Arginase 1 (ARG1) deficiency is a rare urea cycle disorder (UCD). This hypothesis-generating stud... more Arginase 1 (ARG1) deficiency is a rare urea cycle disorder (UCD). This hypothesis-generating study explored clinical phenotypes, metabolic profiles, molecular genetics, and treatment approaches in a cohort of children and adults with ARG1 deficiency to add to our understanding of the underlying pathophysiology. Clinical data were retrieved retrospectively from physicians using a questionnaire survey. Plasma aminoacids, guanidinoacetate (GAA), parameters indicating oxidative stress and nitric oxide (NO) synthesis as well as asymmetric dimethylarginine (ADMA) were measured at a single study site. Nineteen individuals with ARG1 deficiency and 19 matched controls were included in the study. In patients, paraparesis, cognitive impairment, and seizures were significantly associated suggesting a shared underlying pathophysiology. In patients plasma GAA exceeded normal ranges and plasma ADMA was significantly elevated. Compared to controls, nitrate was significantly higher, and the nitrite:...
European Journal of Gastroenterology & Hepatology, 2006
Chlamydia has been associated with autoimmune diseases, but a link between chlamydial infection a... more Chlamydia has been associated with autoimmune diseases, but a link between chlamydial infection and the aetiopathogenesis of inflammatory bowel disease (IBD) remains controversial. In this study we assessed the relationship between chlamydial infection and IBD, as evidenced by serological measurement and DNA analysis of mucosal biopsy specimens. The sera of 78 patients with Crohn's disease (CD), 24 patients with ulcerative colitis (UC), 73 healthy family members, and 20 healthy controls were tested for anti-C. pneumoniae IgG titres. A subgroup consisting of 13 UC and 39 CD patients was screened for the presence of chlamydial DNA on 42 inflamed versus 30 non-inflamed biopsy specimens and for mutations of their NOD2/CARD15 gene. Anti-C. pneumoniae IgG antibodies were found in the sera of 32 (41%) patients with CD, 11 (46%) patients with UC, 35 (48%) of unaffected family members, and nine (45%) unrelated healthy controls. Thirty-five percent of the control, 18% CD and 24% UC biopsy specimens contained C. pneumoniae DNA. In CD, however, C. pneumoniae DNA was significantly more frequently found in inflamed (27%) versus non-inflamed (8%) biopsy specimens (P < 0.05, Fisher's exact test). The frequencies of NOD2/CARD15 mutations were 33% for CD patients with C. pneumoniae DNA compared to 47% for CD patients without C. pneumoniae DNA. We found no marked differences in respect to anti-C. pneumoniae serum IgG or C. pneumoniae DNA between healthy controls and patients with IBD. However, in CD patients, inflamed tissue specimens contained significantly more likely C. pneumoniae DNA compared with biopsies from unaffected areas. Thus C. pneumoniae is unlikely to be of pathogenic importance in IBD while it may still influence local clinical manifestations.
Atherogenesis is an inflammatory process with leukocytes infiltrating the arterial intima. The li... more Atherogenesis is an inflammatory process with leukocytes infiltrating the arterial intima. The lipoxygenase pathways play a role in leukocyte recruitment through the generation of two classes of arachidonic acid lipid mediators, the leukotrienes and the lipoxins, and one class of omega-3 fatty acid metabolites, the resolvins. There is evidence from animal studies and human genetic studies that the leukotrienes and the enzymes necessary for their generation play a role in atherosclerosis, and possibly even in the development of the vulnerable plaque. Less is known about the effect of the anti-inflammatory lipid mediators in atherosclerosis, the lipoxins and the resolvins. Studies modulating the activity of an enzyme necessary for the production of these lipid mediators, 12/15-lipoxygenase, showed discrepant results in several animal models. Also, human genetic studies have not clearly dissected the effect of the enzyme on atherosclerosis. However, stable forms of the lipoxins and the resolvins protect animals from inflammatory diseases. Whether blocking the leukotrienes or applying anti-inflammatory lipoxins and resolvins will be effective in attenuating human atherosclerosis needs to be demonstrated in future studies. In this review, the biosynthesis of these lipid mediators, their biological effects and the evidence for their possible role in atherosclerosis are discussed with an emphasis on human disease.
The Journal of Clinical Endocrinology and Metabolism, Mar 6, 2014
The impact of sugar-sweetened beverages (SSB) on lipid metabolism when consumed in moderate amoun... more The impact of sugar-sweetened beverages (SSB) on lipid metabolism when consumed in moderate amounts by normal weight subjects is debated. The objective of the study was to investigate the effect of different types of sugars in SSB on fatty acid metabolism (ie, fatty acid synthesis and oxidation) in healthy young men. Thirty-four normal-weight men were studied in a randomized crossover study. Four isocaloric 3-week interventions with SSB were performed in random order: medium fructose (MF; 40 g/d); high fructose (HF; 80 g/d), high sucrose (HS; 80 g/d), and high glucose (HG; 80g/d). Fasting total plasma fatty acid composition was measured after each intervention. Acylcarnitines were measured in the fasting state and after a euglycemic hyperinsulinemic clamp in nine subjects. The relative abundance of palmitate (16:0) and the molar fatty acid ratio of palmitate to linoleic acid (16:0 to18:2) as markers of fatty acid synthesis were increased after HF [relative abundance of palmitate: 22.97% ± 5.51% (percentage of total fatty acids by weight ±SD)] and MF (26.1% ± 1.7%) compared with HS (19.40% ± 2.91%, P < .001), HG (19.43% ±3.12 %, P < .001), or baseline (19.40% ± 2.79%, P < .001). After HS and HG, the relative abundance of palmitate was equal to baseline. Fasting palmitoylcarnitine was significantly increased after HF and HS (HF and HS vs. HG: P = .005), decreasing after inhibition of lipolysis by insulin in the clamp. When consumed in moderate amounts, fructose but not sucrose or glucose in SSB increases fatty acid synthesis (palmitate), whereas fasting long-chain acylcarnitines are increased after both fructose and sucrose, indicating an impaired β-oxidation flux.
Respiration International Review of Thoracic Diseases, 2010
Idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertensi... more Idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) share important pathogenic and clinical features. BMPR2 mutations are important in the pathogenesis of IPAH, but little is known about the genetic background in CTEPH. To search for mutations and polymorphisms in genes involved in the BMPR2, serotonin and nitric oxide pathways possibly associated with pulmonary and cardiac disorders in IPAH and CTEPH. In a cohort of Swiss patients with IPAH (n = 16) and CTEPH (n = 16), and in 24 controls with left heart disease without PH, polymorphisms in the BMPR2, 5-HHT, 5-HTR-2A and eNOS genes were analyzed and correlated with various clinical, functional and hemodynamic parameters. We found a BMPR2 missense mutation in a patient with coronary artery disease (CAD) without PH but no BMPR2 mutations in our collective with late-onset sporadic PH. In patients with polymorphic variants of the BMPR2 gene, the number of blood platelets and oxygen saturation were increased. The c.600A-->C synonymous variant was associated with worse exercise capacity and decreased quality of life in PH. We found no significant differences for any measured parameter according to the eNOS, 5-HTR2A and the 5-HTT polymorphisms, although there was a higher allelic frequency of the 5-HTT long variant in IPAH than in CTEPH and controls. Our first report of a BMPR2 mutation in a patient with CAD without PH is interesting and warrants further investigation. Our study may reflect the clinical status and genetic background in a typical PH cohort as seen in a single tertiary care referral center.
Low high-density lipoprotein (HDL) cholesterol is an important risk factor for coronary heart dis... more Low high-density lipoprotein (HDL) cholesterol is an important risk factor for coronary heart disease (CHD). In vitro, HDL exerts several potentially anti-atherogenic activities. HDLs mediate the reverse cholesterol transport (RCT) from peripheral cells to the liver, inhibit oxidation of low-density lipoprotein (LDL), adhesion of monocytes to the endothelium, apoptosis of vascular endothelial and smooth muscle cells and platelet activation, and stimulate the endothelial secretion of vasoactive substances as well as smooth muscle cell proliferation. Hence, raising HDL-cholesterol levels has become an interesting target for anti-atherosclerotic drug therapy. Levels of HDL cholesterol and the composition of HDL subclasses in plasma are regulated by apolipoproteins, lipolytic enzymes, lipid transfer proteins, receptors and cellular transporters. The interplay of these factors leads to RCT and determines the composition and, thereby, the anti-atherogenic properties of HDL. Several inborn errors of metabolism, as well as genetic animal models, are characterised by both elevated HDL cholesterol and increased rather than decreased cardiovascular risk. These findings suggest that the mechanism of HDL modification rather than simply increasing HDL cholesterol determine the efficacy of anti-atherosclerotic drug therapy. In several controlled and prospective intervention studies, patients with low HDL cholesterol and additional risk factors benefited from treatment with fibric acid derivatives (fibrates) or HMG-CoA reductase inhibitors (statins). However, only in some trials was prevention of coronary events in patients with low HDL cholesterol and hypertriglyceridaemia related to an increase in HDL cholesterol. We discuss the clinical and metabolic effects of fibrates, statins, nicotinic acid and sex steroids, and present novel therapeutic strategies that show promise in modifying HDL metabolism. In conclusion, HDL-cholesterol levels increase only moderately after treatment with currently available drugs and do not necessarily correlate with the functionality of HDL. Therefore, the anti-atherosclerotic therapy of high-risk cardiovascular patients should currently be focused on the correction of other risk factors present besides low HDL cholesterol. However, modification of HDL metabolism and improvement of RCT remain an attractive target for the development of new regimens of anti-atherogenic drug therapy.
Journal of immunology (Baltimore, Md. : 1950), 2015
ChemR23 is a G protein-coupled receptor that is triggered by two ligands, the peptide chemerin an... more ChemR23 is a G protein-coupled receptor that is triggered by two ligands, the peptide chemerin and the eicosapentaenoic acid-derived lipid mediator resolvin E1 (RvE1). Chemerin acts as a chemoattractant for monocytes and macrophages, whereas RvE1 promotes resolution of inflammation-inducing macrophage phagocytosis of apoptotic neutrophils. Although ChemR23-mediated signaling plays a role in mononuclear cell migration to inflamed tissue, as well as in the resolution of inflammation, its regulation in different polarization states of macrophages is largely unknown. We analyzed the expression and function of ChemR23 in monocytes and differently activated human primary macrophages. Using 5' RACE, we identified three transcription start sites and several splice variants of ChemR23 in both monocytes and macrophages. Although the promoters P1 and P3 are used equally in unpolarized macrophages, stimulation with LPS or IFN-γ leads to increased transcription from P3 in inflammatory M1 mac...
Low high-density lipoprotein (HDL)-cholesterol (C) is an important risk factor for coronary heart... more Low high-density lipoprotein (HDL)-cholesterol (C) is an important risk factor for coronary heart disease. In vitro, HDL exerts several potentially anti-atherogenic effects including reverse cholesterol transport (RCT) from peripheral cells to the liver. Hence, raising HDL-C has become an interesting target for anti-atherosclerotic drug therapy. Levels of HDL-C and the composition of HDL subclasses in plasma are regulated by apolipoproteins, lipolytic enzymes, lipid transfer proteins, receptors, and cellular transporters. The interplay of these factors leads to RCT and determines the composition and thereby the anti-atherogenic properties of HDL. Recent findings suggest that the mechanism of HDL modification rather than a sole increase in HDL-C determines the efficacy of anti-atherosclerotic drug therapy. In several controlled and prospective intervention studies, patients with low HDL-C and additional risk factors benefited from treatment with fibrates or statins. However, in only ...
We present a plasmid rescue from transgenic Drosophila to study spontaneous and mutagen-induced m... more We present a plasmid rescue from transgenic Drosophila to study spontaneous and mutagen-induced mutations in vivo. Transgenic Drosophila lines were established by transformation with a shuttle vector containing the bacterial lacZ gene as a target for mutagenesis. The target gene can be recovered into bacteria by restriction endonuclease treatment of total genomic DNA, followed by ligation of the recircularized shuttle vectors. The resulting circular plasmids are then transformed back into E. coli lacZ- mutants, where the activity of the lacZ genes is scored on the induction substrate X-Gal. The number of inactivated versus intact lacZ genes directly indicates the mutation frequency. By the described target gene rescue procedure up to 5000 lacZ gene copies can be rescued from one fly routinely. Spontaneous background mutation rates using this system are 2.6 +/- 0.6 x 10(-4). Treatment of larvae with ethylnitrosourea (ENU) resulted in a dose-dependent increase of the mutation frequenc...
Low bone mineral density (BMD) is common in chronic lung diseases and associated with reduced qua... more Low bone mineral density (BMD) is common in chronic lung diseases and associated with reduced quality of life. Little is known about BMD in pulmonary hypertension (PH). Steroid-naïve patients with PH (n=34; 19 idiopathic, 15 chronic thromboembolic) had BMD measured by DXA at the time of diagnostic right heart catheterization. Exercise capacity, quality of life and various parameters related to PH severity and bone metabolism were also assessed. 24 patients with left heart failure (LHF) were similarly assessed as controls. The prevalence of osteopenia was high both in PH (80%) and in controls with LHF (75%). Low BMD was associated with lean body mass, age, lower BMI, impaired exercise capacity and in PH with higher pulmonary vascular resistance. Serum parathyroid hormone (PTH) was elevated and considerably higher in PH than in LHF (above normal, in 55 vs 29%). Secondary hyperparathyroidism was not related to impaired renal function but possibly to low vitamin D status. Osteopenia is common in PH and in chronically ill patients with LHF. Osteopenia is associated with known risk factors but in PH also with disease severity. Preventive measures in an increasingly chronic ill PH population should be considered. Secondary hyperparathyroidism is highly prevalent in PH and might contribute to bone and possibly pulmonary vascular disease. Whether adequate vitamin D substitution could prevent low BMD in PH remains to be determined.
The IV anesthetic, propofol, when administered as fat emulsion-based formulation (Diprivan) promo... more The IV anesthetic, propofol, when administered as fat emulsion-based formulation (Diprivan) promotes insulin resistance, but the direct effects of propofol and its solvent, Intralipid, on cardiac insulin resistance are unknown. Hearts of healthy and type-2 diabetic rats (generated by fructose feeding) were aerobically perfused for 60 minutes with 10 μM propofol in the formulation of Diprivan or an equivalent concentration of its solvent Intralipid (25 μM) ± insulin (100 mU•L). Glucose uptake, glycolysis, and glycogen metabolism were measured using [H]glucose. Activation of Akt, GSK3β, AMPK, ERK1/2, p38MAPK, S6K1, JNK, protein kinase Cθ (PKCθ), and protein kinase CCβII (PKCβII) was determined using immunoblotting. GLUT4 trafficking and phosphorylations of insulin receptor substrate-1 (IRS-1) at Ser307(h312), Ser1100(h1101), and Tyr608(hTyr612) were measured. Mass spectrometry was used to determine acylcarnitines, phospholipids, and sphingolipids. Diprivan and Intralipid reduced insulin-induced glucose uptake and redirected glucose to glycogen stores in diabetic hearts. Reduced glucose uptake was accompanied by lower GLUT4 trafficking to the sarcolemma. Diprivan and Intralipid inactivated GSK3β but activated AMPK and ERK1/2 in diabetic hearts. Only Diprivan increased phosphorylation of Akt(Ser473/Thr308) and translocated PKCθ and PKCβII to the sarcolemma in healthy hearts, whereas it activated S6K1 and p38MAPK and translocated PKCβII in diabetic hearts. Furthermore, only Diprivan phosphorylated IRS-1 at Ser1100(h1101) in healthy and diabetic hearts. JNK expression, phosphorylation of Ser307(h312) of IRS-1, and PKCθ expression and translocation were increased, whereas GLUT4 expression was reduced in insulin-treated diabetic hearts. Phosphatidylglycerol, phosphatidylethanolamine, and C18-sphingolipids accumulated in Diprivan-perfused and Intralipid-perfused diabetic hearts. Propofol and Intralipid promote insulin resistance predominantly in type-2 diabetic hearts.
Oxidative stress and low-grade systemic inflammation may contribute to the pathogenesis of obesit... more Oxidative stress and low-grade systemic inflammation may contribute to the pathogenesis of obesity-induced comorbidities, including nonalcoholic fatty liver disease. Increasing intake of dietary antioxidants might be beneficial, but there are few data in obese children. To examine the effect of antioxidant supplementation on biomarkers of oxidative stress, inflammation, and liver function, we randomly assigned overweight or obese children and adolescents (n = 44; mean ± SD age: 12.7 ± 1.5 y) participating in a lifestyle modification program to a 4-mo intervention with daily antioxidants (vitamin E, 400 IU; vitamin C, 500 mg; selenium, 50 μg) or placebo. We measured anthropometrics, antioxidant status, oxidative stress (F(2)-isoprostanes, F(2)-isoprostane metabolites), inflammation, liver enzymes, fasting insulin and glucose, and lipid profile at baseline and endpoint. There was a significant treatment effect of antioxidant supplementation on antioxidant status [α-tocopherol, β = 23.2 (95% CI: 18.0, 28.4); ascorbic acid, β = 70.6 (95% CI: 51.7, 89.4); selenium, β = 0.07 (95% CI: 0.01, 0.12)] and oxidative stress [8-iso-prostaglandin F2α, β = -0.11 (95% CI: -0.19, -0.02)] but not on any of the inflammatory markers measured. There was a significant treatment effect on alanine aminotransferase [β = -0.13 (95% CI: -0.23, -0.03)], a trend toward a significant effect on aspartate aminotransferase [β = -0.04 (95% CI: -0.09, 0.01)], and no significant effect on γ-glutamyltransferase [β = -0.03 (95% CI: -0.11, 0.06)]. In summary, antioxidant supplementation for 4 mo improved antioxidant-oxidant balance and modestly improved liver function tests; however, it did not reduce markers of systemic inflammation despite significant baseline correlations between oxidative stress and inflammation. The study was registered at clinicaltrials.gov as NCT01316081.
Idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertensi... more Idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) share important pathogenic and clinical features. BMPR2 mutations are important in the pathogenesis of IPAH, but little is known about the genetic background in CTEPH. To search for mutations and polymorphisms in genes involved in the BMPR2, serotonin and nitric oxide pathways possibly associated with pulmonary and cardiac disorders in IPAH and CTEPH. In a cohort of Swiss patients with IPAH (n = 16) and CTEPH (n = 16), and in 24 controls with left heart disease without PH, polymorphisms in the BMPR2, 5-HHT, 5-HTR-2A and eNOS genes were analyzed and correlated with various clinical, functional and hemodynamic parameters. We found a BMPR2 missense mutation in a patient with coronary artery disease (CAD) without PH but no BMPR2 mutations in our collective with late-onset sporadic PH. In patients with polymorphic variants of the BMPR2 gene, the number of blood platelets and oxygen saturation were increased. The c.600A-->C synonymous variant was associated with worse exercise capacity and decreased quality of life in PH. We found no significant differences for any measured parameter according to the eNOS, 5-HTR2A and the 5-HTT polymorphisms, although there was a higher allelic frequency of the 5-HTT long variant in IPAH than in CTEPH and controls. Our first report of a BMPR2 mutation in a patient with CAD without PH is interesting and warrants further investigation. Our study may reflect the clinical status and genetic background in a typical PH cohort as seen in a single tertiary care referral center.
Arginase 1 (ARG1) deficiency is a rare urea cycle disorder (UCD). This hypothesis-generating stud... more Arginase 1 (ARG1) deficiency is a rare urea cycle disorder (UCD). This hypothesis-generating study explored clinical phenotypes, metabolic profiles, molecular genetics, and treatment approaches in a cohort of children and adults with ARG1 deficiency to add to our understanding of the underlying pathophysiology. Clinical data were retrieved retrospectively from physicians using a questionnaire survey. Plasma aminoacids, guanidinoacetate (GAA), parameters indicating oxidative stress and nitric oxide (NO) synthesis as well as asymmetric dimethylarginine (ADMA) were measured at a single study site. Nineteen individuals with ARG1 deficiency and 19 matched controls were included in the study. In patients, paraparesis, cognitive impairment, and seizures were significantly associated suggesting a shared underlying pathophysiology. In patients plasma GAA exceeded normal ranges and plasma ADMA was significantly elevated. Compared to controls, nitrate was significantly higher, and the nitrite:...
European Journal of Gastroenterology & Hepatology, 2006
Chlamydia has been associated with autoimmune diseases, but a link between chlamydial infection a... more Chlamydia has been associated with autoimmune diseases, but a link between chlamydial infection and the aetiopathogenesis of inflammatory bowel disease (IBD) remains controversial. In this study we assessed the relationship between chlamydial infection and IBD, as evidenced by serological measurement and DNA analysis of mucosal biopsy specimens. The sera of 78 patients with Crohn's disease (CD), 24 patients with ulcerative colitis (UC), 73 healthy family members, and 20 healthy controls were tested for anti-C. pneumoniae IgG titres. A subgroup consisting of 13 UC and 39 CD patients was screened for the presence of chlamydial DNA on 42 inflamed versus 30 non-inflamed biopsy specimens and for mutations of their NOD2/CARD15 gene. Anti-C. pneumoniae IgG antibodies were found in the sera of 32 (41%) patients with CD, 11 (46%) patients with UC, 35 (48%) of unaffected family members, and nine (45%) unrelated healthy controls. Thirty-five percent of the control, 18% CD and 24% UC biopsy specimens contained C. pneumoniae DNA. In CD, however, C. pneumoniae DNA was significantly more frequently found in inflamed (27%) versus non-inflamed (8%) biopsy specimens (P < 0.05, Fisher's exact test). The frequencies of NOD2/CARD15 mutations were 33% for CD patients with C. pneumoniae DNA compared to 47% for CD patients without C. pneumoniae DNA. We found no marked differences in respect to anti-C. pneumoniae serum IgG or C. pneumoniae DNA between healthy controls and patients with IBD. However, in CD patients, inflamed tissue specimens contained significantly more likely C. pneumoniae DNA compared with biopsies from unaffected areas. Thus C. pneumoniae is unlikely to be of pathogenic importance in IBD while it may still influence local clinical manifestations.
Atherogenesis is an inflammatory process with leukocytes infiltrating the arterial intima. The li... more Atherogenesis is an inflammatory process with leukocytes infiltrating the arterial intima. The lipoxygenase pathways play a role in leukocyte recruitment through the generation of two classes of arachidonic acid lipid mediators, the leukotrienes and the lipoxins, and one class of omega-3 fatty acid metabolites, the resolvins. There is evidence from animal studies and human genetic studies that the leukotrienes and the enzymes necessary for their generation play a role in atherosclerosis, and possibly even in the development of the vulnerable plaque. Less is known about the effect of the anti-inflammatory lipid mediators in atherosclerosis, the lipoxins and the resolvins. Studies modulating the activity of an enzyme necessary for the production of these lipid mediators, 12/15-lipoxygenase, showed discrepant results in several animal models. Also, human genetic studies have not clearly dissected the effect of the enzyme on atherosclerosis. However, stable forms of the lipoxins and the resolvins protect animals from inflammatory diseases. Whether blocking the leukotrienes or applying anti-inflammatory lipoxins and resolvins will be effective in attenuating human atherosclerosis needs to be demonstrated in future studies. In this review, the biosynthesis of these lipid mediators, their biological effects and the evidence for their possible role in atherosclerosis are discussed with an emphasis on human disease.
The Journal of Clinical Endocrinology and Metabolism, Mar 6, 2014
The impact of sugar-sweetened beverages (SSB) on lipid metabolism when consumed in moderate amoun... more The impact of sugar-sweetened beverages (SSB) on lipid metabolism when consumed in moderate amounts by normal weight subjects is debated. The objective of the study was to investigate the effect of different types of sugars in SSB on fatty acid metabolism (ie, fatty acid synthesis and oxidation) in healthy young men. Thirty-four normal-weight men were studied in a randomized crossover study. Four isocaloric 3-week interventions with SSB were performed in random order: medium fructose (MF; 40 g/d); high fructose (HF; 80 g/d), high sucrose (HS; 80 g/d), and high glucose (HG; 80g/d). Fasting total plasma fatty acid composition was measured after each intervention. Acylcarnitines were measured in the fasting state and after a euglycemic hyperinsulinemic clamp in nine subjects. The relative abundance of palmitate (16:0) and the molar fatty acid ratio of palmitate to linoleic acid (16:0 to18:2) as markers of fatty acid synthesis were increased after HF [relative abundance of palmitate: 22.97% ± 5.51% (percentage of total fatty acids by weight ±SD)] and MF (26.1% ± 1.7%) compared with HS (19.40% ± 2.91%, P < .001), HG (19.43% ±3.12 %, P < .001), or baseline (19.40% ± 2.79%, P < .001). After HS and HG, the relative abundance of palmitate was equal to baseline. Fasting palmitoylcarnitine was significantly increased after HF and HS (HF and HS vs. HG: P = .005), decreasing after inhibition of lipolysis by insulin in the clamp. When consumed in moderate amounts, fructose but not sucrose or glucose in SSB increases fatty acid synthesis (palmitate), whereas fasting long-chain acylcarnitines are increased after both fructose and sucrose, indicating an impaired β-oxidation flux.
Respiration International Review of Thoracic Diseases, 2010
Idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertensi... more Idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) share important pathogenic and clinical features. BMPR2 mutations are important in the pathogenesis of IPAH, but little is known about the genetic background in CTEPH. To search for mutations and polymorphisms in genes involved in the BMPR2, serotonin and nitric oxide pathways possibly associated with pulmonary and cardiac disorders in IPAH and CTEPH. In a cohort of Swiss patients with IPAH (n = 16) and CTEPH (n = 16), and in 24 controls with left heart disease without PH, polymorphisms in the BMPR2, 5-HHT, 5-HTR-2A and eNOS genes were analyzed and correlated with various clinical, functional and hemodynamic parameters. We found a BMPR2 missense mutation in a patient with coronary artery disease (CAD) without PH but no BMPR2 mutations in our collective with late-onset sporadic PH. In patients with polymorphic variants of the BMPR2 gene, the number of blood platelets and oxygen saturation were increased. The c.600A-->C synonymous variant was associated with worse exercise capacity and decreased quality of life in PH. We found no significant differences for any measured parameter according to the eNOS, 5-HTR2A and the 5-HTT polymorphisms, although there was a higher allelic frequency of the 5-HTT long variant in IPAH than in CTEPH and controls. Our first report of a BMPR2 mutation in a patient with CAD without PH is interesting and warrants further investigation. Our study may reflect the clinical status and genetic background in a typical PH cohort as seen in a single tertiary care referral center.
Low high-density lipoprotein (HDL) cholesterol is an important risk factor for coronary heart dis... more Low high-density lipoprotein (HDL) cholesterol is an important risk factor for coronary heart disease (CHD). In vitro, HDL exerts several potentially anti-atherogenic activities. HDLs mediate the reverse cholesterol transport (RCT) from peripheral cells to the liver, inhibit oxidation of low-density lipoprotein (LDL), adhesion of monocytes to the endothelium, apoptosis of vascular endothelial and smooth muscle cells and platelet activation, and stimulate the endothelial secretion of vasoactive substances as well as smooth muscle cell proliferation. Hence, raising HDL-cholesterol levels has become an interesting target for anti-atherosclerotic drug therapy. Levels of HDL cholesterol and the composition of HDL subclasses in plasma are regulated by apolipoproteins, lipolytic enzymes, lipid transfer proteins, receptors and cellular transporters. The interplay of these factors leads to RCT and determines the composition and, thereby, the anti-atherogenic properties of HDL. Several inborn errors of metabolism, as well as genetic animal models, are characterised by both elevated HDL cholesterol and increased rather than decreased cardiovascular risk. These findings suggest that the mechanism of HDL modification rather than simply increasing HDL cholesterol determine the efficacy of anti-atherosclerotic drug therapy. In several controlled and prospective intervention studies, patients with low HDL cholesterol and additional risk factors benefited from treatment with fibric acid derivatives (fibrates) or HMG-CoA reductase inhibitors (statins). However, only in some trials was prevention of coronary events in patients with low HDL cholesterol and hypertriglyceridaemia related to an increase in HDL cholesterol. We discuss the clinical and metabolic effects of fibrates, statins, nicotinic acid and sex steroids, and present novel therapeutic strategies that show promise in modifying HDL metabolism. In conclusion, HDL-cholesterol levels increase only moderately after treatment with currently available drugs and do not necessarily correlate with the functionality of HDL. Therefore, the anti-atherosclerotic therapy of high-risk cardiovascular patients should currently be focused on the correction of other risk factors present besides low HDL cholesterol. However, modification of HDL metabolism and improvement of RCT remain an attractive target for the development of new regimens of anti-atherogenic drug therapy.
Journal of immunology (Baltimore, Md. : 1950), 2015
ChemR23 is a G protein-coupled receptor that is triggered by two ligands, the peptide chemerin an... more ChemR23 is a G protein-coupled receptor that is triggered by two ligands, the peptide chemerin and the eicosapentaenoic acid-derived lipid mediator resolvin E1 (RvE1). Chemerin acts as a chemoattractant for monocytes and macrophages, whereas RvE1 promotes resolution of inflammation-inducing macrophage phagocytosis of apoptotic neutrophils. Although ChemR23-mediated signaling plays a role in mononuclear cell migration to inflamed tissue, as well as in the resolution of inflammation, its regulation in different polarization states of macrophages is largely unknown. We analyzed the expression and function of ChemR23 in monocytes and differently activated human primary macrophages. Using 5' RACE, we identified three transcription start sites and several splice variants of ChemR23 in both monocytes and macrophages. Although the promoters P1 and P3 are used equally in unpolarized macrophages, stimulation with LPS or IFN-γ leads to increased transcription from P3 in inflammatory M1 mac...
Low high-density lipoprotein (HDL)-cholesterol (C) is an important risk factor for coronary heart... more Low high-density lipoprotein (HDL)-cholesterol (C) is an important risk factor for coronary heart disease. In vitro, HDL exerts several potentially anti-atherogenic effects including reverse cholesterol transport (RCT) from peripheral cells to the liver. Hence, raising HDL-C has become an interesting target for anti-atherosclerotic drug therapy. Levels of HDL-C and the composition of HDL subclasses in plasma are regulated by apolipoproteins, lipolytic enzymes, lipid transfer proteins, receptors, and cellular transporters. The interplay of these factors leads to RCT and determines the composition and thereby the anti-atherogenic properties of HDL. Recent findings suggest that the mechanism of HDL modification rather than a sole increase in HDL-C determines the efficacy of anti-atherosclerotic drug therapy. In several controlled and prospective intervention studies, patients with low HDL-C and additional risk factors benefited from treatment with fibrates or statins. However, in only ...
We present a plasmid rescue from transgenic Drosophila to study spontaneous and mutagen-induced m... more We present a plasmid rescue from transgenic Drosophila to study spontaneous and mutagen-induced mutations in vivo. Transgenic Drosophila lines were established by transformation with a shuttle vector containing the bacterial lacZ gene as a target for mutagenesis. The target gene can be recovered into bacteria by restriction endonuclease treatment of total genomic DNA, followed by ligation of the recircularized shuttle vectors. The resulting circular plasmids are then transformed back into E. coli lacZ- mutants, where the activity of the lacZ genes is scored on the induction substrate X-Gal. The number of inactivated versus intact lacZ genes directly indicates the mutation frequency. By the described target gene rescue procedure up to 5000 lacZ gene copies can be rescued from one fly routinely. Spontaneous background mutation rates using this system are 2.6 +/- 0.6 x 10(-4). Treatment of larvae with ethylnitrosourea (ENU) resulted in a dose-dependent increase of the mutation frequenc...
Low bone mineral density (BMD) is common in chronic lung diseases and associated with reduced qua... more Low bone mineral density (BMD) is common in chronic lung diseases and associated with reduced quality of life. Little is known about BMD in pulmonary hypertension (PH). Steroid-naïve patients with PH (n=34; 19 idiopathic, 15 chronic thromboembolic) had BMD measured by DXA at the time of diagnostic right heart catheterization. Exercise capacity, quality of life and various parameters related to PH severity and bone metabolism were also assessed. 24 patients with left heart failure (LHF) were similarly assessed as controls. The prevalence of osteopenia was high both in PH (80%) and in controls with LHF (75%). Low BMD was associated with lean body mass, age, lower BMI, impaired exercise capacity and in PH with higher pulmonary vascular resistance. Serum parathyroid hormone (PTH) was elevated and considerably higher in PH than in LHF (above normal, in 55 vs 29%). Secondary hyperparathyroidism was not related to impaired renal function but possibly to low vitamin D status. Osteopenia is common in PH and in chronically ill patients with LHF. Osteopenia is associated with known risk factors but in PH also with disease severity. Preventive measures in an increasingly chronic ill PH population should be considered. Secondary hyperparathyroidism is highly prevalent in PH and might contribute to bone and possibly pulmonary vascular disease. Whether adequate vitamin D substitution could prevent low BMD in PH remains to be determined.
The IV anesthetic, propofol, when administered as fat emulsion-based formulation (Diprivan) promo... more The IV anesthetic, propofol, when administered as fat emulsion-based formulation (Diprivan) promotes insulin resistance, but the direct effects of propofol and its solvent, Intralipid, on cardiac insulin resistance are unknown. Hearts of healthy and type-2 diabetic rats (generated by fructose feeding) were aerobically perfused for 60 minutes with 10 μM propofol in the formulation of Diprivan or an equivalent concentration of its solvent Intralipid (25 μM) ± insulin (100 mU•L). Glucose uptake, glycolysis, and glycogen metabolism were measured using [H]glucose. Activation of Akt, GSK3β, AMPK, ERK1/2, p38MAPK, S6K1, JNK, protein kinase Cθ (PKCθ), and protein kinase CCβII (PKCβII) was determined using immunoblotting. GLUT4 trafficking and phosphorylations of insulin receptor substrate-1 (IRS-1) at Ser307(h312), Ser1100(h1101), and Tyr608(hTyr612) were measured. Mass spectrometry was used to determine acylcarnitines, phospholipids, and sphingolipids. Diprivan and Intralipid reduced insulin-induced glucose uptake and redirected glucose to glycogen stores in diabetic hearts. Reduced glucose uptake was accompanied by lower GLUT4 trafficking to the sarcolemma. Diprivan and Intralipid inactivated GSK3β but activated AMPK and ERK1/2 in diabetic hearts. Only Diprivan increased phosphorylation of Akt(Ser473/Thr308) and translocated PKCθ and PKCβII to the sarcolemma in healthy hearts, whereas it activated S6K1 and p38MAPK and translocated PKCβII in diabetic hearts. Furthermore, only Diprivan phosphorylated IRS-1 at Ser1100(h1101) in healthy and diabetic hearts. JNK expression, phosphorylation of Ser307(h312) of IRS-1, and PKCθ expression and translocation were increased, whereas GLUT4 expression was reduced in insulin-treated diabetic hearts. Phosphatidylglycerol, phosphatidylethanolamine, and C18-sphingolipids accumulated in Diprivan-perfused and Intralipid-perfused diabetic hearts. Propofol and Intralipid promote insulin resistance predominantly in type-2 diabetic hearts.
Oxidative stress and low-grade systemic inflammation may contribute to the pathogenesis of obesit... more Oxidative stress and low-grade systemic inflammation may contribute to the pathogenesis of obesity-induced comorbidities, including nonalcoholic fatty liver disease. Increasing intake of dietary antioxidants might be beneficial, but there are few data in obese children. To examine the effect of antioxidant supplementation on biomarkers of oxidative stress, inflammation, and liver function, we randomly assigned overweight or obese children and adolescents (n = 44; mean ± SD age: 12.7 ± 1.5 y) participating in a lifestyle modification program to a 4-mo intervention with daily antioxidants (vitamin E, 400 IU; vitamin C, 500 mg; selenium, 50 μg) or placebo. We measured anthropometrics, antioxidant status, oxidative stress (F(2)-isoprostanes, F(2)-isoprostane metabolites), inflammation, liver enzymes, fasting insulin and glucose, and lipid profile at baseline and endpoint. There was a significant treatment effect of antioxidant supplementation on antioxidant status [α-tocopherol, β = 23.2 (95% CI: 18.0, 28.4); ascorbic acid, β = 70.6 (95% CI: 51.7, 89.4); selenium, β = 0.07 (95% CI: 0.01, 0.12)] and oxidative stress [8-iso-prostaglandin F2α, β = -0.11 (95% CI: -0.19, -0.02)] but not on any of the inflammatory markers measured. There was a significant treatment effect on alanine aminotransferase [β = -0.13 (95% CI: -0.23, -0.03)], a trend toward a significant effect on aspartate aminotransferase [β = -0.04 (95% CI: -0.09, 0.01)], and no significant effect on γ-glutamyltransferase [β = -0.03 (95% CI: -0.11, 0.06)]. In summary, antioxidant supplementation for 4 mo improved antioxidant-oxidant balance and modestly improved liver function tests; however, it did not reduce markers of systemic inflammation despite significant baseline correlations between oxidative stress and inflammation. The study was registered at clinicaltrials.gov as NCT01316081.
Idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertensi... more Idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) share important pathogenic and clinical features. BMPR2 mutations are important in the pathogenesis of IPAH, but little is known about the genetic background in CTEPH. To search for mutations and polymorphisms in genes involved in the BMPR2, serotonin and nitric oxide pathways possibly associated with pulmonary and cardiac disorders in IPAH and CTEPH. In a cohort of Swiss patients with IPAH (n = 16) and CTEPH (n = 16), and in 24 controls with left heart disease without PH, polymorphisms in the BMPR2, 5-HHT, 5-HTR-2A and eNOS genes were analyzed and correlated with various clinical, functional and hemodynamic parameters. We found a BMPR2 missense mutation in a patient with coronary artery disease (CAD) without PH but no BMPR2 mutations in our collective with late-onset sporadic PH. In patients with polymorphic variants of the BMPR2 gene, the number of blood platelets and oxygen saturation were increased. The c.600A-->C synonymous variant was associated with worse exercise capacity and decreased quality of life in PH. We found no significant differences for any measured parameter according to the eNOS, 5-HTR2A and the 5-HTT polymorphisms, although there was a higher allelic frequency of the 5-HTT long variant in IPAH than in CTEPH and controls. Our first report of a BMPR2 mutation in a patient with CAD without PH is interesting and warrants further investigation. Our study may reflect the clinical status and genetic background in a typical PH cohort as seen in a single tertiary care referral center.
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Papers by Martin Hersberger