PCSK9 Inhibition with alirocumab increases the catabolism of lipoprotein(a) particles in statin-treated patients with elevated lipoprotein(a).

BACKGROUND: Lipoprotein(a) (Lp(a)) is a low-density lipoprotein (LDL) particle containing apolipoprotein(a) (apo(a)) covalently linked to apolipoprotein B-100 (apoB). Statin-treated patients with elevated Lp(a) have an increased risk of atherosclerotic cardiovascular disease (ASCVD). Recent trials show that proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition decreases Lp(a) and cardiovascular events, particularly in high risk patients with elevated Lp(a). We investigated the kinetic mechanism whereby alirocumab, a PCSK9 inhibitor, lowers Lp(a) in statin-treated patients with high Lp(a) and ASCVD. METHODS: The effects of 12-week alirocumab treatment (150 mg every 2 weeks) on apo(a) kinetics were studied in 21 patients with elevated Lp(a) concentration (>0.5 g/L). Apo(a) fractional catabolic rate (FCR) and production rate (PR) were determined using intravenous D3-leucine administration, mass spectrometry and compartmental modelling. All patients were on long-term statin treatment. RESULTS: Alirocumab significantly decreased plasma concentrations of total cholesterol (-39%), LDL-cholesterol (-67%), apoB (-56%), apo(a) (-25%) and Lp(a) (-22%) (P< 0.001 for all). Alirocumab also significantly lowered plasma apo(a) pool size (-26%, P <0.001) and increased the FCR of apo(a) (+28%, P< 0.001), but did not alter apo(a) PR, which remained significantly higher relative to a reference group of patients on statins with normal Lp(a) (P< 0.001). CONCLUSIONS: In statin-treated patients, alirocumab lowers elevated plasma Lp(a) concentrations by accelerating the catabolism of Lp(a) particles. This may be consequent on marked upregulation of hepatic receptors (principally for LDL) and/or reduced competition between Lp(a) and LDL particles for these receptors; the mechanism could contribute to the benefit of PCSK9 inhibition with alirocumab on cardiovascular outcomes.

The role of receptor for advanced glycation end products in airway inflammation in CF and CF related diabetes.

Cystic Fibrosis (CF) is often accompanied by diabetes leading to worsening lung function, the reason for which is unclear. The receptor for advanced-glycation-end-products (RAGE) regulates immune responses and inflammation and has been linked to diabetes and possibly CF. We performed a pilot study to determine if CF and CF-related diabetes (CFRD) are associated with enhanced RAGE expression. Full length (fl)RAGE, soluble (s)RAGE, endogenous soluble (es)RAGE, S100A12 (enRAGE) and advanced-glycation-end-products (AGE) expression was assessed in serum, white blood cells and sputum of patients with CF; diabetes; CFRD and healthy subjects. Sputum enRAGE/sRAGE ratios were high in CF but particularly in CFRD which negatively correlated with % predicted FEV1. Serum AGE and AGE/sRAGE ratios were high in diabetics but not in CF. A complex, multifaceted approach was used to assess the role of RAGE and its ligands which is fundamental to determining their impact on airway inflammation. There is a clear association between RAGE activity in the airways of CF and CFRD patients that is not evident in the vascular compartment and correlates with lung function, in contrast to diabetes. This strongly suggests a role for RAGE in contributing to the inflammatory overdrive seen in CF and to a greater extent in CFRD.

Dynamic hip screw with locking side plate: a viable treatment option for intertrochanteric fracture.

OBJECTIVE: Dynamic hip screw (DHS) is recommended for the fixation of stable intertrochanteric fractures. Its postoperative cut-out rate ranges from 1% to 6%. In osteoporotic bone, normal screws in DHS blade provide less anchorage compared to locking screws. This study aims to compare DHS with locking side plate and conventional side plate. METHODS: Fifty consecutive patients with intertrochanteric fractures were randomly allocated for fixation with a standard DHS (group A) and locking DHS (Combi plate, group B). We compared the clinical and radiological outcomes for the conventional DHS and locking DHS in intertrochanteric fractures. Functional outcome was evaluated using the Parker mobility score. RESULTS: Coxa valga was found more frequently in group A than in group B (12% vs. 0%, P=0.42). Coxa vara showed the same trend (12% vs. 8%, P=0.81). Rate of restoration of postoperative neck-shaft angle within 20° of sound side was higher in group B (8% cases) than in group A (4% cases, P=0.98). The rate of anteversion angle restoration within 10° of sound side was also higher in group B (100% vs. 88%, P=0.85). The average lag screw slippage in group A and group B was 3.2 mm and 4.2 mm, the average fracture union duration was 17.1 weeks and 16.4 weeks, and the mean Parker score was 5.6 and 5.8 respectively. Screw cut-out was seen in one patient in group A. No cut-out was seen in any of the patient in group B. No patient developed deep infection, avascular necrosis, deep vein thrombosis or any other significant complications. CONCLUSION: The present study demonstrated that treating intertrochanteric fracture with a locking DHS allows sound bone healing and is not associated with any major complications. Although this report is promising, it should be interpreted with caution because only a prospective study with a large sample size would allow definitive conclusion.

Remote ischaemic preconditioning down-regulates kinin receptor expression in neutrophils of patients undergoing heart surgery.

OBJECTIVES: Remote ischaemic preconditioning (RIPC) may protect distant organs against ischaemia-reperfusion injury. We investigated the impact of RIPC on kinin receptor expression in neutrophils following RIPC in patients undergoing coronary artery bypass grafting (CABG). METHODS: Patients undergoing elective CABG with cardiopulmonary bypass (CPB) were randomized to RIPC (n = 15) or control (n = 15) groups. The study group underwent RIPC by inflation of a blood pressure cuff on the arm. Expression of kinin receptors, plasma concentrations of IL-6, IL-8, IL-10, TNF-α and neutrophil elastase were determined at baseline (before RIPC/sham), immediately before surgery (after RIPC/sham) and 30 min and 24 h after surgery. Plasma bradykinin levels were assessed before and after RIPC/sham, and at 30 min, 6, 12 and 24 h after surgery. Serum creatine kinase (CK), troponin I, C-reactive protein (CRP) and lactate levels were measured immediately prior to surgery and 30 min, 6, 12, 24 and 48 h after surgery. RESULTS: Kinin B2 receptor expression did not differ between the groups at baseline (pre-RIPC), but was significantly lower in the RIPC group than in the control group after RIPC/sham (P < 0.05). Expressions of both kinin B1 and B2 receptors were significantly down-regulated in the RIPC group, and this persisted to 24 h after surgery (P < 0.001). Neutrophil elastase levels were significantly increased after surgery. There were no differences in CK, CRP, cytokine, lactate or troponin I levels between the groups. CONCLUSIONS: RIPC down-regulated the expression of kinin B1 and B2 receptors in neutrophils of patients undergoing CABG.

Effects of the demethylating agent, 5-azacytidine, on expression of the kallikrein-kinin genes in carcinoma cells of the lung and pleura.

Tissue kallikrein (KLK1) and plasma kallikrein (KLKB1) may regulate the growth and proliferation of tumours of the lung and pleura, through the generation of kinin peptides that signal through the kinin B(1) (BDKRB1) and B(2) (BDKRB2) receptors. The development and progression of cancer results from genetic mutations, as well as epigenetic changes that include methylation of DNA at CpG islands. The aim of this study was to assess whether expression of the kallikrein-kinin genes in lung cancer and mesothelioma cells is regulated by DNA methylation. Quantitative reverse transcriptase-PCR and immunocytochemistry showed differences in the basal expression of the kallikrein-kinin genes and proteins in lung carcinoma and mesothelioma cells, compared with non-malignant lung epithelial and mesothelial cells, respectively. Following treatment with the demethylating agent, 5-azacytidine (5-AZA), KLKB1 mRNA expression was consistently increased in both lung carcinoma and mesothelioma cells, whereas KLK1, BDKRB1 and BDKRB2 mRNA expression was decreased or unchanged. Increased expression of KLKB1 after 5-AZA treatment suggests it may function as a tumour suppressor gene in cancers of the lung and pleura. Studies on DNA methylation of the kallikrein-kinin genes will enhance understanding of their role in carcinogenesis and provide insights into the importance of kallikreins as tumour biomarkers.

Increases in urinary 9alpha,11beta-prostaglandin f2 indicate mast cell activation in wine-induced asthma.

BACKGROUND: Wine-induced asthmatic symptoms may be caused by sulphite additives. Prostaglandin (PG)D2 and cysteinyl leukotrienes (cysLT) are important mediators of asthmatic responses. To determine whether the sulphite additives in wine alter the production of PGD2 and cysLT, asthmatic patients with compelling histories of wine sensitivity were challenged with high- and low-sulphite wines; the urinary metabolites of PGD2 and cysLT were measured before and after challenge. METHODS: Eight self-reporting wine-sensitive asthmatic patients completed double-blind challenges with high- and low-sulphite wines on separate days. Urine samples were collected before and after consumption of 150 ml of wine. Urinary concentrations of 9alpha,11beta-PGF2 and leukotriene (LT)E4 were measured by enzyme immunoassay. RESULTS: Urinary 9alpha,11beta-PGF2 concentrations increased in all subjects following challenge with high-sulphite wine, and the median concentration increased 1.6-fold (p < 0.01). Urinary 9alpha,11beta-PGF2 also increased 1.5-fold after low-sulphite wine challenge, although this did not reach statistical significance (p = 0.08). The median difference in 9alpha,11beta-PGF2 concentration after high-sulphite wine challenge was not significantly different compared with that after low-sulphite wine challenge. Median urinary LTE4 concentrations did not change significantly after either wine challenge. CONCLUSIONS: Increased urinary 9alpha,11beta-PGF2 concentrations following wine challenge suggest mast cell activation as a possible mechanism for wine-induced asthma, although this did not appear to be related to the sulphite additives in wine. Urinary 9alpha,11beta-PGF2 may warrant further assessment as a potential biomarker of reactivity to wine in asthmatic subjects.

Tolerance and rebound with zafirlukast in patients with persistent asthma.

BACKGROUND: The potential for tolerance to develop to zafirlukast, a cysteinyl leukotriene (CysLT) receptor antagonist (LRA) in persistent asthma, has not been specifically examined. OBJECTIVE: To look for any evidence of tolerance and potential for short-term clinical worsening on LRA withdrawal. Outcome measures included changes in; airway hyperresponsiveness to inhaled methacholine (PD20FEV1), daily symptoms and peak expiratory flows (PEF), sputum and blood cell profiles, sputum CysLT and prostaglandin (PG)E2 and exhaled nitric oxide (eNO) levels. METHODS: A double blind, placebo-controlled study of zafirlukast, 20 mg twice daily over 12 weeks in 21 asthmatics taking beta2-agonists only (Group I), and 24 subjects treated with ICS (Group II). RESULTS: In Group I, zafirlukast significantly improved morning PEF and FEV1compared to placebo (p < 0.01), and reduced morning waking with asthma from baseline after two weeks (p < 0.05). Similarly in Group II, FEV1 improved compared to placebo (p < 0.05), and there were early within-treatment group improvements in morning PEF, beta2-agonist use and asthma severity scores (p < 0.05). However, most improvements with zafirlukast in Group I and to a lesser extent in Group II deteriorated toward baseline values over 12 weeks. In both groups, one week following zafirlukast withdrawal there were significant deteriorations in morning and evening PEFs and FEV1 compared with placebo (p < or = 0.05) and increased nocturnal awakenings in Group II (p < 0.05). There were no changes in PD20FEV1, sputum CysLT concentrations or exhaled nitric oxide (eNO) levels. However, blood neutrophils significantly increased in both groups following zafirlukast withdrawal compared to placebo (p = 0.007). CONCLUSION: Tolerance appears to develop to zafirlukast and there is rebound clinical deterioration on drug withdrawal, accompanied by a blood neutrophilia.

Oxidative stress and lipid-derived inflammatory mediators during acute exacerbations of cystic fibrosis.

BACKGROUND AND OBJECTIVE: In cystic fibrosis (CF) very few studies have assessed sputum 8-iso-PGF2alpha levels during pulmonary exacerbations as a direct measure of airway oxidative stress. The role of other lipid-derived inflammatory mediators, such as the cysteinyl leukotrienes (cys-LTs) and prostaglandin (PG)-E2, during exacerbations is also poorly defined and the effect of conventional antibiotic therapy on these components of the inflammatory process is unclear. METHODS: Sputum 8-iso-PGF2alpha, total cys-LT and PGE2 levels were measured in 17 CF patients experiencing a pulmonary exacerbation and repeated analysis were performed in 15 of these patients after antibiotic treatment. Eight stable CF and nine healthy subjects provided control data. RESULTS: Sputum 8-iso-PGF2alpha was significantly elevated in acute, but not stable CF patients versus healthy controls (P < 0.001). Similarly, sputum cys-LT and PGE2 levels were increased in acute compared with stable CF patients and healthy controls (P