Giovanni Franco Zanon

Tracheal matrices, obtained by a detergent-enzymatic method, support in vitro the adhesion of chondrocytes and tracheal epithelial cells

Several attemps have been performed to achieve a suitable tracheal replacement for the treatment of different conditions characterized by a lack of sufficient tissue for surgical reconstruction. Actually, tracheal homografts can induce long‐term stenosis and their growth potential is not known. Thus, in this work porcine tracheal matrices have been obtained by a detergent‐enzymatic method. The treatment decreased the antigenicity of matrices which were able to support the in vitro adhesion of both chondrocytes and tracheal epithelial cells. On the contrary, only few cells were observed in tracheal matrices prepared with formalin, Thimerosal, and acetone, suggesting that the long‐term stenosis occuering in vivo is probably because of an insufficient cell ingrowth. In summary, our results indicate that the detergent‐enzymatic method allows us to obtain tracheal matrices which can function as a promising support to achieve an in vitro tissue‐engineered cell‐matrix construct.

In vitro reconstructed dermis implanted in human wounds: degradation studies of the HA-based supporting scaffold

The objective of the present study was to demonstrate the safety and efficacy of a dermal replacement for cutaneous wounds of diverse origin. Autologous fibroblasts were cultured in fleece scaffolds made from benzyl esters of hyaluronic acid and applied onto cutaneous lesions. The cases presented are (1) skin removal for multiple epithelioma and (2) chronic deep decubitus ulcer. Dermal-like tissue applied by the surgeon elicited no adverse reactions, and was fully integrated and well-vascularized by 1-3 weeks. In Case 1, the material was fully integrated after 1 week, and after 3 weeks an epidermal autograft was overlaid which showed good take with excellent integration observed after 4 weeks. At 12 months, skin demonstrated visual normo-elastic properties and no signs of excessive scarring. In Case 2, 2-3 weeks after the dermal implant was applied, the wound was invaded with granulation tissue and healing occurred by secondary intention. The ulcer was healed by 8 weeks, with the biomaterial completely resorbed and a complete re-epithelialization over the dermal-like tissue. These results suggest that autologous fibroblast culture in hyaluronan-derived scaffolds may be successfully grafted in diverse cutaneous pathologies and constitute a suitable bed for further epidermal implantation.

Prospective, Randomized Trial of Two Different Modalities of Flushing Central Venous Catheters in Pediatric Patients With Cancer

PURPOSE There are limited prospective data on whether the method of flushing affects the complication rate of tunnelled central venous catheters (CVCs). PATIENTS AND METHODS During a 25-month period, 203 pediatric patients who had newly placed Broviac-Hickman CVCs were randomly assigned to standard flushing with heparin solution or to experimental flushing with normal saline via a positive-pressure cap. RESULTS Two hundred twenty-one complications were recorded among 75,249 CVC-days (2.94 per 1,000 CVC-days). A higher incidence of CVC occlusion (83 v 41 episodes; P = .0002) and bacteremia (24 v 9; P = .01) were found in the experimental arm. The cumulative probability of developing at least one CVC complication was higher in the experimental arm than in the standard arm (65.1% [95% CI, 55% to 75%] v 43.8% [95% CI, 34% to 54%], respectively; P = .01). No difference was found in either the cause or the frequency of premature removal of CVCs between the two study arms. After a median follow-up of 360 days (range, 4 to 1,073), CVC survival was similar: 77% (95% CI, 66% to 84%) for the experimental arm and 69% (95% CI, 53% to 80%) for the standard arm (P = .7). The factors associated with the occurrence of CVC complication were a diagnosis of leukemia/lymphoma, double-lumen CVC, and experimental flushing. The only factor significantly associated with premature removal of a CVC was a diagnosis of leukemia/lymphoma (hazard rate, 2.3; 95% CI, 1.1 to 4.7). CONCLUSION An increased complication rate was found with normal saline flushing, but additional investigation is warranted to clarify whether it is related to saline use or to once-a-week flushing.

Kidney transplantation into bladder augmentation or urinary diversion : Long-term results

Background. We report on a single-institutional experience with renal transplantation in patients with severe lower urinary tract dysfunction (LUTD) who underwent bladder augmentation or urinary diversion, and assess the long-term results. Methods. From September 1987 to January 2005, 255 patients (161 male and 94 female), 7 months to 39 years old of age (median age at time of transplantation 14 years), received 271 kidney transplants. Etiology of end-stage renal disease was LUTD in 83 cases. Among these patients, 24 had undergone bladder augmentation or urinary diversion. Results. We identified two groups of patients surgically treated due to LUTD: group 1 included 16 patients (eight male, eight female) aged 4 to 39 years (median 19 years) with bladder augmentation, whereas in group 2, seven patients (five male, two female) 7 months to 31 years old (median 17 years) with incontinent urinary diversion were reported. In the first group, surgical complications after kidney transplantation included one urinary fistula, one ureteral stenosis. Three patients of second group developed recurrent urinary tract infection. Cumulative graft survival rates of all patients transplanted was 69.4% after 15 years, whereas in the two investigated groups, group 1 and group 2, was 80.7% and 55.5% respectively (P=NS.). Conclusions. Drainage of transplanted kidneys into an augmented bladder or urinary diversion is an appropriate management strategy when the native bladder is unsuitable. Kidney transplantation in patients with bladder augmentation or urinary diversion for LUTD let achieve similar results to those obtained in the general population with normal lower urinary tracts.

Amniotic Fluid Stem Cells Restore the Muscle Cell Niche in a HSA‐Cre, SmnF7/F7 Mouse Model

Mutations in the survival of motor neuron gene (SMN1) are responsible for spinal muscular atrophy, a fatal neuromuscular disorder. Mice carrying a homozygous deletion of Smn exon 7 directed to skeletal muscle (HSA‐Cre, SmnF7/F7 mice) present clinical features of human muscular dystrophies for which new therapeutic approaches are highly warranted. Herein we demonstrate that tail vein transplantation of mouse amniotic fluid stem (AFS) cells enhances the muscle strength and improves the survival rate of the affected animals. Second, after cardiotoxin injury of the Tibialis Anterior, only AFS‐transplanted mice efficiently regenerate. Most importantly, secondary transplants of satellite cells (SCs) derived from treated mice show that AFS cells integrate into the muscle stem cell compartment and have long‐term muscle regeneration capacity indistinguishable from that of wild‐type‐derived SC. This is the first study demonstrating the functional and stable integration of AFS cells into the skeletal muscle, highlighting their value as cell source for the treatment of muscular dystrophies. STEM Cells2012;30:1675–1684

Further experience with OK-432 for lymphangiomas

This study includes all the children treated with OK-432 for lymphangioma at our institute. Twenty-nine children treated between 1999 and 2003 are reported for the first time: twelve cases regressed completely, eight cases regressed more than 50% and seven remained unchanged; two cases were lost at follow-up. The outcome was related to the size of the cysts, the larger ones having a better prognosis. The adverse reactions are discussed and the methods of treatment are described in detail. Fifteen children, treated before 1999 and already reported, are reviewed after a long-term follow-up. Four had a recurrence: one regressed spontaneously and three needed further treatment. The other 11 had no complaints. Even considering the risk of recurrence, OK-432 therapy remains our first line therapy for lymphangiomas, avoiding surgery in most cases.

Successful renal transplantation in children under 6 years of age.

Abstract To evaluate the efficacy of renal transplan- tation in small pediatric patients, we have reviewed 41 allografts performed in 39 children (28 M/11 F) less than 6 years of age between 1987 and 1998 in the North Italy Transplant Program. Of these patients, 39 had a cadaver donor and 2 a living-related donor, with ages ranging from 20 days to 35 years. The mean follow-up was 56 months. Graft survival was 74.5% and 70.5% at 1 and 5 years, respectively. The causes of graft lost were acute rejection (4), graft vascular thrombosis (4), and hemolytic uremic syndrome recurrence (1). Only 1 patient has died due to chickenpox. Double and triple immunosuppressive therapies were used in 63% and 37% of patients, respectively, on the basis of different center protocols, without differences in graft survival. Steroids were successfully administered on alternate days in 37% of patients, 6–12 months after transplantation. Thrombosis was reported in 2 of 6 kidneys from donors less than 1 year of age and in 2 of 35 donors older than 1 year (P<0.05). Thirty rejections occurred in 23 patients: 7 episodes were steroid resistant and were treated with ATG/OKT3. Thirty-four infections were reported in 16 of 41 patients; of these 17 were viral, 14 bacterial, and 3 due to Mycoplasma. Four surgical complications were reported: 1 graft artery stenosis, 1 ureteral stenosis, 1 urinary leak, and 1 lymphocele. Mean height standard deviation score improved from –2.0±1.3 pre transplantation to –1.8±1.4, –1.5±1.3, and –1.5±1.5 at 1, 2, and 5 years post transplantation. Linear growth was significantly better in infants treated with alternate-day steroids. Hypertension was a frequent complication, since 19 of the 30 patients with a 5-year follow-up were still being treated with antihypertensive drugs. In conclusion, graft survival in patients less than 6 years old is satisfactory and similar to that obtained in children aged from 6 to 18 years (70.5% vs. 78.9% at 5 years, P=NS). Consequently, since there are many difficulties in managing infants on maintenance dialysis, an early transplant should be considered. Donors older than 24 months carry a low risk of vascular thrombosis and may be successfully grafted in infants.

Investigation of Intrarenal Viral Infections in Kidney Transplant Recipients Unveils an Association between Parvovirus B19 and Chronic Allograft Injury

BACKGROUND The relevance of viral infections in the development of allograft lesions is still unclear, although some viruses have been implicated. The present study investigated systemic and intrarenal viral infections in kidney transplant recipients and their association with the risk of acute rejection and chronic allograft injuries that are predictive of long-term dysfunction. METHODS The presence of DNA sequences of human herpesviruses, polyomaviruses, and parvovirus B19 was analyzed in renal allograft biopsy specimens obtained at baseline, after acute renal dysfunction, and during follow-up evaluation in 69 transplant recipients who were children or young adults. Results were correlated with clinical data, viral DNAemia, and results of renal function tests and allograft histology analyzed at the same time points. RESULTS Overall, viral DNA was detectable in 46% of baseline and 70% of follow-up biopsy specimens of kidney allografts, where it generally persisted. The most frequently detected viruses were B19 and human herpesvirus 6, already present in donor kidneys, and BK virus and Epstein-Barr virus, usually involving the allograft during follow-up. Among viruses, only the intrarenal persistence of B19 DNA and B19 DNAemia was associated with the development of chronic allograft injury, whereas human cytomegalovirus DNAemia was a risk factor for acute rejection. CONCLUSIONS Parvovirus B19 seems to target the kidney electively. Its intrarenal persistence is associated with chronic kidney allograft injury.

One-year results of basiliximab induction and tacrolimus associated with sequential steroid and MMF treatment in pediatric kidney transplant recipient

We report the 1‐year results with a triple immunosuppressive regimen in pediatric recipients of a first kidney transplant, in order to evaluate its safety and efficacy in the prevention of acute rejection and in the reduction of steroid side effects. The immunosuppression is as follows: (i) basiliximab (20 mg if body weight >30 kg; 10 mg if <30 kg) is given pretransplant and at day 4; (ii) tacrolimus (Tac) is administered in order to obtain blood trough levels of 10–20 and 5–10 ng/ml during and after the first 2 months post‐transplant, respectively; (iii) steroids are tapered during the first 6 months and then replaced by mycophenolate mofetil (depending on previous rejection episodes, infection status and the result of a routine biopsy) at a dosage of 4–600 mg/m2 body surface area. Fifty‐three children (median age 13 years, range 2–20) have entered this protocol. One‐year patient and kidney survival are 100% and 94% respectively. During the first year a total of nine rejections in seven patients (13% of the cohort study) occurred, all but one responsive to steroids. Renal function was satisfactory throughout the first year (mean CrCl was 63.8 ± 18 and 60.9 ± 15.5 ml/min/1.73 m2 at 6 and 12 months respectively). Subclinical signs of rejection were absent in more than 80% of biopsies (grade I Banff) at 6 months (n = 47); at the 12th month biopsy (n = 42) score I was stable in 20 patients (16 after stopping steroids) and had worsened in eight biopsies (six after stopping steroids). Major complications were insulin‐dependent diabetes in three (5.6%) children with the need of insulin for a mean of 3 months; transient hyperglycemia (11 patients), treated with a dietary regimen, symptomatic viral infections (in 11 patients: two parvovirus B19, three cytomegalovirus and two Epstein–Barr virus systemic infections, three interstitial pneumonia, two BK nephritis). Tac doses more than 0.3–0.4 mg/kg/day are at significantly higher risk of viral infection. In conclusion, this immunosuppressive regimen is associated with a low percentage of clinical (13%) and subclinical rejections, but with a relatively high number of infections, prevented by a reduction in Tac doses (<0.3 mg/kg/day) during the first 2 months after transplantation. The assessment of steroid withdrawal needs a longer follow‐up.

Conservative treatment for complex neonatal ovarian cysts: A long-term follow-up analysis

OBJECTIVE We aimed to investigate safety and effectiveness of a conservative approach for complex neonatal ovarian cysts and its long term impact on fertility. STUDY DESIGN Neonates with congenital complex ovarian cysts were conservatively managed and followed from the perinatal period to adolescence. Statistical analysis included Students t-test, Mann-Whitney U-test, the Kaplan-Meier method, and the receiver operating characteristic curve. RESULTS The post-natal progressive dimensional reduction of diagnosed ovarian cyst was statistically significant. The Kaplan-Meier survival curves revealed the probability of persistence of the cyst was up to 5% at the age of 25 months. Long term follow-up revealed both ovaries visible at US in 60% of adolescent patients. CONCLUSION Conservative management of asymptomatic complex neonatal ovarian cysts can be safely undertaken. As far as the chances of the ovarian tissue to survive conservative treatment are concerned, the results are not encouraging.