Torbjörn Åkerfeldt

Increased plasma glucose levels after change of recommendation from NaF to citrate blood collection tubes.

OBJECTIVES To evaluate changes in plasma glucose measurements in an unselected patient population after a change of recommendation from NaF to citrate blood collection vacuum tubes. DESIGN AND METHODS Glucose (n=460 751) and HbA1c (n=55 190) determinations during a period of approximately three years before and after the tube change were extracted from a laboratory information system. RESULTS Median values for plasma glucose determinations increased from 6.03 before to 6.28mmol/L after the tube change. The proportion of glucose determinations above the WHO limit for impaired fasting glucose (6.1mmol/L) and the medical decision limit for diabetes (7.0mmol/L) increased from 48.1 to 55.4% after the change. CONCLUSIONS The change from NaF to citrate tubes caused higher glucose values, and consequently more glucose determinations above the decision limit for diabetes.

Serum MMP-9 and TIMP-1 concentrations and MMP-9 activity during surgery-induced inflammation in humans.

Abstract Background: Matrix metalloproteinase 9 (MMP-9) and the endogenous inhibitor to MMP-9, tissue inhibitor of metalloproteinase 1 (TIMP-1), have important roles in tissue remodelling and are implicated in a number of diseases related to inflammation. The time course in activation and formation of MMPs and TIMPs during an inflammatory reaction is not fully known. This study investigates MMP-9 and TIMP-1 concentrations and MMP-9 activity at different time points after major surgery when a state of noticeable inflammation is expected. Methods: Serum MMP-9 and TIMP-1 concentrations and MMP-9 activity were analysed preoperatively and 4 and 30 days postoperatively in patients undergoing elective surgery (coronary artery bypass n=21; orthopaedic surgery, n=29). Results: Serum TIMP-1 and MMP-9 activity increased significantly 4 days after surgery (p<0.05 and p<0.01, respectively) and decreased again 30 days after surgery (p<0.01, respectively, compared to 4 days after surgery). Serum MMP-9 increased significantly 4 days after surgery (p<0.05) and was still high 30 days after surgery (p<0.01 compared to before surgery). The calculated MMP-9/TIMP-1 ratio was increased 30 days after surgery compared to before surgery (p<0.01). Conclusions: The inflammatory state induced by elective surgery is associated with increased TIMP-1 response and MMP-9 activity in serum within a few days which may be of importance for the postoperative heeling process. The further increase in MMP-9 concentrations at day 30 postoperative did not result in increased MMP-9 activity. Serum MMP-9 concentrations or the calculated MMP-9/TIMP-1 ratio do not entirely represent MMP-9 activity during surgery-induced inflammation.

Inflammatory response is associated with increased cathepsin B and decreased cathepsin S concentrations in the circulation

Abstract Objective. Extracellular matrix remodeling by cathepsins play an important role in many conditions associated with inflammation. The aim of this study was to study the effect of inflammation on circulating levels of human cathepsin B and S. Materials and methods. Blood sampling was carried out prior to surgery and 4 and 30 days after surgery, respectively. Two patient groups were included: (1) patients undergoing orthopedic surgery (n = 29) and coronary bypass patients (n = 21). Serum cathepsin B and S levels were measured using sandwich ELISAs. C-reactive protein (CRP) was analysed by turbidimetry. Results. Serum cathepsin B showed significantly higher values 4 days after surgery in comparison with samples collected prior to surgery. Serum cathepsin S instead showed significantly lower values 4 days after surgery. Similar results were found in both patient groups. Conclusions. Inflammation has different effects on circulating levels of cathepsin B and S.

Metabolic stress-like condition can be induced by prolonged strenuous exercise in athletes

Few studies have examined energy metabolism during prolonged, strenuous exercise. We wanted therefore to investigate energy metabolic consequences of a prolonged period of continuous strenuous work with very high energy expenditure. Twelve endurance-trained athletes (6 males and 6 females) were recruited. They performed a 7-h bike race on high work-load intensity. Physiological, biochemical, endocrinological, and anthropometric muscular compartment variables were monitored before, during, and after the race. The energy expenditure was high, being 5557 kcal. Work-load intensity (% of VO2 peak) was higher in females (77.7%) than in men (69.9%). Muscular glycogen utilization was pronounced, especially in type I fibres (>90%). Additionally, muscular triglyceride lipolysis was considerably accelerated. Plasma glucose levels were increased concomitantly with an unchanged serum insulin concentration which might reflect an insulin resistance state in addition to proteolytic glyconeogenesis. Increased reactive oxygen species (malondialdehyde (MDA)) were additional signs of metabolic stress. MDA levels correlated with glycogen utilization rate. A relative deficiency of energy substrate on a cellular level was indicated by increased intracellular water of the leg muscle concomitantly with increased extracellular levels of the osmoregulatory amino acid taurine. A kindred nature of a presumed insulin-resistant state with less intracellular availability of glucose for erythrocytes was also indicated by the findings of decreased MCV together with increased MCHC (haemoconcentration) after the race. This strenuous energy-demanding work created a metabolic stress-like condition including signs of insulin resistance and deteriorated intracellular glucose availability leading to compromised fuelling of ion pumps, culminating in a disturbed cellular osmoregulation indicated by taurine efflux and cellular swelling.

Postsurgical inflammatory response is not associated with increased serum cystatin C values

OBJECTIVES Cystatin C is used both as a glomerular filtration (GFR) marker and a cardiovascular risk marker. There are several studies showing an association between cystatin C and inflammatory markers and it has been suggested that the inflammatory response in itself could result in elevated cystatin C levels. The aim of this study was to evaluate if an induced inflammatory response has an effect on cystatin C levels in humans. MATERIALS AND METHODS CRP and cystatin C were analyzed in serum samples from orthopedic surgery patients (n=29). The patients were sampled prior to surgery and four and thirty days after surgery. RESULTS The surgery induced a pronounced CRP elevation on day four, median 137.3 (interquartile range 104.1-178.2) mg/L compared to 1.94 (1.20-8.70) mg/L before surgery, P<0.001, but no significant difference in cystatin C levels before and four and thirty days after surgery could be seen. CONCLUSIONS The orthopedic surgery-induced inflammatory response does not cause changes in cystatin C levels.

Analysis of HbA1c on an automated multicapillary zone electrophoresis system

Abstract Hemoglobin A1c (HbA1c) is a frequently requested laboratory test and there is thus a need for high throughput instruments for this assay. We evaluated a new automated multicapillary zone electrophoresis instrument (Capillarys 3 Tera, Sebia, Lisses, France) for analysis of HbA1c in venous samples. Routine requested HbA1c samples were analyzed immunologically on a Roche c6000 instrument (n = 142) and then with the Capillarys 3 Tera instrument. The Capillarys 3 Tera instrument performed approximately 70 HbA1c tests/hour. There was a strong linear correlation between Capillarys 3 Tera and Roche Tina-Quant HbA1c Gen 3 assay (y = 1.003x – 0.3246 R2 = .996). The total CV for the 12 capillaries varied between 0.8 and 2.2% and there was a good agreement between duplicate samples (R2 = .997). In conclusion, the Capillarys 3 Tera instrument has a high assay capacity for HbA1c. It has a good precision and agreement with the Roche Tina-Quant HbA1c method and is well suited for high volume testing of HbA1c.

Lifestyle intervention is associated with decreased concentrations of circulating pentraxin 3 independent of CRP decrease

Abstract Objectives. Pentraxin 3 (PTX3) is an acute phase marker, which is produced at the site of infection or inflammation in contrast to CRP that is mainly synthesized by the liver. The aim of the present study was to see if lifestyle interventions/weight loss would lead to decreased blood plasma concentrations of PTX3. Methods. Study subjects (n = 31) were recruited to a lifestyle intervention program aiming at increased physical activity, improved eating habits, and weight loss. High-sensitivity C-reactive protein (CRP) and PTX3 methods were used for analysis of CRP and PTX3 in plasma samples collected at inclusion and after 4 and 8 weeks of treatment. Results. Wilcoxon paired samples test showed a significant decrease in PTX3 concentrations from 2068 pg/mL at start to 2007 pg/mL at 4 weeks (P = 0.002) and 1748 pg/mL at 8 weeks (P = 0.003). The PTX3 decrease was not significantly correlated with a corresponding decrease in CRP or weight reduction. Conclusions. The lifestyle intervention program resulted in a significant reduction of circulating concentrations of pentraxin 3 already after 4 and 8 weeks of treatment.

Vitamin D in relation to bone health and muscle function in young female soccer players

Abstract The present work investigated serum vitamin D (25(OH)D) status in relation to bone and muscle qualities and functions in 19 female soccer players (13–16 years) resident at northern latitude with very low sun exposure (∼32–36 h/month) during winter season (late January to early March). Serum 25(OH)D, parathyroid hormone and bone turnover markers osteocalcin (OC) and beta carboxy-terminal collagen cross-links (β-Ctx), as well as body composition and muscle performance were examined. Hormones were tested using routine laboratory methods. Fat mass, lean mass, and bone mineral density in whole body, as well as femur and lumbar spine were evaluated with dual-energy X-ray absorptiometry. Muscle performance was assessed through isokinetic knee extension and flexion, countermovement jump, and sprint running. 25(OH)D was low (50.5 ± 12.8 nmol l−1), whereas the values of bone turnover markers were markedly high (OC: 59.4 ± 18.6 µg l−1; β-Ctx: 1075 ± 408 ng l−1). All bone and muscle measurements were normal or above normal. 25(OH)D was not significantly correlated with most of the parameters of bone and muscle quality or function, except the knee extension time to peak torque (r  = −0.50, p = .03). In conclusion, the level of vitamin D is markedly low in adolescent female soccer players during the winter in Sweden. However, vitamin D levels did not significantly correlate with measures of bone and muscle except a moderate correlation in time to peak torque in the knee extensors. The practical implication of low vitamin D levels in young growing female athletes remains unclear.

Elective orthopedic and cardiopulmonary bypass surgery causes a reduction in serum endostatin levels

BackgroundEndostatin is an endogenous inhibitor of angiogenesis that inhibits neovascularisation. The aim of the study was to evaluate the effect of elective surgery on endostatin levels.MethodsBlood samples were collected prior to elective surgery and 4 and 30 days postoperatively in 2 patient groups: orthopedic surgery (n =27) and coronary bypass patients (n =21). Serum endostatin levels were measured by ELISA.ResultsSerum endostatin was significantly reduced 30 days after surgery in comparison with presurgical values in both the orthopedic (P =0.03) and cardiopulmonary surgery (P =0.04) group.ConclusionSerum endostatin is reduced 30 days after surgery. This reduction would favor angiogenesis and wound-healing.

Integration of magnetic resonance imaging and protein and metabolite CSF measurements to enable early diagnosis of secondary progressive multiple sclerosis

Molecular networks in neurological diseases are complex. Despite this fact, contemporary biomarkers are in most cases interpreted in isolation, leading to a significant loss of information and power. We present an analytical approach to scrutinize and combine information from biomarkers originating from multiple sources with the aim of discovering a condensed set of biomarkers that in combination could distinguish the progressive degenerative phenotype of multiple sclerosis (SPMS) from the relapsing-remitting phenotype (RRMS). Methods: Clinical and magnetic resonance imaging (MRI) data were integrated with data from protein and metabolite measurements of cerebrospinal fluid, and a method was developed to sift through all the variables to establish a small set of highly informative measurements. This prospective study included 16 SPMS patients, 30 RRMS patients and 10 controls. Protein concentrations were quantitated with multiplexed fluorescent bead-based immunoassays and ELISA. The metabolome was recorded using liquid chromatography-mass spectrometry. Clinical follow-up data of the SPMS patients were used to assess disease progression and development of disability. Results: Eleven variables were in combination able to distinguish SPMS from RRMS patients with high confidence superior to any single measurement. The identified variables consisted of three MRI variables: the size of the spinal cord and the third ventricle and the total number of T1 hypointense lesions; six proteins: galectin-9, monocyte chemoattractant protein-1 (MCP-1), transforming growth factor alpha (TGF-α), tumor necrosis factor alpha (TNF-α), soluble CD40L (sCD40L) and platelet-derived growth factor AA (PDGF-AA); and two metabolites: 20β-dihydrocortisol (20β-DHF) and indolepyruvate. The proteins myelin basic protein (MBP) and macrophage-derived chemokine (MDC), as well as the metabolites 20β-DHF and 5,6-dihydroxyprostaglandin F1a (5,6-DH-PGF1), were identified as potential biomarkers of disability progression. Conclusion: Our study demonstrates, in a limited but well-defined and data-rich cohort, the importance and value of combining multiple biomarkers to aid diagnostics and track disease progression.