Prospective 10-year evaluation of hypobetalipoproteinemia in a cohort of 772 firefighters and cross-sectional evaluation of hypocholesterolemia in 1,479 men in the National Health and Nutrition Examination Survey I

Prevalence, genetic variants, and clinical implications of hypocholesterolemia in children

BACKGROUND AND AIMS

In contrast to extensively studied hypercholesterolemia, knowledge of hypocholesterolemia is limited. This study aims to assess the prevalence, clinical characteristics, and genetics of children and adolescents with hypocholesterolemia.

METHODS

This national prospective cross-sectional cohort study was part of Slovenia's universal opt-out cholesterol screening program. The first part assessed hypocholesterolemia prevalence among 3538 children aged 5 years, randomly selected at the mandatory check-up. The second part included analysis of demographic and clinical data and genetic testing of 71 individuals with suspected hypocholesterolemia (total cholesterol [TC] < 3.0 mmol/L [116.0 mg/dL]) referred to the Lipid Clinic of University Children's Hospital Ljubljana.

RESULTS

The prevalence of hypocholesterolemia among 3538 children was 2.66 % (95 % CI: 2.13-3.19 %). Among the 71 genetically tested individuals with suspected hypocholesterolemia, those with pathogenic variants had lower TC (2.58 ± 0.44 mmol/L vs. 2.85 ± 0.42 mmol/L [99.77 ± 17.02 mg/dL vs. 110.20 ± 16.24 mg/dL]; p = 0.037) and low-density lipoprotein cholesterol (1.00 ± 0.40 mmol/L vs. 1.33 ± 0.40 mmol/L [38.67 ± 15.47 mg/dL vs. 51.43 ± 15.47 mg/dL]; p = 0.014) compared to those without such variants. Genetic testing identified pathogenic alterations in 15 subjects, including 4 novel loss-of-function variants in the APOB gene. All but one subject were asymptomatic.

CONCLUSIONS

This study provides new clinical and genetic insights into hypocholesterolemia. Asymptomatic patients with hypocholesterolemia may not require further evaluation, but additional research is needed to understand hypocholesterolemia better.

Association of cholesterol levels with hemorrhagic transformation and cerebral edema after reperfusion therapies

Background:

The association between cholesterol levels and cerebral edema (CED) or hemorrhagic transformation (HT) as an expressions of blood-brain barrier (BBB) dysfunction after ischemic stroke is not well established. The aim of this study is to determine the association of total cholesterol (TC) levels with the incidence of HT and CED after reperfusion therapies.

Methods:

We analyzed SITS Thrombolysis and Thrombectomy Registry data from January 2011 to December 2017. We identified patients with data on TC levels at baseline. TC values were categorized in three groups (reference group ⩾200 mg/dl). The two primary outcomes were any parenchymal hemorrhage (PH) and moderate to severe CED on follow up imaging. Secondary outcomes included death and functional independence (mRS 0–2) at 3 months. Multivariable logistic regression analysis adjusted for baseline factors including statin pretreatment was used to assess the association between TC levels and outcomes.

Results:

Of 35,314 patients with available information on TC levels at baseline, 3372 (9.5%) presented with TC levels ⩽130 mg/dl, 8203 (23.2%) with TC 130–200 mg/dl and 23,739 (67.3%) with TC ⩾ 200 mg/dl. In the adjusted analyses, TC level as continuous variable was inversely associated with moderate to severe CED (OR 0.99, 95% CI 0.99–1.00, p = 0.025) and as categorical variable lower TC levels were associated with a higher risk of moderate to severe CED (aOR 1.24, 95% CI 1.10–1.40, p = 0.003). TC levels were not associated with any PH, functional independence, and mortality at 3 months.

Conclusions:

Our findings indicate an independent association between low levels of TC and higher odds of moderate/severe CED. Further studies are needed to confirm these findings.

Serum lipids and suicidal risk among patients with schizophrenia spectrum disorders: Systematic review and meta-analysis

OBJECTIVE

A systematic review of literature was conducted to determine the association between serum lipids and suicidality in people with schizophrenia spectrum disorders.

METHODS

We undertook a systematic search of multiple databases for studies that ascertained an association between serum lipids and suicidality in adult patients with schizophrenia spectrum disorders (18-65 years) from database inception to 2 September 2020. Qualitative analysis was done using National Institute of Health (NIH) scales. The standard mean difference (SMD) and 95% confidence intervals (CI) were calculated for each study and standardized relative to the study. Adjusted p-value, Z-test, and heterogeneity were calculated, as well as testing for publication bias.

RESULTS

Of 1262 records identified, 17 studies (n = 3113) were included in our systematic review, while 11 studies were included in the meta-analysis. The majority of studies (11) rated fair on qualitative analysis. Data from seven studies (n = 1597) revealed a medium effect size for an association between low total cholesterol and suicide attempts (SMD -0.560; 95% CI: 0.949-0.170; p = 0.005). People with history of suicide attempt had a mean cholesterol value 0.56 SD lower than the mean in those without suicide attempts. There were differences in how a suicide attempt was defined and there was high heterogeneity (I² = 83.3%). No significant association was found between any of the serum lipid parameters and suicide ideation. Funnel-plot analysis suggested small study effects with publication bias.

CONCLUSIONS

Suicide attempts in people with schizophrenia spectrum disorders are associated with low mean total cholesterol levels.

Relationship Between Various Coronary Artery Disease Risk Factors in Firefighters

OBJECTIVE

To determine the correlation between the various coronary artery disease risk factors in firefighters.

METHODS

The study used a quantitative, cross-sectional, and correlational study design. A total of 124 full-time firefighters were conveniently recruited to participate. Research procedures were based on the ACSM guidelines.

RESULTS

Significances were found between age and body mass index (BMI) (r = 0.42, P < 0.001), age and waist circumference (WC) (r = 0.52, P < 0.001), BMI and WC (r = 0.88, P < 0.001), BMI and diastolic blood pressure (DBP) (r = 0.48, P < 0.001), between WC and DBP (r = 0.48, P < 0.001) and between gender and cigarette smoking (χ2[1] = 5.66, P = 0.017).

CONCLUSION

There were significant strong relationships between BMI, SBP, DBP, dyslipidemia, and increasing age, especially in male firefighters. Reducing key risk factors should be emphasized.

Prevalence of coronary artery disease risk factors in firefighters in the city of Cape Town fire and rescue service - A descriptive study

Background: Over 45% of firefighter deaths are attributable to sudden cardiac death related to coronary artery disease (CAD), with many of these deaths attributed to comorbidities. The purpose of the study is to determine the prevalence of coronary artery disease (CAD) risk factors in firefighters in the City of Cape Town (CoCT). Design and Methods: The study used a quantitative, cross-sectional and descriptive design. A total of 124 full-time firefighters were conveniently recruited between September and November 2019 from the City of Cape Town Fire and Rescue Service. Results: The most prevalent CAD risk factors among firefighters were hypertension (33.1%), obesity (37.1%), cigarette smoking (39.5%) and dyslipidaemia (40.3%). A total of 41.9% of firefighters were categorized as low-risk, 54.8% as moderate-risk, and 3.2% as high-risk for CAD. Conclusion: The majority of firefighters had at least one CAD risk factor, with older males having the highest prevalence of multiple CAD risk factors. Compared to other regions of the world, the (CoCT) firefighters have higher prevalence of dyslipidaemia and cigarette smoking. Preventative behavioural strategies and education on CAD should be promoted to mitigate the development of CAD.

Begründung für die neuen LDL-Cholesterin-Zielwerte

Die aktualisierte Dyslipidämie-Leitlinie von 2019 definiert noch tiefere Therapieziele in Abhängigkeit der individuellen Risikokategorie, sowohl für die Primär- als auch für die Sekundärprävention. LDL-Cholesterin bleibt das primäre Maß zur Risikoabschätzung und Haupt-Therapieziel. Daneben sollte Lp(a) einmal im Erwachsenenalter zur Identifikation von Risikopersonen bestimmt werden. Die letzten großen randomisierten Studien zu Ezetimib und PCSK9-Inhibitoren konnten eine weitere relative Risikoreduktion für kardiovaskuläre Ereignisse nachweisen. Dabei ist die Verringerung des kardiovaskulären Risikos proportional zur absoluten LDL-C-Senkung. Für Patienten mit sehr hohem Risiko ist das neue LDL-C-Ziel < 1,4 mmol/l (55 mg/dl) bzw. eine zusätzliche prozentuale Reduktion des LDL-C-Ausgangswerts um ≥ 50%. Eine ausreichende zelluläre Cholesterinversorgung besteht bei LDL-Spiegeln von nur 25 mg/dl (0,65 mmol/l), wie sie zur Geburt vorliegen.

LDL-Cholesterol-Lowering Therapy

The causal relation between elevated levels of LDL-C and cardiovascular disease has been largely established by experimental and clinical studies. Thus, the reduction of LDL-C levels is a major target for the prevention of cardiovascular disease. In the last decades, statins have been used as the main therapeutic approach to lower plasma cholesterol levels; however, the presence of residual lipid-related cardiovascular risk despite maximal statin therapy raised the need to develop additional lipid-lowering drugs to be used in combination with or in alternative to statins in patients intolerant to the treatment. Several new drugs have been approved which have mechanisms of action different from statins or impact on different lipoprotein classes.

PCSK9 Inhibitors: potential in cardiovascular therapeutics

Despite the efficacy of statin therapy, patients treated with these agents face substantial residual risk that is associated with achieved levels of LDL cholesterol (LDL-C). These observations suggest a potential benefit of additional strategies to promote further LDL-C reduction. Proprotein convertase subtilisin/kexin type 9 (PCSK9) has emerged as an attractive target in this regard. Abrogation of PCSK9 function prevents PCSK9-mediated catabolism of LDL receptors, increases cell surface LDL receptor density, and promotes clearance of LDL and other atherogenic lipoproteins from the circulation. Thus far, the most advanced approaches to block PCSK9 action are monoclonal antibodies and anti-sense oligonucleotides. Among statin-treated patients, these agents may produce additional LDL-C lowering exceeding 50 %. In rare genetic experiments of nature, individuals with dominant negative or dual loss of function mutations of PCSK9 appear to have no adverse health effects resulting from lifelong, very low levels of LDL-C. In short-term trials, PCSK9 antibodies have been generally well-tolerated. However, evidence to support long-term safety and efficacy of PCSK9 therapy to reduce cardiovascular risk awaits the results of large cardiovascular outcome trials.

Safety and effect of very low levels of low-density lipoprotein cholesterol on cardiovascular events

Based on the cardiovascular (CV) outcomes data derived predominantly from 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor (statin) trials, guidelines have set low-density lipoprotein (LDL) cholesterol targets at successively lower levels over time. Recent data have demonstrated that more-intensive statin therapy (and, consequently, lower LDL cholesterol level) is more effective at reducing CV events than less-intensive statin therapy. Although the average LDL cholesterol level for a United States adult is 119 mg/dl, within the "normal" range (90 to 130 mg/dl) per the United States National Cholesterol Education Program-Adult Treatment Panel III guidelines, data from fetal studies, diet studies, contemporary hunter-gatherer populations, and other mammals have suggested that the "normal" physiologic range for LDL cholesterol in humans is likely 50 to 70 mg/dl. Low LDL cholesterol levels have been sporadically associated with an increased risk of cancer, hemorrhagic stroke, and other complications in population studies and clinical trials. However, statin clinical trials have generally not demonstrated correlations between on-treatment LDL cholesterol levels and safety. Clinical data have suggested a linear relation between LDL cholesterol lowering and CV risk reduction, supporting a favorable risk/benefit ratio for attaining very low levels of LDL cholesterol to minimize the risk of CV events. In conclusion, clinical trial evidence demonstrating the efficacy and safety of LDL cholesterol lowering to a very low level is essential to ascertain the benefits and risks in reducing the residual risk of vascular disease.

The risks of a new hypothesis: why did JUPITER patients have almost twice the predicted event rate of reduction?

High serum cholesterol levels are associated with death from coronary heart disease and statin therapy has been demonstrated to effectively lower low-density lipoprotein (LDL) cholesterol and reduce coronary events in broad sections of the population. Recently, the Justification for the Use of Statins in Primary Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) randomized 17 802 apparently healthy individuals, with levels of LDL cholesterol below current treatment thresholds but with elevated levels of high-sensitivity C-reactive protein, to rosuvastatin 20 mg daily, or placebo. At a median follow-up of almost 2 years, compared to placebo, rosuvastatin treatment was associated with a significant reduction in the incidence of major cardiovascular or cerebrovascular events, that is, almost twice the magnitude found in previous statin trials. Such a noteworthy finding is discussed herein.

siRNA-induced liver ApoB knockdown lowers serum LDL-cholesterol in a mouse model with human-like serum lipids

Increased serum apolipoprotein (apo)B and associated LDL levels are well-correlated with an increased risk of coronary disease. ApoE⁻/⁻ and low density lipoprotein receptor (LDLr)⁻/⁻ mice have been extensively used for studies of coronary atherosclerosis. These animals show atherosclerotic lesions similar to those in humans, but their serum lipids are low in apoB-containing LDL particles. We describe the development of a new mouse model with a human-like lipid profile. Ldlr CETP⁺/⁻ hemizygous mice carry a single copy of the human CETP transgene and a single copy of a LDL receptor mutation. To evaluate the apoB pathways in this mouse model, we used novel short-interfering RNAs (siRNA) formulated in lipid nanoparticles (LNP). ApoB siRNAs induced up to 95% reduction of liver ApoB mRNA and serum apoB protein, and a significant lowering of serum LDL in Ldlr CETP⁺/⁻ mice. ApoB targeting is specific and dose-dependent, and it shows lipid-lowering effects for over three weeks. Although specific triglycerides (TG) were affected by ApoB mRNA knockdown (KD) and the total plasma lipid levels were decreased by 70%, the overall lipid distribution did not change. Results presented here demonstrate a new mouse model for investigating additional targets within the ApoB pathways using the siRNA modality.

Lipid lowering goals: back to nature?

Hypercholesterolemia is one of the main risk factors for the development of atherosclerosis. Decades of research have shown that lower cholesterol is better, but how low should we go? The average low-density lipoprotein cholesterol (LDL-C) level in the untreated western population is ∼130 mg/dl. However, insights from the early phase of life in animals and humans suggest that adult humans were genetically designed for much lower lipids level than is currently considered ‘average’. Adult animals in the wild and more primitive contemporary human societies share diets that are low in fats, and have similar very low blood cholesterol levels. Furthermore, extrapolation of data from meta-analyses of large trials suggest that the incidence of cardiovascular events would approach zero if the LDL-C were <60 mg/dl in primary prevention and approximately 30 mg/dl in secondary prevention. Such goals, which are considerably lower than the recommendations in current guidelines, might be attainable with the use of newer more potent lipid-lowering therapies. To date, achieving such low lipid levels appears safe, but the generalizability of these findings to broader populations and the clinical benefit on the reduction of cardiovascular complications remains to be proven.

Food insecurity and dyslipidemia among adults in the United States

OBJECTIVE

The objective of this study is to estimate the likelihood of dyslipidemia among food insecure men and women.

METHOD

Men, n=2572 and women, n=2977, in the National Health and Nutrition Examination Survey 1999-2002 cholesterol screening sample were included in this study. Gender-stratified descriptive comparisons and logistic regression models were used to study associations between food insecurity and dyslipidemia indicated by abnormal levels of fasting serum triglyceride (TRG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and their ratios.

RESULTS

Food insecurity did not associate with dyslipidemia among men. Among women, the associations between food insecurity and dyslipidemia were not consistent. Compared with the fully food secure, women who were marginally food secure were more likely to have abnormal levels of LDL-C (adjusted OR, 1.85; P=0.045) and TRG/HDL-C ratio (adjusted OR, 1.91; P=0.046). Women who were food insecure without hunger were more likely to have abnormal levels of TRG (adjusted OR, 1.90; P=0.041).

CONCLUSION

Intermediate-level food insecurity associated with some indicators of dyslipidemia among women but not among men. This observation shows food insecure women may be at risk of dyslipidemia.

Effect of fire smoke on some biochemical parameters in firefighters of Saudi Arabia

BACKGROUND

Firefighters who are facing fires, are frequently exposed to hazardous materials including carbon monoxide, hydrogen cyanide, hydrogen chloride, benzene, sulphur dioxide, etc. This study aimed to evaluate some relevant serum biochemical and blood hematological changes in activity involved firefighters in comparison to normal subjects.

SUBJECTS AND METHODS

Two groups of male firefighters volunteered to participate in the study. The first included 28 firefighters from Jeddah, while the second included 21 firefighters from Yanbu, with overall age ranged 20-48 years. An additional group of 23 male non-firefighters volunteered from both cities as normal control subjects, of age range 20-43 years. Blood samples were collected from all volunteer subjects and investigated for some relevant serum biochemical and blood hematological changes.

RESULTS

The results obtained showed that, there were statistically significant differences in liver function, kidney function, serum lipid profile, cortisol, creatine kinase, lactate dehydrogenase, iron and its biologically active derivatives, and blood picture in firefighters as compared with the normal control group. These results indicate that, fire smoke mainly affects serum biochemical and blood hematological parameters. Such results might point out to the need for more health protective and prophylactic measures to avoid such hazardous health effects that might endanger firefighters under their highly drastic working conditions.

CONCLUSION

Besides using of personal protective equipments for firefighters to protect them against exposure to toxic materials of fire smoke, it is recommended that, firefighters must be under continuous medical follow up through a standard timetabled medical laboratory investigations to allow for early detection of any serum biochemical or blood hematological changes that might happen during their active service life and to allow for early treatment whenever necessary.

Intensive statin therapy in acute coronary syndromes and stable coronary heart disease: a comparative meta-analysis of randomised controlled trials

BACKGROUND

Intensive statin therapy reduces major adverse cardiovascular events (MACE), but the effect on mortality is unclear.

OBJECTIVE

To determine whether intensive statin therapy reduces all-cause mortality compared with moderate statin therapy in patients with recent acute coronary syndromes (ACS) and stable coronary heart disease (CHD).

METHODS

Medline, Embase, the Cochrane Database, the internet, and conference proceedings from 1966 to 2006 were searched to identify relevant trials. Selection criteria were randomised allocation to intensive statin therapy (atorvastatin 80 mg/day, simvastatin 80 mg/day, or rosuvastatin 20-40 mg/day) versus moderate statin therapy, recent ACS or stable CHD at the time of randomisation, and > or =6 months of follow-up.

RESULTS

Six trials, encompassing 110 271 patient-years, were pooled. In patients with recent ACS, intensive statin therapy reduced all-cause mortality from 4.6% to 3.5% over 2.0 years (OR = 0.75, 95% CI 0.61 to 0.93). In patients with stable CHD, intensive statin therapy had no effect on all-cause mortality over 4.7 years (OR = 0.99, 95% CI 0.89 to 1.11). Overall, intensive statin therapy was associated with a reduction in MACE (OR = 0.84, 95% CI 0.77 to 0.91) and admissions to hospital for heart failure (OR = 0.72, 95% CI 0.62 to 0.83). Intensive statin therapy was also associated with an increase in hepatic transaminases >3 times normal (OR = 3.73, 95% CI 2.11 to 6.58) and a trend towards increased creatine kinase >10 times normal and/or rhabdomyolysis (OR = 1.96, 95% CI 0.50 to 7.63).

CONCLUSIONS

Compared with moderate statin therapy, intensive statin therapy reduces all-cause mortality in patients with recent ACS but not in patients with stable CHD.

Associations between apolipoprotein B, apolipoprotein AI, the apolipoprotein B/AI ratio and coronary heart disease: a literature-based meta-analysis of prospective studies

OBJECTIVES

To assess associations of circulating levels of apolipoprotein (apo) AI, apoB and the apoB/AI ratio (apoB/A) with risk of incident coronary heart disease (CHD).

DESIGN

Literature-based meta-analysis of prospective studies.

DATA SOURCES

Prospective studies in essentially general populations that reported on associations between apoAI, apoB or apoB/A and first incident CHD outcomes. Studies were identified by computer-based searches and by manual searches of the relevant literature.

RESULTS

Data from 23 relevant studies were identified. For apoAI, with 6333 CHD cases in 21 studies, comparison of individuals in the bottom third with those in the top third of baseline values yielded a combined relative risk of 1.62 (95% confidence interval: 1.43-1.83), i.e. an inverse association. For apoB, a combined analysis of 6320 CHD cases from 19 studies gave a relative risk of 1.99 (1.65-2.39) for a comparison of individuals in the top third versus those in the bottom third of baseline values. For apoB/A, with 3730 CHD cases from seven studies, a comparison of individuals in the top third versus the bottom third of baseline values gave a combined relative risk of 1.86 (1.55-2.22). These associations were somewhat stronger following correction for within-person variations in apolipoprotein levels. There was evidence of heterogeneity amongst the published studies, but it was only partly explained by available study-level characteristics.

CONCLUSIONS

The present quantitative review suggests the existence of moderately strong associations between baseline levels of each of apoAI, apoB, and apoB/A and risk of CHD. More detailed analysis, perhaps based on individual participant data from prospective studies, could help to overcome several limitations in the present review and to clarify any relevance of these apolipoproteins to disease prediction and aetiology.

Combination Drug Therapy: A Strategy for Aggressive Lipid Modification

This continuing feature will update readers on recent developments in cardiovascular pharmacotherapy. Cardiovascular disease remains the number one killer in the US, and more clinical outcome trials have been conducted in cardiology than in any other field of medicine. Given this rapidly expanding knowledge base, pharmacists can have a significant impact on prevention and treatment — if they keep current with developments in drug therapy.

Therapeutic silencing of an endogenous gene by systemic administration of modified siRNAs

RNA interference (RNAi) holds considerable promise as a therapeutic approach to silence disease-causing genes, particularly those that encode so-called 'non-druggable' targets that are not amenable to conventional therapeutics such as small molecules, proteins, or monoclonal antibodies. The main obstacle to achieving in vivo gene silencing by RNAi technologies is delivery. Here we show that chemically modified short interfering RNAs (siRNAs) can silence an endogenous gene encoding apolipoprotein B (apoB) after intravenous injection in mice. Administration of chemically modified siRNAs resulted in silencing of the apoB messenger RNA in liver and jejunum, decreased plasma levels of apoB protein, and reduced total cholesterol. We also show that these siRNAs can silence human apoB in a transgenic mouse model. In our in vivo study, the mechanism of action for the siRNAs was proven to occur through RNAi-mediated mRNA degradation, and we determined that cleavage of the apoB mRNA occurred specifically at the predicted site. These findings demonstrate the therapeutic potential of siRNAs for the treatment of disease.

Lack of oxidative stress in a selenium deficient area in Ivory Coast--potential nutritional antioxidant role of crude palm oil

BACKGROUND

Previous studies have described an important selenium deficiency in a mountain region (Glanle) in the west of Ivory Coast.

AIM OF THE STUDY

To assess the antioxidant capacity of subjects from a selenium deficient area in Ivory Coast (Glanle region).

METHODS

This study involved 57 subjects, 18 to 69 years old, living in the Glanle region and 56 healthy controls living in the southern coastal region (Bodou). In the Glanle region families consume basically a vegetarian and crude palm oil diet, whereas in the Bodou region, families eat a fish-based diet with principally refined palm oil. Fasting blood samples were collected to assess the following parameters: lipid status (plasma total lipids; total-, HDL and LDL-cholesterol; triglycerides; phospholipids; fatty acid composition), plasma protein status (total protein, albumin, transthyretin, orosomucoid, CRP, transferrin), antioxidant capacity (plasma selenium, uric acid, retinol, alpha-tocopherol and tocotrienols levels, plasma seleno-glutathione peroxidase (GSHPx) activity) and oxidative stress markers (malondialdehyde (MDA) and advanced oxidation protein products (AOPP)).

RESULTS

The mountain region samples (Glanle) were characterized by significantly lower plasma albumin, total-, HDL- and LDL-cholesterol, retinol and selenium levels, plasma PUFA content and GSHPx activity, but significantly higher alpha-tocopherol index and total tocotrienol level, than controls from the coastal area (Bodou). These results suggest a higher exposure risk to oxidative stress for the mountain region subjects. However, the absence of oxidative damage in this group provides evidence of a selenium independent protection mechanism against oxidative stress. This protection is related to lower plasma LDL cholesterol and PUFA content, and to higher alpha-tocopherol index, delta and total tocotrienols.

CONCLUSION

The long-term consumption of crude palm oil could be considered as an effective protective factor against oxidative stress.

Optimal low-density lipoprotein is 50 to 70 mg/dl: lower is better and physiologically normal

The normal low-density lipoprotein (LDL) cholesterol range is 50 to 70 mg/dl for native hunter-gatherers, healthy human neonates, free-living primates, and other wild mammals (all of whom do not develop atherosclerosis). Randomized trial data suggest atherosclerosis progression and coronary heart disease events are minimized when LDL is lowered to <70 mg/dl. No major safety concerns have surfaced in studies that lowered LDL to this range of 50 to 70 mg/dl. The current guidelines setting the target LDL at 100 to 115 mg/dl may lead to substantial undertreatment in high-risk individuals.

Reduction of serum LDL-C levels: a relationship to clinical benefits

The association between elevated serum cholesterol levels and cardiovascular risk was established several decades ago by studies such as the Framingham study and the Multiple Risk Factor Intervention Trial (MRFIT). Both primary and secondary prevention trials of cholesterol lowering, using HMG-CoA reductase inhibitors, have demonstrated clear benefits for lipid lowering in preventing both cardiovascular morbidity and mortality over a wide spectrum of coronary heart disease (CHD) risk. Even so, risk of events has been reduced by about 30% in these trials, leaving 70% of events occurring even in the presence of substantial cholesterol lowering. It is unknown whether further reduction of serum cholesterol levels will lower risk factors. The relationship between cholesterol lowering and cardiovascular risk, moreover, is not completely defined; it is unclear, at lower cholesterol levels, whether that relationship follows a threshold, a linear, or a curvilinear model. Early studies of low-density lipoprotein-cholesterol (LDL-C) lowering with HMG-CoA reductase inhibitors suggested that non-cardiovascular mortality might be increased at low serum LDL-C levels, however, these concerns have not been supported by subsequent clinical trials. Recent studies have shed further light on the potential benefits of lowering serum cholesterol levels beyond current guideline targets with HMG-CoA reductase inhibitors. More potent agents in development are likely to make such levels more readily achievable, as well as making guideline targets attainable for many of the large number of patients who currently fail to reach them.

[Hypocholesterolemia in hospitalized elderly: relations with inflammatory and nutritional status]

PURPOSE

Hypocholesterolemia is a common finding in hospitalized elderly people and is associated with increased mortality. Changes in plasma lipid levels are well known in the acute phase response. It has also been suggested that malnutrition is a cause of hypocholesterolemia. However, malnutrition is the reflect of general condition, and the respective roles of malnutrition and inflammation have not yet been clearly established. This research project was undertaken to examine the impact of nutritional and inflammatory status on the hypocholesterolemia.

METHODS

In a prospective study, 597 elderly patients (83 +/- 7 years) consecutively admitted in a geriatric acute care unit were included. Clinical and anthropometric data: Body Mass Index (BMI), Tricipital Skinfold Thickness (TSF), Sub-Scapular Skinfold Thickness (SSF), Mid Arm Circumference (MAC) have been collected. The blood samples were obtained within the 72 hours following the admission. Nutritional proteins (albumin, prealbumin, transferrin, retinol binding protein); inflammatory proteins (CRP, alpha-1 acid glycoprotein), and blood lipids (cholesterol, LDL, HDL cholesterol, triglycerides, apoproteins A1 and B) were dosed.

RESULTS

The anthropometric and biologic parameters have been compared on the two sexes, significant differences were observed only for blood lipids. The analyses are thus realized and presented by sex separately. Four groups of patients are generated according to the quartile of total cholesterol. Means and standard deviation for all factors are calculated within each group. Both, the trend of means and analyses of correlation show associations with cholesterol in the two sexes. The analysis of variance showed that the cholesterolemia is associated with 1/ decrease in the values of the anthropometrics, and nutritional proteins and 2/ upward trends of the inflammatory parameters. Significant correlations were observed for all transport proteins and CRP with total cholesterol in men and women. The multiple linear regression of the total cholesterol retained albumin, APO A1, APO B and RBP as predictor factors of cholesterolemia for women and APO A1, APO B and tryglicerid for men. When patients with infectious diseases were compared to the others, significant differences have been observed for total cholesterol and all blood lipids, as well as for nutritional and inflammatory proteins.

CONCLUSION

The results confirm an association between nutritional status and hypocholesterolemia, and suggest also the responsability of inflammation as a cause of hypocholesterolemia.

Phenotypic expression of familial hypobetalipoproteinemia in three kindreds with mutations of apolipoprotein B gene

We report the clinical phenotype in three kindreds with familial heterozygous hypobetalipoproteinemia (FHBL) carrying novel truncated apolipoprotein Bs (apoBs) of different sizes (apoB-8.15, apoB-33.4 and apoB-75.7). In D.A. kindred, we found three carriers of a C-deletion in exon 10 leading to the synthesis of apoB-8.15 not detectable in plasma. They showed steatorrhea and fatty liver. In N.L. kindred, the proband is heterozygous for a nonsense mutation in exon 26, leading to the formation of apoB-33.4. He had premature cerebrovascular disease and fatty liver; two apoB-33.4 carriers in this kindred showed only fatty liver. In B.E. kindred, the proband is heterozygous for a T-deletion in exon 26, which converts tyrosine at codon 3435 into a stop codon, resulting in apoB-75.7. The proband, a heavy alcohol drinker, had steatohepatitis, whereas his teetotaller daughter, an apoB-75.7 carrier, had no detectable fatty liver. This study suggests that: i) fatty liver invariably develops in FHBL carriers of short and medium-size truncated apoBs (< apoB-48), but its occurrence needs additional environmental factors in carriers of longer apoB forms; ii) intestinal lipid malabsorption develops only in carriers of short truncated apoBs, which are not secreted into the plasma; and iii) cerebrovascular disease due to premature atherosclerosis may occur even in FHBL subjects.

A study of fatty liver disease and plasma lipoproteins in a kindred with familial hypobetalipoproteinemia due to a novel truncated form of apolipoprotein B (APO B-54.5)

BACKGROUND/AIMS

Familial hypobetalipoproteinemia (FHBL) is a co-dominant disorder characterized by reduced plasma levels of low-density lipoproteins. It can be caused by mutations in the gene encoding apolipoprotein B-100 (apo B), leading to the formation of truncated apo Bs which have a reduced capacity to export lipids from the hepatocytes as lipoprotein constituents. Case reports suggest the occurrence of liver disease in FHBL, but there are no studies of liver involvement in FHBL with defined apo B gene mutations. The presence of fatty liver disease was investigated in a large FHBL kindred.

METHODS

Plasma lipoprotein and apolipoprotein analysis, liver function tests, and apo B gene sequence were performed in 16 members of a FHBL kindred. The presence of fatty liver was assessed by ultrasound and computed tomography scanning.

RESULTS

The proband, a non-obese heavy drinker male with hypobetalipoproteinemia, had steatohepatitis with fibrosis. He was heterozygous for a novel non-sense mutation of apo B gene producing a truncated apo B of 2745 amino acids (designated apo B-54.5, having half the size of normal apo B-100). Seven other members of his kindred carried apo B-54.5. Although all of them were hypolipidemic, their lipid levels showed a large inter-individual variability not accounted for by polymorphisms of genes involved in apo B metabolism. Four carriers (two heavy drinkers and two teetotallers), irrespective of their plasma lipid levels, had ultrasonographic evidence of fatty liver. In the other four carriers no evidence of fatty liver was found.

CONCLUSIONS

In this kindred apo B-54.5 predisposes to fatty liver, which however may require some additional factors to become clinically relevant.