Miia Valkonen

Intense physical training decreases circulating antioxidants and endothelium-dependent vasodilatation in vivo

Physical training increases free radical production and consumes antioxidants. It has previously been shown that acute exercise markedly increases the susceptibility of LDL to oxidation but whether such changes are observed during physical training is unknown. We measured circulating antioxidants, lipids and lipoproteins, and blood flow responses to intrabrachial infusions of endothelium-dependent (acetylcholine, ACh, L-N-monomethyl-arginine, L-NMMA) and -independent (sodium nitroprusside, SNP) vasoactive agents, before and after 3 months of running in 9 fit male subjects. Maximal aerobic power increased from 53 +/- 1 to 58 +/- 2 ml/kg min (P < 0.02). All circulating antioxidants (uric acid, SH-groups, alpha-tocopherol, beta-carotene, retinol) except ascorbate decreased significantly during training. Endothelium-dependent vasodilatation in forearm vessels decreased by 32-35% (P < 0.05), as determined from blood flow responses to both a low (10.8 +/- 2.1 vs. 7.3 +/- 1.5 ml/dl min, 0 vs. 3 months) and a high (14.8 +/- 2.6 vs. 9.6 +/- 1.8) ACh dose. The % endothelium-dependent blood flow (% decrease in basal flow by L-NMMA), decreased through training from 37 +/- 3 to 22 +/- 7% (P < 0.05). Blood flow responses to SNP remained unchanged. The decrease in uric acid was significantly correlated with the change in the % decrease in blood flow by L-NMMA (r = 0.74, P < 0.05). The lag time for the susceptibility of plasma LDL to oxidation in vitro, LDL size and the concentration of LDL cholestetol remained unchanged. We conclude that relatively intense aerobic training decreases circulating antioxidant concentrations and impairs endothelial function in forearm vessels.

Passive Smoking Induces Atherogenic Changes in Low-Density Lipoprotein

BACKGROUND According to the American Heart Association, passive smoking is an important risk factor for coronary heart disease (CHD), but the mechanisms underlying this association are not fully understood. We studied the acute effect of passive smoking on the factors that influence the development of CHD: the antioxidant defense of human serum, the extent of lipid peroxidation, and the accumulation of LDL cholesterol in cultured human macrophages, the precursors of foam cells in atherosclerotic lesions. METHODS AND RESULTS Blood samples were collected during 2 ordinary working days from healthy, nonsmoking subjects (n=10) before and after (up to 5.5 hours) spending half an hour in a smoke-free area (day 1) or in a room for smokers (day 2). Passive smoking caused an acute decrease (1.5 hours after exposure) in serum ascorbic acid (P<.001) and in serum antioxidant defense (P<.001), a decreased capacity of LDL to resist oxidation (P<.01), and the appearance of increased amounts of lipid peroxidation end products in serum (P<.01). Finally, LDL isolated from subjects after passive smoking was taken up by cultured macrophages at an increased rate (P<.05). CONCLUSIONS Exposure of nonsmoking subjects to secondhand smoke breaks down the serum antioxidant defense, leading to accelerated lipid peroxidation, LDL modification, and accumulation of LDL cholesterol in human macrophages. These data provide the pathophysiological background for the recent epidemiological evidence about the increased CHD risk among passive smokers.

A marathon run increases the susceptibility of LDL to oxidation in vitro and modifies plasma antioxidants

Physical activity increases the production of oxygen free radicals, which may consume antioxidants and oxidize low-density lipoprotein (LDL). To determine whether this occurs during strenuous aerobic exercise, we studied 11 well-trained runners who participated in the Helsinki City Marathon. Blood samples were collected before, immediately after, and 4 days after the race to determine its effect on circulating antioxidants and LDL oxidizability in vitro. LDL oxidizability was increased as determined from a reduction in the lag time for formation of conjugated dienes both immediately after (180 +/- 7 vs. 152 +/- 4 min, P < 0.001) and 4 days after (155 +/- 7 min, P < 0.001) the race. No significant changes in lipid-soluble antioxidants in LDL or in the peak LDL particle size were observed after the race. Total peroxyl radical trapping antioxidant capacity of plasma (TRAP) and uric acid concentrations were increased after the race, but, except for TRAP, these changes disappeared within 4 days. Plasma thiol concentrations were reduced after the race. No significant changes were observed in plasma ascorbic acid, alpha-tocopherol, beta-carotene, and retinol concentrations after the marathon race. We conclude that strenuous aerobic exercise increases the susceptibility of LDL to oxidation in vitro for up to 4 days. Although the increase in the concentration of plasma TRAP reflects an increase of plasma antioxidant capacity, it seems insufficient to prevent the increased susceptibility of LDL to oxidation in vitro, which was still observed 4 days after the race.Physical activity increases the production of oxygen free radicals, which may consume antioxidants and oxidize low-density lipoprotein (LDL). To determine whether this occurs during strenuous aerobic exercise, we studied 11 well-trained runners who participated in the Helsinki City Marathon. Blood samples were collected before, immediately after, and 4 days after the race to determine its effect on circulating antioxidants and LDL oxidizability in vitro. LDL oxidizability was increased as determined from a reduction in the lag time for formation of conjugated dienes both immediately after (180 ± 7 vs. 152 ± 4 min, P < 0.001) and 4 days after (155 ± 7 min, P < 0.001) the race. No significant changes in lipid-soluble antioxidants in LDL or in the peak LDL particle size were observed after the race. Total peroxyl radical trapping antioxidant capacity of plasma (TRAP) and uric acid concentrations were increased after the race, but, except for TRAP, these changes disappeared within 4 days. Plasma thiol concentrations were reduced after the race. No significant changes were observed in plasma ascorbic acid, α-tocopherol, β-carotene, and retinol concentrations after the marathon race. We conclude that strenuous aerobic exercise increases the susceptibility of LDL to oxidation in vitro for up to 4 days. Although the increase in the concentration of plasma TRAP reflects an increase of plasma antioxidant capacity, it seems insufficient to prevent the increased susceptibility of LDL to oxidation in vitro, which was still observed 4 days after the race.

Vitamin C prevents the acute atherogenic effects of passive smoking.

During passive smoking the body is attacked by an excess of free radicals inducing oxidative stress. In nonsmoking subjects even a short period of passive smoking breaks down serum antioxidant defense (TRAP) and accelerates lipid peroxidation leading to accumulation of their low-density lipoprotein (LDL) cholesterol in cultured human macrophages. We now studied whether these acute proatherogenic effects of secondhand smoke could be prevented by an effective free radical scavenger, vitamin C. Blood samples were collected from nonsmoking subjects (n = 10) as they were consecutively exposed to normal air or cigarette smoke during four separate days. During the last 2 d, a single dose of vitamin C (3 g) was given, which doubled its plasma concentration. Vitamin C did not influence the plasma antioxidant defense or the resistance of LDL to oxidation in normal air, but prevented the smoke-induced decrease in plasma TRAP (p <.001), the decrease in the resistance of LDL to oxidation (p <.05), and the accelerated formation of serum thiobarbituric acid reactive substances (TBARS) (p <.05) otherwise observed 1.5 h after the beginning of passive smoking. Vitamin C protected nonsmoking subjects against the harmful effects of free radicals during exposure to secondhand smoke.

Rhabdomyolysis in a patient receiving atorvastatin and fluconazole

The hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are widely used hypolipidemic agents which decrease cardiovascular morbidity and mortality in both primary and secondary prevention. Lovastatin, simvastatin, atorvastatin, fluvastatin, pravastatin and rosuvastatin are globally available. In general, statins are well tolerated, and serious adverse effects are rare. The most important adverse effect of statins is myopathy [1–3]. Clinically relevant myopathy is often defined as a proximal or generalised pain and/or weakness in skeletal muscles, and a creatine phosphokinase (CK) value higher than ten times the upper limit of the normal range. Statin-associated myopathy may also occur with normal CK levels [4]. Statin myopathy can progress to necrosis of muscle cells (rhabdomyolysis) which may lead to myoglobinuria and acute renal failure [1–3]. CYP3A4 catalyses the biotransformation of lovastatin, simvastatin and atorvastatin [5]. Erythromycin, clarithromycin, itraconazole and ketoconazole are examples of widely used drugs that inhibit CYP3A4. The concomitant use of these drugs with lovastatin, simvastatin or atorvastatin leads to increased bioavailability and reduced elimination of the statin, thereby greatly increasing the potential for myotoxicity [2, 5, 6]. One case of rhabdomyolysis after concomitant use of fluconazole and simvastatin has been reported [7], but, to our knowledge, there are no reported cases of rhabdomyolysis associated with concomitant intake of fluconazole and atorvastatin. We describe a fatal case of rhabdomyolysis in a 76-year-old male after use of this drug combination.

Rhabdomyolysis associated with concomitant use of simvastatin and clarithromycin

TO THE EDITOR: We report a case of rhabdomyolysis due to a probable simvastatin–clarithromycin interaction. Case Report. A 49-year-old man had been followed as an outpatient in a cardiovascular prevention clinic for 2 years due to familial combined hyperlipidemia. His fasting serum cholesterol level fluctuated between 275 and 697 mg/dL (normal <194) and triglycerides between 425 and 4098 mg/dL (35–150). The patient was a binge alcoholic, but reported abstinence between binges. He had been treated throughout with simvastatin, which was increased to 80 mg once daily. Six weeks later, the patient was admitted to the Helsinki University Central Hospital for muscle pain and weakness. Four days earlier, a general practitioner had prescribed clarithromycin 500 mg twice daily for bronchitis. On admission, serum creatine kinase (CK) and myoglobin values were increased and, on hospital day 2, reached their maximum levels of 43 200 U/L (normal <270) and 20 577 μg/L (<70 μg/L), respectively. Therefore, the patient underwent hemodiafiltration 3 times over the following 2 days until the serum myoglobin value had been reduced to 4763 μg/L. Simvastatin and clarithromycin had been discontinued on admission. Concurrently with hemodiafiltration, urinary alkalization with sodium bicarbonate was provided for 4 days, with a target urine pH >7.5. On hospital day 5, the patient was transferred from the intensive care unit, to which he was admitted on hospital day 1, to the general ward and was discharged after 14 days in the hospital. At his 2-week follow-up visit, the patient felt well and the muscle weakness had subsided. The CK value was normal. Discussion. Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) decrease cardiovascular morbidity and mortality both in primary and secondary prevention.1 In general, statins are well tolerated, and serious adverse effects are rare. Dose-dependent hepatic enzyme elevations are seen in approximately 1% of statin recipients.2 Even rarer is the elevation of muscle enzymes, which occurs in approximately 0.1–0.5% of statin recipients and is also dose related. CYP3A4 is predominantly responsible for the metabolism of lovastatin, simvastatin, and atorvastatin.3 The myotoxicity of statins may increase up to tenfold when they are given concomitantly with agents that either inhibit or are metabolized by the CYP3A4 pathway, such as clarithromycin. In our case, rhabdomyolysis resulted from the myotoxicity of simvastatin during combined treatment with clarithromycin. An objective causality assessment using the Naranjo algorithm revealed that this effect was probable.4 This accords with the findings by Kantola et al.,5 who studied the pharmacokinetics of simvastatin coadministered with another macrolide antimicrobial, erythromycin. Erythromycin increased the peak serum concentration of simvastatin 3.4-fold and the AUC at 24 hours 6.2-fold (p < 0.001). Although rhabdomyolysis associated with the use of statins is rare, this potentially serious and expensive complication might be avoided by better awareness of drug– drug interactions among physicians, pharmacists, and patients.

Susceptibility of LDL to oxidation in vitro and antioxidant capacity in familial combined hyperlipidemia: comparison of patients with different lipid phenotypes

BACKGROUND. There is increasing evidence that oxidation of low-density lipoprotein (LDL) plays an important role in atherogenesis. AIM. To explore the LDL oxidizability and its determinants in familial combined hyperlipidemia (FCHL) patients with different phenotypes. METHOD. The study included 59 FCHL family members with different lipid phenotypes, 39 non-affected relatives, and 30 spouses as healthy controls. RESULTS. The lag time for LDL oxidation was significantly shorter in FCHL patients with different lipid phenotypes as compared to healthy controls. There were no significant differences in the propagation rate and conjugated diene formation and f -tocopherol content in LDL between the FCHL groups and healthy controls. Plasma concentrations of f -tocopherol in all FCHL patients and uric acid in FCHL patients with IIB and IV phenotypes were significantly higher than in healthy controls. Plasma total peroxyl radical trapping capacity measured (TRAP mea ) and TRAP calc tended to be higher in affected FCHL groups, but the difference was significant only for IIB phenotype. The peak LDL particle size in the combined group of FCHL patients was significantly smaller than in healthy controls. The lag time for LDL oxidation correlated significantly with LDL size both in the group of FCHL family members (r = 0.477, P < 0.001) and in the healthy controls (r = 0.482, P < 0.01). CONCLUSIONS. LDL from FCHL patients irrespectively of lipid phenotypes is more susceptible to oxidation in vitro than LDL from healthy controls. This increased susceptibility of LDL to oxidation in vitro seems to be attributed to the abundance of small dense LDL particles and not to the defect of antioxidant capacity in FCHL.

Targeting matrix metalloproteinases with intravenous doxycycline in severe sepsis – A randomised placebo-controlled pilot trial

An overwhelming inflammatory process is the hallmark of severe sepsis and septic shock. Matrix metalloproteinases (MMPs)-8 and -9 are released from neutrophils and activated in sepsis to participate in inflammation in several ways. High levels of MMP-8 may associate with increased ICU mortality. The activity of MMP-8 and -9 is regulated by a natural inhibitor, tissue inhibitor of metalloproteinases-1 (TIMP-1). Moreover, MMPs are chemically inhibited by tetracycline-group antibiotics, such as doxycycline. We therefore aimed to study plasma concentration and MMP inhibition after intravenous doxycycline in critically ill patients with severe sepsis and septic shock in a prospective, randomised, placebo-controlled double-blinded pilot trial. Twenty-four patients with severe sepsis or septic shock were randomised in 3 groups. Group 1 received 200, 100 and 100mg, group 2 100, 50 and 50mg of intravenous doxycycline and group 3 placebo on three consecutive days. We measured doxycycline concentrations from baseline up to day 5. MMPs and TIMP-1 concentrations were measured from baseline up to day 10 of study and we compared their changes over time from baseline to 72 h and from baseline to 120 h. Data from 23 patients were analysed. At 72 h all patients in group 1 showed doxycycline concentrations >1 mg/l, whereas none in group 2 did. No serious adverse effects of the drug were recorded. We observed no differences over time up to 72 or up to 120 h in the concentrations or activities of MMP-8, -9 or TIMP-1 in any of the groups. We found intravenous doxycycline 100, 50 and 50mg to be adequate to achieve a sub-antimicrobial concentration in patients with severe sepsis or septic shock but having no impact on MMP-8, -9 or TIMP-1 concentrations or activities.

Complete Genome Sequences of Influenza A/H1N1 Strains Isolated from Patients during the 2013-2014 Epidemic Season in Finland

ABSTRACT Here, we report 40 complete genome sequences of influenza A/H1N1 strains isolated from 33 nonhospitalized and 7 hospitalized patients during the 2013-2014 epidemic season in Finland. An analysis of the aligned sequences revealed no oseltamivir-resistant genotypes. As a whole, the recent viruses have drifted from the prototype A/California/7/2009 virus by ca. 1.3%.

Influenza pH1N1 Virus Accumulated H275Y Mutation in Neuraminidase during Propagation in MDCK Cells

ABSTRACT Here, we sequenced the genome of the influenza A/Finland/741 M/2014(H1N1) virus and found that the virus accumulated oseltamivir resistance mutation H275Y in its neuraminidase during propagation in cell culture. This indicates that propagation in cell culture modifies virus genomes. The instability of influenza genomes should be taken into consideration during drug-sensitivity studies.