemical properties of dairy ingredients is reviewed, with particular emphasis on behavior during processing and storage. Particularly important features in this respect are whether lactose is in the (glassy) amorphous phase or in the crystalline phase, which is strongly affected by precrystallization conditions (e.g., in lactose, permeate, and whey powders) and by drying conditions. Furthermore, the moisture content and water activity of the ingredients are important parameters to consider, as they determine both mobility and reactivity, influencing Maillard reactions and concomitant browning, the crystallization of amorphous lactose during storage of dairy ingredients, glass transitions temperatures, and associated stickiness and caking phenomena. For the stickiness and caking, a crucial aspect to take into account is powder particle surface composition in relation to the bulk powder. Lactose is typically underrepresented at the powder surface, as a result of which deviations between observed lactose-induced caking and stickiness temperatures, and determined glass transition temperatures arise. By considering lactose as an integral part of ingredient composition along with all other compositional and environmental properties, lactose behavior in dairy ingredients can be understood, controlled, and optimized. Routes to achieve this are outlined in this review paper., (Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Background and Aims: Visfatin is associated with atherosclerosis-related diseases. We assessed in non-diabetic individuals the association of plasma visfatin levels with cardiovascular disease (CVD) risk and the atherosclerosis-related metabolic variables., Methods and Results: When study population (n = 179, age 49 ± 11 years) was divided according to visfatin tertiles, the 10-year CVD Framingham risk scores were significantly increased in the top visfatin tertile. We observed a positive association between visfatin tertiles with waist circumference and blood pressure, as well as with total cholesterol and triglyceride levels, but not with apolipoprotein C-III, fibrinogen or pre-beta1 high density lipoprotein (HDL). The percentage of large HDL subclasses was significantly lower and the percentage of small HDL subclasses over the HDL-C concentration was significantly higher in the top visfatin tertile compared with the other tertiles. The atherogenic small dense low density lipoprotein subclasses (sdLDL-C) were significantly increased in the top visfatin tertile compared with the lower tertiles. High sensitivity C-reactive protein (hsCRP) concentration was significantly increased in the top visfatin tertile compared with the lower tertiles. Although age and sex distribution did not differ between visfatin tertiles, the simultaneous adjustment for these parameters attenuated the significance of the differences observed in sdLDL-C and hsCRP levels. Similarly, after adjustment for hsCRP or waist circumference, only triglycerides and blood pressure levels, as well as the distribution of HDL subclasses, remained significantly different between visfatin tertiles., Conclusions: Our results support a role for visfatin in the detection of subjects with many metabolic abnormalities, which result in increased CVD risk., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Introduction: Several studies implicate an inverse relationship between 25-hydroxy vitamin D (25(OH)Vit D) serum levels and metabolic syndrome (MetS). We sought to investigate a possible relationship between 25(OH)Vit D and emerging risk factors associated with MetS, such as small dense low-density lipoprotein cholesterol (sdLDL-C) concentration, lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) activity and high-sensitivity C-reactive protein (hsCRP) levels., Material and Methods: We studied 110 consecutive otherwise healthy individuals. Of these, 52 were diagnosed with MetS and 58 who did not meet the MetS criteria served as controls. Low-density lipoprotein (LDL) subclass analysis was performed by polyacrylamide gel electrophoresis. Lp-PLA(2) activity was determined in total plasma by the trichloroacetic acid precipitation procedure. Serum 25(OH)Vit D was determined quantitatively by an enzyme immunoassay method., Results: Metabolic syndrome subjects had significantly lower 25(OH)Vit D levels (11.8 [0.6-48.3] ng/ml; 29.5 [1.5-120.75] nmol/l) compared with controls (17.2 [4.8-62.4] ng/ml; 43 [12-156] nmol/l, p = 0.027). Univariate regression analysis showed that 25(OH)Vit D concentration was inversely related to triglycerides (r= - 0.416, p = 0.003) and sdLDL-C (r= - 0.305, p = 0.004). There was no association of 25(OH)Vit D with waist circumference, blood pressure, high-density lipoprotein cholesterol (HDL-C), fasting glucose, Lp-PLA(2) and hsCRP. In multivariate regression analysis the relationship between 25(OH)Vit D and sdLDL-C became insignificant when triglycerides were included in the model., Conclusions: Subjects with MetS exhibit lower 25(OH)Vit D serum levels compared with non-MetS individuals. Low 25(OH)Vit D is associated with higher sdLDL-C levels possibly through elevated triglycerides. No association between 25(OH)Vit D and Lp-PLA(2) or hsCRP was found.

Objective: To evaluate the effects of acute infection with Epstein-Barr virus (infectious mononucleosis, IM) on lipids and lipoproteins., Methods: Fasting serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TGs), apolipoproteins (apo) A-I, B, E, C-II, C-III and lipoprotein (a) [Lp(a)] were determined in patients with IM on diagnosis and 4 months after the resolution of febrile illness and in age- and sex-matched controls. Activities of cholesteryl-ester transfer protein (CETP), lipoprotein-associated phospholipase A2 (Lp-PLA2) and paraoxonase 1 (PON1) as well as levels of several cytokines were determined. LDL subclass analysis was performed with the Lipoprint LDL System., Results: Twenty-nine patients (16 males, aged 24.3±14.6 years) and 30 controls were included. TC, HDL-C, LDL-C, apoA-I, apoB, apoC-III and Lp(a) levels were lower at baseline whereas apoB/apoA-I ratio, TG levels and CETP activity were elevated compared with 4 months later. At baseline, higher levels in cytokines and the cholesterol concentration of small-dense LDL particles (sdLDL-C) were noticed, whereas LDL particle size was lower compared with follow-up. Activities of Lp-PLA2 and PON1 were similar at baseline and 4 months later. Four months after the resolution of IM levels of TGs, apoE, apoC-III, Lp(a), sdLDL-C and cytokines as well as LDL particle size, apoB/apoA-I ratio, CETP and Lp-PLA2 activities were similar to controls. PON1 activities both at baseline and 4 months later were lower in patients compared with controls., Conclusions: IM is associated with atherogenic changes of lipids and lipoproteins that are partially restored 4 months after its resolution., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Objective: Experimental studies have shown that the prebeta-1 subclass of high-density lipoprotein particles (prebeta-1 HDL) may play an important role in the reverse cholesterol transport pathway as the initial acceptors of cellular cholesterol. The aim of the present study was the direct comparison of prebeta-1 HDL values in individuals with various types of primary dyslipidemias., Methods: Four hundred and eighty-six unrelated individuals were included in the study. According to their lipid values study participants were subdivided into four groups: control group (n=206), type IIA dyslipidemia group (n=148), type IIB dyslipidemia group (n=49) and type IV dyslipidemia group (n=83)., Results: All dyslipidemic patients displayed higher concentrations of prebeta-1 HDL compared to control individuals. However, patients with dyslipidemias characterized by an abnormal catabolism of triglyceride-rich lipoproteins (such as dyslipidemias of type IIB and IV) tend to have higher prebeta-1 HDL values compared to patients with hypercholesterolemia, and this increase is proportional to the degree of hypertriglyceridemia. In addition, patients with metabolic syndrome exhibited significantly higher levels of prebeta-1 HDL compared to individuals that do not fulfill the criteria for the diagnosis of this syndrome. Multiple regression analysis revealed that serum triglyceride concentrations and body mass index (BMI) values were the most important determinants of prebeta-1 HDL levels in our population., Conclusion: All dyslipidemic patients exhibit increased prebeta-1 HDL concentrations as compared to normolipidemic individuals. Whether this increase represents a defensive mechanism against atherosclerosis or it is indicative of impaired maturation of HDL particles and thus of a defective reverse cholesterol transport mechanism remains to be established., (Copyright 2009 Elsevier Ireland Ltd. All rights reserved.)

Serum lipid changes during infection may be associated with atherogenesis. No data are available on the effect of Brucellosis on lipids. Lipid parameters were determined in 28 patients with Brucellosis on admission and 4 months following treatment and were compared with 24 matched controls. Fasting levels of total cholesterol (TC), HDL-cholesterol (HDL-C), triglycerides, apolipoproteins (Apo) A, B, E CII, and CIII, and oxidized LDL (oxLDL) were measured. Activities of serum cholesterol ester transfer protein (CETP), paraoxonase 1 (PON1), and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) and levels of cytokines [interleukins (IL)-1beta, IL-6, and tumor necrosis factor (TNFa)] were also determined. On admission, patients compared with controls had 1) lower levels of TC, HDL-C, LDL-cholesterol (LDL-C), ApoB, ApoAI, and ApoCIII and higher LDL-C/HDL-C and ApoB/ApoAI ratios; 2) higher levels of IL-1b, IL-6, and TNFa; 3) similar ApoCII and oxLDL levels and Lp-PLA(2) activity, lower PON1, and higher CETP activity; and 4) higher small dense LDL-C concentration. Four months later, increases in TC, HDL-C, LDL-C, ApoB, ApoAI, and ApoCIII levels, ApoB/ApoAI ratio, and PON1 activity were noticed compared with baseline, whereas CETP activity decreased. LDL-C/HDL-C ratio, ApoCII, and oxLDL levels, Lp-PLA(2) activity, and small dense LDL-C concentration were not altered. Brucella infection is associated with an atherogenic lipid profile that is not fully restored 4 months following treatment.

Patients with metabolic syndrome (MetS) usually have low high density lipoprotein cholesterol (HDL-C) levels. We determined the HDL distribution profile as well as the HDL-related lipoprotein associated phospholipase A(2) (HDL-LpPLA(2)) and paraoxonase-1 (PON1) activities in subjects with MetS (n = 189) but otherwise healthy. Age and sex-matched individuals (n = 166) without MetS served as controls. The lower HDL-C concentration in MetS patients was due to a reduction in both large and small HDL subclasses (P < 0.001 and P < 0.05, respectively). As the number of MetS components increased, the HDL phenotype comprised of a greater percentage of small HDL-3 and less large HDL-2 subclasses, resulting in a decreased HDL-2/HDL-3 ratio (P < 0.001 for all trends). Multivariate analysis revealed that HDL-2 levels and the HDL-2/HDL-3 ratio significantly and independently correlated with HDL-C (positively) and TG (negatively) levels. HDL-3 concentration significantly and independently positively correlated with HDL-C and TG levels. HDL-LpPLA(2) activity was decreased in MetS patients (P < 0.01), a phenomenon that may contribute to the defective antiatherogenic activity of HDL in MetS. PON1 activity did not differ between groups. We conclude that MetS, in addition to the decrease in HDL-C concentration, is associated with alterations in the HDL phenotype, which is comprised of a greater percentage of small HDL subclasses. Furthermore, HDL-LpPLA(2) activity is decreased in MetS patients.

Objective: We assessed the effect of orlistat and fenofibrate, alone or in combination, on plasma high-density lipoprotein (HDL) subfractions and plasma pre-beta1-HDL levels in overweight and obese subjects with metabolic syndrome (MetS)., Methods: Patients (n = 89) were prescribed a low-fat low-calorie diet and were randomly allocated to receive orlistat 120 mg three times daily (O group), micronized fenofibrate 200 mg/day (F group) or both (OF group) for 6 months. HDL subfractions were determined using a polyacrylamide gel tube electrophoresis method and pre-beta1-HDL levels using enzyme-linked immunoabsorbent assay., Results: We observed a significant change of high-density lipoprotein cholesterol (HDL-C) levels only in the F group (+3%, p < 0.05). Large HDL-C levels were significantly increased and small HDL-C levels were significantly reduced with O administration. In F group we observed a significant increase of small HDL-C levels. No significant change of large or small HDL-C levels was observed with combination treatment. We observed a significant increase of pre-beta1-HDL levels in all groups, which was significantly greater in OF group compared with O or F monotherapy., Conclusion: OF combination increased the antiatherogenic pre-beta1-HDL levels in overweight and obese patients with MetS. Furthermore, OF combination counterbalanced the reduction of small HDL-C levels observed with orlistat monotherapy.

Aim: To compare the Framingham and Prospective Cardiovascular Munster (PROCAM) risk calculations., Methods: We calculated the risk in 234 dyslipidaemic patients without overt vascular disease and in different subgroups. For example, the proportion of patients with coronary heart disease (CHD) risk >or= 20%, the effect of including the family history (FaHist) and of adjusting raised triglyceride (TG) levels., Results: The Framingham risk was significantly (p < 0.0001) higher than the PROCAM risk (with and without including the FaHist) in different subgroups and when the TGs were adjusted to 1.7 mmol/l. The percentage of patients with CHD risk >or= 20% calculated by the Framingham (based on systolic or diastolic blood pressure) and PROCAM equations was 21.4% or 23.1% and 16.2% respectively. In the tertile with the highest PROCAM risk, the Framingham score was significantly greater than the PROCAM risk only when the FaHist was included in the Framingham calculation. When we analysed risk by gender, the Framingham score did not differ but the PROCAM risk was significantly (p < 0.0001) greater in men. When TG values were adjusted to 1.7 mmol/l, the predicted risk using PROCAM changed by 0% to -2% in all subgroups., Conclusions: In dyslipidaemic patients without overt vascular disease the Framingham model predicted a higher risk than PROCAM. Thus, the Framingham equation probably leads to substantial overtreatment compared with PROCAM. However, according to the literature, even the PROCAM equation may overestimate risk. This has considerable cost implications. New more accurate risk engines are needed to calculate risk in dyslipidaemic patients without overt vascular disease.

Background: Increased concentration of small dense LDL cholesterol (sdLDL-C) and activity of lipoprotein-associated phospholipase A2 (Lp-PLA(2)) are considered as emerging cardiovascular risk factors and are commonly encountered in subjects with metabolic syndrome (MetS)., Objective: The primary endpoint of this study was the effect of orlistat and fenofibrate, alone or in combination, on Lp-PLA(2) activity and LDL phenotype in overweight and obese patients (body mass index>28 kg/m(2)) with MetS., Methods: Patients (n=89) were prescribed a low-fat low-calorie diet and were randomly allocated to receive orlistat 120 mg three times daily (O group), micronized fenofibrate 200mg/day (F group) or both (OF group) for 6 months., Results: Significant reductions of sdLDL-C levels were observed in all treatment groups. Groups F and OF experienced a greater reduction in sdLDL-C levels (p<0.05) together with a greater increase in LDL particle diameter (p<0.05) compared with group O. Total plasma Lp-PLA(2) activity significantly decreased in all treatment groups. The reduction of Lp-PLA(2) was more pronounced with OF administration compared with each monotherapy (p<0.05)., Conclusion: Orlistat and fenofibrate exhibited favorable effects on Lp-PLA(2) activity and LDL phenotype in overweight and obese patients with MetS. Importantly, combination treatment had a more favorable effect on these risk factors.

Background: Recent studies suggest that the distribution of lipoprotein subfractions is an independent predictor of vascular events. Therefore, we evaluated the effect of ezetimibe (a selective cholesterol transport inhibitor) on the concentrations of lipoprotein subfractions in patients with primary dyslipidaemia., Materials and Methods: Patients (n = 50) with primary dyslipidaemias were recruited. The concentrations of the individual lipoprotein subfractions were measured using the Lipoprint system at baseline and after 16 weeks of treatment., Results: Ezetimibe reduced total, low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (HDL-C) values as well as apolipoprotein B concentrations. Subfractionation of apolipoprotein B-containing lipoproteins showed that the reduction in LDL-C values was due to a fall in the concentrations of all LDL subfractions. However, a more pronounced trend towards a decrease in the concentrations of dense LDL subfractions was observed. Patients with triglyceride values >1.7 mmol/L had significantly greater reductions in the concentrations of small, dense LDL particles compared with those with normal triglyceride levels (49 vs. 19%, respectively; p < 0.05). Ezetimibe decreased the concentrations of HDL-C mainly due to a fall in the concentration of dense HDL subfractions., Conclusion: Ezetimibe can favourably affect the distribution of LDL subfractions, especially in patients with elevated triglyceride values. Further studies are needed to clarify the significance of the ezetimibe-induced reduction in the concentrations of dense HDL particles.

Recently published data suggest that the assessment of LDL subfraction profiles may contribute to the determination of the cardiovascular risk. In this study, we tested the ability of various metabolic parameters to estimate the presence or the preponderance of small, dense LDL particles (sdLDL). One hundred and fifty individuals attending the Outpatient Clinics of the University Hospital of Ioannina for suspected metabolic abnormalities were included in the study. Individuals were excluded if they were found to be diabetic or if they had a history of cardiovascular disease. Patients with thyroid dysfunction, liver or kidney diseases as well as those receiving drugs that may interfere with lipids or glucose metabolism were also excluded from the study. The ability of the various parameters to identify individuals with pattern B LDL phenotype or, alternatively, with measurable quantities of sdLDL particles was tested with the calculation of the areas under the ROC curves. The ratio of triglycerides to HDL-C was the best predictor of the presence of the pattern B LDL phenotype. Nevertheless, when the variable of interest was the presence of measurable quantities of sdLDL subfractions, the ratio of apoB to apoAI had the best predictive ability. In conclusion the ratios of apoB to apoAI and of triglycerides to HDL-C can reliably predict the presence of measurable quantities of sdLDL particles and of the pattern B LDL phenotype, respectively. However, since the quantitative determination of sdLDL concentrations may contribute to the determination of the cardiovascular risk, whereas the role of the LDL particle size remains controversial, apoB to apoAI ratio could provide more valuable information compared to markers that simply predict the presence of the pattern B LDL phenotype.

Atherosclerosis may be more prevalent and more extensive in individuals with rheumatoid arthritis (RA) compared with the general population. Despite the fact that traditional and novel cardiovascular disease (CVD) risk factors are clinically important in these patients, it seems that inflammation--a key feature of RA--plays a crucial role in atherogenesis. Reducing the CVD burden in patients with RA is a more complex process than in the general population, mostly due to inadequate inflammation suppression as well as multiple concomitant drug therapy. Furthermore, there is no current consensus on whether RA patients should be treated as individuals at high-risk for vascular events. Statins have proved their efficacy in reducing CVD events in the general population. Despite the fact that they are not specifically indicated in RA, there is evidence supporting a beneficial effect on CVD risk factors as well as disease activity and progression. The present review considers the traditional and novel as well as the RA-specific CVD risk factors. The current evidence supporting the use of statins in this patient population is also discussed.

The renoprotective effect of statins has been recently disputed because of observations of proteinuria associated with rosuvastatin treatment, the newest drug of the class. Statin-induced proteinuria findings were mainly based on crudely quantitative dipstick assays. The authors quantitatively evaluated the effect of rosuvastatin at the recommended starting dose of 10 mg/d, on urine protein excretion in patients with primary dyslipidemia. Serum lipid and nonlipid parameters as well as urinary electrolyte, creatinine, and protein (total, albumin, immunoglobulin G, and alpha-1 microglobulin) levels were measured in 40 patients treated with rosuvastatin and 30 controls at baseline and after 12 weeks. The protein-to-creatinine ratios were used to assess urinary protein excretion. Rosuvastatin improved the lipid profile, produced no deterioration of kidney function, but induced a small but significant increase in the excretion of alpha-1 microglobulin (by 16%, P < .05) indicating that statin-related proteinuria involves low-molecular-weight proteins and is of proximal tubular origin.

Emerging scientific evidence suggests that increases in body iron represent a risk factor for the development of metabolic syndrome and diabetes. The aim of our study was to determine the body iron stores in patients with metabolic syndrome, and to evaluate the potential relationship of iron overload with specific features of the metabolic syndrome, such as fatty liver. A total of 490 individuals were enrolled. The diagnosis of metabolic syndrome was based on National Cholesterol Education Program-Adult Treatment Panel III (ATPIII) criteria. The metabolic syndrome group was consisted of 185 patients having three or more criteria, whereas individuals with less than three criteria constituted the control group. Metabolic syndrome patients displayed higher ferritin concentration as compared to control individuals. Ferritin levels were positively correlated with insulin concentration, as well as with Homeostasis Model Assessment (HOMA) index values. Multiple regression analysis revealed that ferritin was the most important independent determinant of insulin resistance indices. Patients with metabolic syndrome also exhibited increased concentrations of alanine aminotransferase and gamma-glutamyltranspeptidase compared to controls. Multiple regression analysis revealed that ferritin concentration was the most important determinant of gamma-glutamyltranspeptidase levels. Patients with the metabolic syndrome exhibit an increase in body iron stores as well as elevated concentrations of liver enzymes compared to the individuals who do not fulfill the criteria for the diagnosis of this syndrome. Our data support a direct role of increased body iron in the pathogenesis of insulin resistance, whereas iron overload may also contribute to the development of specific features of the metabolic syndrome, such as fatty liver.

It has been proposed that the most common lipid abnormalities associated with the metabolic syndrome are elevated triglyceride and low high-density lipoprotein concentrations as well as the existence of small, dense low-density lipoprotein (LDL) particles. However, so far there are only limited clinical data concerning the distribution of LDL particles in patients with this syndrome. The aim of our study was to directly determine the concentration and relative distribution of LDL subfractions in patients with metabolic syndrome. One hundred seventy-five individuals were included. Patients with metabolic syndrome (n = 105) exhibited higher concentrations of dense LDL particles and lower mean LDL particle size than the control population (n = 70). Both of these parameters were significantly correlated with the number of components of metabolic syndrome. Multivariate analysis revealed that serum triglyceride concentration was the most important determinant of the presence of small, dense LDL particles. In conclusion, patients with metabolic syndrome exhibit higher concentrations of small, dense LDL subfractions than individuals who do not fulfill the criteria for the diagnosis of this syndrome. This increase is directly related to the number of components of metabolic syndrome and is mainly determined by the serum concentrations of triglycerides.

Background: The Friedewald formula (LDL-F) for the estimation of low-density lipoprotein (LDL) cholesterol concentrations is the most often used formula in clinical trials and clinical practice. However, much concern has been raised as to whether this formula is applicable in all patient populations such as the presence of chylomicronaemia and/or hypertriglyceridaemia. The aim of the present study was to evaluate various LDL cholesterol calculation formulas as well as LDL cholesterol levels provided by the Lipoprint LDL System (LDL-L) in patients with the metabolic syndrome (MetSyn)., Results: LDL-F showed significant differences from other formulas in the total cohort, as well as in MetSyn individuals. This was not the case in nonMetSyn subjects, where LDL-F did not differ with other formulas, with the exception of one formula (LDL by Planella, LDL-P). The bias between LDL-F and other LDL estimation formulas were significantly higher in MetSyn subjects compared to nonMetSyn individuals, except for LDL-L which produced similar bias with LDL-F in both study groups., Conclusion: LDL-F seems to exhibit some limitations as far as the calculation of LDL-C levels in patients with the MetSyn is concerned. LDL-L might be more accurate in MetSyn subjects, but so far its use is limited for the estimation of small, dense LDL (sdLDL) cholesterol levels and mean LDL particle size for research purposes only.

Dyslipidaemia is common in solid organ transplant recipients and its presence is associated with chronic rejection and accelerated atherosclerosis, leading to an increased prevalence of cardiovascular disease (CVD). CVD is a major cause of morbidity and mortality in transplant recipients. It is therefore of interest and clinical value to introduce agents that effectively and safely reduce the incidence of this outcome. In the present review we consider the potential benefits of statin administration in adults who have undergone solid organ (mainly renal, heart and liver) transplantation, as well as in paediatric transplant patients. We also briefly review the effects of combination therapy with ezetimibe and statins in this population. Overall, statins are efficient and safe drugs for the management of dyslipidaemias in transplant populations, and in most trials they had a beneficial effect on long-term survival rates, CVD events and rejection rates. The transplanted population is different from other patient groups, mostly due to concomitant immunosuppressive therapy. Statins, at an appropriate dosage, should be prescribed to dyslipidaemic transplanted patients but they should be closely monitored for adverse effects.

Background: Recent clinical studies showed that lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is a predictor for incident atherosclerotic disease. We have previously shown that among the LDL subfractions, Lp-PLA(2) activity is preferentially associated with the atherogenic small, dense (sdLDL) particles in vitro. We investigated whether Lp-PLA(2) could be a marker of sdLDL in human plasma., Methods: One hundred and seventy-six individuals participated in the study. LDL subclass analysis was performed by polyacrylamide gel electrophoresis. Lp-PLA(2) activity and mass were determined in total plasma and in apolipoprotein B-depleted plasma (HDL-Lp-PLA(2)). Non-HDL-Lp-PLA(2) activity and mass were calculated by subtracting the HDL-Lp-PLA(2) from total plasma Lp-PLA(2)., Results: On the basis of the LDL subclass analysis, participants were categorized into phenotype A and non-A (total cholesterol mass of the sdLDL subfractions < or =0.155 and >0.155 mmol/L, respectively). Unlike total plasma Lp-PLA(2) mass, total plasma Lp-PLA(2) activity and non-HDL-Lp-PLA(2) activity and mass were significantly higher in persons with phenotype non-A compared with persons with phenotype A, whereas HDL-Lp-PLA(2) activity and mass were lower in persons with phenotype non-A compared with phenotype A. Total plasma activity and non-HDL-Lp-PLA(2) activity and mass, but not Lp-PLA(2) mass, were correlated with sdLDL-cholesterol mass, proportion, and mean LDL particle size. In multiple regression analysis, total plasma and non-HDL-Lp-PLA(2) activities were the second best predictors of the presence of sdLDL particles in human plasma after serum triglyceride concentrations. At serum triglyceride concentrations >1.356 mmol/L, total plasma and non-HDL-Lp-PLA(2) activity added significantly to the prediction of the presence of sdLDL in plasma., Conclusions: Lp-PLA(2) activity, but not the enzyme mass, is a marker of sdLDL in human plasma.

Plasma- and lipoprotein-associated activity of the platelet activating factor acetylhydrolase (PAF-acetylhydrolase, PAF-AH) plays an important role in inflammation and in atherosclerotic process, which are present in the metabolic syndrome (MS). Paraoxonase 1 (PON1) is an esterase associated with high-density lipoprotein (HDL) which contributes to the anti-atherogenic effects of this lipoprotein. We investigated the activities of both enzymes in 60 patients with MS and 110 age- and sex-matched subjects without it (non-MS group). Plasma PAF-AH activity was higher in the MS compared to the non-MS group, while HDL-PAF-AH and serum PON1 activities were lower in the MS compared to the non-MS group. Univariate regression analysis in the MS group showed that plasma PAF-AH activity was positively associated with systolic blood pressure, whereas HDL-PAF-AH activity was inversely associated with the homeostasis model assessments (HOMA) index. Both associations remained significant in the multivariate regression analysis, suggesting that insulin resistance and systolic hypertension are major determinants for the alterations in plasma and HDL-associated PAF-AH activity among those observed in MS patients.