Long-Term Intracellular Tracking of Label-Free Nanoparticles in Live Cells and Tissues with Confocal Microscopy

The label-free imaging of inorganic nanoparticles (NPs) using confocal laser scanning microscopy (CLSM) provides a powerful and versatile tool for studying interactions between NPs and biological systems. Without the need for exogenous labels or markers, it simply benefits from the differential scattering of visible photons between biomaterials and inorganic NPs. Validation experiments conducted on fixed and living cells in real-time, as well as mouse tissue sections following parenteral administration of NPs. Additionally, by incorporating reporter fluorophores and utilizing both reflectance and fluorescence imaging modalities, the method enables high-resolution multiplex imaging of cellular structures and NPs. Different sizes and concentrations of Au NPs are tested as for Ag, Fe3O4, and CeO2 NPs, all with biological interest. Overall, the comprehensive study of NP imaging by confocal microscopy in reflectance mode provides valuable insights and tools for researchers interested in monitoring the nano-bio interactions.

Blocking Hemopexin With Specific Antibodies: A New Strategy for Treating Diabetic Retinopathy

Hemopexin (HPX) is overexpressed in the retina of patients with diabetes and induces the breakdown of the blood-retinal barrier in vitro. The aim of this study was to evaluate whether HPX blockade by specific antibodies (aHPX) could avoid vascular leakage in vivo and microvascular angiogenesis in vitro and ex vivo. For this purpose, the effect of intravitreal (IVT) injections of aHPX on vascular leakage was evaluated in db/db mice and rats with streptozotocin-induced diabetes using the Evans Blue method. Retinal neurodegeneration and inflammation were also evaluated. The antiangiogenic effect of aHPX on human retinal endothelial cells (HRECs) was tested by scratch wound healing and tube formation using standardized methods, as well as by choroidal sprouting assays from retinal explants obtained in rats. We found that IVT injection of aHPX significantly reduced vascular leakage, retinal neurodegeneration, and inflammation. In addition, treatment with aHPX significantly reduced HREC migration and tube formation induced by high glucose concentration and suppressed choroidal sprouting even after vascular endothelial growth factor stimulation, with this effect being higher than obtained with bevacizumab. The antipermeability and antiangiogenic effects of IVT injection of aHPX suggest the blockade or inhibition of HPX as a new strategy for the treatment of advanced stages of diabetic retinopathy.

ARTICLE HIGHLIGHTS

Hemopexin (HPX) is the best-characterized permeability factor in steroid-sensitive nephrotic syndrome. We have previously reported that HPX is overexpressed in the retina of patients with diabetes and induces the breakdown of the blood-retinal barrier in vitro. Here, we report that intravitreal injection of anti-HPX antibodies significantly reduces vascular leakage, retinal neurodegeneration, and inflammation in diabetic murine models and that the immunoneutralization of HPX exerts a significant antiangiogenic effect in vitro and in retinal explants. The blockade of HPX can be considered as a new therapy for advanced stages of diabetic retinopathy.

Minimum Effective Dose of DPP-4 Inhibitors for Treating Early Stages of Diabetic Retinopathy in an Experimental Model

The neurovascular unit (NVU) plays an essential role in the development of diabetic retinopathy (DR). We previously reported that the topical administration (eye drops) of sitagliptin and saxagliptin, two dipeptidyl peptidase-4 inhibitors (DPP-4i), prevents retinal neurodegeneration and vascular leakage in db/db mice. The aim of the present study is to evaluate the minimum effective dose of the topical administration of these DPP-4i. For this purpose, sitagliptin and saxagliptin were tested at different concentrations (sitagliptin: 1 mg/mL, 5 and 10 mg/mL, twice per day; saxagliptin: 1 and 10 mg/mL, once or twice per day) in db/db mice. As end points of efficacy, the hallmarks of NVU impairment were evaluated: reactive gliosis, neural apoptosis, and vascular leakage. These parameters were assessed by immunohistochemistry, cell counting, and the Evans blue method, respectively. Our results demonstrated that the minimum effective dose is 5 mg/mL twice per day for sitagliptin, and 10 mg/mL twice per day for saxagliptin. In conclusion, this study provides useful results for the design of future preclinical regulatory studies and for planning clinical trials.

Extracellular HMGA1 Promotes Tumor Invasion and Metastasis in Triple-Negative Breast Cancer

PURPOSE

The study of the cancer secretome suggests that a fraction of the intracellular proteome could play unanticipated roles in the extracellular space during tumorigenesis. A project aimed at investigating the invasive secretome led us to study the alternative extracellular function of the nuclear protein high mobility group A1 (HMGA1) in breast cancer invasion and metastasis.

EXPERIMENTAL DESIGN

Antibodies against HMGA1 were tested in signaling, adhesion, migration, invasion, and metastasis assays using breast cancer cell lines and xenograft models. Fluorescence microscopy was used to determine the subcellular localization of HMGA1 in cell lines, xenograft, and patient-derived xenograft models. A cohort of triple-negative breast cancer (TNBC) patients was used to study the correlation between subcellular localization of HMGA1 and the incidence of metastasis.

RESULTS

Our data show that treatment of invasive cells with HMGA1-blocking antibodies in the extracellular space impairs their migration and invasion abilities. We also prove that extracellular HMGA1 (eHMGA1) becomes a ligand for the Advanced glycosylation end product-specific receptor (RAGE), inducing pERK signaling and increasing migration and invasion. Using the cytoplasmic localization of HMGA1 as a surrogate marker of secretion, we showed that eHMGA1 correlates with the incidence of metastasis in a cohort of TNBC patients. Furthermore, we show that HMGA1 is enriched in the cytoplasm of tumor cells at the invasive front of primary tumors and in metastatic lesions in xenograft models.

CONCLUSIONS

Our results strongly suggest that eHMGA1 could become a novel drug target in metastatic TNBC and a biomarker predicting the onset of distant metastasis.

Topical administration of DPP-IV inhibitors prevents retinal neurodegeneration in experimental diabetes

AIMS/HYPOTHESIS

The main aims of the present study were: (1) to assess the expression and content of dipeptidyl peptidase IV (DPP-IV) in human and db/db mouse retinas, and in human vitreous fluid; and (2) to determine whether the topical administration of the DPP-IV inhibitors (DPP-IVi) would prevent retinal neurodegeneration and vascular leakage in db/db mice by reducing endogenous glucagon-like peptide 1 (GLP-1) degradation.

METHODS

To assess the expression and content of DPP-IV, human samples of vitreous fluid and retinas were obtained from participants with type 2 diabetes (n = 8) and age-matched non-diabetic individuals (n = 8), as well as from db/db (n = 72) and db/+ (n = 28) mice. The interventional study, which included 72 db/db mice, consisted of the topical administration (eye drops) of saxagliptin, sitagliptin or vehicle for 14 days. DPP-IV mRNA levels were assessed by RT-PCR, and protein content was measured by ELISA or western blotting. GLP-1 was assessed by immunofluorescence, and its downstream effector exchange protein activated by cAMP-1 (EPAC-1) was used as a measure of GLP-1 receptor activation. Retinal analyses were performed in vivo by electroretinography and ex vivo by RT-PCR (Epac-1, Iba-1 [also known as Aif1]), western blotting (EPAC-1, glial fibrillar acidic protein [GFAP], glutamate-aspartate transporter [GLAST]) and immunofluorescence measurements (GLP-1, GFAP, ionised calcium binding adaptor molecule 1 [IBA-1], TUNEL, GLAST, albumin and collagen IV). Glutamate was quantified by HPLC. In addition, vascular leakage was examined by the Evans Blue method.

RESULTS

DPP-IV was present in human vitreous fluid but in a range 100-fold less than in plasma. Both mRNA levels and protein content were much lower in the retina than in the liver or bowel, but were significantly higher in retinal pigment epithelium (RPE) from diabetic donors in comparison to non-diabetic donors (p < 0.05). Topical treatment with DPP-IVi prevented glial activation, apoptosis and vascular leakage induced by diabetes in db/db mice (p < 0.05). Moreover, it also significantly prevented diabetes-induced functional abnormalities in the electroretinogram. A significant increase of both GLP-1 and EPAC-1 was found after treatment with DPP-IVi (p < 0.05). Furthermore, GLAST downregulation induced by diabetes was prevented, resulting in a significant reduction of extracellular glutamate concentrations. All these effects were observed without any changes in blood glucose levels.

CONCLUSIONS/INTERPRETATION

The topical administration of DPP-IVi is effective in preventing neurodegeneration and vascular leakage in the diabetic retina. These effects can be attributed to an enhancement of GLP-1, but other mechanisms unrelated to the prevention of GLP-1 degradation cannot be ruled out.

Calcium dobesilate prevents the oxidative stress and inflammation induced by diabetes in the retina of db/db mice

AIM

Calcium dobesilate (CaD) is beneficial in early stages of diabetic retinopathy (DR), but its mechanisms of action remains to be elucidated. The aim was to investigate the effect of CaD on proinflammatory cytokines and oxidative stress.

METHODS

db/db mice were randomly assigned to daily oral treatment with CaD (200mg/kg/day) or vehicle for 15days. Biomarkers of oxidative stress (dihydroethidium, malondialdehyde), NF-κB, and proinflammatory cytokines (IL-1β, IL-6, IL-8, TNF-α, MCP-1) were examined in the retina by immunohistochemical analysis. Cultures of human retinal endothelial cells (HRECs) were used for complementary experiments.

RESULTS

CaD significantly reduced the biomarkers of oxidative stress in the retina of db/db mice. In addition, CaD prevented the increase of NF-κB, IL-6, IL-8, TNF-α and MCP-1 induced by diabetes. CaD inhibited the activation of NF-kβ induced by IL-1β by preventing IKKB-α phosphorylation in HRECs and reduced the upregulation of IL-6 and IL-18 induced by TNF-α in a dose-dependent manner.

CONCLUSION

Our results suggest that antioxidant and antiinflammatory effects are crucial in accounting for the effectiveness of CaD for treating DR.

Calcium Dobesilate Prevents Neurodegeneration and Vascular Leakage in Experimental Diabetes

PURPOSE

The mechanisms involved in the reported beneficial effects of Calcium dobesilate monohydrate (CaD) for the treatment of diabetic retinopathy (DR) remain to be elucidated. The main aim of the present study is to examine whether CaD prevents early events in the pathogenesis of DR such as neurodegeneration and vascular leakage. In addition, putative mediators of both neurodegeneration (glutamate/GLAST, ET-1/ETB receptor) and early microvascular impairment (ET-1/ETA receptor, oxidative stress, VEGF, and the PKC-delta-p38 MAPK pathway) have been examined.

METHODS

Diabetic (db/db) mice were randomly assigned to daily oral treatment with CaD (200 mg/Kg/day) (n = 12) or vehicle (n = 12) for 14 days. In addition, 12 non-diabetic (db/+) mice matched by age were used as the control group. Functional abnormalities were assessed by electroretinography. Neurodegeneration and microvascular abnormalities were evaluated by immunohistochemistry and Western blot. Glutamate was determined by HPLC.

RESULTS

CaD significantly decreased glial activation and apoptosis and produced a significant improvement in the electroretinogram parameters. Mechanistically, CaD prevented the diabetes-induced up-regulation of ET-1 and its cognate receptors (ETA-R and ETB-R), which are involved in microvascular impairment and neurodegeneration, respectively. In addition, treatment with CaD downregulated GLAST, the main glutamate transporter, and accordingly prevented the increase in glutamate. Finally, CaD prevented oxidative stress, and the upregulation of VEGF and PKC delta-p38 MAPK pathway induced by diabetes, thus resulting in a significant reduction in vascular leakage.

CONCLUSIONS

Our findings demonstrate for the first time that CaD exerts neuroprotection in an experimental model of DR. In addition, we provide first evidence that CaD prevents the overexpression of ET-1 and its receptors in the diabetic retina. These beneficial effects on the neurovascular unit could pave the way for clinical trials addressed to confirm the effectiveness of CaD in very early stages of DR.

Liver Graft Allocation by Means of a New, Regionally Shared "Mixed" Model: The Experience in Lazio

INTRODUCTION

Since 2013, the regional network of transplantation centers "LAZIO TRANSPLANT" have adopted a new, mixed system for the allocation of liver grafts.

METHODS

The organs from donors aged <65 are assigned to patients with higher Model for End-stage Liver Disease (MELD) scores on a common regional waiting list, whereas those from donors aged >65 are allocated to patients with higher MELD scores on a specific local waiting list (LWL) at each center, on a rotational basis.

RESULTS

The new mixed allocation model grants a more rational allocation of the "standard" organs to the patients with the actual worst MELD score in the entire region, avoiding the possibility that a patient in relatively better clinical condition might be transplanted before a more severely ill patient on another center's waiting list. Nonstandard organs, presenting slightly increased transplant risks, are still allocated on a rotational basis among the different transplant centers, ensuring them the possibility to select, on the basis of a global clinical risk evaluation, those patients in their LWL whose MELD score would not grant any possibility to compete for the "standard" organ allocation.

CONCLUSIONS

The application of the new model had no negative impact on the overall number of transplants performed or on the global list-satisfaction percentages, but has slightly improved the cumulative mortality of the patients in the waiting list, granting to the clinically worst patients a prompt graft allocation, independent of the local center belonging.

The scavenger protein apoptosis inhibitor of macrophages (AIM) potentiates the antimicrobial response against Mycobacterium tuberculosis by enhancing autophagy

Apoptosis inhibitor of macrophages (AIM), a scavenger protein secreted by tissue macrophages, is transcriptionally regulated by the nuclear receptor Liver X Receptor (LXR) and Retinoid X Receptor (RXR) heterodimer. Given that LXR exerts a protective immune response against M. tuberculosis, here we analyzed whether AIM is involved in this response. In an experimental murine model of tuberculosis, AIM serum levels peaked dramatically early after infection with M. tuberculosis, providing an in vivo biological link to the disease. We therefore studied the participation of AIM in macrophage response to M. tuberculosis in vitro. For this purpose, we used the H37Rv strain to infect THP-1 macrophages transfected to stably express AIM, thereby increasing infected macrophage survival. Furthermore, the expression of this protein enlarged foam cell formation by enhancing intracellular lipid content. Phagocytosis assays with FITC-labeled M. tuberculosis bacilli indicated that this protein was not involved in bacterial uptake; however, AIM expression decreased the number of intracellular cfus by up to 70% in bacterial killing assays, suggesting that AIM enhances macrophage mycobactericidal activity. Accordingly, M. tuberculosis-infected AIM-expressing cells upregulated the production of reactive oxygen species. Moreover, real-time PCR analysis showed increased mRNA levels of the antimicrobial peptides cathelicidin and defensin 4B. These increases were concomitant with greater cellular concentrations of the autophagy-related molecules Beclin 1 and LC3II, as well as enhanced acidification of mycobacterial phagosomes and LC3 co-localization. In summary, our data support the notion that AIM contributes to key macrophage responses to M. tuberculosis.

Long-Term Effectiveness of Combined Mechanotransduction Treatment in Jumper's Knee

The aim of the study was to show that the addition of extracorporeal shockwave therapy (ESWT) may significantly improve beneficial effects of eccentric training together with high efficiency focused acoustic waves for jumper's knee. We speculate that such an effect may be due to increased mechanotransduction effects on affected tissues. We assessed changes in pain and function in 42 male football players (aged 1834 years) after a treatment protocol consisting of I session with focused ESWT per week combined with 3 physiotherapy sessions per week, for 3 consecutive weeks. While treatment protocol was administered, ordinary activities, but not playing football were permitted. Their condition was evaluated before treatment, at the end of the rehabilitation period (3 weeks) and at 2 months, 4 months and 6 months after the end of treatment by clinical examination, instrumental analysis and VAS for pain assessment. Functional ability related to symptoms was assessed with VISA score. At the end of 2005,2006,2007,2008 and 2009 we carried out a telephone interview to investigate changes in pain and function and the efficacy of the treatment over time. Follow-up controls showed a reduction of average VAS score; after 6 months, tendons showed a structure closer to normal at ultrasonographic investigation. At the last telephone interview in 2009 many patients reported to consider ESWT as an effective treatment and described a significant improvement in their functional abilities, a significant reduction in drug consumption and 88% of subjects continued to play agonistic football. In conclusion, our results showed that, through the addition of ESWT, the effects of the classic vibration and eccentric training combination were improved compared to those found in our experience without ESWT. Although a control group was not included in the study (vibration and eccentric training without ESWT), results show a promising improvement and justify future prospective studies with a control group and more case series.

Mineralocorticoid antagonists treatment versus surgery in primary aldosteronism

Recent evidence indicates a greater frequency of primary aldosteronism (PA) among patients with hypertension than the previously accepted prevalence. PA was once considered a relatively benign form of hypertension associated with low incidence of organ complications. Recent views, however, suggest that long-term exposure to increased aldosterone levels might result in cardiovascular, renal, and metabolic sequelae that occur independently of the blood pressure level. Cross-sectional comparisons with patients with essential hypertension have demonstrated that patients with PA are at higher risk of cardiovascular events, have more frequent left ventricular hypertrophy and diastolic dysfunction, have greater urinary albumin losses as a marker of a hemodynamic intrarenal adaptation, and are insulin resistant. Some of these findings have been corroborated by the results of short-term, follow-up studies where it was shown that unilateral adrenalectomy or treatment with mineralocorticoid receptor (MR) antagonists are effective in correcting hypertension and hypokalemia. Normalization of blood pressure and correction of hypokalemia, however, are not the only goals in managing PA and effective prevention of organ complications is mandatory in these patients. The relative efficacy of adrenalectomy and MR antagonists, in the long-term, on the cardiovascular, renal, and metabolic outcomes still needs evaluation, being the aldosterone-induced tissue damage the main factor that could justify the cost of increasing efforts in screening of disease and differentiation of subtypes. In this narrative review, we summarize the results obtained with either surgical or medical treatment of PA and outline the findings of long-term, prospective studies on the effects of treatment on cardiovascular and renal outcomes and on insulin sensitivity.

Hypercholesterolaemia alters the responses of the plasma lipid profile and inflammatory markers to supplementation of the diet with n-3 polyunsaturated fatty acids from fish oil

BACKGROUND

The influence of supplementing the diet with long-chain n-3 polyunsaturated fatty acids (PUFA) from fish oil on plasma lipids and lipid peroxides and the production of pro-inflammatory mediators in normolipidaemic and hypercholesterolaemic rats were studied.

MATERIALS AND METHODS

Rats were divided into four groups and fed one of the following diets: a control diet (containing 4% corn oil); an n-3 PUFA diet [containing 4% eicospentaenoic (EPA) + docosahexaenoic (DHA)]; a hypercholesterolaemic diet (HCH); or a HCH + n-3 PUFA diet over a 4-week period. Plasma lipids, lipid peroxides, cytokines [tumour necrosis factor (TNF)alpha, interleukin (IL)-6, interferon (IFN)gamma] and mRNA for hepatic nuclear factor-4alpha (HNF4alpha) were determined.

RESULTS

Plasma triglyceride (TG), but not cholesterol, levels were decreased by the n-3 PUFA as compared with the control diet (P < 0.001), but the addition of n-3 PUFA to the HCH diet decreased both the TG (P < 0.01) and cholesterol (P < 0.05) concentrations. Plasma lipid peroxides and expression HNF4alpha mRNA were increased by n-3 PUFA in the normolipidaemic (P < 0.05), but not in the hyperlipidaemic rats. Compared with the control diet group, plasma concentrations of TNFalpha and IL-6 were increased in the n-3 PUFA (P < 0.05) and HCH diet (P < 0.05, P < 0.01, respectively) groups, but not in animals given the HCH + n-3 PUFA diet, whereas IFNgamma levels were increased in hypercholesterolaemia (P < 0.05), but were unaffected by n-3 PUFA.

CONCLUSION

These results demonstrate that the major effect of fish oil n-3 PUFA is to lower the TG levels in both normo- and hyperlipidaemia. Furthermore, in the hypercholesterolaemic state, fish oil n-3 PUFA induces additional beneficial changes in the immune and peroxidation responses.

Sirolimus in kidney transplantation from marginal donors

Nephrotoxicity caused by calcineurin inhibitors can lead to either delayed graft function or long-term decline of renal function after kidney transplantation. Therefore, recipients of renal transplants from marginal donors require non-nephrotoxic immunosuppression. Eighteen patients received kidney transplants from marginal donors, with a calcineurin inhibitor-free immunosuppressive regimen, based on basiliximab, mycophenolate mofetil, steroids, and sirolimus. Renal graft biopsy was performed in all cases before surgery. Mean follow-up was 11.8 months. We report immediate renal function in 9 patients, delayed graft function in 5 and acute tubular necrosis in 4 patients. One patient was successfully treated for biopsy-proven acute rejection. Hypercholesterolemia and hypertriglyceridemia were the most common adverse effects (n = 13) associated with arthralgia (n = 2) and thrombocytopenia (n = 2). Five patients underwent a switch to tacrolimus, due to sirolimus-induced side effects. Immunosuppression without the use of calcineurin inhibitors is a safe and effective regimen in kidney transplantation, although sirolimus-related side effects still represent a morbidity factor in these patients.

Living donor transplant: wider selection criteria

The availability of cadaveric donor organs is insufficient for actual needs. The organ demand increases by 20% per year. Living donor transplant (LDT) may be a valid therapeutical alternative provided one uses proper criteria. LDT provides many advantages, like improved patient and organ survival, short waiting time, and the possibility to carefully plan the procedure. Potential risks include perioperative mortality and renal dysfunction in the kidney donor. At present, kidney LDTs in Italy represent 8% of the total, with an organ survival rate of 97% after 1 year (vs 93% for cadaveric transplants) and donors mortality rate of almost null. Most LDTs are performed from kinsmen. Presently, law no. 458, 26 June 1967, is in force in Italy for kidney LDT and law no. 453, 16 December 1999, for liver LDT. The foundations of LDT are, of course, the recipient's condition, the donor's motivation, and the altruism of the donation. It is desirable that in the future an increasing number of LDT be performed, supported by a careful, widespread health education regarding organ donation from living subjects and by the possibility to obtain insurance for the donor, which has been considered but never provided by actual laws.

A monoclonal antibody, MIN/3/60, that recognizes the sulpho-Lewis(x) and sulpho-Lewis(a) sequences detects a sub-population of epithelial glycans in the crypts of human colonic epithelium

Monoclonal antibodies (MAbs) directed to Lewis(x) (Le(x)) and related carbohydrate sequences have been invaluable in anticipating biological roles for these oligosaccharides by detecting the remarkable changes that occur in their expression from the earliest stages of embryogenesis, through development and sequential stages of cell differentiation and maturation. A notable impact has been in the molecular dissection of ligand-receptor interactions in key cell adhesion events at the initial stages of leukocyte recruitment in inflammation, and almost certainly in the metastasis of epithelial tumours. Antibodies that recognise Le(x) and the 3'-sialyl forms were observed to identify leukocyte subsets; these were subsequently found to match those recognized by the leukocyte-endothelium adhesion molecules, the E- and P-selectins. We now describe a MAb (rat hybridoma MIN/3/60) raised to 3'-sulpho-Le(x), a carbohydrate sequence which, in vitro, is bound not only by the E-, L-, and P-selectins, but also by the cysteine-rich domain of the macrophage endocytosis receptor. We observe that MIN/3/60 is bispecific, however; it binds 3'-sulpho-Le(a) as well as 3'-sulpho-Le(x). Nevertheless, our exploratory studies reveal that it may be a useful histochemical reagent when used in conjunction with a monospecific antibody to 3'-sulpho-Le(a). The MIN/3/60 antibody reveals a sub-population of epithelial glycans in the crypts of Lieberkühn in normal human colon.

Impact of donor-specific antibodies on chronic rejection occurrence and graft loss in renal transplantation: posttransplant analysis using flow cytometric techniques

BACKGROUND

Improvements in immunosuppressive therapy have greatly reduced acute rejection (ARj) episodes, ensuring better short-term graft outcome, but have not modified long-term survival in renal transplantation. It is now well accepted that chronic rejection (CRj) can be determined by both immune and/or nonimmune mechanisms. The aim of this study was to evaluate the importance of the posttransplant humoral immune response towards mismatched HLA graft antigens in CRj occurrence and graft outcome.

METHODS

Serum samples from 120 nonpresensitized renal transplant recipients were prospectively screened for 1 year after surgery by means of flow cytometry cross-match (FCXM) and FlowPRA beads (microbeads coated with purified HLA class I and class II antigens) assays. All transplants were followed-up for 2 years or until graft removal.

RESULTS

FCXM monitoring identified donor-specific antibodies (DS-Abs) in 29 (24.2%) of 120 transplanted patients. Correlation with clinical data highlighted a higher incidence of ARj in DS-Abs-positive patients compared to negative patients (62% vs. 13%, P<0.00001). Furthermore, graft failure occurred more frequently among FCXM-positive patients than among negative patients (34% vs. 1%, P<0.00001). The deleterious effect of DS-Abs on graft function was confirmed by serum creatinine levels 2 years after transplantation. These were in fact higher in subjects producing DS-Abs than in subjects with only ARj (mean creatinine: 2.5+/-1.3 mg/dL vs.1.7+/-0.5 mg/dL, P=0.04). FlowPRA analysis of DS-Ab HLA specificity highlighted the presence of anti-HLA class I antibodies in 85% of FCXM-positive patients, who also presented with a higher incidence of HLA-B mismatches than FCXM-negative patients (1.23+/-0.66 vs. 0.92+/-0.59, P=0.02).

CONCLUSIONS

Flow cytometric techniques are precious tools for investigating the activation of the humoral response against HLA antigens of the graft in renal transplantation. DS-Abs production has a worse impact on organ function and survival than ARj episodes. These findings represent further proof of the threat posed by DS-Abs on long-term graft function and draw attention to the need for a specific immunosuppressive therapy aimed at counteracting the different kinds of immune activation toward graft.

Posttransplant donor-specific antibody characterization and kidney graft survival

This study was designed to investigate the clinical relevance of donor-specific antibodies (DS-Abs) and their influence on graft survival. Among 106 patients who underwent cadaveric kidney donor transplantation and were monitored by flow cytometry crossmatch (FCXM) during the 1st posttransplantation year, 25 (23.6%) resulted positive for DS-Ab production. During a 2-year follow up only 12 of the 81 FCXM-negative patients (14.8%) suffered rejection vs 17 of 25 FCXM-positive patients (68%; P = 0.00001). Correlating graft loss to DS-Ab production, 9 FCXM-positive patients lost the graft vs only 1 among the FCXM-negative patients. A worse graft function was evidenced in FCXM-positive subjects who had also suffered rejection episodes than in those which had acute rejection but did not produce DS-Abs. A high incidence of HLA-AB mismatches was found in FCXM-positive subjects which produced anti-class I antibodies. FCXM appears useful in estimating posttransplant alloimmune response. Moreover our findings confirm the harmful effects of anti-class I DS-Abs on long-term graft survival.

[Planning of transplantation centers]

Health policies are correlated with the economics resources invested in each specific field. The planning of organ transplant centres depends on the relationship between health demand and health offer. The health demand is due to the number of the patients which are waiting for a transplant, while the health offer is represented by all the specific resources: number of cadaver donors and transplant centres. The analysis of transplant activity performed in Italy during the period 1996-1998 suggests that it is not necessary to increase the number of transplant centres but that of organ donors.

PTOV1, a novel protein overexpressed in prostate cancer containing a new class of protein homology blocks

In a search for molecular markers of progression in prostate cancer by means of differential display, we have identified a new gene, which we have designated PTOV1. Semiquantitative RT-PCR has established that nine out of 11 tumors overexpress PTOV1 at levels significantly higher than benign prostatic hyperplasia or normal prostate tissue. The human PTOV1 protein consists almost entirely of two repeated blocks of homology of 151 and 147 amino acids, joined by a short linker peptide, and is encoded by a 12-exon gene localized in chromosome 19q13.3. A Drosophila melanogaster PTOV1 homolog also contains two tandemly arranged PTOV blocks. A second gene, PTOV2, was identified in humans and Drosophila, coding for proteins with a single PTOV homology block and unrelated amino- and carboxyl-terminal extensions. A 1.8-Kb PTOV1 transcript was detected abundantly in normal human brain, heart, skeletal muscle, kidney and liver, and at low levels in normal prostate. Immunocytochemical analysis and expression of chimeric GFP-PTOV1 proteins in cultured cells showed a predominantly perinuclear localization of PTOV1. In normal prostate tissue and in prostate adenomas, PTOV1 was undetectable or expressed at low levels, whereas nine out of 11 prostate adenocarcinomas showed a strong immunoreactivity, with a focal distribution in areas of carcinoma and prostatic intraepithelial neoplasia. Therefore, PTOV1 is a previously unknown gene, overexpressed in early and late stages of prostate cancer. The PTOV homology block represents a new class of conserved sequence blocks present in human, rodent and fly proteins.

Fusion of the human gene for the polyubiquitination coeffector UEV1 with Kua, a newly identified gene

UEV proteins are enzymatically inactive variants of the E2 ubiquitin-conjugating enzymes that regulate noncanonical elongation of ubiquitin chains. In Saccharomyces cerevisiae, UEV is part of the RAD6-mediated error-free DNA repair pathway. In mammalian cells, UEV proteins can modulate c-FOS transcription and the G2-M transition of the cell cycle. Here we show that the UEV genes from phylogenetically distant organisms present a remarkable conservation in their exon-intron structure. We also show that the human UEV1 gene is fused with the previously unknown gene Kua. In Caenorhabditis elegans and Drosophila melanogaster, Kua and UEV are in separated loci, and are expressed as independent transcripts and proteins. In humans, Kua and UEV1 are adjacent genes, expressed either as separate transcripts encoding independent Kua and UEV1 proteins, or as a hybrid Kua-UEV transcript, encoding a two-domain protein. Kua proteins represent a novel class of conserved proteins with juxtamembrane histidine-rich motifs. Experiments with epitope-tagged proteins show that UEV1A is a nuclear protein, whereas both Kua and Kua-UEV localize to cytoplasmic structures, indicating that the Kua domain determines the cytoplasmic localization of Kua-UEV. Therefore, the addition of a Kua domain to UEV in the fused Kua-UEV protein confers new biological properties to this regulator of variant polyubiquitination.

[Oxidative stress in kidney failure: an experimental study]

We studied the activity of some enzymes directly involved in the endogenous antioxidative defense system: glutathione-peroxidase (GPX), glutathione s-transferase (GST) and superoxide dismutase (SOD). We have investigated the effects of selenium and vitamin E diet supplementation, in form of selenium-vitamin E enriched yeast, in Wistar rats that were undergone to surgical right nephrectomy and 30 minutes of hypoxia. Blood samples were tested for several parameters as glucose, cholesterol, etc. to assess the general health conditions. The protocol consisted of 3 groups of 25 Wistar rats: a control group, a pre-fed group and a post-fed group. The results showed a significative difference in the behaviour of azotemia, proteins and cholesterol. In the control group the activity rapidly increased, then the values decreased slowly and differently for each substance. The pre and post-fed group showed a pronounced increase after 48 h but the normal values are reached more rapidly. We observed an increase in the activity of the GPX and GST after surgical operation and ischemia, but the GPX in pre-fed group reached the normal value before the other groups.

The role of DRB1 amino acid residue differences on donor-specific antibody production and acute rejection after cadaveric renal transplant

The correlation between DRB1 amino acid residue matching, post-transplant humoral response and acute rejection (ARj) episodes was analysed in 51 renal transplant donor-recipient pairs in order to determine new criteria for organ assignment based on the alloreactivity of the residue within the peptide binding groove. HLA class I and II compatibility was defined using serological and genomic techniques; a sequence-based typing (SBT) was used for a higher resolution of DRB1 alleles. Humoral response was monitored in the first post-transplant year using triple staining flow cytometric analysis of donor-specific antibodies (Abs). Our data showed that DRB1 residue compatibility was always correlated to the absence of ARj while the presence of one or more aminoacid differences was associated with a similar frequency of ARj. Analysis of the mismatched DRB1 amino acid residue localised in the beta-pleated sheet and the alpha-helix of the DRB 1 molecule revealed that the frequency of beta-pleated sheet residue mismatches (MMs) was higher in the ARj-positive than in the ARj-negative group. A significant increase in the alpha-helix residue MMs was observed in patients with anti-class II Ab production (p = 0.034). Furthermore, analysing in detail DRB 1 MMs at the level of single amino acid residue, we found that the frequency of the mismatches localized in codon 9 and codon 28 in the beta-pleated sheet, as well as in codon 57 in the alpha-helix, was higher in patients who experienced ARj; on the other hand, MMs in codon 58 of the alpha-helix were more frequently associated with anti-class II Ab production. The identification of the residues more involved in alloreactivity onset will make it possible to define the existence of "permissive" or immunogenic" allele combinations which could simplify and increase the chances of a successful transplant.

Rat MAbs to the product of the c-erbB-2 proto-oncogene for diagnosis and therapy in breast cancer

The product of the c-erbB-2 protooncogene (p185) is a member of the EGF receptor family of transmembrane tyrosine kinases. Amplification of this gene and overexpression of the product has been observed in adenocarcinomas and has been correlated with poor prognosis in patients with breast and ovarian cancer. The very low levels of expression of p185 by normal adult tissues makes the receptor an almost tumor-specific target. We have prepared rat monoclonal antibodies against five distinct epitopes on the external domain of the c-erbB-2 product overexpressed by the breast cancer line BT474. The antibodies bind to the protein core of p185 and stain specifically the membranes in frozen sections of tumors overexpressing the c-erbB-2 product. Three of the antibodies, ICR12 (epitope A), ICR54, and ICR55 (epitope E), also stain the cell membrane in formalin-fixed, paraffin-embedded sections and bind to p185 in Western blots. An investigation of the stability of the antigen-antibody complexes indicates that the majority are not readily internalized by SKOV3 cells growing in vitro. Antibodies ICR12 (IgG2a) and ICR55 (IgG2a), which are directed against separate epitopes on the c-erbB-2 p185, are both of high affinity and immunoreactivity (> 75%) and localize specifically and stably to xenografted breast and ovarian carcinomas growing in athymic mice when labeled with 125I (up to 13% injected dose/g, ICR12 and ICR55) or a range of other radionuclides (up to 20% id/g, ICR12). We conclude that these antibodies may be useful as therapeutic vehicles for targeting radionuclides (imaging and therapy) or enzymes for activating prodrugs (ADEPT).