Paraoxonase 1: evolution of the enzyme and of its role in protecting against atherosclerosis.

PURPOSE OF REVIEW: To review the discoveries which led to the concept that serum paraoxonase 1 (PON1) is inversely related to atherosclerotic cardiovascular disease (ASCVD) incidence, how this association came to be regarded as causal and how such a role might have evolved. RECENT FINDINGS: Animal models suggest a causal link between PON1 present on HDL and atherosclerosis. Serum PON1 activity predicts ASCVD with a similar reliability to HDL cholesterol, but at the extremes of high and low HDL cholesterol, there is discordance with PON1 being potentially more accurate. The paraoxonase gene family has its origins in the earliest life forms. Its greatest hydrolytic activity is towards lactones and organophosphates, both of which can be generated in the natural environment. It is active towards a wide range of substrates and thus its conservation may have resulted from improved survival of species facing a variety of evolutionary challenges. SUMMARY: Protection against ASCVD is likely to be the consequence of some promiscuous activity of PON1, but nonetheless has the potential for exploitation to improve risk prediction and prevention of ASCVD.

Pancreatic and cardiometabolic complications of severe hypertriglyceridaemia.

PURPOSE OF REVIEW: This review endeavours to explore the aetiopathogenesis and impact of severe hypertriglyceridemia (SHTG) and chylomicronaemia on cardiovascular, and pancreatic complications and summarizes the novel pharmacological options for management. RECENT FINDINGS: SHTG, although rare, presents significant diagnostic and therapeutic challenges. Familial chylomicronaemia syndrome (FCS), is the rare monogenic form of SHTG, associated with increased acute pancreatitis (AP) risk, whereas relatively common multifactorial chylomicronaemia syndrome (MCS) leans more towards cardiovascular complications. Despite the introduction and validation of the FCS Score, FCS continues to be underdiagnosed and diagnosis is often delayed. Longitudinal data on disease progression remains scant. SHTG-induced AP remains a life-threatening concern, with conservative treatment as the cornerstone while blood purification techniques offer limited additional benefit. Conventional lipid-lowering medications exhibit minimal efficacy, underscoring the growing interest in novel therapeutic avenues, that is, antisense oligonucleotides (ASO) and short interfering RNA (siRNA) targeting apolipoprotein C3 (ApoC3) and angiopoietin-like protein 3 and/or 8 (ANGPTL3/8). SUMMARY: Despite advancements in understanding the genetic basis and pathogenesis of SHTG, diagnostic and therapeutic challenges persist. The rarity of FCS and the heterogenous phenotype of MCS underscore the need for the development of predictive models for complications and tailored personalized treatment strategies. The establishment of national and international registries is advocated to augment disease comprehension and identify high-risk individuals.

Established and potential cardiovascular risk factors in metabolic syndrome: Effect of bariatric surgery.

PURPOSE OF REVIEW: The aim of this review was to provide an overview of the role of novel biomarkers in metabolic syndrome, their association with cardiovascular risk and the impact of bariatric surgery on these biomarkers. RECENT FINDINGS: Metabolic syndrome encompasses an intricate network of health problems, and its constituents extend beyond the components of its operational definition. Obesity-related dyslipidaemia not only leads to quantitative changes in lipoprotein concentration but also alteration in qualitative composition of various lipoprotein subfractions, including HDL particles, rendering them proatherogenic. This is compounded by the concurrent existence of obstructive sleep apnoea (OSA) and nonalcoholic fatty liver disease (NAFLD), which pave the common pathway to inflammation and oxidative stress culminating in heightened atherosclerotic cardiovascular disease (ASCVD) risk. Bariatric surgery is an exceptional modality to reverse both conventional and less recognised aspects of metabolic syndrome. It reduces the burden of atherosclerosis by ameliorating the impact of obesity and its related complications (OSA, NAFLD) on quantitative and qualitative composition of lipoproteins, ultimately improving endothelial function and cardiovascular morbidity and mortality. SUMMARY: Several novel biomarkers, which are not traditionally considered as components of metabolic syndrome play a crucial role in determining ASCVD risk in metabolic syndrome. Due to their independent association with ASCVD, it is imperative that these are addressed. Bariatric surgery is a widely recognized intervention to improve the conventional risk factors associated with metabolic syndrome; however, it also serves as an effective treatment to optimize novel biomarkers.

What should be the goal of cholesterol-lowering treatment? A quantitative evaluation dispelling guideline myths.

PURPOSE OF REVIEW: Guidelines for cholesterol-lowering treatment generally include extensive review of epidemiological and clinical trial evidence. However, the next logical step, the translation of evidence into clinical advice, occurs not entirely by reasoning, but by a form of consensus in which the prejudices and established beliefs of the societies with interests in cardiovascular disease convened to interpret the evidence are prominent. Methods, which are the subject of this review, have, however, been developed by which clinical trial evidence can be translated objectively into best practice. RECENT FINDINGS: Guidelines differ in their recommended goals for cholesterol-lowering treatment in the prevention of atherosclerotic cardiovascular disease (ASCVD). Proposed goals are LDL-cholesterol 2.6 mmol/l (100 mg/dl) or less in lower risk, LDL-cholesterol 1.8 mmol/l (70 mg/dl) or less in higher risk, non-HDL-cholesterol decrease of at least 40% or LDL-cholesterol 1.8 mmol/l (70 mg/dl) or less or decreased by at least 50% whichever is lower. Evidence from clinical trials of statins, ezetimibe and proprotein convertase subtilisin/kexin type 9-inhibitors can be expressed in simple mathematical terms to compare the efficacy on ASCVD incidence of clinical guidance for the use of cholesterol-lowering medication. The target LDL-cholesterol of 2.6 mmol/l (100 mg/dl) is ineffective and lacks credibility. Cholesterol-lowering medication is most effective in high-risk people with raised LDL-cholesterol. The best overall therapeutic target is LDL-cholesterol 1.8 mmol/l (70 mg/dl) or less or decreased by at least 50% whichever is lower. The use of non-HDL-cholesterol as a therapeutic goal is less efficacious. Aiming for LDL-cholesterol 1.4 mmol/l (55 mg/dl) or less as opposed to 1.8 mmol/l produces only a small additional benefit. Evidence for apolipoprotein B targets in hypertriglyceridaemia and in very high ASCVD risk should be more prominent in future guidelines. SUMMARY: The LDL-cholesterol goal of 2.6 mmol/l or less should be abandoned. Percentage decreases in LDL-cholesterol or non-HDL-cholesterol concentration are better in people with initial concentrations of less than 3.6 mmol/l. The LDL-cholesterol target of 1.8 mmol/l is most effective when initial LDL-cholesterol is more than 3.6 mmol/l in both primary and secondary prevention.

Lipoprotein (a) in familial hypercholesterolaemia.

PURPOSE OF REVIEW: The role of lipoprotein (a) in atherogenesis has been the subject of argument for many years. Evidence that it is raised in familial hypercholesterolaemia has been disputed not least because a mechanism related to low density lipoprotein (LDL) receptor mediated catabolism has been lacking. Whether lipoprotein (a) increases the already raised atherosclerotic cardiovascular disease (ASCVD) risk in familial hypercholesterolaemia is also more dubious than is often stated. We review the evidence in an attempt to provide greater clarity. RECENT FINDINGS: Lipoprotein (a) levels are raised as a consequence of inheriting familial hypercholesterolaemia. The mechanism for this is likely to involve increased hepatic production, probably mediated by PCSK9 augmented by apolipoprotein E. The extent to which raised lipoprotein (a) contributes to the increased ASCVD risk in familial hypercholesterolaemia remains controversial.Unlike, for example, statins which are effective across the whole spectrum of LDL concentrations, drugs in development to specifically lower lipoprotein (a) are likely to be most effective in people with the highest levels of lipoprotein (a). People with familial hypercholesterolaemia may therefore be in the vanguard of those in whom theses agents should be exhibited. SUMMARY: Inheritance of familial hypercholesterolaemia undoubtedly increases the likelihood that lipoprotein (a) will be raised. However, in familial hypercholesterolaemia when ASCVD incidence is already greatly increased due to high LDL cholesterol, whether lipoprotein (a) contributes further to this risk cogently needs to be tested with drugs designed to specifically lower lipoprotein (a).

Bariatric surgery leads to an improvement in small nerve fibre damage in subjects with obesity.

INTRODUCTION: Subjects with obesity have metabolic risk factors for nerve fibre damage. Because bariatric surgery improves these risk factors we have assessed whether this can ameliorate nerve fibre damage. METHODS: Twenty-six obese subjects without diabetes (age: 46.23 ± 8.6, BMI: 48.7 ± 1.5, HbA1c: 38.0 ± 4.5) and 20 controls (age: 48.3 ± 6.2, BMI: 26.8 ± 4.2, HbA1c: 39.1 ± 2.6) underwent detailed assessment of neuropathy at baseline and 12 months after bariatric surgery. RESULTS: Obese subjects had normal peroneal (45.9 ± 5.5 vs. 48.1 ± 4.5, P = 0.1) and sural (46.9 ± 7.6 vs. 47.9 ± 10.6, P = 0.1) nerve conduction velocity, but a significantly higher neuropathy symptom profile (NSP) (4.3 ± 5.7 vs. 0.3 ± 0.6, P = 0.001), vibration perception threshold (VPT) (V) (10.2 ± 6.8 vs. 4.8 ± 2.7, P < 0.0001), warm threshold (C°) (40.4 ± 3.5 vs. 37.2 ± 1.8, P = 0.003) and lower peroneal (3.8 ± 2.2 vs. 4.9 ± 2.2, P = 0.02) and sural (8.9 ± 5.8 vs. 15.2 ± 8.5, P < 0.0001) nerve amplitude, deep breathing-heart rate variability (DB-HRV) (beats/min) (21.7 ± 4.1 vs. 30.1 ± 14, P = 0.001), corneal nerve fibre density (CNFD) (n/mm2) (25.6 ± 5.3 vs. 32.0 ± 3.1, P < 0.0001), corneal nerve branch density (CNBD) (n/mm2) (56.9 ± 27.5 vs. 111.4 ± 30.7, P < 0.0001) and corneal nerve fibre length (CNFL) (mm/mm2) (17.9 ± 4.1 vs. 29.8 ± 4.9, P < 0.0001) compared to controls at baseline. In control subjects there was no change in neuropathy measures over 12 months. However, 12 months after bariatric surgery there was a significant reduction in BMI (33.7 ± 1.7 vs. 48.7 ± 1.5, P = 0.001), HbA1c (34.3 ± 0.6 vs. 38.0 ± 4.5, P = 0.0002), triglycerides (mmol/l) (1.3 ± 0.6 vs. 1.6 ± 0.8, P = 0.005) and low-density lipoprotein cholesterol (mmol/l) (2.7 ± 0.7 vs. 3.1 ± 0.9, P = 0.02) and an increase in high-density lipoprotein cholesterol (mmol/l) (1.2 ± 0.3 vs. 1.04 ± 0.2, P = 0.002). There was a significant improvement in NSP (1.6 ± 2.7 vs. 4.3 ± 5.7, P = 0.004), neuropathy disability score (0.3 ± 0.9 vs. 1.3 ± 2.0, P = 0.03), CNFD (28.2 ± 4.4 vs. 25.6 ± 5.3, P = 0.03), CNBD (64.7 ± 26.1 vs. 56.9 ± 27.5, P = 0.04) and CNFL (20.4 ± 1.2 vs. 17.9 ± 4.1, P = 0.02), but no change in cold and warm threshold, VPT, DB-HRV or nerve conduction velocity and amplitude. Increase in CNFD correlated with a decrease in triglycerides (r = -0.45, P = 0.04). CONCLUSION: Obese subjects have evidence of neuropathy, and bariatric surgery leads to an improvement in weight, HbA1c, lipids, neuropathic symptoms and deficits and small nerve fibre regeneration without a change in quantitative sensory testing, autonomic function or neurophysiology.

Non-HDL or LDL cholesterol in heterozygous familial hypercholesterolaemia: findings of the Simon Broome Register.

PURPOSE OF REVIEW: The role of non-HDL-C in the identification and management of lipid disorders is not clearly defined, although UK guidelines recommend its wider use in assessing the need for lipid-lowering therapy and as a treatment target. RECENT FINDINGS: We examined the implications of the use of non-HDL-C as opposed to LDL-C in 253 people with hypercholesterolaemia before treatment and 573 after treatment in whom fasting total serum cholesterol, HDL-C and LDL-C had been recorded and the diagnosis of heterozygous familial hypercholesterolemia (heFH) was investigated by genetic testing. The difference and the limits of agreement between non-HDL-C and LDL-C calculated using the Friedewald formula were assessed in those with and without heFH-causing mutations. SUMMARY: There were 147 mutation-positive and 106 mutation-negative pretreatment participants and 395 mutation-positive and 178 mutation-negative patients receiving treatment. The difference between non-HDL-C and LDL-C pretreatment in mutation-positive people (mean LDL-C 7.73 mmol/l) was 0.67 mmol/l (95% CI 0.62-0.73) and posttreatment (mean LDL-C 4.71 mmol/l) was 0.62 mmol/l (95% CI 0.59-0.65) with wide limits of agreement of -0.02 to 1.37 and 0.07-1.18 mmol/l, respectively. Among patients with heterozygous familial hypercholesterolaemia, use of estimated LDL-C derived from non-HDL-C in place of calculated LDL-C may result in diagnostic misclassification and difficulty in assessing the true reduction in LDL-C with treatment, because of the wide inter-individual limits of agreement around the mean difference between non-HDL-C and LDL-C.

Non-HDL cholesterol should not generally replace LDL cholesterol in the management of hyperlipidaemia.

PURPOSE OF REVIEW: Non-HDL cholesterol was originally conceived as a therapeutic target for statin treatment in hypertriglyceridaemia when apolipoprotein B100 assays were not widely available. Recently non-HDL cholesterol has been recommended to replace LDL cholesterol in the clinical management of dyslipidaemia routinely in general medical practice. This is misguided. RECENT FINDINGS: Non-HDL cholesterol is heterogeneous, constituting a mixture of triglyceride-rich VLDL, intermediate density lipoprotein and LDL in which small dense LDL is poorly represented and to which VLDL cholesterol contributes increasingly as triglyceride levels rise. This makes it unsuitable as a goal of lipid-lowering treatment or as an arbiter of who should receive such treatment. Results of trials designed to lower LDL cholesterol are not easily translated to non-HDL cholesterol. Fasting is no longer thought essential for screening the general population for raised LDL cholesterol. ApoB100 measurement also does not require fasting even in rarer more extreme lipoprotein disorders encountered in the Lipid Clinic, provides greater precision and specificity and overcomes the problems posed by LDL and non-HDL cholesterol. It is more easily interpreted both in diagnosis and as a therapeutic goal and it includes SD-LDL. SUMMARY: If we are to discourage use of LDL cholesterol, it should be in favour of apoB100 not non-HDL cholesterol.

Serum kidney injury molecule 1 and ß2-microglobulin perform as well as larger biomarker panels for prediction of rapid decline in renal function in type 2 diabetes.

AIMS/HYPOTHESIS: As part of the Surrogate Markers for Micro- and Macrovascular Hard Endpoints for Innovative Diabetes Tools (SUMMIT) programme we previously reported that large panels of biomarkers derived from three analytical platforms maximised prediction of progression of renal decline in type 2 diabetes. Here, we hypothesised that smaller (n ≤ 5), platform-specific combinations of biomarkers selected from these larger panels might achieve similar prediction performance when tested in three additional type 2 diabetes cohorts. METHODS: We used 657 serum samples, held under differing storage conditions, from the Scania Diabetes Registry (SDR) and Genetics of Diabetes Audit and Research Tayside (GoDARTS), and a further 183 nested case-control sample set from the Collaborative Atorvastatin in Diabetes Study (CARDS). We analysed 42 biomarkers measured on the SDR and GoDARTS samples by a variety of methods including standard ELISA, multiplexed ELISA (Luminex) and mass spectrometry. The subset of 21 Luminex biomarkers was also measured on the CARDS samples. We used the event definition of loss of >20% of baseline eGFR during follow-up from a baseline eGFR of 30-75 ml min-1 [1.73 m]-2. A total of 403 individuals experienced an event during a median follow-up of 7 years. We used discrete-time logistic regression models with tenfold cross-validation to assess association of biomarker panels with loss of kidney function. RESULTS: Twelve biomarkers showed significant association with eGFR decline adjusted for covariates in one or more of the sample sets when evaluated singly. Kidney injury molecule 1 (KIM-1) and ß2-microglobulin (B2M) showed the most consistent effects, with standardised odds ratios for progression of at least 1.4 (p < 0.0003) in all cohorts. A combination of B2M and KIM-1 added to clinical covariates, including baseline eGFR and albuminuria, modestly improved prediction, increasing the area under the curve in the SDR, Go-DARTS and CARDS by 0.079, 0.073 and 0.239, respectively. Neither the inclusion of additional Luminex biomarkers on top of B2M and KIM-1 nor a sparse mass spectrometry panel, nor the larger multiplatform panels previously identified, consistently improved prediction further across all validation sets. CONCLUSIONS/INTERPRETATION: Serum KIM-1 and B2M independently improve prediction of renal decline from an eGFR of 30-75 ml min-1 [1.73 m]-2 in type 2 diabetes beyond clinical factors and prior eGFR and are robust to varying sample storage conditions. Larger panels of biomarkers did not improve prediction beyond these two biomarkers.

Acquired low cholesterol: diagnosis and relevance to safety of low LDL therapeutic targets.

PURPOSE OF REVIEW: Acquired hypocholesterolaemia occurs more commonly than inherited hypocholesterolaemia but has received little attention in the literature. In this review, we discuss the causes and underlying mechanisms of acquired hypocholesterolaemia and its relevance to safety of therapeutically induced decreased LDL cholesterol levels. RECENT FINDINGS: Hypocholesterolaemia is increasingly identified as cholesterol testing becomes more widespread in the assessment of cardiovascular risk. Lower therapeutic targets for LDL cholesterol are also being achieved more regularly with the introduction of more intensive cholesterol-lowering regimens. Acquired hypocholesterolaemia may be the presenting feature of treatable diseases. Understanding its mechanisms may also provide new treatment approaches for neoplastic disease, such as breast cancer, and infections, such as tuberculosis. SUMMARY: When hypocholesterolaemia is discovered, it is important to identify its cause. Further research into the pathogenesis of hypocholesterolaemia may provide new therapies for primary diseases underlying it.

Evidence for more intensive cholesterol lowering.

PURPOSE OF REVIEW: In randomized clinical trials, reduction in cardiovascular disease (CVD) risk with cholesterol-lowering drugs correlates with the LDL cholesterol decrease. However, because the majority have investigated a fixed statin dose, current guidelines disagree about the use of statin dose titration or non-statin adjunctive cholesterol-lowering drugs. RECENT FINDINGS: We conducted a meta-analysis of all randomized controlled trials with CVD end-points, comparing two intensities of lipid-lowering regimens within the same population, using varying statins doses and/or potency, ezetimibe or PCSK9 inhibitors and compared the observed number of patients needed to be treated for 10 years to prevent one CVD event (NNT) with NNT predicted from trials of predominantly single-dose statin.Some 75439 participants in 10 randomized studies were included. The mean 10-year CVD risk in controls was around 50% and the incremental mean LDL cholesterol decrease 0.95 mmol/l (36.7 mg/dl). Observed NNT closely correlated with those predicted from predominantly single-dose statin trials [18.2 and 17.1; Pearson R=0.844 (P=0.001)]. When pre-treatment LDL cholesterol exceeded 4 mmol/l (155 mg/dl), achieving a target LDL cholesterol of 1.8 mmol/l (70 mg/dl) was the most effective strategy. At lower pre-treatment levels, fixed-dose statin equivalent to atorvastatin 80 mg daily was superior. The target of 40% reduction in non-high density lipoprotein cholesterol was least effective regardless of pre-treatment LDL cholesterol. SUMMARY: We conclude that when initial LDL cholesterol exceeds 4 mmol/l and absolute CVD risk demands it, a target value of 1.8 mmol/l should be achieved, if necessary by adding ezetimibe and/or PCSK9 inhibitors to statin treatment.

Meta-analysis of genome-wide association studies of HDL cholesterol response to statins.

BACKGROUND: In addition to lowering low density lipoprotein cholesterol (LDL-C), statin therapy also raises high density lipoprotein cholesterol (HDL-C) levels. Inter-individual variation in HDL-C response to statins may be partially explained by genetic variation. METHODS AND RESULTS: We performed a meta-analysis of genome-wide association studies (GWAS) to identify variants with an effect on statin-induced high density lipoprotein cholesterol (HDL-C) changes. The 123 most promising signals with p<1×10-4 from the 16 769 statin-treated participants in the first analysis stage were followed up in an independent group of 10 951 statin-treated individuals, providing a total sample size of 27 720 individuals. The only associations of genome-wide significance (p<5×10-8) were between minor alleles at the CETP locus and greater HDL-C response to statin treatment. CONCLUSIONS: Based on results from this study that included a relatively large sample size, we suggest that CETP may be the only detectable locus with common genetic variants that influence HDL-C response to statins substantially in individuals of European descent. Although CETP is known to be associated with HDL-C, we provide evidence that this pharmacogenetic effect is independent of its association with baseline HDL-C levels.

Diabetic dyslipidaemia.

PURPOSE OF REVIEW: The purpose is to discuss recent developments in the understanding of lipoprotein metabolism in diabetes, the cardiovascular risk associated with both type 1 and type 2 diabetes, recently published guidelines on the management of this risk, concerns over the use of statin treatment in diabetes, and other therapeutic options. RECENT FINDINGS: Diabetic dyslipidaemia can be gross with massive hypertriglyceridemia, or subtle with a lipid profile which would be regarded as normal in a nondiabetic patient, but which hides underlying increases in atherogenic subfractions of LDL (e.g., small dense LDL, glycated LDL) and remnant lipoproteins. Statins can decrease these without the clinician being aware from routine biochemistry. In type 2 diabetes, HDL cholesterol levels are often reduced, whereas in type 1, insulin can raise HDL, but its antiatherogenic properties are compromised. Dyslipidaemia and hypertension predate the onset of glycaemia of diabetic proportions (metabolic syndrome). Obese people can thus die of diabetes before they develop it. Obesity should be prevented and treated. Statins decrease the risk of cardiovascular disease in diabetes or metabolic syndrome regardless of whether glycaemia worsens. SUMMARY: One unassailable truth is that statin therapy is beneficial and should rarely, if ever, be withheld.

Effect of atorvastatin on glycaemia progression in patients with diabetes: an analysis from the Collaborative Atorvastatin in Diabetes Trial (CARDS).

AIMS/HYPOTHESIS: In an individual-level analysis we examined the effect of atorvastatin on glycaemia progression in type 2 diabetes and whether glycaemia effects reduce the prevention of cardiovascular disease (CVD) with atorvastatin. METHODS: The study population comprised 2,739 people taking part in the Collaborative Atorvastatin Diabetes Study (CARDS) who were randomised to receive atorvastatin 10 mg or placebo and who had post-randomisation HbA1c data. This secondary analysis used Cox regression to estimate the effect of atorvastatin on glycaemia progression, defined as an increase in HbA1c of ≥ 0.5% (5.5 mmol/mol) or intensification of diabetes therapy. Mixed models were used to estimate the effect of atorvastatin on HbA1c as a continuous endpoint. RESULTS: Glycaemia progression occurred in 73.6% of participants allocated placebo and 78.1% of those allocated atorvastatin (HR 1.18 [95% CI 1.08, 1.29], p < 0.001) by the end of follow-up. The HR was 1.22 (95% CI 1.19, 1.35) in men and 1.11 (95% CI 0.95, 1.29) in women (p = 0.098 for the sex interaction). A similar effect was seen in on-treatment analyses: HR 1.20 (95% CI 1.07, 1.35), p = 0.001. The net mean treatment effect on HbA1c was 0.14% (95% CI 0.08, 0.21) (1.5 mmol/mol). The effect did not increase through time. Diabetes treatment intensification alone did not differ with statin allocation. Neither baseline nor 1-year-attained HbA1c predicted subsequent CVD, and the atorvastatin effect on CVD did not vary by HbA1c change (interaction p value 0.229). CONCLUSIONS/INTERPRETATION: The effect of atorvastatin 10 mg on glycaemia progression among those with diabetes is statistically significant but very small, is not significantly different between sexes, does not increase with duration of statin and does not have an impact on the magnitude of CVD risk reduction with atorvastatin.

Cholesterol, not just cardiovascular risk, is important in deciding who should receive statin treatment.

AIMS: Guidelines for primary prevention of cardiovascular disease (CVD) with statins, including the most recent, fail to make the best use of the evidence from clinical trials by concentrating on absolute CVD risk as a statin indication and not also considering that a major determinant of therapeutic benefit is the magnitude of the low-density lipoprotein (LDL) (or non-HDL) cholesterol reduction achieved. This decrease is proportional to the pretreatment concentration. We set out to apply this knowledge to the calculation of the number needed to treat to prevent one event (NNT) and to assess critically how current guidelines performed at different degrees of CVD risk across a range of LDL (or non-HDL) cholesterol concentrations. METHODS AND RESULTS: Number needed to treat to prevent one event revealed exclusion from the treatment of some people with higher cholesterol levels, who may benefit more than others needlessly exposed to statins with no realistic prospect of benefit. Furthermore, abandonment of cholesterol therapeutic goals disadvantaged people with higher levels. CONCLUSION: These problems can be overcome by basing the decision to treat on the NNT calculated both from absolute CVD risk and also on the LDL (or non-HDL) cholesterol reduction achievable with statin treatment. This need not adds an additional layer of complexity for the clinician, because computer programmes already used to estimate CVD risk could be easily amended, thus permitting more effective deployment of statins in the population.

Liver Fat Measured by MR Spectroscopy: Estimate of Imprecision and Relationship with Serum Glycerol, Caeruloplasmin and Non-Esterified Fatty Acids.

Magnetic resonance spectroscopy (MRS) is a non-invasive method for quantitative estimation of liver fat. Knowledge of its imprecision, which comprises biological variability and measurement error, is required to design therapeutic trials with measurement of change. The role of adipocyte lipolysis in ectopic fat accumulation remains unclear. We examined the relationship between liver fat content and indices of lipolysis, and determine whether lipolysis reflects insulin resistance or metabolic liver disease. Imprecision of measurement of liver fat was estimated from duplicate measurements by MRS at one month intervals. Patients provided fasting blood samples and we examined the correlation of liver fat with indices of insulin resistance, lipolysis and metabolic liver disease using Kendall Tau statistics. The coefficient of variation of liver fat content was 14.8%. Liver fat was positively related to serum insulin (T = 0.48, p = 0.042), homeostasis model assessment (HOMA)-B% (T = -0.48, p = 0.042), and body mass index (BMI) (T = 0.59, p = 0.012); and inversely related to HOMA-S% (T = -0.48, p = 0.042), serum glycerol (T = -0.59, p = 0.014), and serum caeruloplasmin (T = 0.055, p = 0.047). Our estimate of total variability in liver fat content (14.8%) is nearly twice that of the reported procedural variability (8.5%). We found that liver fat content was significantly inversely related to serum glycerol but not to non-esterified fatty acids (NEFA), suggesting progressive suppression of lipolysis. Reduction of caeruloplasmin with increasing liver fat may be a consequence or a cause of hepatic steatosis.

How HDL protects LDL against atherogenic modification: paraoxonase 1 and other dramatis personae.

PURPOSE OF REVIEW: To summarize the current evidence about how HDL impedes the oxidative and glycative atherogenic modification of LDL. RECENT FINDINGS: Paraoxonase 1 (PON1) is located on HDL. Meta-analysis of clinical epidemiological investigations reveals a substantial association of low serum PON1 activity with coronary heart disease incidence independent of other risk factors including HDL cholesterol and apolipoprotein AI (apoAI). Transgenic animal models also indicate an antiatherosclerotic role for PON1. However, highly purified and recombinant PON1 do not retain their antioxidant properties. SUMMARY: The therapeutic potential of PON1 should be recognized in preventing atherosclerosis and combating infection and organophosphate toxicity. In unleashing this potential, it is important to consider that both highly purified and recombinant PON1 are dissociated from the lipid phase and other components of HDL, such as apoAI and apoM, all of which may be required for HDL (through its PON1 component) to hydrolyze more lipophilic substrates.

Unintended positive and negative effects of drugs on lipoproteins.

PURPOSE OF REVIEW: Dyslipidaemia is an important cardiovascular disease risk factor. Many drugs affect lipid profile and lipoprotein metabolism. We reviewed unintended effects of nonlipid modifying, commonly used medications on lipid profile and lipoprotein metabolism. RECENT FINDING: Several detrimental effects of many drug classes such as diuretics, antidepressant, anticonvulsant and antiretroviral drugs have been reported, whereas other drug classes such as antiobesity, alpha 1-blockers, oestrogens and thyroid replacement therapy were associated with positive effects. SUMMARY: Dyslipidaemia is a common side-effect of many medications. This should be taken into consideration, especially in patients at high risk of cardiovascular disease. Other drugs demonstrated positive effects on circulating lipids and lipoproteins. The impact of these unintended effects on atherosclerotic disease risk and progression is unclear.

Effect of atorvastatin on C-reactive protein and benefits for cardiovascular disease in patients with type 2 diabetes: analyses from the Collaborative Atorvastatin Diabetes Trial.

AIMS/HYPOTHESIS: We investigated whether atorvastatin 10 mg daily lowered C-reactive protein (CRP) and whether the effects of atorvastatin on cardiovascular disease (CVD) varied by achieved levels of CRP and LDL-cholesterol. METHODS: CRP levels were measured at baseline and 1 year after randomisation to atorvastatin in 2,322 patients with type 2 diabetes (40-75 years, 69% males) in a secondary analysis of the Collaborative Atorvastatin Diabetes Study, a randomised placebo-controlled trial. We used Cox regression models to test the effects on subsequent CVD events (n = 147) of CRP and LDL-cholesterol lowering at 1 year. RESULTS: After 1 year, the atorvastatin arm showed a net CRP lowering of 32% (95% CI -40%, -22%) compared with placebo. The CRP response was highly variable, with 45% of those on atorvastatin having no decrease in CRP (median [interquartile range, IQR] per cent change -9.8% [-57%, 115%]). The LDL-cholesterol response was less variable, with a median (IQR) within-person per cent change of -41% (-51%, -31%). Baseline CRP did not predict CVD over 3.8 years of follow-up (HRper SD log 0.89 [95% CI 0.75, 1.06]), whereas baseline LDL-cholesterol predicted CVD (HRper SD 1.21 [95% CI 1.02, 1.44]), as did on-treatment LDL-cholesterol. There was no significant difference in the reduction in CVD by atorvastatin, with above median (HR 0.57) or below median (HR 0.52) change in CRP or change in LDL-cholesterol (HR 0.61 vs 0.50). CONCLUSIONS/INTERPRETATION: CRP was not a strong predictor of CVD. Statin efficacy did not vary with achieved CRP despite considerable variability in CRP response. The use of CRP as an indicator of efficacy of statin therapy on CVD risk in patients with type 2 diabetes is not supported by these data. Trial registration NCT00327418.

The importance of considering LDL cholesterol response as well as cardiovascular risk in deciding who can benefit from statin therapy.

PURPOSE OF REVIEW: Guidelines seeking to deploy statin treatment rely heavily on the use of estimates of absolute cardiovascular disease (CVD) risk as an arbiter of who should receive statins. We question whether this is an effective strategy unless the LDL-cholesterol (LDL-C) response is also considered. RECENT FINDINGS: Recently, meta-analyses of randomized clinical trials of statins have revealed that CVD risk decreases linearly by 22% for each 1 mmol/l reduction in LDL-C. Calculation of the number needed to treat with statins to prevent one CVD event using both the pretreatment absolute CVD risk and the LDL-C response that can be achieved is thus possible. Application of this evidence reveals that many people (including younger ones) with high LDL-C levels can benefit more than people currently receiving statin treatment solely on the basis of their absolute CVD risk, whereas others at higher CVD risk, but with lower LDL-C, will derive little benefit. This does not seem to have been adequately considered in recent clinical guidelines. SUMMARY: A simple additional mathematical step in risk assessment to take account of the LDL-C response to statins and provide knowledge of number needed to treat would greatly improve individual management, cost-effectiveness and the population impact of statins.