MO060: HIF1Α and Succinate Pathway: Role in Deceased Kidney Donors Inflammation

BACKGROUND AND AIMS

The type of donor has an important impact on the renal prognosis of the recipient. Thus, it has been observed that the decline of renal function is higher in deceased donor (DD) than those observed in living donors (LD). These could be related with the pre-implantation inflammation state of the donor and the development of fibrotic processes.

Own data indicate that the enzymatic complex succinate dehydrogenase (SDH) has a lower gene expression in DD grafts and is associated with inflammatory markers, macrophages and purinergic receptors and a worse renal function after transplantation. The aim of this study is to determine that in renal DD donation, ischemia/hypoxia can increase renal succinate levels, inducing infiltration of inflammatory cells.

METHOD

Preimplantation kidneys biopsies from 47 DD and 19 LD were collected in our institution. About 159 genes from these samples were analyzed by qRT–PCR with the TaqMan gene expression assay. Relative quantification of gene expression was performed with three internal controls. Genes with high positive correlation with HIF1α (Rho > 0.5) have been grouped in clusters using STRING database (http://string-db.org/).

Succinate levels were measured in serum from 27 renal DD and in 10 healthy volunteers with the EnzyChromTM Succinate Assay Kit.

All statistical data were analyzed using GraphPad Prism 5. HIF, SDH subunits and succinate levels in serum were analyzed with a Student's T-test (P-value of 0.001). Pearson correlation Test (Rho >0.5) was performed to analyze interdependence of HIF1α with the rest of genes.

RESULTS

To determine the hypoxia status of kidney donors, transcription levels of HIF1α and HIF2α were determined from renal tissue samples. In the graphic (Figure. 1A), a significant increase in HIF1α genic expression is observed in DD compared with LD (P < 0.001). The next figure (Figure. 2B) shows clusters in DD that are not present in LD and have a high correlation with HIF1a (Rho > 0.5). Twenty-four genes showed this strong correlation and can be grouped in three different clusters: Cluster 1: Transcription factors and metalloproteinases, Cluster 2: Extracellular Matrix (ECM) proteins and integrins and finally, Cluster 3: Inflammatory and Macrophages Markers.

As is shown Figure 2A, we found reduced mRNA expression of all the SDH subunits (SDHA, SDHB, SDHC and SDHD) (P < 0.001) in DD samples compared with LD ones. As a consequence, succinate cannot be converted to fumarate in concordance with the greater succinate levels (P = 0.002) observed in sera of DD shown in the picture (Figure. 2B).

CONCLUSION

These results indicate that kidneys from DD undergo a greater hypoxia compared with LD, demonstrated by the increased transcription rate of HIF1α. Hypoxia not only increases HIF1α but also may disrupt the Krebs cycle, reducing the expression of SDH subunits, increasing extracellular levels of succinate that has a role in the maintenance of HIF1α levels, which could take part in a sustained inflammatory/anti-inflammatory process in kidney from DD.

Effects of CK2β subunit down-regulation on Akt signalling in HK-2 renal cells

The PI3K/Akt pathway is interconnected to protein kinase CK2, which directly phosphorylates Akt1 at S129. We have previously found that, in HK-2 renal cells, downregulation of the CK2 regulatory subunit β (shCK2β cells) reduces S129 Akt phosphorylation. Here, we investigated in more details how the different CK2 isoforms impact on Akt and other signaling pathways.

We found that all CK2 isoforms phosphorylate S129 in vitro, independently of CK2β. However, in HK-2 cells the dependence on CK2β was confirmed by rescue experiments (CK2β re-expression in shCK2β HK-2 cells), suggesting the presence of additional components that drive Akt recognition by CK2 in cells. We also found that CK2β downregulation altered the phosphorylation ratio between the two canonical Akt activation sites (pT308 strongly reduced, pS473 slightly increased) in HK-2 cells. Similar results were found in other cell lines where CK2β was stably knocked out by CRISPR-Cas9 technology. The phosphorylation of rpS6 S235/S236, a downstream effector of Akt, was strongly reduced in shCK2β HK-2 cells, while the phosphorylation of two Akt direct targets, PRAS40 T246 and GSK3β S9, was increased. Differently to what observed in response to CK2β down-regulation, the chemical inhibition of CK2 activity by cell treatment with the specific inhibitor CX-4945 reduced both the Akt canonical sites, pT308 and pS473. In CX-4945-treated cells, the changes in rpS6 pS235/S236 and GSK3β pS9 mirrored those induced by CK2β knock-down (reduction and slight increase, respectively); on the contrary, the effect on PRAS40 pT246 phosphorylation was sharply different, being strongly reduced by CK2 inhibition; this suggests that this Akt target might be dependent on Akt pS473 status in HK-2 cells.

Since PI3K/Akt and ERK1/2/p90rsk pathways are known to be interconnected and both modulated by CK2, with GSK3β pS9 representing a convergent point, we investigated if ERK1/2/p90rsk signaling was affected by CK2β knock-down and CX-4945 treatment in HK-2 cells. We found that p90rsk was insensitive to any kind of CK2 targeting; therefore, the observation that, similarly, GSK3β pS9 was not reduced by CK2 blockade suggests that GSK3β phosphorylation is mainly under the control of p90rsk in these cells. However, we found that the PI3K inhibitor LY294002 reduced GSK3β pS9, and concomitantly decreased Snail1 levels (a GSK3β target and Epithelial-to-Mesenchymal transition marker). The effects of LY294002 were observed also in CK2β-downregulated cells, suggesting that reducing GSK3β pS9 could be a strategy to control Snail1 levels in any situation where CK2β is defective, as possibly occurring in cancer cells.

Analysis of the quality of patient therapeutic education and information in a high complexity reference hospital

BACKGROUND AND OBJECTIVES

The application and monitoring of quality criteria in information and therapeutic patient education can identify areas to improve care. The objectives of this study were: (1) To analyze the characteristics of patient information materials, educational activities, and self-management programs, and (2) to determine health care provider (HCP) proposals on therapeutic patient education.

MATERIALS AND METHODS

Using a cross-sectional study, an online questionnaire was sent to hospital departments in a high complexity reference hospital from September to December 2013 to record: (a) information materials, (b) patient educational activities, and self-management program characteristics, (c) HCP proposals. The materials were analyzed using Health Promoting Hospitals (HPH) recommendations.

RESULTS

(1) An analysis was performed on 258 materials (leaflets [54%]) for chronic patients (86%), acute patients (7%), and the general population (7%). More than half (55%) lacked the authors, and 43% the year issued, and 69% followed HPH recommendations. (2) An evaluation was made of 70 educational activities and 37 self-management programs addressed to patients/relatives with diabetes/obesity, musculoskeletal disorders, COPD/asthma, pelvic-floor disorders, transplantation, bowel-inflammation/liver disease, hypertension, cancer, heart failure, acquired immune deficiency syndrome, chronic renal insufficiency, splenectomy, anticoagulation and older-patient dependence. The structure, process and outcome evaluation varied. (3) HCP proposals included: standardization of materials criteria, web accessibility, list of accredited websites, cross-sectional use, and HCP training in self-management education.

CONCLUSIONS

The online questionnaire showed the weaknesses and strengths of patient information and education, and can be used to monitor their quantity and quality. These results help in the definition of a useful model to improve patient information and education policies.

The importance of negative determinants as modulators of CK2 targeting. The lesson of Akt2 S131

CK2 is a pleiotropic S/T protein kinase (formerly known as casein kinase 2) which is attracting increasing interest as therapeutic target, and the identification of its substrates is a crucial step in determining its involvement in different pathological conditions. We recently found that S131 of Akt2 (homologous to the well established CK2 target S129 of Akt1) is not phosphorylated by CK2 either in vitro or in vivo, although the consensus sequence recognized by CK2 (S/T-x-x-E/D/pS/pT) is conserved in it. Here, by exploiting synthetic peptides, in cell transfection experiments, and computational analysis, we show that a single sequence element, a T at position n+1, hampers phosphorylation, causing an α-helix structure organization which prevents the recognition of its own consensus by CK2. Our results highlight the role of negative determinants as crucial modulators of CK2 targeting and corroborate the concept that Akt1 and Akt2 display isoform specific features. Experiments with synthetic peptides suggest that Akt2 S131 could be phosphorylated by kinases of the Plk (Polo-like kinase) family, which are insensitive to the presence of the n+1 T. The low phylogenetic conservation of the Akt2 sequence around S131, as opposed to the extremely well-conserved Akt1 homologous sequence, would indicate a dominant positive role in the selective pressure only for the Akt1 phosphoacceptor site committed to undergo phosphorylation by CK2. By contrast, Akt2 S131 may mediate the response to specific physio/pathological conditions, being consequently shielded against basal CK2 targeting.

Under-expression of CK2β subunit in ccRCC represents a complementary biomarker of p-STAT3 Ser727 that correlates with patient survival

Clear cell renal cell carcinoma (ccRCC) is the most common and aggressive subtype of renal cancer. STAT3 pathway is altered in these tumors and p-STAT3 Ser727 is an independent prognostic factor for ccRCC. Protein kinase CK2 is altered in different types of tumors and overexpression of CK2α is considered predictive of bad prognosis and metastatic risk. CK2 subunits analyses in ccRCC samples showed increased CK2α/α’ nuclear content in all cases, but decreased cytosolic CK2β (CK2βcyt) levels in the more advanced tumors. Stable downregulation of CK2β in renal proximal tubular (HK-2) and clear cell adenocarcinoma (786-O) cells triggered changes in E-cadherin, vimentin and Snail1 protein levels indicative of epithelial-to-mesenchymal transition (EMT), and increased HIF-α. Moreover, CK2β was required in order to observe STAT3 Ser727 phosphorylation in HK-2 but not in 786-O cells.

We also observed that CK2β improved the prognostic value of p-STAT3 Ser727, as CK2βcyt>41 (median value) discriminates patients free of disease for a period of 10 years upon surgery, from those with CK2βcyt<41, when p-STAT3 Ser727levels are low.

We conclude that CK2β down-regulation might represent a mechanism to support EMT and angiogenesis and that CK2βcyt levels are instrumental to refine prognosis of ccRCC patients with low p-STAT3 Ser727 levels.

Protein kinase CK2 modulates HSJ1 function through phosphorylation of the UIM2 domain

HSJ1 (DNAJB2), a member of the DNAJ family of molecular chaperones, is a key player in neuronal proteostasis maintenance. It binds ubiquitylated proteins through its Ubiquitin Interacting Motifs (UIMs) and facilitates their delivery to the proteasome for degradation. Mutations in the DNAJB2 gene lead to inherited neuropathies such as Charcot-Marie-Tooth type-2, distal hereditary motor neuropathies, spinal muscular atrophy with parkinsonism and the later stages can resemble amyotrophic lateral sclerosis. HSJ1 overexpression can reduce aggregation of neurodegeneration-associated proteins in vitro and in vivo; however, the regulation of HSJ1 function is little understood. Here we show that CK2, a ubiquitous and constitutively active protein kinase, phosphorylates HSJ1 within its second UIM, at the dominant site Ser250 and the hierarchical site Ser247. A phospho-HSJ1 specific antibody confirmed phosphorylation of endogenous HSJ1a and HSJ1b. A tandem approach of phospho-site mutation and treatment with CK2 specific inhibitors demonstrated that phosphorylation at these sites is accompanied by a reduced ability of HSJ1 to bind ubiquitylated clients and to exert its chaperone activity. Our results disclose a novel interplay between ubiquitin- and phosphorylation-dependent signalling, and represent the first report of a regulatory mechanism for UIM-dependent function. They also suggest that CK2 inhibitors could release the full neuroprotective potential of HSJ1, and deserve future interest as therapeutic strategies for neurodegenerative disease.

Ribosomal proteins as novel players in tumorigenesis

Ribosome biogenesis is the most demanding energetic and metabolic expenditure of the cell. The nucleolus, a nuclear compartment, coordinates rRNA transcription, maturation, and assembly into ribosome subunits. The transcription process is highly coordinated with ribosome biogenesis. In this context, ribosomal proteins (RPs) play a crucial role. In the last decade, an increasing number of studies have associated RPs with extraribosomal functions related to proliferation. Importantly, the expression of RPs appears to be deregulated in several human disorders due, at least in part, to genetic mutations. Although the deregulation of RPs in human malignancies is commonly observed, a more complex mechanism is believed to be involved, favoring the tumorigenic process, its progression and metastasis. This review explores the roles of the most frequently mutated oncogenes and tumor suppressor genes in human cancer that modulate ribosome biogenesis, including their interaction with RPs. In this regard, we propose a new focus for novel therapies.

Cwc21p promotes the second step conformation of the spliceosome and modulates 3' splice site selection

Pre-mRNA splicing involves two transesterification steps catalyzed by the spliceosome. How RNA substrates are positioned in each step and the molecular rearrangements involved, remain obscure. Here, we show that mutations in PRP16, PRP8, SNU114 and the U5 snRNA that affect this process interact genetically with CWC21, that encodes the yeast orthologue of the human SR protein, SRm300/SRRM2. Our microarray analysis shows changes in 3′ splice site selection at elevated temperature in a subset of introns in cwc21Δ cells. Considering all the available data, we propose a role for Cwc21p positioning the 3′ splice site at the transition to the second step conformation of the spliceosome, mediated through its interactions with the U5 snRNP. This suggests a mechanism whereby SRm300/SRRM2, might influence splice site selection in human cells.

HAVCR/KIM-1 activates the IL-6/STAT-3 pathway in clear cell renal cell carcinoma and determines tumor progression and patient outcome

Renal cell carcinoma (RCC), the third most prevalent urological cancer, claims more than 100,000 lives/year worldwide. The clear cell variant (ccRCC) is the most common and aggressive subtype of this disease. While commonly asymptomatic, more than 30% of ccRCC are diagnosed when already metastatic, resulting in a 95% mortality rate. Notably, nearly one-third of organ-confined cancers treated by nephrectomy develop metastasis during follow-up care. At present, diagnostic and prognostic biomarkers to screen, diagnose, and monitor renal cancers are clearly needed. The gene encoding the cell surface molecule HAVCR1/KIM-1 is a suggested susceptibility gene for ccRCC and ectodomain shedding of this molecule may be a predictive biomarker of tumor progression. Microarray analysis of 769-P ccRCC-derived cells where HAVCR/KIM-1 levels have been upregulated or silenced revealed relevant HAVCR/KIM-1-related targets, some of which were further analyzed in a cohort of 98 ccRCC patients with 100 month follow-up. We found that HAVCR/KIM-1 activates the IL-6/STAT-3/HIF-1A axis in ccRCC-derived cell lines, which depends on HAVCR/KIM-1 shedding. Moreover, we found that pSTAT-3 S727 levels represented an independent prognostic factor for ccRCC patients. Our results suggest that HAVCR/KIM-1 upregulation in tumors might represent a novel mechanism to activate tumor growth and angiogenesis and that pSTAT-3 S727 is an independent prognostic factor for ccRCC.

Hepatitis A virus cellular receptor 1/kidney injury molecule-1 is a susceptibility gene for clear cell renal cell carcinoma and hepatitis A virus cellular receptor/kidney injury molecule-1 ectodomain shedding a predictive biomarker of tumour progression

AIM OF THE STUDY

To correlate hepatitis A virus cellular receptor (HAVCR)/kidney injury molecule-1 (KIM-1) expression in clear cell renal cell carcinoma (ccRCC) tumours with patient outcome and study the consequences of HAVCR/KIM-1 ectodomain shedding.

METHODS

HAVCR/KIM-1 expression in ccRCC, oncocytomes, papillary carcinomas and unaffected tissue counterparts was evaluated. Minimal change disease and pre-clamping normal and ccRCC tissue biopsies were included. Tissue microarrays from 98 ccRCC tumours were analysed. Tumour registry data and patient outcome were retrospectivelly collected. Deletions in HAVCR/KIM-1 ectodomain and lentiviral infection of 786-O cells with HAVCR/KIM-1 mutated constructs to determine their subcellular distribution and invasive capacity were performed.

RESULTS

HAVCR/KIM-1 was expressed in ccRCC, papillary tumours and in tubule cells of adjacent and distal unaffected counterparts of ccRCC tumours. The latest was not related to ischemic or tumour-related paracrine effects since pre-clamping normal biopsies were positive for HAVCR/KIM-1 and unaffected counterparts of papillary tumours were negative. HAVCR/KIM-1 analyses in patients and the invasive capacity of HAVCR/KIM-1 shedding mutants in cell lines demonstrated that: (i) relative low HAVCR/KIM-1 membrane levels correlate with activated shedding in ccRCC patients and mutant cell lines; (ii) augmented shedding directly correlates with higher invasiveness and tumour malignancy. CONCLUDING STATEMENTS: Constitutive expression of HAVCR/KIM-1 in kidney might constitute a susceptibility trait for ccRCC tumour development. Enhanced HAVCR/KIM-1 ectodomain shedding promotes invasive phenotype in vitro and more aggressive tumours in vivo.

EULID project: European living donation and public health

The choice of transplantation from a living donor offers advantages over a deceased donor. However, it also carries disadvantages related to donor risks in terms of health and safety. Furthermore, there are several controversial ethical aspects to be taken into account. Several national and international institutions and the scientific community have stated standards that have great influence on professional codes and legislations. Living organ donation and transplantation are to some extent regulated by parliamentary acts in most European countries. It is necessary to take a step forward to develop a legal framework to regulate all of these processes to guarantee the quality and to prevent illegal and nonethical practices. It is also necessary to develop and implement living donor protection practices not only in terms of physical health, but also to minimize potential impacts on the psychological, social, and economic spheres. Finally, an additional effort should be made to create a database model with recommendations for registration practices as part of the standardized follow-up care for the living donor. The European Living Donation (EULID) project's (http://www.eulivingdonor.eu/) main objective was to contribute to a European consensus to set standards and recommendations about legal, ethical, and living donor protection practices to guarantee the health and safety of living donors.

Characterization of the Organ Donor With Bacteremia

INTRODUCTION

The presence of bloodstream infection in the donor is a common finding that could be transmitted to the recipient. To safely expand the donor pool, we examined its relevance.

MATERIALS AND METHODS

We described the clinical characteristics of organ donors grafted in our center between 1997 and 2006 who had bacteremia detected in blood cultures obtained during organ procurement.

RESULTS

Among 1353 organ donors, 75 were non-heart-beating donors type II and the others brain-dead donors. Only 186 donors (14%) showed bacteremia during retrieval. This mean age was 49.8 years (range 12 to 86 years, SD 18) including 63% men. Causes of death were cerebrovascular accident in 60%; craneoencephalic trauma, 25%; and other causes, 15%. The average length of the intensive care unit stay was 3 days (interquartile range: 2 to 7 days). Twenty-nine percent of donors presented previous infectious complications (90% from respiratory origin). The most prevalent pathogen isolated in blood cultures was coagulase negative Staphylococci (46,2%), followed by S aureus (15%), Streptococcus group viridans (9.1%), enterobacteria (9%), Enterococcus faecalis (7.5%) and gram-negative bacilli nonfermentative (6.2%). In 3.1%, the bloodstream infections were polymicrobial. The bronchial aspiration cultures were positive in 50% of cases and the urine culture in 8,6%. In 17% of donors the isolated microorganism was coincident between blood and bronchial cultures. Pseudomonas spp and S aureus were more common than the others (P = .004 and P = .058, respectively).

CONCLUSIONS

The incidence of bacteremia in our cohort was 14%. The respiratory tract was the most common clinical focus. Pseudomonas spp or S aureus isolated in bronchial cultures are risk factors to develop bacteremia. According to these findings, it is important to start specific antibiotics against those microorganisms in the donor and the recipients.

Telephone Consent in Tissue Donation: Effectiveness and Efficiency in Postmortem Tissue Generation

One reason for the loss of donors is the impossibility to contact family members for an interview. We sought to determine the effectiveness [(donors/total deaths) x 100] and efficiency [(donors/potential donors) x 100] of the telephone interview to obtain tissue for transplant purposes.

METHODS

A prospective, comparative cross-sectional study was performed on the personal and telephone interviews with family members during the tissue donation application process from January 1, 2004 to December 31, 2005.

RESULTS

Of the 3625 deaths hospital registered, we obtained 770 potential donors (21%). On 65% of occasions (503/770), the interview was held personally; on 29% (222/770), it had to be held over the telephone; and on 6% (45/770), family members could not be located. The refusals by family members over the telephone represented 48% (106/222), and the refusals during personal interviews were 37% (188/503). A positive family answer was obtained over the telephone on 116/431 donations (27%), and in the physical presence of the coordinator for 315/431 donors (73%). The donations obtained over the telephone were only for corneas in 83% (96/116) of cases, and for multiple tissues in 17% (20/116). The donor-generation effectiveness reached 9% in personal interviews and 12% if the telephone interviews were included. The donor generation efficiency reached 43% for personal interviews and 59% when telephone interviews were included. The use of the telephone enabled a 16% increase in tissue generation with a year-on-year increase of 4%.

CONCLUSIONS

The telephone has shown itself to be a useful tool for obtaining tissues postmortem.

Use of Quality Index in the Evaluation of Organ Procurement and Transplant Programs in a University Hospital

AIM

To evaluate organ procurement efficiency at Hospital Clinic of Barcelona (HCP), a University Hospital, in 2000 and 2003 compared with other Catalan, other Spanish, and American (US) results.

METHODS

Efficacy rate of the donor procurement was calculated per million population per year (pmp/y). Efficacy rate in kidney, liver, and heart transplantation was calculated also in pmp/y. We evaluated 1-year graft survival.

RESULTS

During this period, the average rate number of donors was 49.1 pmp/y in HCP, 38 in Catalonia, 33.4 in Spain, and 21.7 in the United States. The average rate of kidney transplantation was 74 pmp/y in HCP, 55 in Catalonia, 47 in Spain, and 24.6 in the United States. The average rate of liver transplantation was 44.5, 26.6, 23.2, and 18 pmp/y, respectively. The average rate of heart transplantation was 13.3, 8.5, 7.8, and 6.4 pmp/y, respectively. One-year graft survival in HCP was 90.6% for kidney, 89.5% for liver, and 88.2% for heart transplants.

DISCUSSION

The results show that organ procurement and transplantation programs in HCP are efficient. The organizational model is based on a hospital transplant coordinator and efficient, well-trained transplant teams.

[GESIDA/GESITRA-SEIMC, PNS and ONT consensus document on solid organ transplant (SOT) in HIV-infected patients in Spain (March, 2005)]

Solid organ transplant may be the only therapeutic alternative in some HIV-infected patients. Experience in North America and Europe during the last five years shows that survival at three years after an organ transplant is similar to that observed in HIV-negative patients. The criteria agreed upon to select HIV patients for transplant are: no opportunistic infections (except tuberculosis, oesophageal candidiasis or P. jiroveci -previously carinii- pneumonia), CD4 lymphocyte count above 200 cells/.L (100 cells/.L in the case of liver transplant) and an HIV viral load which is undetectable or suppressible with antiretroviral therapy. Another criterion is a two-year abstinence from heroin and cocaine, although the patient may be in a methadone programme. The main problems in the post-transplant period are pharmacokinetic and pharmacodynamic interactions between antiretorivirals and immunosuppressors, rejection and the management of relapse of HCV infection, which is one of the main causes of post-liver transplant mortality. Up to now, experience with pegylated interferon and ribavirin is scarce in this population. The English version of the manuscript is available at http://www.gesidaseimc.com.

[Ethical and legal features of living donor kidney transplantation. Management and coordination of the process of living donation]

OBJECTIVES

Living donors for kidney transplantation have attracted interest from different points of view because medical issues are accompanied by other features involving ethical, legal and social issues. We analyze all aspects involved in living donation for kidney transplantation.

METHODS

We analyze: (1) ETHICAL ISSUES: requirements to become living donor, donor-receptor relationship, informed consent, donor's motivations, risk/benefit. (2) Legal issues: We review Spanish laws and Council of Europe's recommendations. (3) We also analyze how to coordinate the process in order to guarantee protection to donors.

RESULTS/CONCLUSIONS

Living donor kidney transplantation is a growing therapeutic option. The process of living donation should comply with several legal and ethical requirements, and cooperation between different professionals to guarantee protection to donors.

Optimizing cadaveric organ procurement: the catalan and Spanish experience

The need to face the increasing gap between the supply and the demand of transplants has led to the development of a permanent network of trained medical staff responsible for the organ donation and removal process in all centers accredited for that process. In Spain, this activity received a specific budget, like any other medical activity in hospitals, and the responsible staff became accountable for performance. This system dramatically increased the number of potential donors referred, not only young donors with trauma, but also elderly donors dying from stroke. The effect was that the donation rate increased by more than 100% in 10 years (from 14 to 34 donors per million population). Consequently, so did all the transplant figures. In some areas, such as Catalonia, it has been demonstrated that sustained kidney transplant activity of over 60 procedures per million population can maintain or slightly decrease the waiting list, despite increasing incidence and prevalence of end-stage renal failure. Quality monitoring of the donation and retrieval process shows that there are still opportunities for improvement if all potential donors are referred and all technical problems are overcome. Living donation and nonheart beating organ retrieval should also be promoted.

Functions, responsibilities, dedication, payment, organization, and profile of the hospital transplant coordination in Spain in 2002

In Spain, the number of donors per million of population and the activity of transplantation is a direct consequence of the continued work of the hospital transplant coordinators. There are 146 procurement hospitals with approximately 534 transplant coordinators (13.6 coordinators per hospital and 12.7 per million of population). A voluntary survey of 74 Spanish transplant coordinators revealed 67.6% to be men and 32.4% women of average age 43 years with specialization of 75.7%, Intensive Care Medicine; 8.1%, Anesthesiology; 6.7%, Nephrologists; and the rest, General Surgery or without any specialization. Among the group who responded to the injury, 86.5% were doctors and 13.5%, nurses. The overall team is composed of 52% doctors, 27.7% nurses and others with 70.3% working part-time and 27%, full-time. Previous experience was noted to be less than 5 years among 51.4%, and more in the rest of the cases. The 85% work under medical direction by management. Their payment includes salary plus activity in 48.7% of the cases; 21.6%, only salary, and 18.9%, only activity. Each coordinator generates between 3 and 7 organ as well as 3 and 11 of tissue donors. In conclusion, comparing this data with the practice in the United States demonstrates the unique aspects of the Spanish system.

Percutaneous renal artery embolisation of non-functioning renal allografts with clinical intolerance

The aim of the study was to evaluate the efficacy and safety of percutaneous renal artery embolisation of non-functioning renal allografts in patients with graft intolerance syndrome (GIS). Transcatheter artery embolisation was performed in 30 kidney transplant recipients with GIS. The duration of graft function had been 60+/-45 months. Infectious disease was ruled out in all patients. Embolisation consisted of the injection of polyvinyl alcohol microspheres followed by the insertion of a stainless steel coil in the renal artery branches. Symptoms of GIS included: fever-graft pain (44%, n=13), fever-hematuria-pain (20%, n=6), fever-hematuria (13%, n=4) and fever alone (23%, n=7). Latency time between graft failure and embolisation was 184+/-227 (17-1181) days. Embolisation was clinically successful with the prolonged disappearance of GIS in 24 patients (80%). Six patients showed initial clinical improvement, but GIS reappeared at 40+/-18 days, and graft nephrectomy was required. There were no major complications associated with embolisation and no deaths. Perirenal collateral supply was a risk factor for the reappearance of GIS. Renal vascular embolisation is a simple, safe and effective technique for treating renal allograft intolerance syndrome and could be a feasible alternative for the first-line treatment.

Pharmacokinetics and pharmacodynamics of mycophenolic acid in stable renal transplant recipients treated with low doses of mycophenolate mofetil

Suboptimal doses of mycophenolate mofetil (MMF) are frequently employed in renal transplant (Tx) patients, with drug-related side effects or low weight. The aim of this study was to compare the mycophenolic acid (MPA) pharmacokinetic profile and its pharmacodynamic effect on patients receiving either standard (2 g) or low (1.5 g or 1 g) MMF doses, in order to evaluate the therapeutic efficacy of such low doses in inhibiting IMPDH activity. Twenty-seven stable renal Tx recipients aged 18-65 years, with a post-Tx follow-up of 38.5 +/- 44.8 months (6-166 months), receiving 1 g (n = 10), 0.75 g (n = 7) and 0.5 g (n = 10) MMF twice a day in association with cyclosporine and prednisone, were included. The control group was made up of untreated healthy volunteers (n = 5). Plasma concentrations of MPA were analyzed by reverse-phase HPLC. IMPDH activity was determined in lymphocytes by the measurement of 3H release from [2,8-(3)H] hypoxantine. The mean value of areas under the concentration-time curves (AUC(0-12)) of MPA throughout the 12-h dosing interval in patients treated with 2 g was higher than the corresponding data in patients receiving 1.5 g or 1 g bid, but no statistical differences were observed between the three groups. There was no correlation between MPA-AUC(0-12) values and MMF dose (expressed in g/day or g/kg per day). Predose MPA concentrations correlated only weakly with the respective MPA-AUC(0-12) values (r2 from 0.385 to 0.655), whereas an acceptable correlation was observed between MPA Cmax and MPA-AUC(0-12) (r2 from 0.626 to 0.759) in 2 g, 1.5 g, and 1 g MMF groups. An inverse relationship between MPA concentrations and IMPDH activity was observed. In general, the maximum MPA concentration was achieved from 1 h to 2 h after dosing, and the maximum inhibition of IMPDH was also from 1 h to 2 h after dosing. The evaluation of IMPDH activity demonstrated that there was a significant statistical difference between samples from 0 to 1 h (P = 0.008) and 0 to 2 h (P = 0.04). In conclusion, concentration-time profiles of renal transplant recipients administered 0.75 g and 0.5 g twice a day are slightly lower than those from the 2 g group, but nor significantly. On the other hand, inhibition of IMPDH activity was comparable in the three groups, indicating considerable interindividual pharmacodynamic variability. Pharmacodynamic monitoring of the degree of immunosuppression and its correlation with MPA plasma concentrations will be assessed further in future studies.

Mycophenolic acid plasma concentrations: influence of comedication

Mycophenolate mofetil (MMF) in combination with cyclosporine (CsA) or Tacrolimus (TAC) has been show to be a potent immunosuppressive agent. The authors assessed the mycophenolic acid (MPA) plasma levels achieved in clinical practice and evaluated the effect of concomitant administration of CsA and TAC . One hundred forty transplant patients (kidney: 120 and lung: 20) received a triple immunosuppression regimen of CsA or TAC, prednisone and MMF. Twenty-two renal transplant patients received double therapy with MMF and prednisone. There was no correlation between MMF dose and MPA trough concentrations (r = -0.0657). The medians (range) of the MPA dose-to-concentration ratio (D/C) in the CsA and TAC groups were 0.90 (0.11-8.33) and 0.56 (0.11-14.3), respectively (p < 0.0001). According to the post transplant period (1-3, 4-6 and >6 months), D/C values were significantly lower in patients receiving MMF and TAC than those receiving MMF and CsA in all three periods. MPA levels in patients treated with MMF and CsA were significantly lower than those obtained in double therapy. The D/C ratio in CsA-treated patients, increased significantly (p = 0.0005) when CsA level increased. There was no relationship between D/C ratio and TAC blood concentrations. These results suggest that CsA exerts an influence on MPA trough levels, although further work is required to characterize the mechanism of interaction.

The odyssey of a regulated transcript

The transcript of the Saccharomyces cerevisiae gene, RPL30, is subject to regulated splicing and regulated translation, due to a structure that interacts with its own product, ribosomal protein L30. We have followed the fate of the regulated RPL30 transcripts in vivo. Initially, these transcripts abortively enter the splicing pathway, forming an unusually stable association with U1 snRNP. A large proportion of the unspliced molecules, however, are found in the cytoplasm. Most of these are still bound by L30, as only a small fraction are engaged in translation. Eventually, the unspliced RPL30 transcripts escape the grasp of L30, associate with ribosomes, and fall prey to nonsense mediated decay.

Assessment of Mycophenolic Acid-induced Immunosuppression: A New Approach

Background: Mycophenolic acid (MPA), a metabolite of mycophenolate mofetil (MMF), is an immunosuppressive agent that inhibits inosine monophosphate dehydrogenase (IMPDH), a key enzyme in the ex novo synthesis of GTP. We measured IMPDH activity in peripheral blood mononuclear cells (PBMCs) from MMF-treated patients to evaluate the efficacy of MMF in individual patients.

Methods: IMPDH activity was measured by 3H released from [2,8-3H]IMP that had been formed in the cells from added [2,8-3H]hypoxanthine in PBMCs of 35 renal transplant recipients treated with cyclosporin A and corticoids plus MMF: 2 g (n = 10), 1.5 g (n = 7), 1 g (n = 10), or 0 g (n = 8) per day. An alternative method, based on the capacity of the patients’ sera to inhibit spontaneous proliferation of the CEM cell line, was also analyzed.

Results: The IMPDH activity of PBMCs in transplanted patients was highly variable. For the method based on CEM cell line proliferation: (a) cell proliferation was inhibited only in MMF-treated patients; (b) there was a clear postdose increase in inhibition; (c) inhibition was not affected by other immunosuppressants in vitro or in vivo; (d) inhibition from predose to predose sample was correlated; and (e) when the MMF dosage was &lt;20 mg · kg−1 · day−1, two groups of patients were identified, one that maintained a high inhibitory capacity in all dose intervals, and one with periods of low inhibitory capacity.

Conclusions: Measurement of the inhibition of CEM cell line proliferation by sera from MMF-treated patients may be useful for evaluating the relative efficacy of MMF treatment in individual patients, especially those receiving low doses of MMF.

Assessment of mycophenolic acid-induced immunosuppression: a new approach

BACKGROUND

Mycophenolic acid (MPA), a metabolite of mycophenolate mofetil (MMF), is an immunosuppressive agent that inhibits inosine monophosphate dehydrogenase (IMPDH), a key enzyme in the ex novo synthesis of GTP. We measured IMPDH activity in peripheral blood mononuclear cells (PBMCs) from MMF-treated patients to evaluate the efficacy of MMF in individual patients.

METHODS

IMPDH activity was measured by (3)H released from [2,8-(3)H]IMP that had been formed in the cells from added [2,8-(3)H]hypoxanthine in PBMCs of 35 renal transplant recipients treated with cyclosporin A and corticoids plus MMF: 2 g (n = 10), 1.5 g (n = 7), 1 g (n = 10), or 0 g (n = 8) per day. An alternative method, based on the capacity of the patients' sera to inhibit spontaneous proliferation of the CEM cell line, was also analyzed.

RESULTS

The IMPDH activity of PBMCs in transplanted patients was highly variable. For the method based on CEM cell line proliferation: (a) cell proliferation was inhibited only in MMF-treated patients; (b) there was a clear postdose increase in inhibition; (c) inhibition was not affected by other immunosuppressants in vitro or in vivo; (d) inhibition from predose to predose sample was correlated; and (e) when the MMF dosage was <20 mg. kg(-1). day(-1), two groups of patients were identified, one that maintained a high inhibitory capacity in all dose intervals, and one with periods of low inhibitory capacity.

CONCLUSIONS

Measurement of the inhibition of CEM cell line proliferation by sera from MMF-treated patients may be useful for evaluating the relative efficacy of MMF treatment in individual patients, especially those receiving low doses of MMF.

Multiple functions of an evolutionarily conserved RNA binding domain

Ribosomal protein L30 of Saccharomyces cerevisiae binds to a distinct RNA structure to inhibit the splicing and the translation of its own transcript. Remarkably, the ortholog of L30 from the archaeon Sulfolobus acidocaldarius binds specifically to the same RNA fragment and inhibits splicing both in vitro and in vivo. Indeed, expression of Sulfolobus L30 in yeast severely reduces growth by limiting production of the endogenous L30. This conservation of binding specificity implies that the target of regulation in the RPL30 transcript mimics a site in the rRNA that has been conserved for more than a billion years. We identify this site, whose location suggests that L30, which has no apparent eubacterial ortholog, is responsible for establishing the orientation of a key bridge between the large and small ribosomal subunits.

Ribosomal protein L32 of Saccharomyces cerevisiae influences both the splicing of its own transcript and the processing of rRNA

Ribosomal protein L32 of Saccharomyces cerevisiae binds to and regulates the splicing and the translation of the transcript of its own gene. Selecting for mutants deficient in the regulation of splicing, we have identified a mutant form of L32 that no longer binds to the transcript of RPL32 and therefore does not regulate its splicing. The mutation is the deletion of an isoleucine residue from a highly conserved hydrophobic domain near the middle of L32. The mutant protein supports growth, at a reduced rate, and is found at normal levels in mature ribosomes. However, in cells homozygous for the mutant gene, the rate of processing of the ribosomal RNA component of the 60S ribosomal subunit is severely reduced, leading to an insufficiency of 60S subunits. L32 must be considered a remarkable protein. Composed of only 104 amino acids, it appears to interact with three distinct RNA molecules to influence three different elements of RNA processing and function in three different locations of the cell: the processing of pre-rRNA in the nucleolus, the splicing of the RPL32 transcript in the nucleus, and the translation of the spliced RPL32 mRNA in the cytoplasm.

[Chronic myeloid leukemia after renal transplantation: report of a new case and review of the bibliography]

The increase in cancer incidence in renal transplant recipients is a well recognized fact, which has been related to post-transplant immunosuppressive therapy. Solid tumors, skin cancer and non-Hodgkin's lymphomas account for most of the neoplasms in these patients, whereas chronic myeloproliferative disorders are infrequent. A patient is reported who developed chronic myelogenous leukemia (CML) six years after renal transplantation, which was followed by immunosuppressive with azathioprine, and the published data on such an association are reviewed. In all 10 cases reported azathioprine had been administered after transplantation. The amount and type of post-transplant immunosuppressive therapy seems to be the most important risk factor for the development of secondary CML in these patients, since no cases of CML in patients receiving cyclosporine A have been reported.

[Pneumocystis carinii pneumonia in the transplant recipient]

BACKGROUND

The aim of the present was to study the clinical characteristics and prognostic factors of 20 cases of pneumonia by Pneumocystis carinii (NPC) diagnosed over the last 10 years in renal, renopancreatic, liver and bone marrow transplant recipients.

METHODS

The clinical histories of all the patients transplanted in the authors' hospital from 1985 to 1994 who developed NPC were analyzed. Diagnosis was established by visualization of cysts in methenamine silver staining of bronchialveolar lavage (BAL) samples.

RESULTS

The global incidence of NPC in our transplant population was 1%. However, the incidence was 3% in the recipients who did not receive prophylaxis. No patient in this series received prophylaxis at the time of diagnosis. Ninety percent of the patients had history or rejection. Pneumonia was observed in 15 (75%) in the first 6 months post transplantation. The mean length of the symptoms prior to diagnosis was 10 days. Ninety-five percent of the patients presented cough, dysnea and fever. Radiology demonstrated diffuse alveolointerstitial infiltrates in 18 patients (90%). Basal arterial PO2 was lower than 60 mmHg in 14 (70%) patients and the alveoloarterial gradient of oxygen was greater than 60 mmHg in 9 (45%). Mechanical ventilation was required in 50% of the patients. BAL demonstrated cytologic alterations compatible with CMV infection in 50% of the cases and in two Aspergillus fumigatus was associated. Mortality was 35%. The only variable significantly associated with bad prognosis was the need for mechanical ventilation (p = 0.003).

CONCLUSIONS

The incidence of pneumonia by P. carinii in a population of transplant recipients was 1%. No patient received primary prophylaxis at the time of diagnosis. Most of the episodes were observed during the first 6 months post transplant. Mortality was 35% with the only variable with prognostic significance being the need for mechanical ventilation.

An RNA structure involved in feedback regulation of splicing and of translation is critical for biological fitness

While studies of the regulation of gene expression have generally concerned qualitative changes in the selection or the level of expression of a gene, much of the regulation that occurs within a cell involves the continuous subtle optimization of the levels of proteins used in macromolecular complexes. An example is the biosynthesis of the ribosome, in which equimolar amounts of nearly 80 ribosomal proteins must be supplied by the cytoplasm to the nucleolus. We have found that the transcript of one of the ribosomal protein genes of Saccharomyces cerevisiae, RPL32, participates in such fine tuning. Sequences from exon I of the RPL32 transcript interact with nucleotides from the intron to form a structure that binds L32 to regulate splicing. In the spliced transcript, the same sequences interact with nucleotides from exon II to form a structure that binds L32 to regulate translation, thus providing two levels of autoregulation. We now show, by using a sensitive cocultivation assay, that these RNA structures and their interaction with L32 play a role in the fitness of the cell. The change of a single nucleotide within the 5' leader of the RPL32 transcript, which abolishes the site for L32 binding, leads to detectably slower growth and to eventual loss of the mutant strain from the culture. Experiments designed to assess independently the regulation of splicing and the regulation of translation are presented. These observations demonstrate that, in evolutionary terms, subtle regulatory compensations can be critical. The change in structure of an RNA, due to alteration of just one noncoding nucleotide, can spell the difference between biological success and failure.

Study of kidney rejection following simultaneous kidney-pancreas transplantation

Simultaneous kidney-pancreas (SKP) transplantation is associated with increased risk of kidney rejection (KR) due to an unknown mechanism. The aim of this study is to analyze the characteristics of KR in 44 SKP transplantations under quadruple immunosuppressive therapy and to evaluate the response to treatment and its effect on renal allograft survival and renal function. The mean follow-up was 25 +/- 14 months. Seventy-seven percent of the patients (34 of 44) presented an acute renal allograft rejection. Sixty-six percent (29 of 44) had one rejection episode and 11% (5 of 4) 2 episodes. KR was early (85% in the first month after transplantation), intense (3.7-fold increase in creatinine) and had great clinical features. Twenty-eight percent of the patients had an early relapse during the first month after treatment. KR did not affect the survival of the renal allograft in the short-term (1 and 2 years). Overall, 62% were corticosensitive (CS) and the remaining 38% were corticoresistant (CR). The group with an isolated rejection without relapse was CS in 69% of the cases, achieved complete remission in 73% and renal function was not affected at 1 and 2 years [115 +/- 26 mumol/l (1.3 +/- 0.3 mg/dl) and 150 +/- 53 mumol/l (1.7 +/- 0.6 mg/dl)] in comparison with the group without rejection [97 +/- 18 mumol/l (1.1 +/- 0.2 mg/dl) and 115 +/- 35 mumol/l (1.3 +/- 0.4 mg/dl); p = NS]. On the other hand, the group with an early relapse of the first rejection and the group with two rejections were principally CR (62 and 60%, respectively), had partial remission with treatment (50 and 60%) and had worse renal function at 1 and 2 years [212 +/- 71 mumol/l (2.4 +/- 0.8 mg/dl) and 221 +/- 53 mumol/l (2.5 +/- 0.6 mg/dl)] than in the group with isolated KR (p < 0.05 and p < 0.001). In conclusion, despite intense immunosuppressive treatment, the frequency of rejection of a renal allograft in SKP is high. The response to treatment is satisfactory and does not affect the survival of the allograft in the short-term. However, multiple episodes or early relapse of rejection are associated with higher creatinine levels.

Characterization of the pre-mRNA binding site for yeast ribosomal protein L32: the importance of a purine-rich internal loop

The structure of the RNA binding target for Saccharomyces cerevisiae ribosomal protein L32 was examined using chemical and enzymatic probes as well as thermodynamic methods. In vivo, the production of yeast RPL32 is regulated by a feedback mechanism whereby RPL32 binds to the 5' end of its transcript and inhibits splicing. The binding site of ribosomal protein L32 on the L32 RNA transcript can be reduced to fewer than 30 nucleotides which compromise a stem-internal loop-stem structural motif. The internal loop is closed by a potential G-U pair, is asymmetric and contains mostly purines. The existence of the two helical regions was confirmed by chemical and enzymatic probing. The reactivity of the loop region suggests a structure intermediate between that of single and double-stranded RNA. Base stacking continues into the loop, but two loop bases are extremely reactive to chemical agents. The interaction between the model RNA and the protein is specific and has a dissociation constant of approximately 10 nM. Several of the loop bases are critical for protein binding, as demonstrated by mutational data and chemical protection and modification interference studies. The internal loop destabilizes the RNA, and allows the RNA to melt in an all-or-none fashion.