Serum Level of Lipopolysaccharide-binding Protein (LBP) and Atherosclerosis in Hemodialysis Patients
Condition: Systemic Inflammatory Response Syndrome
MeSH terms: Systemic Inflammatory Response Syndrome
Study type: Observational

Summary: 
      Background In hemodialysis (HD) patients, impaired gut barrier and alteration in microbiota
      in the gut is thought to increase the risk of bacterial translocation and chronic
      inflammation. Lipopolysaccharide-binding protein (LBP) is an acute-phase reactant that
      mediates immune responses triggered by microbial products. Our aim is to investigate the
      relationship between circulating levels of LBP, inflammatory markers and incident
      atherosclerotic vascular events in HD patients and follow-up this defined cohort for 3 years.

      Methods A total of 300 HD patients will be recruited. The LBP and inflammatory markers will
      be determined using immuoassay methods annually. A bioimpedance spectroscopy device will used
      for body fat composition measurement and measurements will be done annually. Arterial
      stiffness is evaluated by measuring PWV in the heart-femoral segment using an automatic
      waveform analyzer.
    

Detailed description: 
      Study Design and Population

      Patient Population

      To be included in the study, patients have to be at least 20-years-old and on outpatient
      hemodialysis (HD) for at least 3 months. Patients are excluded if they had an acute infection
      or malignancy. A total of 360 long-term HD patients are randomly invited and agreed to
      participate in the study. The medical record is thoroughly reviewed for each subject by a
      collaborating physician in the study. Information such as underlying kidney disease,
      cardiovascular disease history, and other comorbid illnesses will be abstracted.

      Study Parameters

      Predialysis blood samples are obtained on a mid-week day. Within 30 min after sampling, the
      remaining blood is centrifuged at 3,000 g for 10 min, immediately aliquoted and frozen at
      -70°C until further analysis. Total serum cholesterol is measured through the reaction of
      cholesterol esterase/cholesterol oxidase/peroxidase, using Hitachi 747 (Hitachi, Bohemia, NY,
      USA). HDL cholesterol is quantified after precipitation with polyethylene glycol at room
      temperature. Serum glucose concentrations are measured by the glucose oxidase method.
      Low-density lipoprotein cholesterol is calculated using the Friedewald formula. Total serum
      triglycerides are measured through the reaction of glycerol/phosphate/oxidase and peroxidase.
      The serum levels of high-sensitivity C-reactive protein (hsCRP) are measured using a Behring
      Nephelometer II (Dade Behring, Tokyo, Japan). Plasma levels of Interleukin-6 (IL-6) and
      soluble CD14(sCD14) are measured by a commercially available enzyme linked immunosorbent
      assay (ELISA) (Quantikine HS Immunoassay kit, R&D System, Minneapolis, MN). Concentrations
      Interleukin-6(IL-10), and Tumor necrosis factor-alpha(TNF-α) are simultaneously determined by
      the Multiplex® (R&D Systems, Minnesota, MN, USA). Serum levels of LBP will be measured using
      a commercial enzyme-linked immunosorbent assay (HK315-02, HyCult Biotech Inc., Uden, the
      Netherlands) as per manufacturer's instructions. The intra- and inter-assay coefficients of
      LBP variation are <5 and <10%, respectively. Besides, serum from 40 normal control subjects
      will be used for interassay variation. Both the intra- and the interassay coefficients of
      variation were <8.0%. All samples will be measured in duplicates and the mean value is
      reported in μg/mL

      Percent fat is measured with Bioelectric Impedance Spectroscopy

      Whole-body bioelectric impedance spectroscopy (BIS) measurement using a body composition
      monitor (BCM: Fresenius Medical Care, Bad Homburg, Germany) is performed on each of the
      participants enrolled in the study as described previously [28]. Briefly, measurements were
      taken on the day before dialysis with the patient calm, supine, and relaxed in the dialysis
      bed for 10 minutes. Four electrodes were placed on the patient's hand and foot on the side
      contra lateral to their arteriovenous fistula. The basic principle of this machine is the use
      of the bioimpedance spectroscopy which determines the fluid content of the body by measuring
      the serial values of electric impedance by applying small microAmp electric currents at 50
      different frequencies between 5 and 1000 kHz. These impedance data are used to obtain the
      amount of total body water, intracellular water and extracellular water through a special
      fluid model and information about other body compositions, such as fat tissue or lean tissue,
      through a physiological body composition model [29]. The major estimates the body composition
      measured by BCM-BIS are as follows: (1) lean tissue mass (LTM -mainly muscle), fat mass
      (FAT), and adipose tissue mass (ATM-mainly fat with its relevant hydration)

      Measurement of arterial stiffness

      Arterial stiffness is evaluated by measuring PWV in the heart-femoral segment using an
      automatic waveform analyzer.
    

Observational model: Case-Crossover
Time perspective: Cross-Sectional
Sampling method: Probability Sample
Study population: 
        patients have to be at least 20-years-old and on outpatient hemodialysis (HD) for at least
        3 months.
      
Keywords: Lipopolysaccharide-binding protein; inflammation; ASCVD