||Blood, 24-hour urine, faeces, nails and hair will be collected from the participants at each TransplantLines
visit. Participants will be instructed to collect a 24-hour urine sample according to strict protocol on the day
before their visit to the outpatient clinic, that is, discard their morning urine specimen, collect all subsequent
urine throughout the next 24 hours and include the next morning’s first specimen of the day of the visit to the outpatient clinic. Blood will be drawn after an overnight fasting period of 8–12 hours in the morning after completion of the 24-hour urine collection. Blood drawing and receipt of the collected 24-hour urine samples are performed by experienced nurses at our outpatient clinic.
As blood samples, one serum tube of 10mL, two EDTA samples of 10mL, one citrate tube of 6mL, one lithium-heparin tube of 10mL and one PAXgene tube of 10mL will be collected from each participant at each TransplantLines visit. Subsequently, tubes will be centrifuged by technicians at 1300g for 10min, except for the citrate tube which is centrifuged at 2500g for 10min. Of the 24-hour urine collection, three urine tubes will be collected, of which one tube will be partially acidified. All blood and urine samples will be subsequently aliquoted by technicians and shipped to the core laboratory for storage in −80°C (−112°F) freezers (Panasonic, ‘s-Hertogenbosch, The Netherlands). Blood and urine samples will be analysed in the following years for multiple research questions that will arise.
Participants will be asked to collect a faeces sample the day prior to the TransplantLines visit. A FecesCatcher
(TAG Hemi VOF, Zeijen, The Netherlands) will be sent to the patient’s home, and faeces sample will be collected in appropriate tubes and frozen immediately after collection. The participant will transport the faeces sample in cold storage (with ice cubes or in a cooler) to the TransplantLines visit the following day. Subsequently, the faeces sample will be immediately stored at −80°C (−112°F). Faeces samples will be primarily used for microbiome analyses. Solid organ transplant recipients have a shift in the gut microbiome with a decrease in predominant
organisms, a loss of bacterial diversity and emergence of new dominant population. These may result in increased
risk of infection, rejection and mortality. Therefore, we would like to examine the gut microbiome in relation to
the development of health problems after transplantation.
Additional blood and urine samples will also be collected in the event of worsening graft function and an organ transplant biopsy is indicated. Prior to the biopsy, one serum tube of 10mL, two EDTA samples of 10mL, one citrate tube of 6mL, one lithium-heparin tube of 10mL and one PAXgene tube of 10mL will be collected. At the same time, one serum tube of 10mL, one EDTA sample of 10mL and one spot urine sample of 10mL will be collected and directly stored on ice to prevent (ongoing) in vitro complement activation.
Furthermore, during transplant surgery and transplant biopsies, tissue samples will be collected of the transplanted organ and surrounding tissues, including fat, skin, ureter, tracheal, biliary, and arterial and venous
tissues, that have been discarded as pathological waste.