Major reduction in plasma Lp(a) levels during sepsis and burns

Lipoprotein(a) in Children and Adolescents: Risk or Causal Factor for Cardiovascular Disease? A Narrative Review

The evaluation of serum Lp(a) values in childhood and adolescence has been widely debated, and in the last few years, many authors have tried to better define Lp(a) role in atherosclerosis pathogenesis, starting from childhood. In our narrative review, we have evaluated the main historical stages of Lp(a) studies in childhood, trying to focus on pathogenic mechanisms linked to elevated serum Lp(a) values, starting from ischemic stroke and vascular damage, and to its possible direct involvement in premature atherosclerosis from childhood onwards. Historic manuscripts on Lp(a) in pediatric patients have mainly focused on serum Lp(a) values and increased stroke risk. More recently, many studies have evaluated Lp(a) as a coronary vascular disease (CVD) risk factor starting from childhood, especially related to a positive family history of premature CVD. Finally, only a few studies evaluated the role of Lp(a) in premature atherosclerotic processes and endothelial and vascular damage in pediatric patients. Lastly, we have hypothesized a future perspective, with the hope that plasma Lp(a) levels will be treated with a tailored pharmacologic approach, and Lp(a) will become a precocious therapeutic target to control the atherosclerotic pathways from the first years of life.

Elevated lipoprotein(a) levels: A crucial determinant of cardiovascular disease risk and target for emerging therapies

Cardiovascular disease (CVD) remains a significant global health challenge despite advancements in prevention and treatment. Elevated Lipoprotein(a) [Lp(a)] levels have emerged as a crucial risk factor for CVD and aortic stenosis, affecting approximately 20 of the global population. Research over the last decade has established Lp(a) as an independent genetic contributor to CVD and aortic stenosis, beginning with Kare Berg's discovery in 1963. This has led to extensive exploration of its molecular structure and pathogenic roles. Despite the unknown physiological function of Lp(a), studies have shed light on its metabolism, genetics, and involvement in atherosclerosis, inflammation, and thrombosis. Epidemiological evidence highlights the link between high Lp(a) levels and increased cardiovascular morbidity and mortality. Newly emerging therapies, including pelacarsen, zerlasiran, olpasiran, muvalaplin, and lepodisiran, show promise in significantly lowering Lp(a) levels, potentially transforming the management of cardiovascular disease. However, further research is essential to assess these novel therapies' long-term efficacy and safety, heralding a new era in cardiovascular disease prevention and treatment and providing hope for at-risk patients.

Consensus on lipoprotein(a) of the Spanish Society of Arteriosclerosis. Literature review and recommendations for clinical practice

The irruption of lipoprotein(a) (Lp(a)) in the study of cardiovascular risk factors is perhaps, together with the discovery and use of proprotein convertase subtilisin/kexin type 9 (iPCSK9) inhibitor drugs, the greatest novelty in the field for decades. Lp(a) concentration (especially very high levels) has an undeniable association with certain cardiovascular complications, such as atherosclerotic vascular disease (AVD) and aortic stenosis. However, there are several current limitations to both establishing epidemiological associations and specific pharmacological treatment. Firstly, the measurement of Lp(a) is highly dependent on the test used, mainly because of the characteristics of the molecule. Secondly, Lp(a) concentration is more than 80% genetically determined, so that, unlike other cardiovascular risk factors, it cannot be regulated by lifestyle changes. Finally, although there are many promising clinical trials with specific drugs to reduce Lp(a), currently only iPCSK9 (limited for use because of its cost) significantly reduces Lp(a). However, and in line with other scientific societies, the SEA considers that, with the aim of increasing knowledge about the contribution of Lp(a) to cardiovascular risk, it is relevant to produce a document containing the current status of the subject, recommendations for the control of global cardiovascular risk in people with elevated Lp(a) and recommendations on the therapeutic approach to patients with elevated Lp(a).

Lp(a) - an overlooked risk factor

Lipoprotein(a) (Lp(a)) is an increasingly discussed and studied risk factor for atherosclerotic cardiovascular disease and aortic valve stenosis. Many genetic and epidemiological studies support the important causal role that Lp(a) plays in the incidence of cardiovascular disease. Although dependent upon the threshold and unit of measurement of Lp(a), most estimates suggest between 20 and 30% of the world's population have elevated serum levels of Lp(a). Lp(a) levels are predominantly mediated by genetics and are not significantly modified by lifestyle interventions. Efforts are ongoing to develop effective pharmacotherapies to lower Lp(a) and to determine if lowering Lp(a) with these medications ultimately decreases the incidence of adverse cardiovascular events. In this review, the genetics and pathophysiological properties of Lp(a) will be discussed as well as the epidemiological data demonstrating its impact on the incidence of cardiovascular disease. Recommendations for screening and how to currently approach patients with elevated Lp(a) are also noted. Finally, the spectrum of pharmacotherapies under development for Lp(a) lowering is detailed.

LP(a): Structure, Genetics, Associated Cardiovascular Risk, and Emerging Therapeutics

Lipoprotein(a) [Lp(a)] is a molecule bound to apolipoprotein(a) with some similarity to low-density lipoprotein cholesterol (LDL-C), which has been found to be a risk factor for cardiovascular disease (CVD). Lp(a) appears to induce inflammation, atherogenesis, and thrombosis. Approximately 20% of the world's population has increased Lp(a) levels, determined predominantly by genetics. Current clinical practices for the management of dyslipidemia are ineffective in lowering Lp(a) levels. Evolving RNA-based therapeutics, such as the antisense oligonucleotide pelacarsen and small interfering RNA olpasiran, have shown promising results in reducing Lp(a) levels. Phase III pivotal cardiovascular outcome trials [Lp(a)HORIZON and OCEAN(a)] are ongoing to evaluate their efficacy in secondary prevention of major cardiovascular events in patients with elevated Lp(a). The future of cardiovascular residual risk reduction may transition to a personalized approach where further lowering of either LDL-C, triglycerides, or Lp(a) is selected after high-intensity statin therapy based on the individual risk profile and preferences of each patient.

Changes in Lipoprotein(a) Levels in People after ST Elevation Myocardial Infarction-The STEMI-Lipids Study

Lipoprotein(a) (Lp(a)) is considered an independent risk factor for cardiovascular diseases. The plasma concentration of Lp(a) is largely genetically determined but varies over a wide range within the population. This study investigated changes in Lp(a) levels after an acute myocardial infarction. Patients who underwent coronary angiography due to an ST elevation myocardial infarction were enrolled (n = 86), and Lp(a) levels were measured immediately after the intervention, one day, two days, and at a post-discharge follow-up visit at 3 to 6 months after the acute myocardial infarction. Median Lp(a) levels increased from a median of 7.9 mg/dL (3.8-37.1) at hospital admission to 8.4 mg/dL (3.9-35.4) on the following day, then to 9.3 mg/dL (3.7-39.1) on day two (p < 0.001), and to 11.2 mg/dL (4.4-59.6) at the post-discharge follow-up (p < 0.001). Lp(a) levels were the lowest during the acute myocardial infarction and started to increase significantly immediately thereafter, with the highest levels at the post-discharge follow-up. The moderate but significant increase in Lp(a) in people with acute myocardial infarction appears to be clinically relevant on an individual basis, especially when specific Lp(a) cut-off levels are supposed to determine the initiation of future treatment. Hence, a repeated measurement of Lp(a) after myocardial infarction should be performed.

Frequent questions and responses on the 2022 lipoprotein(a) consensus statement of the European Atherosclerosis Society

In 2022, the European Atherosclerosis Society (EAS) published a new consensus statement on lipoprotein(a) [Lp(a)], summarizing current knowledge about its causal association with atherosclerotic cardiovascular disease (ASCVD) and aortic stenosis. One of the novelties of this statement is a new risk calculator showing how Lp(a) influences lifetime risk for ASCVD and that global risk may be underestimated substantially in individuals with high or very high Lp(a) concentration. The statement also provides practical advice on how knowledge about Lp(a) concentration can be used to modulate risk factor management, given that specific and highly effective mRNA-targeted Lp(a)-lowering therapies are still in clinical development. This advice counters the attitude: "Why should I measure Lp(a) if I can't lower it?". Subsequent to publication, questions have arisen relating to how the recommendations of this statement impact everyday clinical practice and ASCVD management. This review addresses 30 of the most frequently asked questions about Lp(a) epidemiology, its contribution to cardiovascular risk, Lp(a) measurement, risk factor management and existing therapeutic options.

Clinical significance of dynamic variation of low cholesterol and its prognostic value in patients with pyogenic liver abscesses: a retrospective study

BACKGROUND

Serum lipids variations are closely related to the sepsis progression; however, their value for patients with pyogenic liver abscesses (PLA) has rarely been studied. We investigated the serum lipid level variations in patients with PLA and its predictive value to the disease.

METHODS

The study included 328 patients with PLA hospitalized in the First Affiliated Hospital of Nanjing Medical University from January 2017 to December 2021; 35 (10.67%) in the severe group (SG) and 293 (89.33%) in the non-severe group (nSG). Their clinical records were analyzed retrospectively, and dynamic curves were drawn to clarify the changes in different indicators during the course of the disease.

RESULTS

High-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and lipoprotein(a) (Lp(a)) in the SG were significantly lower than those in nSG (P < 0.001). Total cholesterol (TC) at baseline (OR = 0.184, P < 0.001) was an independent risk factor for severe patients and had the highest predictive value, with an area under the curve of 0.859 and a cut-off value of 2.70 mmol/L (sensitivity = 94.3%, specificity = 63.5%). For patients who met the criteria for drainage surgery, TC, HDL-C and LDL-C levels continued to decrease with antibiotic therapy alone before drainage and began to increase after the surgery.

CONCLUSIONS

Low TC level on admission is an independent risk factor for the progression of severe illness in PLA patients, with the highest predictive value surpassing other routine clinical indices. Abscess drainage should be performed as soon as possible for patients whose TC continues to decline after medical treatment.

Lipoprotein(a) in atherosclerotic cardiovascular disease and aortic stenosis: a European Atherosclerosis Society consensus statement

This 2022 European Atherosclerosis Society lipoprotein(a) [Lp(a)] consensus statement updates evidence for the role of Lp(a) in atherosclerotic cardiovascular disease (ASCVD) and aortic valve stenosis, provides clinical guidance for testing and treating elevated Lp(a) levels, and considers its inclusion in global risk estimation. Epidemiologic and genetic studies involving hundreds of thousands of individuals strongly support a causal and continuous association between Lp(a) concentration and cardiovascular outcomes in different ethnicities; elevated Lp(a) is a risk factor even at very low levels of low-density lipoprotein cholesterol. High Lp(a) is associated with both microcalcification and macrocalcification of the aortic valve. Current findings do not support Lp(a) as a risk factor for venous thrombotic events and impaired fibrinolysis. Very low Lp(a) levels may associate with increased risk of diabetes mellitus meriting further study. Lp(a) has pro-inflammatory and pro-atherosclerotic properties, which may partly relate to the oxidized phospholipids carried by Lp(a). This panel recommends testing Lp(a) concentration at least once in adults; cascade testing has potential value in familial hypercholesterolaemia, or with family or personal history of (very) high Lp(a) or premature ASCVD. Without specific Lp(a)-lowering therapies, early intensive risk factor management is recommended, targeted according to global cardiovascular risk and Lp(a) level. Lipoprotein apheresis is an option for very high Lp(a) with progressive cardiovascular disease despite optimal management of risk factors. In conclusion, this statement reinforces evidence for Lp(a) as a causal risk factor for cardiovascular outcomes. Trials of specific Lp(a)-lowering treatments are critical to confirm clinical benefit for cardiovascular disease and aortic valve stenosis.

Transient hypertriglyceridemia: a common finding during Epstein-Barr virus-induced infectious mononucleosis

Background

Hypertriglyceridemia can occur in lymphoproliferative disorders. Infectious mononucleosis is a self-limiting, benign lymphoproliferative disorder. This study aimed to investigate the serum triglyceride concentrations and their change over time in patients with infectious mononucleosis.

Methods

We evaluated an adult patient with severe hypertriglyceridemia (>1000 mg/dL) during infectious mononucleosis and reviewed the records of 360 patients admitted to our hospital because of infectious mononucleosis (median age, 19 years; range, 15-87 years; 51.4% male). We compared the serum triglyceride concentrations with those of a control sample from the general population (n=75). A second triglyceride measurement, obtained during convalescence (median of 30 days after the initial determination), was available for 160 patients.

Results

The triglyceride concentrations in the acute phase (median: 156 mg/dL) were significantly higher than those of the controls (median, 76 mg/dL; P<0.001). A total of 194 (53.9%) patients presented with hypertriglyceridemia (>150 mg/dL), which was more common in the patients older than 30 years than in the younger patients (78.6% vs. 50.6%; P<0.001). A significant correlation (P<0.005) was observed between the triglyceride levels and white blood cell counts, total cholesterol levels, and liver damage markers. The triglyceride concentrations decreased during convalescence (P<0.001) and were lower than the initial measurement in 83.7% of the cases. Conversely, the total cholesterol concentrations during the acute phase were lower than those of the controls and increased during convalescence (P<0.001).

Conclusions

Patients with severe infectious mononucleosis frequently show mild, transient hypertriglyceridemia. Further studies are needed to elucidate the mechanisms underlying this finding.

Low lipoprotein(a) levels and risk of disease in a large, contemporary, general population study

AIMS

With the current focus on lipoprotein(a) as a likely causal risk factor for cardiovascular disease and new drugs potentially on the market to lower lipoprotein(a) levels, the safety of lowering lipoprotein(a) to low levels becomes increasingly important. We tested whether low levels of lipoprotein(a) and corresponding LPA genotypes associate with major disease groups including cancers and infectious disease.

METHODS AND RESULTS

We included 109 440 individuals from the Copenhagen General Population Study. For main World Health Organization International Classification of Diseases 10th edition chapter diseases, the only concordant association of low levels of lipoprotein(a) plasma levels and corresponding LPA genotypes with risk of disease was with low risk of diseases of the circulatory system. Furthermore, no concordant association of low levels of lipoprotein(a) plasma levels and corresponding LPA genotypes with the risk of any cancer (i.e. cancer subtypes combined) or infectious disease was seen. The hazard ratio for the risk of any cancer was 1.06 [95% confidence interval (CI): 0.97-1.15] for the first vs. the fourth quartile of lipoprotein(a), 1.02 (0.97-1.07) for the fourth vs. the first quartile of KIV-2 number of repeats, and 1.01 (0.96-1.07) for rs10455872 non-carriers vs. carriers. The corresponding hazard ratios for the risk of hospitalization for infection were 1.05 (95% CI: 0.99-1.10), 1.02 (0.98-1.07), and 0.97 (0.93-1.03), respectively.

CONCLUSION

In a large, contemporary, general population cohort, apart from the well-established association with cardiovascular disease, low levels of lipoprotein(a) and corresponding LPA genotypes did not concordantly associate with any major disease groups including cancers and infections. There is no safety signal from our results to indicate that low levels of lipoprotein(a) are harmful.

Apolipoprotein(a), an enigmatic anti-angiogenic glycoprotein in human plasma: A curse or cure?

Angiogenesis is a finely co-ordinated, multi-step developmental process of the new vascular structure. Even though angiogenesis is regularly occurring in physiological events such as embryogenesis, in adults, it is restricted to specific tissue sites where rapid cell-turnover and membrane synthesis occurs. Both excessive and insufficient angiogenesis lead to vascular disorders such as cancer, ocular diseases, diabetic retinopathy, atherosclerosis, intra-uterine growth restriction, ischemic heart disease, stroke etc. Occurrence of altered lipid profile and vascular lipid deposition along with vascular disorders is a hallmark of impaired angiogenesis. Among lipoproteins, lipoprotein(a) needs special attention due to the presence of a multi-kringle protein subunit, apolipoprotein(a) [apo(a)], which is structurally homologous to many naturally occurring anti-angiogenic proteins such as plasminogen and angiostatin. Researchers have constructed different recombinant forms of apo(a) (rhLK68, rhLK8, RHACK2, KV-11, and AU-6) and successfully exploited its potential to inhibit unwanted angiogenesis during tumor metastasis and retinal neovascularization. Similar to naturally occurring anti-angiogenic proteins, apo(a) can directly interfere with angiogenic signaling pathways. Besides this, apo(a) can also exert its anti-angiogenic effect indirectly by inducing endothelial cell apoptosis, by inhibiting endothelial progenitor cell functions or by upregulating nuclear factors in endothelial cells via apo(a)-bound oxPLs. However, the impact of the anti-angiogenic potential of native apo(a) during physiological angiogenesis in embryos and wounded tissues is not yet explored. In this context, we review the studies so far done to demonstrate the anti-angiogenic activity of apo(a) and the recent developments in using apo(a) as a therapeutic agent to treat impaired angiogenesis during vascular disorders, with emphasis on the gaps in the literature.

Possible Serological Markers to Predict Mortality in Acute Exacerbation of Idiopathic Pulmonary Fibrosis

Background and objectives: Idiopathic pulmonary fibrosis (IPF) has a particularly poor prognosis, and most IPF-related deaths are due to acute exacerbation (AE) of this condition. Few reports about biomarkers to predict prognosis of AE-IPF have been published since the release of the new AE-IPF criteria in 2016. The present study investigated relationships between serological markers and in-hospital mortality after the onset of AE-IPF. Methods: Demographic, serological, and imaging data from patients hospitalized at the Maebashi Red Cross Hospital (Gunma, Japan) between 1 January 2013, and 31 December 2017, were retrospectively reviewed. Subjects fulfilling the diagnostic criteria for AE-IPF were divided into those who survived or died; statistical analysis of risk factors was performed using data from these two groups. Results: Diagnostic criteria for AE-IPF were fulfilled by 84 patients (59 males (70.2%)), with a median age of 78 years (range, 56-95 years). IPF was diagnosed before hospitalization in 50 (59.5%) patients and 38 (45.2%) died in hospital. Among the serological markers at hospitalization in the deceased group, C-reactive protein (CRP) was significantly higher than in the survivor group (p = 0.002), while total serum protein (p = 0.031), albumin (p = 0.047) and total cholesterol (p = 0.039) were significantly lower. Cox hazard analysis of factors predicting mortality, corrected for age, sex and BMI, revealed the following: CRP (hazard ratio (HR) 1.080 (95% confidence interval (CI) 1.022-1.141); p = 0.006), LDH (HR 1.003 (95% CI 1.000-1.006); p = 0.037), and total cholesterol (HR 0.985 (95% CI 0.972-0.997); p = 0.018). Conclusions: Our data suggest that CRP, LDH, and total cholesterol may be biomarkers predicting mortality in patients with AE-IPF. However, only prospective controlled studies can confirm or not our observation as a generalizable one.

Survival benefit of a low ratio of visceral to subcutaneous adipose tissue depends on LDL clearance versus production in sepsis

Background

Patients with sepsis with a high ratio of visceral adipose tissue (VAT) to subcutaneous adipose tissue (SAT) have increased mortality. Our goal was to investigate the mechanism of this effect, noting that low LDL levels are also associated with increased sepsis mortality. Accordingly we tested for association between VAT/SAT, low-density lipoprotein (LDL) levels, and mortality. Then we examined the effect of statin treatment, which decreases LDL production, and the effect of PCSK9 genotype, which increases LDL clearance.

Methods

We performed retrospective analysis of a cohort of patients with sepsis from a tertiary care adult intensive care unit in Vancouver, Canada, who underwent abdominal computed tomography (CT) (n = 75) for clinical reasons. We compared LDL levels in patients with sepsis according to high versus low VAT/SAT and 90-day survival. We next examined the effects of statin therapy and PCSK9 loss-of-function genotype on survival.

Results

Patients with a low VAT/SAT had increased 90-day survival and were relatively protected against low LDL levels in sepsis compared to high VAT/SAT. Statin treatment abrogated the beneficial effects of low VAT/SAT; eliminating the difference in LDL levels and survival between patients with low and high VAT/SAT. PSCK9 loss-of-function genotype similarly eliminated the increased LDL levels in low VAT/SAT patients but, in contrast, increased the survival advantage of low VAT/SAT compared to high VAT/SAT.

Conclusions

Low LDL levels per se are not simply associated with decreased sepsis survival because lowering LDL levels by inhibiting LDL production (statin treatment) is associated with adverse outcomes, while increased LDL clearance (PCSK9 loss-of-function genotype) is associated with improved outcomes in patients with low VAT/SAT.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-1985-1) contains supplementary material, which is available to authorized users.

Lipid testing in infectious diseases: possible role in diagnosis and prognosis

INTRODUCTION

Acute infections lead to significant alterations in metabolic regulation including lipids and lipoproteins, which play a central role in the host immune response. In this regard, several studies have investigated the role of lipid levels as a marker of infection severity and prognosis.

SCOPE OF REVIEW

We review here the role of lipids in immune response and the potential mechanisms underneath. Moreover, we summarize studies on lipid and lipoprotein alterations in acute bacterial, viral and parasitic infections as well as their diagnostic and prognostic significance. Chronic infections (HIV, HBV, HCV) are also considered.

RESULTS

All lipid parameters have been found to be significantly dearranged during acute infection. Common lipid alterations in this setting include a decrease of total cholesterol levels and an increase in the concentration of triglyceride-rich lipoproteins, mainly very low-density lipoproteins. Also, low-density lipoprotein cholesterol, apolipoprotein A1, low-density lipoprotein cholesterol and apolipoprotein-B levels decrease. These lipid alterations may have prognostic and diagnostic role in certain infections.

CONCLUSION

Lipid testing may be of help to assess response to treatment in septic patients and those with various acute infections (such as pneumonia, leptospirosis and others). Diagnostically, new onset of altered lipid levels should prompt the clinician to test for underlying infection (such as leishmaniasis).

Structure, function, and genetics of lipoprotein (a)

Lipoprotein (a) [Lp(a)] has attracted the interest of researchers and physicians due to its intriguing properties, including an intragenic multiallelic copy number variation in the LPA gene and the strong association with coronary heart disease (CHD). This review summarizes present knowledge of the structure, function, and genetics of Lp(a) with emphasis on the molecular and population genetics of the Lp(a)/LPA trait, as well as aspects of genetic epidemiology. It highlights the role of genetics in establishing Lp(a) as a risk factor for CHD, but also discusses uncertainties, controversies, and lack of knowledge on several aspects of the genetic Lp(a) trait, not least its function.

IL-6 blockade by monoclonal antibodies inhibits apolipoprotein (a) expression and lipoprotein (a) synthesis in humans

Lipoprotein (a) [Lp(a)] is a highly atherogenic lipid particle. Although earlier reports suggested that Lp(a) levels are mostly determined by genetic factors, several recent studies have revealed that Lp(a) induction is also caused by chronic inflammation. Therefore, we aimed to examine whether cytokine blockade by monoclonal antibodies may inhibit Lp(a) metabolism. We found that interleukin 6 (IL-6) blockade by tocilizumab (TCZ) reduced Lp(a) while TNF-α-inhibition by adalimumab in humans had no effect. The specificity of IL-6 in regulating Lp(a) was further demonstrated by serological measurements of human subjects (n = 1,153) revealing that Lp(a) levels are increased in individuals with elevated serum IL-6. Transcriptomic analysis of human liver biopsies (n = 57) revealed typical IL-6 response genes being correlated with the LPA gene expression in vivo. On a molecular level, we found that TCZ inhibited IL-6-induced LPA mRNA and protein expression in human hepatocytes. Furthermore, examination of IL-6-responsive signal transducer and activator of transcription 3 binding sites within the LPA promoter by reporter gene assays, promoter deletion experiments, and electrophoretic mobility shift assay analysis showed that the Lp(a)-lowering effect of TCZ is specifically mediated via a responsive element at -46 to -40. Therefore, IL-6 blockade might be a potential therapeutic option to treat elevated Lp(a) serum concentrations in humans and might be a noninvasive alternative to lipid apheresis in the future.

Decreased serum level of lipoprotein cholesterol is a poor prognostic factor for patients with severe community-acquired pneumonia that required intensive care unit admission

PURPOSE

The purpose of this study is to investigate the prognostic values of the serum levels of lipids in patients with severe community-acquired pneumonia (CAP) that required intensive care unit (ICU) admission.

MATERIALS AND METHODS

Patients who had severe CAP that required ICU admission were included. Serum lipid level was collected on the days 1 and 7 of ICU stay. Clinical outcome, including length of ICU stay, hospital stay, and death, were monitored prospectively.

RESULTS

A total of 40 patients were enrolled in this study. Lower high-density lipoprotein (HDL) and low-density lipoprotein (LDL) were found in nonsurvival group on ICU admission day 7 (survivors vs nonsurvivors; mean HDL, 41.8 vs 13.0 mg/dL, P = .002; LDL, 62.3 vs 30.3 mg/dL, P = 0.006, respectively). High-density lipoprotein cholesterol level of less than or equal to 17 mg/dL on day 7 (odds ratio, 1.23) and LDL cholesterol level of less than or equal to 21 mg/dL on day 7 (odds ratio, 1.10) could be a predictor of hospital mortality. The mean change in levels of HDL cholesterol in nonsurvivors decreased significantly than those in survivors from days 1 to 7 (8.5 vs -17.4 mg/dL, P = .04) but not LDL cholesterol.

CONCLUSIONS

Decreased serum HDL cholesterol level from days 1 to 7 may be of prognostic value.

Visceral leishmaniasis is associated with marked changes in serum lipid profile

BACKGROUND

Infection is often accompanied by lipid profile alterations. The aim of this study was to evaluate the lipid profile changes in patients with visceral leishmaniasis (VL).

MATERIALS AND METHODS

We included 15 patients [10 men, aged 50 (24-82) years old] with VL and 15 age- and sex-matched controls. The parameters estimated at diagnosis and 4 months after VL resolution were total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), apolipoproteins (apo) A-Ι, B, E, C-II, C-III, lipoprotein (a) [Lp(a)], activities of lipoprotein-associated phospholipase A2 (Lp-PLA2), HDL-Lp-PLA2, PON1 (paraoxonase 1) and cholesterol ester transfer protein (CETP), cytokines (interleukins 1β and 6 and tumour necrosis factor α), as well as LDL subfraction profile.

RESULTS

Patients with VL at diagnosis had lower levels of TC, LDL-C, apoΒ and Lp(a), and higher TG and apoE concentrations compared with 4 months after VL resolution. The activities of Lp-PLA2, HDL-Lp-PLA2 and ΡΟΝ1 were reduced at diagnosis compared with post-treatment values. VL patients had decreased levels of both large and sdLDL-C at diagnosis; no effect on mean LDL particle size was observed. Patients with VL at diagnosis had decreased HDL-C and apoA-I concentrations; these increased 4 months after VL resolution, but remained lower compared with controls. The activities of HDL-Lp-PLA2 and PON1 remained lower in patients after VL resolution compared with controls.

CONCLUSIONS

Patients with VL exhibit increased TG levels and decreased cholesterol subclasses at diagnosis. HDL-C, apoA-I and associated enzymes remain lower 4 months after VL resolution compared with controls.

When should we measure lipoprotein (a)?

Recently published epidemiological and genetic studies strongly suggest a causal relationship of elevated concentrations of lipoprotein (a) [Lp(a)] with cardiovascular disease (CVD), independent of low-density lipoproteins (LDLs), reduced high density lipoproteins (HDL), and other traditional CVD risk factors. The atherogenicity of Lp(a) at a molecular and cellular level is caused by interference with the fibrinolytic system, the affinity to secretory phospholipase A2, the interaction with extracellular matrix glycoproteins, and the binding to scavenger receptors on macrophages. Lipoprotein (a) plasma concentrations correlate significantly with the synthetic rate of apo(a) and recent studies demonstrate that apo(a) expression is inhibited by ligands for farnesoid X receptor. Numerous gaps in our knowledge on Lp(a) function, biosynthesis, and the site of catabolism still exist. Nevertheless, new classes of therapeutic agents that have a significant Lp(a)-lowering effect such as apoB antisense oligonucleotides, microsomal triglyceride transfer protein inhibitors, cholesterol ester transfer protein inhibitors, and PCSK-9 inhibitors are currently in trials. Consensus reports of scientific societies are still prudent in recommending the measurement of Lp(a) routinely for assessing CVD risk. This is mainly caused by the lack of definite intervention studies demonstrating that lowering Lp(a) reduces hard CVD endpoints, a lack of effective medications for lowering Lp(a), the highly variable Lp(a) concentrations among different ethnic groups and the challenges associated with Lp(a) measurement. Here, we present our view on when to measure Lp(a) and how to deal with elevated Lp(a) levels in moderate and high-risk individuals.

Leptospirosis is associated with markedly increased triglycerides and small dense low-density lipoprotein and decreased high-density lipoprotein

The objective of the present study was to evaluate the effects of acute infection with Leptospira interrogans on lipids, lipoproteins and associated enzymes. Fasting serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), apolipoproteins (apo) A-Ι, B, E, C-II, C-III and lipoprotein (a) [Lp(a)] were determined in patients with Leptospirosis on diagnosis and 4 months after recovery as well as in age- and sex-matched controls. Activities of cholesteryl-ester transfer protein (CETP) and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) as well as paraoxonase 1 (PON1) hydrolysing activity and levels of cytokines were determined. LDL subclass analysis was performed with Lipoprint LDL System. Eleven patients (10 men, mean age 49.5 ± 8.4 years) and 11 controls were included. TC, HDL-C, LDL-C, apoA-I, apoB and Lp(a) levels were lower at baseline, whereas TG and apoE levels were elevated compared with 4 months later. At baseline, higher levels of cytokines and cholesterol concentration of small dense LDL particles (sdLDL-C) were noticed, whereas LDL particle size was lower compared with follow-up. Activities of plasma Lp-PLA(2) and HDL-associated Lp-PLA(2) were lower at baseline compared with post treatment values, whereas PON1 activity was similar at baseline and 4 months later. 4 months after recovery, the levels of all lipid parameters evaluated did not differ compared with controls, except for HDL-C which remained lower. PON1 activity both at baseline and 4 months later was lower in patients compared with controls. Leptospirosis is associated with atherogenic changes of lipids, lipoproteins and associated enzymes.

Enigmatic role of lipoprotein(a) in cardiovascular disease

Lipoprotein (a), [Lp(a)] has many properties in common with low-density lipoprotein, (LDL) but contains a unique protein apolipoprotein(a), linked to apolipoprotein B-100 by a single disulfide bond. There is a substantial size heterogeneity of apo(a), and generally smaller apo(a) sizes tend to correspond to higher plasma Lp(a) levels, but this relation is far from linear, underscoring the importance to assess allele-specific apo(a) levels. The presence of apo(a), a highly charged, carbohydrate-rich, hydrophilic protein may obscure key features of the LDL moiety and offer opportunities for binding to vessel wall elements. Recently, interest in Lp(a) has increased because studies over the past decade have confirmed and more robustly demonstrated a risk factor role of Lp(a) for cardiovascular disease. In particular, levels of Lp(a) carried in particles with smaller size apo(a) isoforms are associated with coronary artery disease (CAD). Other studies suggest that proinflammatory conditions may modulate risk factor properties of Lp(a). Further, Lp(a) may act as a preferential acceptor for proinflammatory oxidized phospholipids transferred from tissues or from other lipoproteins. However, at present only a limited number of agents (e.g., nicotinic acid and estrogen) has proven efficacy in lowering Lp(a) levels. Although Lp(a) has not been definitely established as a cardiovascular risk factor and no guidelines presently recommend intervention, Lp(a)-lowering therapy might offer benefits in subgroups of patients with high Lp(a) levels.

Apolipoprotein(a) inhibits lipopolysaccharide-induced IL-6 secretion in human astrocytoma cell line by interfering with lipopolysaccharide signaling

OBJECTIVE

To examine the role of lipoprotein(a) [Lp(a)] on the inflammatory response of cells in the nervous system by investigating its effect on lipopolysaccharide (LPS)-induced interleukin-6 (IL-6) secretion.

MATERIALS AND METHODS

Human astrocytoma U373 cells were treated with recombinant apolipoprotein(a) [r-apo(a)] A10K (175-11 nM), alone or in combination with LPS (100 and 10 ng/ml). IL-6 levels were evaluated by immunoblotting. Statistical analysis was performed by one-way ANOVA.

RESULTS

r-apo(a) caused dose-dependent inhibition of LPS-induced IL-6 secretion (100 ng/ml LPS, p = 0.0205; 10 ng/ml LPS, p = 0.0005). Pre-treatment of cells with 88 nM r-apo(a), rinsing, and activation with 10 ng/ml LPS did not reverse the inhibition (p = 0.0048), which could be reversed by supplementation with excess serum (5-20%) (p = 0.0454) or recombinant CD14 (2.0-0.05 μg/ml) (p = 0.0230).

CONCLUSIONS

Our data indicate that apo(a) plays a natural anti-endotoxin role which relies on its interference with cell-associated and serum components of LPS signaling.

Plasma levels of apolipoprotein A1 in malaria-exposed primigravidae are associated with severe anemia

Background

Plasmodium falciparum placental malaria (PM) contributes to 10,000 maternal deaths due to severe anemia (SA) each year in Africa, primarily among primigravid women who are most susceptible. Increased levels of proinflammatory cytokines like TNF-α are associated with maternal anemia in first time mothers but not in other women. Here we aimed to identify additional changes in the plasma proteome associated with pregnancy malaria that may contribute to the development of malaria-related maternal anemia.

Principal Findings

A semi-quantitative mass spectrometry approach was used to compare the relative abundance of plasma proteins in anemic versus non-anemic women with PM. Levels of 24 proteins differed significantly between anemic and non-anemic primigravidae, including several lipid metabolism proteins and molecular transport proteins involved in the acute phase response signaling network. These differences were not observed in multigravid women who enjoy specific immunity that protect them from PM. In a confirmatory study of a larger cohort of primigravid women, levels of the lipid metabolism protein Apolipoprotein (Apo)-AI were significantly lower in PM+ women with SA.

Conclusions

Apo-AI levels are significantly lower in severely anemic primigravidae with PM, and ApoA1 levels positively correlate with hemoglobin levels in primigravid but not multigravid women. Apo-AI is known to have anti-inflammatory effects, and thus Apo-AI reductions may contribute to the inflammatory processes that result in SA.

Persistence of an atherogenic lipid profile after treatment of acute infection with Brucella

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.

High levels of inflammatory biomarkers are associated with increased allele-specific apolipoprotein(a) levels in African-Americans

BACKGROUND

A role of inflammation for cardiovascular disease (CVD) is established. Lipoprotein(a) [Lp(a)] is an independent CVD risk factor where plasma levels are determined by the apolipoprotein(a) [apo(a)] gene, which contains inflammatory response elements.

DESIGN

We investigated the effect of inflammation on allele-specific apo(a) levels in African-Americans and Caucasians. We determined Lp(a) levels, apo(a) sizes, allele-specific apo(a) levels, fibrinogen and C-reactive protein (CRP) levels in 167 African-Americans and 259 Caucasians.

RESULTS

Lp(a) levels were increased among African-Americans with higher vs. lower levels of CRP [<3 vs. > or =3 mg/liter (143 vs. 108 nmol/liter), P = 0.009] or fibrinogen (<340 vs. > or =340 mg/liter, P = 0.002). We next analyzed allele-specific apo(a) levels for different apo(a) sizes. No differences in allele-specific apo(a) levels across CRP or fibrinogen groups were seen among African-Americans or Caucasians for small apo(a) sizes (<22 kringle 4 repeats). Allele-specific apo(a) levels for medium apo(a) sizes (22-30 kringle 4 repeats) were significantly higher among African-Americans, with high levels of CRP or fibrinogen compared with those with low levels (88 vs. 67 nmol/liter, P = 0.014, and 91 vs. 59 nmol/liter, P < 0.0001, respectively). No difference was found for Caucasians.

CONCLUSIONS

Increased levels of CRP or fibrinogen are associated with higher allele-specific medium-sized apo(a) levels in African-Americans but not in Caucasians. These findings indicate that proinflammatory conditions result in a selective increase in medium-sized apo(a) levels in African-Americans and suggest that inflammation-associated events may contribute to the interethnic difference in Lp(a) levels between African-Americans and Caucasians.

Lipoprotein(a), lipids and proinflammatory cytokines in patients undergoing major abdominal surgery

Background

The aims were to investigate whether surgical stress can induce a positive or negative lipoprotein(a) acute response, to determine any association with apolipoprotein(a) phenotypes, and to establish whether any such response is dependent on changes in lipids and proinflammatory cytokines. In addition, the impact of interleukin (IL) 6 genetic variability on the cytokine response to surgery was examined.

Methods

This prospective, observational study included 41 patients with cancer referred for abdominal surgery. Preoperative (T0) plasma concentrations of lipoprotein(a), IL-6, tumour necrosis factor α, and serum concentrations of transforming growth factor β1 and lipids, were compared with values obtained 5 h (T1), 24 h (T2) and 5 days (T3) after surgery. Apolipoprotein(a) Kringle IV (KIV)-VNTR (variable-number tandem repeat) and IL-6 − 174 G/C polymorphisms were analysed.

Results

Lipoprotein(a) was found to act as a negative acute-phase reactant (30·0 per cent reduction at T2) (P = 0·009). Surgery had a more profound impact on subjects with low KIV-VNTR. After surgery, lipoprotein(a) correlated significantly with corrected low-density lipoprotein (LDL)-cholesterol (r = 0·408 at T2). IL-6 inversely correlated with lipoprotein(a) (r = −0·321 at T1) and LDL-cholesterol (r = −0·418 at T1). The IL-6 response could be predicted from a combination of the surgical severity and −174 G/C genotype.

Conclusion

Although temporal associations did not indicate causality, these data provide a hypothesis to explain the inverse relationship between lipoprotein(a) and IL-6.

Avaliação da variação da temperatura cutânea, proteína C reativa e velocidade de hemossedimentação na artroplastia total do joelho primária, isenta de complicações

OBJETIVO: Estudar a variação dos valores da temperatura cutânea (deltaT) do sítio operatório, da proteína C reativa (PCR) e da velocidade de hemossedimentação (VHS) em pacientes submetidos a artroplastia total do joelho (ATJ) primária, tentando estabelecer correlação entre suas curvas ao longo do tempo. MATERIAL E MÉTODOS: Esse estudo clínico prospectivo, avaliou 29 pacientes acompanhados por 12 semanas, sendo aferida a temperatura cutânea em ambos os joelhos e realizada dosagem sérica da PCR e VHS. RESULTADOS: Após a comparação entre as variáveis testadas (deltaT, PCR e VHS), observou-se tanto para o teste de Pearson (avaliação paramétrica), quanto para o de Spearman (avaliação não-paramétrica) que não houve correlação estatística entre elas. A variação da temperatura cutânea segue um padrão diferente do observado tanto para a PCR quanto para a VHS, não existindo correlação entre as curvas. Foi estabelecida a curva padrão das três variáveis, verificando-se redução estatisticamente significativa nos valores da PCR e da VHS entre o pré e o pós-operatório. CONCLUSÃO: Não foi observada correlação entre a temperatura cutânea e os níveis de VHS e PCR em pacientes submetidos a ATJ primária, isenta de complicações.

Long-chain polyunsaturated fatty acids, endothelial lipase and atherosclerosis

Endothelial lipase (EL), a new member of the lipase gene family, was recently cloned and has been shown to have a significant role in modulating the concentrations of plasma high-density lipoprotein levels (HDL). EL is closely related to lipoprotein and hepatic lipases both in structure and function. It is primarily synthesized by endothelial cells, functions at the cell surface, and shows phospholipase A1 activity. Overexpression of EL decreases HDL cholesterol levels whereas blocking its action increases concentrations of HDL cholesterol. Pro-inflammatory cytokines suppress plasma HDL cholesterol concentrations by enhancing the activity of EL. On the other hand, physical exercise and fish oil (a rich source of eicosapentaenoic acid and docosahexaenoic acid) suppress the activity of EL and this, in turn, enhances the plasma concentrations of HDL cholesterol. Thus, EL plays a critical role in the regulation of plasma HDL cholesterol concentrations and thus modulates the development and progression of atherosclerosis. The expression and actions of EL in specific endothelial cells determines the initiation and progression of atherosclerosis locally explaining the patchy nature of atheroma seen, especially, in coronary arteries. Both HDL cholesterol and EPA and DHA enhance endothelial nitric oxide (eNO) and prostacyclin (PGI2) synthesis, which are known to prevent atherosclerosis. On the other hand, pro-inflammatory cytokines augment free radical generation, which are known to inactivate eNO and PGI2. Thus, interactions between EL, pro- and anti-inflammatory cytokines, polyunsaturated fatty acids, and the ability of endothelial cells to generate NO and PGI2 and neutralize the actions of free radicals may play a critical role in atherosclerosis.

Lipoprotein(a) as a risk factor for atherosclerosis and thrombosis: mechanistic insights from animal models

Evidence continues to accumulate from epidemiological studies that elevated plasma concentrations of lipoprotein(a) [Lp(a)] are a risk factor for a variety of atherosclerotic and thrombotic disorders. Lp(a) is a unique lipoprotein particle consisting of a moiety identical to low-density lipoprotein to which the glycoprotein apolipoprotein(a) [apo(a)] that is homologous to plasminogen is covalently attached. These features have suggested that Lp(a) may contribute to both proatherogenic and prothrombotic/antifibrinolytic processes and in vitro studies have identified many such candidate mechanisms. Despite intensive research, however, definition of the molecular mechanisms underlying the epidemiological data has proven elusive. Moreover, an effective and well-tolerated regimen to lower Lp(a) levels has yet to be developed. The use of animal models holds great promise for resolving these questions. Establishment of animal models for Lp(a) has been hampered by the absence of this lipoprotein from common small laboratory animals. Transgenic mice and rabbits expressing human apo(a) have been developed and these have been used to: (i) examine regulation of apo(a) gene expression; (ii) study the mechanism and molecular determinants of Lp(a) assembly from LDL and apo(a); (iii) demonstrate that apo(a)/Lp(a) are indeed proatherogenic and antifibrinolytic; and (iv) identify structural domains in apo(a) that mediate its pathogenic effects. The recent construction of transgenic apo(a) rabbits is a particularly promising development in view of the excellent utility of the rabbit as a model of advanced atherosclerosis.

Assessment of the efficacy of different statins in murine collagen-induced arthritis

OBJECTIVE

Hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) are widely used lipid-lowering agents. In addition to their well-known effect on cholesterol levels, statins have been reported to display antiinflammatory activities both in vitro and in vivo. In this context, in vivo prophylactic and therapeutic effects of simvastatin were recently demonstrated in mouse collagen-induced arthritis, a well-described experimental model for human rheumatoid arthritis (RA). The aim of this study was to further investigate in vivo effects of 3 different statins, atorvastatin, rosuvastatin, and simvastatin, using the same experimental model.

METHODS

Different doses and routes of administration were used for the various statins in an attempt to elicit antiarthritic activity in preventive and curative treatment protocols.

RESULTS

Atorvastatin and rosuvastatin had no in vivo efficacy, as indicated by clinical, histologic (synovial hyperplasia, exudate, and cartilage damage), immunologic (anti-type II collagen IgG production), and biochemical (interleukin-6, serum amyloid A, and glucocorticoid production) parameters of inflammation and autoimmunity. The previously described beneficial effects of administration of intraperitoneal simvastatin were reproduced in our experiments, but could be accounted for by very severe side effects of the treatment, leading to increased glucocorticoid levels.

CONCLUSION

This work shows that different statins have no effect in a murine model of arthritis, an unexpected observation given the previously described therapeutic effect of statins in immune-mediated inflammatory diseases. It is still unclear whether statins will have benefit in the treatment of RA.

Effects of infection and inflammation on lipid and lipoprotein metabolism: mechanisms and consequences to the host

Infection and inflammation induce the acute-phase response (APR), leading to multiple alterations in lipid and lipoprotein metabolism. Plasma triglyceride levels increase from increased VLDL secretion as a result of adipose tissue lipolysis, increased de novo hepatic fatty acid synthesis, and suppression of fatty acid oxidation. With more severe infection, VLDL clearance decreases secondary to decreased lipoprotein lipase and apolipoprotein E in VLDL. In rodents, hypercholesterolemia occurs attributable to increased hepatic cholesterol synthesis and decreased LDL clearance, conversion of cholesterol to bile acids, and secretion of cholesterol into the bile. Marked alterations in proteins important in HDL metabolism lead to decreased reverse cholesterol transport and increased cholesterol delivery to immune cells. Oxidation of LDL and VLDL increases, whereas HDL becomes a proinflammatory molecule. Lipoproteins become enriched in ceramide, glucosylceramide, and sphingomyelin, enhancing uptake by macrophages. Thus, many of the changes in lipoproteins are proatherogenic. The molecular mechanisms underlying the decrease in many of the proteins during the APR involve coordinated decreases in several nuclear hormone receptors, including peroxisome proliferator-activated receptor, liver X receptor, farnesoid X receptor, and retinoid X receptor. APR-induced alterations initially protect the host from the harmful effects of bacteria, viruses, and parasites. However, if prolonged, these changes in the structure and function of lipoproteins will contribute to atherogenesis.

Lipoprotein (a) and acute-phase response in patients with vestibular neuronitis

BACKGROUND

Vestibular neuronitis (VN) is a relatively common condition characterized by the acute onset of vertigo, nausea and vomiting, in the absence of auditory or central nervous system involvement. The exact aetiology (inflammatory, viral or vascular?) remains obscure. Lipoprotein (a) [Lp(a)] is an atherogenic particle. Its serum levels are mainly genetically determined and vary widely between individuals. Whether Lp(a) is consistently a positive acute-phase reactant is controversial.

PURPOSE

We evaluated the alterations in lipidaemic parameters and serum biological markers (including acute-phase reactants) in adult patients presenting acutely with VN.

SUBJECTS AND METHODS

A total of 34 consecutive VN patients (24 men and 11 women) and 37 apparently healthy controls (25 men and 12 women) were studied. Laboratory evaluation was performed during the acute episode and 6 months later (stable state).

RESULTS

Serum Lp(a) concentrations were significantly lower at the time of presentation (median value 6.4 vs. 16.4 mg dL-1 in the stable state, P < 0.001), whereas fibrinogen levels were significantly higher during the acute episode than in the stable state (median value 293.0 vs. 202.0 mg dL-1, respectively, P < 0.0001). During the acute episode, plasma fibrinogen correlated with CRP levels (Spearman r = 0.84, P < 0.0001). By contrast, inverse correlations were noted between Lp(a) levels and CRP (Spearman r = -0.47, P = 0.007) as well as between Lp(a) and fibrinogen levels (Spearman r = -0.35, P = 0.05).

CONCLUSION

Vestibular neuronitis episodes are associated with evidence of an acute inflammatory response as reflected by significant elevations in plasma fibrinogen and CRP concentrations, whereas Lp(a) behaves as a negative acute-phase reactant.

Acute inflammation and infection maintain circulating phospholipid levels and enhance lipopolysaccharide binding to plasma lipoproteins

Circulating lipoproteins are thought to play an important role in the detoxification of lipopolysaccharide (LPS) by binding the bioactive lipid A portion of LPS to the lipoprotein surface. It has been assumed that hypocholesterolemia contributes to inflammation during critical illness by impairing LPS neutralization. We tested whether critical illness impaired LPS binding to lipoproteins and found, to the contrary, that LPS binding was enhanced and that LPS binding to the lipoprotein classes correlated with their phospholipid content. Whereas low serum cholesterol was almost entirely due to the loss of esterified cholesterol (a lipoprotein core component), phospholipids (the major lipoprotein surface lipid) were maintained at near normal levels and were increased in a hypertriglyceridemic subset of septic patients. The levels of phospholipids found in the LDL and VLDL fractions varied inversely with those in the HDL fraction, and LPS bound predominantly to lipoproteins in the LDL and VLDL fractions when HDL levels were low. Lipoproteins isolated from the serum of septic patients neutralized the bioactivity of the LPS that had bound to them. Our results show that the host response to acute inflammation and infection tends to maintain lipoprotein phospholipid levels and that, despite hypocholesterolemia and reduced HDL levels, circulating lipoproteins maintain their ability to bind and neutralize an important bacterial agonist, LPS.

Helicobacter pylori is associated with modified lipid profile: impact on Lipoprotein(a)

OBJECTIVES

Helicobacter pylori is a controversial risk factor for atherosclerosis. We investigated whether the bacterium persistent inflammation or the expression of the cytotoxin-associated gene A (CagA) may affect serum lipids as well as Lipoprotein(a).

DESIGN AND METHODS

Two hundred-eleven healthy volunteers were evaluated for lipids and Lipoprotein(a). Helicobacter pylori was characterized by Urea Breath Test and IgG-anti-CagA. apo(a) Kringle-IV polymorphism was genotyped.

RESULTS

Prevalence of the infection was 72%; 43% of subjects expressed CagA reactivity. Infected subjects showed increased levels of cholesterol, LDL-cholesterol, and cholesterol/HDL-cholesterol atherogenic index. Association with the Helicobacter pylori CagA(-) strains persisted after the adjustment for covariates. Significant difference between infected and uninfected subjects was found in Lipoprotein(a) levels. This difference did not arise from the Kringle-IV genotype.

CONCLUSIONS

The infection per se significantly modified serum lipid and Lipoprotein(a) concentrations. CagA does not seem to be a reliable marker of pathogenicity for the atherogenic complications of H. pylori infection.

Changes in the concentration and composition of plasma lipoproteins during the acute phase response

The acute phase reactions, associated with injury, inflammation, or sepsis, markedly affect the concentration and composition of plasma lipids and lipoproteins. Hepatic production of triglycerides and very low density lipoprotein formation are increased, but do not necessarily result in high plasma triglyceride levels. In contrast, all conditions lower plasma cholesterol by decreasing its content in both low-density and high-density lipoproteins. In addition, substantial changes in protein and lipid composition of lipoproteins are observed that may redefine the function of these particles, but also increase their atherogenic and inflammatory properties.

Plasma apolipoprotein(a) co-deposits with fibrin in inflammatory arthritic joints

Extravascular coagulation and diminished fibrinolysis are processes that contribute to the pathology of both inflammatory arthritis and atherosclerosis. We hypothesized that, given its homology with plasminogen, apolipoprotein (apo) (a), the distinctive glycoprotein of the atherogenic lipoprotein (Lp) (a), may be equally implicated in inflammatory arthritis. We detected the presence of apo(a) as part of Lp(a) in human arthritic synovial fluid. The abundance of apo(a) in synovial fluid rose in proportion to plasma apo(a) levels and was higher in inflammatory arthritides than in osteoarthritis. In addition, apo(a) immunoreactive material, but not apo(a) transcripts, was detected in inflammatory arthritic synovial tissues. These data indicated that synovial fluid apo(a) originates from circulating Lp(a) and that diffusion of Lp(a) through synovial tissue is facilitated in inflammatory types of arthritis. In synovial tissues, apo(a) co-localized with fibrin. These observations could be reproduced in a model of antigen-induced arthritis, using transgenic mice expressing human Lp(a). Although in this mouse model the presence of apo(a) did not change the severity of arthritis, the co-localization of apo(a) with fibrin in synovial tissue suggests that, in humans, apo(a) may modulate locally the fibrinolytic activity and may thus contribute to the persistence of intra-articular fibrin in inflammatory arthritis.