GDF15 reflects beta cell function in obese patients independently of the grade of impairment of glucose metabolism.

BACKGROUND AND AIMS: Growth differentiation factor 15 (GDF15) is a strong predictor of cardiovascular morbidity and mortality found to be both marker and target of impaired glucose metabolism. GDF15 increases following glucose administration and is up-regulated in obesity and diabetes. We investigate here the relationship between GDF15 and beta cell function. METHODS AND RESULTS: In this cross-sectional study we evaluated GDF15 concentrations in 160 obese subjects (BMI 35-63 kg/m2, age 39.4 ± 18.6 years, m/f 38/122) who underwent a 75 g oral glucose tolerance test (OGTT). Based on the OGTT results, the cohort was divided into two groups: 1) normal fasting glucose and normal glucose tolerance (n = 80), 2) impaired fasting glucose, impaired glucose tolerance or type 2 diabetes (n = 80). The relationship of GDF15 to fasting and OGTT-based dynamic insulin sensitivity and insulin secretion parameters was evaluated. GDF15 was higher in the prediabetes and diabetes groups and correlated with HbA1c, glucose, insulin as well as baseline and dynamic indices of insulin sensitivity and estimated beta cell function. Multiple regression analysis revealed that age, waist-to-height ratio, glomerular filtration rate and prehepatic beta cell function, but not the grade of impairment of glucose metabolism, were independent predictors of GDF15. Subgroup analysis showed that of all parameters of glucose metabolism only C-peptide, fasting prehepatic beta cell function and insulinogenic index remained significantly related to GDF15 in both groups. CONCLUSION: We conclude that in patients with severe obesity, GDF15 strongly relates to beta cell function and should be further investigated as a potential therapeutic target and biomarker guiding treatment options.

European consensus for starting and stopping enzyme replacement therapy in adult patients with Pompe disease: a 10-year experience.

BACKGROUND AND PURPOSE: Pompe disease is a rare inheritable muscle disorder for which enzyme replacement therapy (ERT) has been available since 2006. Uniform criteria for starting and stopping ERT in adult patients were developed and reported here. METHODS: Three consensus meetings were organized through the European Pompe Consortium, a network of experts from 11 European countries in the field of Pompe disease. A systematic review of the literature was undertaken to determine the effectiveness of ERT in adult patients on a range of clinical outcome measures and quality of life. A narrative synthesis is presented. RESULTS: Consensus was reached on how the diagnosis of Pompe disease should be confirmed, when treatment should be started, reasons for stopping treatment and the use of ERT during pregnancy. This was based on expert opinion and supported by the literature. One clinical trial and 43 observational studies, covering a total of 586 individual adult patients, provided evidence of a beneficial effect of ERT at group level. At individual patient level, the response to treatment varied, but factors associated with a patient's response to ERT were not described in many studies. Eleven observational studies focused on more severely affected patients, suggesting that ERT can also be beneficial in these patients. There are no studies on the effects of ERT in pre-symptomatic patients. CONCLUSIONS: This is the first European consensus recommendation for starting and stopping ERT in adult patients with Pompe disease, based on the extensive experience of experts from different countries.

Identification of matrix metalloproteinase-12 as a candidate molecule for prevention and treatment of cardiometabolic disease.

Obesity is strongly associated with metabolic syndrome, a combination of risk factors that predispose to the development of the cardiometabolic diseases: atherosclerotic cardiovascular disease and type 2 diabetes mellitus. Prevention of metabolic syndrome requires novel interventions to address this health challenge. The objective of this study was the identification of candidate molecules for the prevention and treatment of insulin resistance and atherosclerosis, conditions that underlie type 2 diabetes mellitus and cardiovascular disease, respectively. We used an unbiased bioinformatics approach to identify molecules that are upregulated in both conditions by combining murine and human data from a microarray experiment and meta-analyses. We obtained a pool of eight genes that were upregulated in all the databases analysed. This included well known and novel molecules involved in the pathophysiology of type 2 diabetes mellitus and cardiovascular disease. Notably, matrix metalloproteinase 12 (MMP12) was highly ranked in all analyses and was therefore chosen for further investigation. Analyses of visceral and subcutaneous white adipose tissue from obese compared to lean mice and humans convincingly confirmed the up-regulation of MMP12 in obesity at mRNA, protein and activity levels. In conclusion, using this unbiased approach an interesting pool of candidate molecules was identified, all of which have potential as targets in the treatment and prevention of cardiometabolic diseases.

Common dysregulated pathways in obese adipose tissue and atherosclerosis.

BACKGROUND: The metabolic syndrome is becoming increasingly prevalent in the general population that is at simultaneous risk for both type 2 diabetes and cardiovascular disease. The critical pathogenic mechanisms underlying these diseases are obesity-driven insulin resistance and atherosclerosis, respectively. To obtain a better understanding of molecular mechanisms involved in pathogenesis of the metabolic syndrome as a basis for future treatment strategies, studies considering both inherent risks, namely metabolic and cardiovascular, are needed. Hence, the aim of this study was to identify pathways commonly dysregulated in obese adipose tissue and atherosclerotic plaques. METHODS: We carried out a gene set enrichment analysis utilizing data from two microarray experiments with obese white adipose tissue and atherosclerotic aortae as well as respective controls using a combined insulin resistance-atherosclerosis mouse model. RESULTS: We identified 22 dysregulated pathways common to both tissues with p values below 0.05, and selected inflammatory response and oxidative phosphorylation pathways from the Hallmark gene set to conduct a deeper evaluation at the single gene level. This analysis provided evidence of a vast overlap in gene expression alterations in obese adipose tissue and atherosclerosis with Il7r, C3ar1, Tlr1, Rgs1 and Semad4d being the highest ranked genes for the inflammatory response pathway and Maob, Bckdha, Aldh6a1, Echs1 and Cox8a for the oxidative phosphorylation pathway. CONCLUSIONS: In conclusion, this study provides extensive evidence for common pathogenic pathways underlying obesity-driven insulin resistance and atherogenesis which could provide a basis for the development of novel strategies to simultaneously prevent type 2 diabetes and cardiovascular disease in patients with metabolic syndrome.

Strong association of serum- and glucocorticoid-regulated kinase 1 with peripheral and adipose tissue inflammation in obesity.

OBJECTIVE: The serum- and glucocorticoid-regulated kinase 1 (SGK1) is an early transcriptional target of glucocorticoids and is activated via insulin. Here we investigate the regulation of SGK1 expression in human obesity, diet-induced murine obesity and human monocytic cell line THP-1 monocytes. SUBJECTS AND METHODS: SGK1 expression was studied in subcutaneous and omental adipose tissue (AT) of 20 morbidly obese and 20 age- and gender-matched non-obese controls in murine diet-induced obesity and the THP-1 cell line. The regulation of SGK1 by inflammatory signals was tested in THP-1 cells. RESULTS: Murine diet-induced obesity is associated with a significant upregulation of Sgk1 in gonadal AT. Sgk1 expression is highest in the macrophage-rich stromal vascular fraction and lower in adipocytes. In humans, AT SGK1 is predominantly expressed in CD14(+) macrophages and significantly upregulated in omental and subcutaneous AT of obese subjects. SGK1 mRNA expression in both omental and subcutaneous AT correlates with body mass index, circulating leptin and C-reactive protein, and the local expression of inflammatory markers including monocyte chemotactic protein-1 and macrophage inflammatory protein-1α. The expression of SGK1 in THP-1 cells is upregulated by inflammatory signals, such as lipopolysaccharide and tumour necrosis factor-α, as well as during the induction of monocyte-to-macrophage maturation. CONCLUSIONS: Our data present the first link between SGK1 and obesity-associated inflammation. SGK1 expression is stimulated in response to inflammatory signals and increased in AT macrophages. The characterisation of SGK1 functions in obesity and immunity may help identify potential therapeutic targets in the treatment of obesity.

Severe obesity increases adipose tissue expression of interleukin-33 and its receptor ST2, both predominantly detectable in endothelial cells of human adipose tissue.

OBJECTIVE: Obesity is associated with chronic inflammation of the adipose tissue, which contributes to obesity-associated complications such as insulin resistance and type 2 diabetes. Interleukin (IL)-33 acts via its receptor ST2 and is involved in the pathogenesis of inflammatory disorders including atherosclerosis and heart disease. IL-33 has been demonstrated to promote endothelial cell inflammatory response, but also anti-inflammatory and protective actions such as TH2 and M2 polarization of T cells and macrophages, respectively. IL-33 and ST2 have been shown to be expressed in human and murine adipose tissue. Our objective was to investigate alterations in obesity and a possible role of IL-33 in adipose tissue inflammation. SUBJECTS AND METHODS: We investigated severely obese patients (BMI>40 kg m(-2), n=20) and lean to overweight controls (BMI<30 kg m(-2); n=20) matched for age and sex, as well as diet-induced obese and db/db mice, in order to determine the impact of obesity on IL-33 and ST2 gene and protein expression levels in adipose tissue and blood, and their correlation with inflammatory and metabolic parameters. Furthermore, we examined the cellular source and location of IL-33 and ST2 in situ. RESULTS: IL-33 and ST2 expression levels were markedly elevated in omental and subcutaneous adipose tissue of severely obese humans and in diet-induced obese mice, but not in leptin receptor-deficient db/db mice. In addition, soluble ST2, but not IL-33 serum levels, were elevated in obesity. The main source for IL-33 in adipose tissue were endothelial cells, which, in humans, exclusively expressed ST2 on their surface. IL-33 expression strongly correlated with leptin expression in human adipose tissue. CONCLUSIONS: Expression of IL-33 and its receptor ST2 in human adipose tissue is predominantly detectable in endothelial cells and increased by severe obesity indicating an autocrine action. Thus, the adipose tissue microvasculature could participate in obesity-associated inflammation and related complications via IL-33/ST2.

Osteopontin deficiency protects against obesity-induced hepatic steatosis and attenuates glucose production in mice.

AIMS/HYPOTHESIS: Obesity is strongly associated with the development of non-alcoholic fatty liver disease (NAFLD). The cytokine osteopontin (OPN) was recently shown to be involved in obesity-induced adipose tissue inflammation and reduced insulin response. Accumulating evidence links OPN to the pathogenesis of NAFLD. Here we aimed to identify the role of OPN in obesity-associated hepatic steatosis and impaired hepatic glucose metabolism. METHODS: Wild-type (WT) and Opn (also known as Spp1) knockout (Opn (-/-)) mice were fed a high-fat or low-fat diet to study OPN effects in obesity-driven hepatic alterations. RESULTS: We show that genetic OPN deficiency protected from obesity-induced hepatic steatosis, at least in part, by downregulating hepatic triacylglycerol synthesis. Conversely, absence of OPN promoted fat storage in adipose tissue thereby preventing the obesity-induced shift to ectopic fat accumulation in the liver. Euglycaemic-hyperinsulinaemic clamp studies revealed that insulin resistance and excess hepatic glucose production in obesity were significantly attenuated in Opn (-/-) mice. OPN deficiency markedly improved hepatic insulin signalling as shown by enhanced insulin receptor substrate-2 phosphorylation and prevented upregulation of the major hepatic transcription factor Forkhead box O1 and its gluconeogenic target genes. In addition, obesity-driven hepatic inflammation and macrophage accumulation was blocked by OPN deficiency. CONCLUSIONS/INTERPRETATION: Our data strongly emphasise OPN as mediator of obesity-associated hepatic alterations including steatosis, inflammation, insulin resistance and excess gluconeogenesis. Targeting OPN action could therefore provide a novel therapeutic strategy to prevent obesity-related complications such as NAFLD and type 2 diabetes.

Newly identified adipose tissue macrophage populations in obesity with distinct chemokine and chemokine receptor expression.

OBJECTIVE: Infiltration by macrophages is a hallmark of obesity-related adipose tissue (AT) inflammation that is tightly linked to insulin resistance. Although CD11c+ AT macrophages (ATMs) have recently been shown to promote inflammation in obese mice, the knowledge on phenotype and function of different ATM populations is still very limited. This study aimed at identifying and characterizing ATM populations in obesity. METHODS: Isolation of ATM populations defined by CD11c and mannose receptor (MR) expression and analysis of gene expression in high-fat diet-induced obese mice. RESULTS: Obesity provoked a shift from a predominant MR+CD11c⁻ population ('MR-ATM') to two MR⁻ populations, namely MR⁻CD11c+ ('CD11c-ATM') and MR⁻CD11c⁻ (double negative, 'DN-ATM'). Although CD11c-ATMs were of a clear inflammatory M1 phenotype, DN-ATMs expressed few inflammatory mediators and highly expressed genes for alternative activation (M2) markers involved in tissue repair, such as arginase and YM1. In contrast, MR-ATMs marginally expressed M1 and M2 markers but highly expressed chemokines, including Mcp-1 (Ccl2) and Mcp-3 (Ccl7). Both CD11c-ATMs and DN-ATMs, but not MR-ATM, highly expressed a panel of chemokine receptors (namely Ccr2, Ccr5, Ccr3 and Cx3cr1), whereas the expression of Ccr7 and Ccr9 was selective for CD11c-ATMs and DN-ATMs, respectively. Notably, stressed adipocytes upregulated various chemokines capable of attracting CD11c-ATM and DN-ATM. CONCLUSION: This study identifies a novel ATM population with a putatively beneficial role in AT inflammation. This DN-ATM population could be attracted to the obese AT by similar chemokines such as inflammatory CD11c-ATM, on which only Ccr7 is uniquely expressed.

Diminished upregulation of visceral adipose heme oxygenase-1 correlates with waist-to-hip ratio and insulin resistance.

OBJECTIVE: Insulin resistance in visceral obesity is substantially driven by adipose tissue inflammation, particularly by macrophages accumulating in obese adipose tissue. In contrast, adipose tissue macrophages express the hemoglobin scavenger receptor (CD163) and heme oxygenase-1 (gene: HMOX1) that together protect from oxidative stress. Our aim was to evaluate the expression of CD163 and HMOX1 in intra-abdominal visceral (omental) and subcutaneous adipose tissue as well as circulating soluble CD163 concentrations in human obesity and its association with adipose tissue inflammation, body fat distribution and insulin resistance. METHODS: CD163, HMOX1 and CD68 mRNA expression in visceral and subcutaneous adipose tissue, serum concentration of soluble CD163 in morbidly obese patients (body mass index (BMI) >40 kg m(-2)), who underwent laparoscopic surgery for gastric banding (n=20), matched for age and sex to controls (BMI<30 kg m(-2); n=20) was analyzed. RESULTS: CD163 expression was highly upregulated in human adipose tissue and soluble CD163 serum concentration was elevated in obese vs lean subjects. HMOX1 was upregulated in adipose tissue by obesity as well and expressed predominantly in macrophages. Although CD163 expression strictly correlated with macrophage abundance, HMOX1 was additionally upregulated within macrophages. This upregulation was significantly lower in visceral compared with subcutaneous adipose tissue. Strikingly, relative visceral adipose tissue expression of HMOX1 negatively correlated with waist-to-hip ratio and the homeostasis model assessment of insulin resistance (both P=0.024). CONCLUSIONS: Visceral obesity is associated with defective upregulation of heme oxygenase-1 in visceral adipose tissue. A lack of this antioxidative and anti-inflammatory enzyme in visceral adipose tissue could contribute to the development of insulin resistance.

Polyunsaturated fatty acids inhibit T cell signal transduction by modification of detergent-insoluble membrane domains.

Polyunsaturated fatty acids (PUFAs) exert immunosuppressive effects, but the molecular alterations leading to T cell inhibition are not yet elucidated. Signal transduction seems to involve detergent-resistant membrane domains (DRMs) acting as functional rafts within the plasma membrane bilayer with Src family protein tyrosine kinases being attached to their cytoplasmic leaflet. Since DRMs include predominantly saturated fatty acyl moieties, we investigated whether PUFAs could affect T cell signaling by remodeling of DRMs. Jurkat T cells cultured in PUFA-supplemented medium showed a markedly diminished calcium response when stimulated via the transmembrane CD3 complex or glycosyl phosphatidylinositol (GPI)- anchored CD59. Immunofluorescence studies indicated that CD59 but not Src family protein tyrosine kinase Lck remained in a punctate pattern after PUFA enrichment. Analysis of DRMs revealed a marked displacement of Src family kinases (Lck, Fyn) from DRMs derived from PUFA-enriched T cells compared with controls, and the presence of Lck in DRMs strictly correlated with calcium signaling. In contrast, GPI-anchored proteins (CD59, CD48) and ganglioside GM1, both residing in the outer membrane leaflet, remained in the DRM fraction. In conclusion, PUFA enrichment selectively modifies the cytoplasmic layer of DRMs and this alteration could underlie the inhibition of T cell signal transduction by PUFAs.

Pompe disease in Austria: clinical, genetic and epidemiological aspects.

In this study, we performed a survey of infantile and late-onset Pompe disease (IOPD and LOPD) in Austria. Paediatric and neuromuscular centres were contacted to provide a set of anonymized clinical and genetic data of patients with IOPD and LOPD. The number of patients receiving enzyme replacement therapy (ERT) was obtained from the pharmaceutical company providing alglucosidase alfa. We found 25 patients in 24 families, 4 IOPD and 21 LOPD with a resulting prevalence of 1:350,914. The most frequent clinical manifestation in LOPD was a lower limb-girdle phenotype combined with axial weakness. Three patients were clinically pauci- or asymptomatic and were diagnosed because of persistent hyperCKemia. Diagnostic delay in LOPD was 7.4 ± 9.7 years. The most common mutation was c.-32-13T > G. All IOPD and 17 symptomatic LOPD patients are receiving ERT. Standardized follow-up was only available in six LOPD patients for the 6-min walk test (6minWT) and in ten for the forced vital capacity (FVC). Mean FVC did not decline (before ERT; 63.6 ± 39.7%; last evaluation during ERT: 61.9 ± 26.9%; P = 0.5) while there was a trend to decline in the mean distance covered by the 6minWT (before ERT: 373.5 ± 117.9 m; last evaluation during ERT: 308.5 ± 120.8 m; P = 0.077). The study shows a lower prevalence of Pompe disease in Austria than in other European countries and corroborates a limb-girdle phenotype with axial weakness as the most common clinical presentation, although asymptomatic hyperCKemia may be the first indication of LOPD.

The novel immunosuppressant FK778 inhibits formation of the immunologic Synapse.

The malononitrilamide FK778 is a derivative of A77 1726, the active metabolite of the antirheumatic drug leflunomide. A77 1726 inhibits de novo pyrimidine synthesis and activity of Src-family kinases; thus, it may interfere with T-cell proliferation as well as with early T-cell signaling. Formation of a stable interaction between T cells and antigen-presenting cells (APC)--the immunologic synapse--has emerged to be of crucial importance for T-cell activation. Here in we show that FK778 inhibits formation of the immunologic synapse by blocking superantigen-stimulated relocalization of adhesion (LFA-1), and signaling molecules (CD3) to the T-cell/APC contact site. These data show that FK778 affects T-cell/APC interactions, particularly events crucial for T-cell adhesion and formation of stable conjugates underlying sustained and effective T-cell activation. Thus, in this model system close to physiologic T-cell stimulation, FK778 affects critical events in the course of T-cell-mediated immune responses earlier than T-cell proliferation, which may contribute to its immunosuppressive potential.

The malononitrilamide FK778 inhibits activation of NF-kappaB in human dendritic cells.

FK778, a derivative of the active leflunomide-metabolite, A77 1726, has been shown to be a powerful immunosuppressant in several transplantation models, particularly efficient in prevention of chronic allograft rejection. However, the cellular and molecular mechanisms underlying these effects of FK778 have not been investigated yet in detail. Because dendritic cells (DCs) are a crucial cell type in initiation of immune responses including chronic allograft rejection, we investigated whether FK778 affects this peculiar cell population. NF-kappaB is the essential transcription factor involved in DC activation and function. We found that lipopolysaccharide (LPS)-induced activation of NF-kappaB, as assessed using electromobility shift assay, is markedly inhibited by FK778 in human monocyte-derived DCs. Hence, FK778 could exert its immunosuppressive effects via inhibition of activation and thus function of the central antigen-presenting cell, ie, DC.

Effect of a low-fat diet enriched either with rapeseed oil or sunflower oil on plasma lipoproteins in children and adolescents with familial hypercholesterolaemia. Results of a pilot study.

BACKGROUND/OBJECTIVES: There is convincing evidence that unsaturated fatty acids exert favourable effects on plasma cholesterol levels. However, it is not clear which type of oil has the most pronounced effect, especially not in paediatric patients. The aim was to compare two low-fat diet regimes enriched with either monounsaturated fatty acids by rapeseed oil (RO) or polyunsaturated fatty acids by sunflower oil (SO) in children affected with familial hypercholesterolaemia (FH). SUBJECTS/METHODS: Twenty-one children aged 6-18 years affected with FH were enrolled in this randomized and double-blind pilot trial. The subjects and their families were trained to adhere to a low-fat/low-cholesterol diet. All visible fats were to be replaced by either RO or SO (14-27 g/day) for 13 weeks. Dietary adherence was controlled by repeated 4-day dietary records; plasma lipids, lipoproteins and risk markers were assessed at baseline and post-intervention. Out of 21 subjects, 16 could be followed-up after 6 months. RESULTS: Both fat-modified diets resulted in significant reduction in total cholesterol concentrations of 9.4% (RO P<0.005 vs SO P<0.05) and low-density lipoprotein (LDL) cholesterol concentrations of 12.7% (P<0.005) for RO and 11.3% (P<0.05) for SO. The reduction of the LDL/high-density lipoprotein (HDL) cholesterol ratio (RO 9% vs SO 3.5%) and high-sensitivity C-reactive protein (RO 16.8% vs SO 1.7%) were not statistically significant, respectively. In most participating families, a change in eating habits could be observed. CONCLUSIONS: A fat-modified diet enriched with RO seems to have very similar effects on cholesterol levels as with SO. However, our study suggests that RO has possibly more favourable effects concerning cardiovascular risk profile. Both diets appear to be feasible and were well accepted among our subjects. Although these results are promising, larger trials will be required to validate our findings.

Duchenne muscular dystrophy: lack of differences in the expression of endogenous carbohydrate- and heparin-binding proteins (lectins) in cultured fibroblasts.

Duchenne muscular dystrophy (DMD), the most severe form of inherited muscular dystrophies, is known to be caused by a deficiency of the protein "dystrophin", but the pathophysiologic consequences of this lack have not as yet been elucidated. Investigations with cultured fibroblasts point to altered adhesion mechanisms in cells from DMD patients. Because endogenous carbohydrate-binding proteins (lectins) play an important role in cell-cell and cell-matrix interactions and therefore might be involved in these alterations, we separated such proteins with specificities for beta-galactosyl-, alpha-mannosyl-, and alpha-glucosyl-residues, as well as heparin-binding proteins from cultured fibroblasts. Owing to enormous interindividual variations among DMD patients and among healthy controls our hypothesis could not be confirmed. In the course of the experiments we could detect a growth-related binding of heparin to nuclei of cells from DMD patients and healthy controls restricted to rapidly growing cultures and telophases of mitoses, but not in contact-inhibited monolayers. This finding suggested a possible involvement of the cellular ligand in growth control and coincided with the occurrence of basic fibroblast growth factor.

Serum glycoprotein hormones and their free alpha-subunit in a healthy elderly population selected according to the SENIEUR protocol. Analyses with ultrasensitive time resolved fluoroimmunoassays.

The SENIEUR protocol was elaborated by a working party of European Community's Concerted Action Programme on Aging (EURAGE) to define strict admission criteria for 'healthy' elderly subjects and young controls for immunogerontological studies. This protocol, which is based on case history, laboratory values and drug consumption, intends to limit the influence of underlying disease and/or medication in order to allow analyses of the aging process per se. In a group of 38 male and 37 female individuals we determined the impact of age and classification according to the SENIEUR protocol on luteinizing hormone (LH), follicle stimulating hormone (FSH), human chorionic gonadotropin (hCG) and free glycoprotein hormone alpha-subunit serum values. Analyses were performed by a set of ultrasensitive time-resolved immunofluorometric assays (IFMA) using our own panel of monoclonal antibodies (MCA). HLH and hFSH, but also hCG and free alpha serum levels increased highly significantly with age in the female population (P < 0.001). In males hFSH, hLH hCG and the free alpha-subunit increased with age. However, only the rise of hFSH and of Free alpha was statistically significant (P < 0.01). The influence of the SENIEUR status on the respective hormone serum levels was determined using two factor analysis of variance, which revealed no statistically significant difference (P > 0.01) between SENIEUR and NON-SENIEUR individuals for all four analytes in both sexes. We conclude that the age related increase of hLH, hFSH, hCG and free alpha is an intrinsic age-dependent phenomen and is not modified by or due to underlying disease or medication as demonstrated by analyses of SENIEUR individuals. Since SENIEUR and NON-SENIEUR individuals had comparable hormone values, a randomly chosen, 'apparently healthy' population seems to be sufficient for physiological studies on serum GPH levels. Lastly, these age related hormonal changes in an extremely well defined healthy population underline the need for age adjusted 'normal' hormone values as elaborated in this communication.

Estimation of reference intervals from a SENIEUR protocol compatible aged population for immunogerontological studies.

Because many laboratory values change with age, the study of healthy aging as well as diagnosis of disease in geriatric patients requires specific age-corrected reference intervals. We have established such reference intervals for a healthy population aged 65-74 years by selection of a sample group applying the clinical criteria of the SENIEUR protocol and we have compared them with those of a young control group (20-33 years) fulfilling the same criteria. Significant or minor elevations were seen, e.g. for plasma concentrations of fasting glucose, urea, total and LDL-cholesterol, triglycerides, gamma-glutamyl-transferase, alkaline phosphatase, erythrocyte sedimentation rate and serum neopterin levels. These reference intervals can be used for selecting a SENIEUR compatible population aged between 65 and 74 years. Additionally, plasma lipid parameters (cholesterol, triglycerides) are proposed to be included in the SENIEUR protocol.

Prospective randomised cross-over comparison of three LDL-apheresis systems in statin pretreated patients with familial hypercholesterolaemia.

Various LDL-apheresis systems have gained wider clinical acceptance in recent years to treat patients with severe familial hypercholesterolaemia, in particular in patients with coronary artery disease. For each single device data on efficacy have been provided, but up to now no comparative analysis including the novel direct adsorption of lipoproteins from whole blood has been reported. This prospectively designed cross-over comparison of three commercially available LDL-apheresis systems (immunoadsorption, IMAL; dextran sulphate adsorption, DSA; direct adsorption of lipoproteins, DALI) was performed in eight patients with homozygous (n = 3) and heterozygous (n = 5) familial hypercholesterolaemia. Removal of atherogenic lipoproteins was highly effective in all systems, for LDL-cholesterol in particular: DSA: - 84.3 +/- 6.2%; IMAL: -82.1 +/- 8.3%; DALI: -76.6 +/- 7.2% (P < 0.05 as compared DALI versus IMAL and DSA). A reduction in Lp(a) of about 63% was achieved by each device. Loss in HDL-cholesterol was highest with IMAL (-21.3 +/- 4.9%, P < 0.05) as compared to the other two treatment modalities. DSA decreased HDL-cholesterol by - 10.4 +/- 6.1% and the DALI system by -12.7 +/- 5.0%. Remarkable differences were found for the removal of fibrinogen (DSA: -29.8 +/- 14.7%, (P < 0.05 versus DALI/IMAL); IMAL: -21.4 +/- 10.1% (P < 0.05 versus DALI); DALI: -14.8 +/- 8.0%). The shortest duration for treatment was achieved by the DALI system (135 +/- 20 min, P < 0.05 versus IMAL (195 +/- 20 min) and DSA (187 +/- 29 min)). No side effects were recorded in the total of 96 treatments performed during the study. Long-term observations have yet to prove whether these differences in efficacy may be of clinical relevance.

Properties of low density lipoproteins relevant to oxidative modifications change paradoxically during aging.

Atherosclerosis is a common problem among the elderly. Because lipid peroxidation is considered a contributor to the development of atherosclerosis, we compared oxidative properties of lipoproteins in an otherwise healthy (SENIEUR-classified) aged population (65-74 years) with young controls (18-30 years). Relative amounts of oxidatively altered low density lipoprotein (LDL), estimated by means of an antibody against LDL modified by 4-hydroxynonenal, a product of lipid peroxidation, were increased marginally in serum from the elderly (9.8 vs. 7.4%, P = 0.07). In contrast, isolated LDL from the elderly revealed a decreased susceptibility to in vitro oxidation: the lag time was increased (2.34 vs. 2.10 h, P < 0.01), and the maximal rate of LDL oxidation decreased (0.88 vs. 1.01 O.D./h, P = 0.001). However, there were no age-related changes in lipid composition of native LDL and consumption of fatty acids during in vitro oxidation. The serum concentrations of ascorbic acid and most lipophilic anti-oxidants (the latter expressed per g serum lipids) were significantly decreased in the elderly except tocopherols which tended to be higher. In conclusion, our data reveal paradox age-related alterations of LDL as to its behaviour in oxidation in vivo vs. in vitro.

Altered switch in lipid composition during T-cell blast transformation in the healthy elderly.

Decreased mitogen responsiveness of lymphocytes during aging correlates inversely with membrane microviscosity, which reflects an altered lipid composition. Therefore, we addressed the question, whether age-related alterations of lipid metabolism affect the switch in lipid composition during formation of blasts. Membrane lipids and fatty acids of peripheral blood lymphocytes from SENIEUR protocol compatible ("healthy") elderly donors (66-77 yr) and young controls (18-30 yr) were quantified after incubation with or without the mitogen phytohaemagglutinin. The blastic change in membrane lipid composition was different for young controls with respect to cholesterol, phosphatidylethanolamine, total phospholipids, as well as several fatty acids. Moreover, the age-related alterations in the switch of membrane lipids and fatty acids were significantly correlated with a decreased mitogen response. Thus, the alterations in membrane reorganization during blast formation of lymphocytes from the elderly point to a disturbed cellular lipid homeostasis with possible impact on the age-related reduction in immune function.