1. Tissue contamination during multi-tissue harvesting
2. Antibiotic cocktails
3. Tissue decontamination
4. Validating a new antibiotic cocktail
5. Amniotic membrane use in ophthalmology
6. Valve decellularization
7. Amniotic membrane assessment
Tissue contamination is of major importance for any tissue bank. The aim of all tissue banks is to reduce bacterial growth on harvested tissues to a minimum in order to guarantee safety and quality standards of excellence. We conducted a study of tissue contaminations from 2008 onwards, matching them to possible relevant factors such as age, donor gender and type, cause of death, whether an organ and/or skin harvest, cadaveric time, number of operators performing harvesting and number of tissues retrieved. The data are currently being processed and we will soon be publishing a complete overview determining the variables that significantly influence tissue bacterial contamination.
We studied the tissue decontamination efficacy of the antibiotic cocktail currently used at our facility by examining cadaver tissue collected between 2008 and 2012. The analyses were conducted on tissues at three different stages: at the time of harvesting in the operating theatre, during processing (after the first decontamination) and during the preservation phase (after the second decontamination). We are currently analysing the microbiological findings to assess the decontamination capability of the antibiotic cocktail used and identify the type and quantity of any resistant microbial strains.
We are analysing the ability of sodium hypochlorite to reduce or eliminate tissue contamination during the harvesting phase. Tissues are immersed in a diluted solution of sodium hypochlorite (for different durations depending on tissue type) and then rinsed with saline. 2000 tissues were analysed and compared with as many tissues not undergoing sodium-hypochlorite treatment.
One of the main aims of a tissue bank is to reduce microbial contamination. This can be achieved both by analysing and acting on the variables that influence harvesting (see research project 1) and by using a more specific, more powerful antibiotic cocktail. The antibiotic cocktail currently used in our facility was compared with 2 other new antibiotic combinations on 102 bacterial species isolated from donor tissues.
Given the wide use of amniotic membrane to treat eye diseases, we have - in partnership with the Veneto Eye Bank Foundation (Fondazione Banca degli Occhi del Veneto) – examined tissue use over the last 12 years of activity: a total of 5,349 patches distributed for transplantation. Corneal ulceration is the disease most frequently treated with donor tissue implant, followed by keratitis, pterygium, trauma from chemical substances and malignancies. Clinical results are based on one-year follow up data and show excellent results in terms of management and control of inflammation and pain, with the implanted tissues promoting re-epithelization and the formation of corneal epithelium.
The research project aims to validate the TRICOL method, which involves the use of a non-ionic detergent and sodium cholate to decellularize human aortic valves. Together with the Padua team of Dr Gerosa, we assessed the efficacy of this method by carrying out histological and immunohistochemical analyses of diverse cardiac specimens before and after the decellularization procedure. We demonstrated that HLA Class I and II antigens and the cell component are removed while the extracellular structure with its collagen and elastic fibres remain intact. The resultant decellularized valve lowers the likelihood of calcification, promotes good haemodynamics and provides the structural elements needed for host cell re-population
The aim of the project is to provide an extensive description of the ultrastructural aspect and cytokine content of amniotic membrane. Fresh-frozen amniotic membrane samples were compared with freeze-dried samples that had been irradiated with 10, 20 and 30 kGy. 9 important cytokines were titered before and after freeze-drying and irradiation. In addition, electron microscopy histology was performed to quantify damage to the extracellular matrix, especially the epithelium, basal membrane and lamina densa.
Amniotic membrane has for some years become an important biological substitute in a wide range of conditions from ophthalmological diseases, burns and diabetic ulcers to oral cavity, genital, tendon and nerve reconstruction surgery. This is because amniotic membrane has a wide range of properties. For this reason the TTBF, in collaboration with the neurosurgery unit of Treviso, Padua and Verona, has promoted the use of amniotic membrane to replace dural tissues. The study aims to confirm the efficacy, already demonstrated by other centres, of amniotic membrane in neurosurgical cases as a homologous substitute for dural tissue after decompressive craniectomy surgery. We aim to support the clinical results with histological and MRI data and demonstrate that amniotic membrane provides comparable if not better outcomes than standard procedures.
In partnership with the Maxillofacial Surgery Unit of the Castelfranco hospital, a study was carried out on patients receiving alveolar ridge reconstruction with fresh-frozen bone, processed and preserved in our facility. Preliminary results are more than satisfactory. Over 90% of cases presented no graft-related problems, and homologous bone has been shown to be an excellent, safe and effective tissue substitute in an alveolar ridge reconstruction setting.