In Vivo Gene Expression Profiling of Staphylococcus aureus during Infection Informs Design of Stemless Leukocidins LukE and -D as Detoxified Vaccine Candidates

Staphylococcus aureus is a clinically important bacterial pathogen that has become resistant to treatment with most routinely used antibiotics. Alternative strategies, such as vaccination and phage therapy, are therefore actively being investigated to prevent or combat staphylococcal infections. Vaccination requires that vaccine targets are expressed at sufficient quantities during infection so that they can be targeted by the host's immune system. While our knowledge of in vitro expression levels of putative vaccine candidates is comprehensive, crucial in vivo expression data are scarce and promising vaccine candidates during in vitro assessment often prove ineffective in preventing S. aureus infection. Here, we show how a newly developed high-throughput quantitative reverse transcription-PCR (qRT-PCR) assay monitoring the expression of 84 staphylococcal genes encoding mostly virulence factors can inform the selection and design of effective vaccine candidates against staphylococcal infections. We show that this assay can accurately quantify mRNA expression levels of these genes in several host organs relying only on very limited amounts of bacterial mRNA in each sample. We selected two highly expressed genes, lukE and lukD, encoding pore-forming leukotoxins, to inform the design of detoxified recombinant proteins and showed that immunization with recombinant genetically detoxified LukED antigens conferred protection against staphylococcal skin infection in mice. Consequently, knowledge of in vivo-expressed virulence determinants can be successfully deployed to identify and select promising candidates for optimized design of effective vaccine antigens against S. aureus. Notably, this approach should be broadly applicable to numerous other pathogens. IMPORTANCE Vaccination is an attractive strategy for preventing bacterial infections in an age of increased antimicrobial resistance. However, vaccine development frequently suffers significant setbacks when candidate antigens that show promising results in in vitro experimentation fail to protect from disease. An alluring strategy is to focus resources on developing bacterial virulence factors that are expressed during disease establishment or maintenance and are critical for bacterial in-host survival as vaccine targets. While expression profiles of many virulence factors have been characterized in detail in vitro, our knowledge of their in vivo expression profiles is still scarce. Here, using a high-throughput qRT-PCR approach, we identified two highly expressed leukotoxins in a murine infection model and showed that genetically detoxified derivatives of these elicited a protective immune response in a murine skin infection model. Therefore, in vivo gene expression can inform the selection of promising candidates for the design of effective vaccine antigens.

Is there long-term value of pathology scoring in immunoglobulin A nephropathy? A validation study of the Oxford Classification for IgA Nephropathy (VALIGA) update

Background

It is unknown whether renal pathology lesions in immunoglobulin A nephropathy (IgAN) correlate with renal outcomes over decades of follow-up.

Methods

In 1130 patients of the original Validation Study of the Oxford Classification for IgA Nephropathy (VALIGA) cohort, we studied the relationship between the MEST score (mesangial hypercellularity, M; endocapillary hypercellularity, E; segmental glomerulosclerosis, S; tubular atrophy/interstitial fibrosis, T), crescents (C) and other histological lesions with both a combined renal endpoint [50% estimated glomerular filtration rate (eGFR) loss or kidney failure] and the rate of eGFR decline over a follow-up period extending to 35 years [median 7 years (interquartile range 4.1–10.8)].

Results

In this extended analysis, M1, S1 and T1–T2 lesions as well as the whole MEST score were independently related with the combined endpoint (P < 0.01), and there was no effect modification by age for these associations, suggesting that they may be valid in children and in adults as well. Only T lesions were associated with the rate of eGFR loss in the whole cohort, whereas C showed this association only in patients not treated with immunosuppression. In separate prognostic analyses, the whole set of pathology lesions provided a gain in discrimination power over the clinical variables alone, which was similar at 5 years (+2.0%) and for the whole follow-up (+1.8%). A similar benefit was observed for risk reclassification analyses (+2.7% and +2.4%).

Conclusion

Long-term follow-up analyses of the VALIGA cohort showed that the independent relationship between kidney biopsy findings and the risk of progression towards kidney failure in IgAN remains unchanged across all age groups and decades after the renal biopsy.

«Physiological» and «Pharmacological» Dialysate Sodium Concentrations

Forty three uremic patients on regular hemodialysis treatment (4 hours 3 times/week) were dialyzed for a period of 28.95 ± 14.46 months with a dialysate sodium concentration (NaD) of 142 mEq/l, similar to their plasma water sodium concentration corrected for the Donnan factor («physiological» NaD). Blood pressure (BP) and body weight (BW) dropped significantly.

During two following periods, lasting 18 and 14 months, with NaD 148 mEq/l, similar to the patients’ plasma water sodium concentration («pharmacologically high» NaD), cardiovascular stability improved and BP did not show significant increase.

Using «physiological» and «pharmacologically high» NaD the removal of water and sodium by convection improves the cardiovascular stability and the patients’ well being, without bringing about the feared long-term cardiovascular side effects, if an appropriate dry body weight is achieved, because of better correction of the cellular overhydration.

Phagocyte subsets and lymphocyte clonal deletion behind ineffective immune response to Staphylococcus aureus

Lack of known mechanisms of protection against Staphylococcus aureus in humans is hindering development of efficacious vaccines. Preclinical as well as clinical data suggest that antibodies play an important role against S. aureus. For instance, certain hypogammaglobulinaemic patients are at increased risk of staphylococcal infections. However, development of effective humoral response may be dampened by converging immune-evasion mechanisms of S. aureus. We hypothesize that B-cell proliferation induced by staphylococcal protein A (SpA) and continuous antigen exposure, without the proper T-cell help and cytokine stimuli, leads to antigen-activated B-cell deletion and anergy. Recent findings suggest an important role of type I neutrophils (PMN-I) and conventionally activated macrophages (M1) against S. aureus, while alternatively activated macrophages (M2) favour biofilm persistence and sepsis. In addition, neutrophil-macrophage cooperation promotes extravasation and activation of neutrophils as well as clearance of bacteria ensnared in neutrophil extracellular traps. Activation of these processes is modulated by cytokines and T cells. Indeed, low CD4(+) T-cell counts represent an important risk factor for skin infections and bacteraemia in patients. Altogether, these observations could lead to the identification of predictive correlates of protection and ways for shifting the balance of the response to the benefit of the host through vaccination.

High density lipoprotein cholesterol levels are an independent predictor of the progression of chronic kidney disease

OBJECTIVES

Patients with chronic kidney disease (CKD) often present with reduced plasma HDL cholesterol (HDL-C) levels. Whether this reduction in an epiphenomenon or is involved in disease progression is unclear. The aim of this study was to investigate the relation between HDL-C levels/function and CKD progression in patients with different degrees of disease.

DESIGN

A total of 176 patients with CKD [glomerular filtration rate (GFR) 50.3 ± 29.1 mL min⁻¹] were recruited and followed for up to 84 months. Lipid profile, metabolic status and kidney function were evaluated at predetermined times. Age-matched control subjects were selected from the PLIC study (n = 453). Scavenger receptor class B member 1 (SR-BI) and ATP-binding cassette transporter A1 (ABCA-1)-dependent efflux of cholesterol were measured in CKD patients and in age-matched control subjects.

RESULTS

Low HDL-C levels, diabetes and hypertension were associated with reduced GFR. At follow-up, low HDL-C levels were associated with earlier entry in dialysis or doubling of the plasma creatinine level (P = 0.017); HDL-C levels were the only lipid parameter that affected the progression of CKD (hazard ratio 0.951, 95% confidence interval 0.917-0.986, P = 0.007), independently of the presence of diabetes. Only SR-BI-mediated serum cholesterol efflux was significantly reduced in the group of CKD patients with low HDL-C levels compared to the control group.

CONCLUSIONS

CKD patients with low levels of plasma HDL-C have a poor prognosis. HDL functionality is also impaired in renal dysfunction. These data support the relevance of HDL in influencing CKD progression.

Expression profiling of genes involved in the formation of aroma in two peach genotypes

The expression profile of flavour-related genes during ripening was investigated in two peach genotypes, Bolero and OroA, which have been selected for their contrasting aroma/ripening behaviour. A new peach microarray containing 4776 oligonucleotide probes corresponding to a set of ESTs specifically enriched in secondary metabolism (μPEACH2.0) was designed to investigate transcriptome changes during three fruit ripening stages, revealing 1807 transcripts differentially expressed within and between the two genotypes. Differences in the expression of genes involved in the biosynthesis of aroma compounds were detected during the ripening process within and between the two genotypes. In particular, a subset of 12 transcripts involved in metabolism of esters, norisoprenoids, phenylpropanoids and lactones, varied in expression during ripening and between Bolero and OroA.

Opsonic and protective properties of antibodies raised to conjugate vaccines targeting six Staphylococcus aureus antigens

Staphylococcus aureus is a major cause of nosocomial and community-acquired infections for which a vaccine is greatly desired. Antigens found on the S. aureus outer surface include the capsular polysaccharides (CP) of serotype 5 (CP5) or 8 (CP8) and/or a second antigen, a β-(1→6)-polymer of N-acetyl-D-glucosamine (PNAG). Antibodies specific for either CP or PNAG antigens have excellent in vitro opsonic killing activity (OPKA), but when mixed together have potent interference in OPKA and murine protection. To ascertain if this interference could be abrogated by using a synthetic non-acetylated oligosaccharide fragment of PNAG, 9GlcNH(2), in place of chemically partially deacetylated PNAG, three conjugate vaccines consisting of 9GlcNH(2) conjugated to a non-toxic mutant of alpha-hemolysin (Hla H35L), CP5 conjugated to clumping factor B (ClfB), or CP8 conjugated to iron-surface determinant B (IsdB) were used separately to immunize rabbits. Opsonic antibodies mediating killing of multiple S. aureus strains were elicited for all three vaccines and showed carbohydrate antigen-specific reductions in the tissue bacterial burdens in animal models of S. aureus skin abscesses, pneumonia, and nasal colonization. Carrier-protein specific immunity was also shown to be effective in reducing bacterial levels in infected lungs and in nasal colonization. However, use of synthetic 9GlcNH(2) to induce antibody to PNAG did not overcome the interference in OPKA engendered when these were combined with antibody to either CP5 or CP8. Whereas each individual vaccine showed efficacy, combining antisera to CP antigens and PNAG still abrogated individual OPKA activities, indicating difficulty in achieving a multi-valent vaccine targeting both the CP and PNAG antigens.

Methicillin resistance alters the biofilm phenotype and attenuates virulence in Staphylococcus aureus device-associated infections

Clinical isolates of Staphylococcus aureus can express biofilm phenotypes promoted by the major cell wall autolysin and the fibronectin-binding proteins or the icaADBC-encoded polysaccharide intercellular adhesin/poly-N-acetylglucosamine (PIA/PNAG). Biofilm production in methicillin-susceptible S. aureus (MSSA) strains is typically dependent on PIA/PNAG whereas methicillin-resistant isolates express an Atl/FnBP-mediated biofilm phenotype suggesting a relationship between susceptibility to β-lactam antibiotics and biofilm. By introducing the methicillin resistance gene mecA into the PNAG-producing laboratory strain 8325-4 we generated a heterogeneously resistant (HeR) strain, from which a homogeneous, high-level resistant (HoR) derivative was isolated following exposure to oxacillin. The HoR phenotype was associated with a R₆₀₂H substitution in the DHHA1 domain of GdpP, a recently identified c-di-AMP phosphodiesterase with roles in resistance/tolerance to β-lactam antibiotics and cell envelope stress. Transcription of icaADBC and PNAG production were impaired in the 8325-4 HoR derivative, which instead produced a proteinaceous biofilm that was significantly inhibited by antibodies against the mecA-encoded penicillin binding protein 2a (PBP2a). Conversely excision of the SCCmec element in the MRSA strain BH1CC resulted in oxacillin susceptibility and reduced biofilm production, both of which were complemented by mecA alone. Transcriptional activity of the accessory gene regulator locus was also repressed in the 8325-4 HoR strain, which in turn was accompanied by reduced protease production and significantly reduced virulence in a mouse model of device infection. Thus, homogeneous methicillin resistance has the potential to affect agr- and icaADBC-mediated phenotypes, including altered biofilm expression and virulence, which together are consistent with the adaptation of healthcare-associated MRSA strains to the antibiotic-rich hospital environment in which they are frequently responsible for device-related infections in immuno-compromised patients.

The acquisition of mecA, which encodes penicillin binding protein 2a (PBP2a) and methicillin resistance, by Staphylococcus aureus has added to an already impressive array of virulence mechanisms including enzyme and toxin production, biofilm forming capacity and immune evasion. And yet clinical data does not indicate that healthcare-associated methicillin resistant S. aureus (MRSA) strains are more virulent than their methicillin-susceptible counterparts. Here our findings suggest that MRSA sacrifices virulence potential for antibiotic resistance and that expression of methicillin resistance alters the biofilm phenotype but does not interfere with the colonization of implanted medical devices in vivo. High level expression of PBP2a, which was associated with a mutation in the c-di-AMP phosphodiesterase gene gdpP, resulted in these pleiotrophic effects by blocking icaADBC-dependent polysaccharide type biofilm development and promoting an alternative PBP2a-mediated biofilm, repressing the accessory gene regulator and extracellular protease production, and attenuating virulence in a mouse device-infection model. Thus the adaptation of MRSA to the hospital environment has apparently focused on the acquisition of antibiotic resistance and retention of biofilm forming capacity, which are likely to be more advantageous than metabolically-expensive enzyme and toxin production in immunocompromised patients with implanted medical devices offering a route to infection.

Methicillin resistance reduces the virulence of healthcare-associated methicillin-resistant Staphylococcus aureus by interfering with the agr quorum sensing system

The difficulty in successfully treating infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has led to them being referred to as highly virulent or pathogenic. In our study of one of the major healthcare-associated MRSA (HA-MRSA) clones, we show that expression of the gene responsible for conferring methicillin resistance (mecA) is also directly responsible for reducing the ability of HA-MRSA to secrete cytolytic toxins. We show that resistance to methicillin induces changes in the cell wall, which affects the bacteria's agr quorum sensing system. This leads to reduced toxin expression and, as a consequence, reduced virulence in a murine model of sepsis. This diminished capacity to cause infection may explain the inability of HA-MRSA to move into the community and help us understand the recent emergence of community-associated MRSA (CA-MRSA). CA-MRSA typically express less penicillin-binding protein 2a (encoded by mecA), allowing them to maintain full virulence and succeed in the community environment.

Is suboptimal prescribing a risk factor for poor health outcomes in community-dwelling elders? The ICARe Dicomano study

PURPOSE

Mostly because of comorbidity and drugs consumption, older persons are often exposed to an increased risk of sub-optimal prescribing (SP). At present, few studies investigated the association between SP and long-term health outcomes. We examined the relation between SP and the risk of mortality and hospitalization in Italian older community-dwellers.

METHODS

Older (65+ years) community-dwelling residents of a small town in Tuscany were enrolled in a longitudinal study. SP was defined as polypharmacy (use of 5+ drugs), prescription of inappropriate drugs (ID) according to Beers' criteria, and of potentially interacting drugs (PID), evaluated in 1995 and 1999. These three forms of SP were entered as time-dependent exposures into multivariable Cox regression analysis models, whose outcomes were mortality and hospitalizations through 2003.

RESULTS

Of 1022 participants (mean age 73.0 +/- 6.8, 57% women), 220 were evaluated in 1995, 234 in 1999 and 568 in both waves. In univariate analysis, mortality was two-fold higher in participants with polypharmacy (73.4/1000 person/years, 95% CI 58.2-92.4 vs. 34.1, 95% CI 29.7-39.2; p < 0.001) or PID (72.7/1000 person/years, 95% CI 46.3-113.9 vs. 38.0, 95% CI 33.5-43.1; p < 0.001), whereas it was unrelated to the presence of ID. Hospitalization rates were independent of any form of SP. In multivariable models, polypharmacy, ID, and PID were no longer associated with an increased risk of death, and ID predicted a slightly increased risk of hospitalizations (HR 1.03, 95% CI 1.0-1.06, p = 0.048).

CONCLUSIONS

In this cohort, SP was not associated with an excess risk of poor health outcomes.

CK2 and GSK3 phosphorylation on S29 controls wild-type ATXN3 nuclear uptake

In the present work we show that murine ATXN3 (ATXN3Q6) nuclear uptake is promoted by phosphorylation on serine 29, a highly conserved residue inside the Josephin domain. Both casein kinase 2 (CK2) and glycogen synthase kinase 3 (GSK3) are able to carry out phosphorylation on this residue. S29 phosphorylation was initially assessed in vitro on purified ATXN3Q6, and subsequently confirmed in transfected COS-7 cells, by MS analysis. Site-directed mutagenesis of S29 to an alanine was shown to strongly reduce nuclear uptake, in COS-7 transiently transfected cells overexpressing ATXN3Q6, while substitution with phospho-mimic aspartic acid restored the wild-type phenotype. Finally, treatment with CK2 and GSK3 inhibitors prevented S29 phosphorylation and strongly inhibited nuclear uptake, showing that both kinases are involved in ATXN3Q6 subcellular sorting. Although other authors have previously addressed this issue, we show for the first time that ATXN3 is phosphorylated inside the Josephin domain and that S29 phosphorylation is involved in nuclear uptake of ATXN3.

Offsetting virulence and antibiotic resistance costs by MRSA

The prevalence of diverse MRSA (methicillin-resistant Staphylococcus aureus) types in both hospital and community settings is a major health problem worldwide. Here we compare hospital-acquired MRSAs with large type II SCCmec elements with those prevalent in both hospital and community settings with smaller type IV SCCmec elements. We find that the type II but not the type IV SCCmec element causes the bacteria to reduce their levels of costly toxin expression. We compare the relative growth rates of these MRSA types and show that the type II SCCmec carrying MRSAs are more affected than those carrying type IV elements and from this we hypothesize that offsetting the costs associated with antibiotic resistance and toxin expression is why the type II are confined to hospital environments where antibiotic use, the prevalence of immunocompromised individuals and vector-mediated transmission is high. In contrast, those MRSAs that are also successful in the community can maintain their high levels of toxin expression due to a lower fitness burden associated with the smaller SCCmec element.

[The role of steroids in the treatment of IgA nephropathy]

IgA nephropathy (IgAN) is characterized by a variable natural history. Welldefined risk factors from a clinical point of view are renal function impairment, associated hypertension, and proteinuria, while tubular-interstitial fibrosis constitutes a histological risk factor. These are serious clinical symptoms and histological signs, indicating long-lasting and severe damage. The available therapeutic tools belong essentially to two categories: 1) angiotensin inhibitors and 2) steroids, associated or not with immunosuppressive drugs. ACE inhibitors have limited toxicity and no significant side effects, and nephrologists are inclined to use them in case of moderate proteinuria. Steroids, in some cases associated with immunosuppressive agents, are obviously more demanding for the patient. Decisions must be made by the clinicians regarding the timing and the possible presence of contraindications. Furthermore, the treatment may not yield the expected results and a critical approach by the nephrologist is necessary. This controversy highlights the theoretical and practical issues related to steroid therapy in IgAN and here we discuss the different approaches to indications, doses, duration and route of administration.

[Treatment of IgA nephropathy with chronic renal failure]

INTRODUCTION

About 25-50% of patients with IgA nephropathy (IgAN) progress toward end-stage renal disease (ESRD) within 25 years. Negative prognostic factors are hypertension, proteinuria >1 g/day, high values of plasma creatinine, and the extension of chronic histological lesions.

METHODS AND RESULTS

Only a few studies have evaluated the effectiveness of treatment in IgAN patients with chronic renal failure (CRF) and most of these had methodological flaws. However, some studies produced interesting results. Alexopoulos and Donadio found that the progression of IgAN slowed down with the use of omega-3 fatty acids; Woo and Nakao used angiotensin inhibitors to obtain the same result, while Ballardie used immunosuppressors. Evidence of treatment efficacy in chronic histological lesions is almost completely lacking. Yoshikawa found that a two-year course of corticosteroids and azathioprine could arrest the progression of glomerular sclerosis, and Shoji obtained similar results using corticosteroids alone for one year. In 2007 we presented the results of a study that compared corticosteroids alone vs corticosteroids and azathioprine in 253 IgAN patients. In all patients, including 46 with serum creatinine >2 mg/dL, both therapy schemes appeared effective in slowing the progression towards ESRD, even if patients in the azathioprine group experienced more side effects.

CONCLUSIONS

At the moment, Italian nephrologists preferably use ACE inhibitors alone or associated with corticosteroids in patients with IgAN and CRF. Recently, the Renal Immunopathology Group of the Italian Society of Nephrology (SIN) proposed a therapeutic study that would compare steroids and ACE inhibitors in patients with IgAN and CRF in order to provide more certain therapeutic indications.

The long-term prognosis of renal transplant in patients with systemic vasculitis

Little information is available about the long-term outcome of renal transplantation in patients with systemic vasculitis (SV). We compared the outcomes of 19 renal transplant recipients with SV with those of 38 controls matched for time of transplantation, age, gender and source of donor. The mean post-transplant follow-up was 58 +/- 57 months for vasculitic patients and 61 +/- 49 months for controls. The actuarial 10-year patient survival was 87% in vasculitic patients and 90% in controls, death-censored graft survival were 84% and 100%, respectively. The risks of acute and chronic rejection, and arterial hypertension were not significantly different between the two groups. Infection was significantly more frequent in vasculitic patients (74% vs. 34%; p = 0.01). Seven patients (36.8%) had a recurrence of vasculitis in mean 45 months after renal transplant (0.076/patients/year). After recurrence, one patient had an irreversible humoral rejection, another died from hemophagocytosis and another restarted dialysis 1 year later. Long-term patient and renal allograft survival in vasculitic patients was good. Although graft function recovered in most relapsers after reinforcement of immunosuppression, one patient died and two lost graft function.

Association between methicillin susceptibility and biofilm regulation in Staphylococcus aureus isolates from device-related infections

Production of icaADBC-encoded polysaccharide intercellular adhesin, or poly-N-acetylglucosamine (PIA/PNAG), represents an important biofilm mechanism in staphylococci. We previously described a glucose-induced, ica-independent biofilm mechanism in four methicillin-resistant Staphylococcus aureus (MRSA) isolates. Here, biofilm regulation by NaCl and glucose was characterized in 114 MRSA and 98 methicillin-sensitive S. aureus (MSSA) isolates from diagnosed device-related infections. NaCl-induced biofilm development was significantly more prevalent among MSSA than MRSA isolates, and this association was independent of the isolate's genetic background as assessed by spa sequence typing. Among MSSA isolates, PIA/PNAG production correlated with biofilm development in NaCl, whereas in MRSA isolates grown in NaCl or glucose, PIA/PNAG production was not detected even though icaADBC was transcribed and regulated. Glucose-induced biofilm in MRSA was ica independent and apparently mediated by a protein adhesin(s). Experiments performed with strains that were amenable to genetic manipulation revealed that deletion of icaADBC had no effect on biofilm in a further six MRSA isolates but abolished biofilm in four MSSA isolates. Mutation of sarA abolished biofilm in seven MRSA and eight MSSA isolates. In contrast, mutation of agr in 13 MRSA and 8 MSSA isolates substantially increased biofilm (more than twofold) in only 5 of 21 (23%) isolates and had no significant impact on biofilm in the remaining 16 isolates. We conclude that biofilm development in MRSA is ica independent and involves a protein adhesin(s) regulated by SarA and Agr, whereas SarA-regulated PIA/PNAG plays a more important role in MSSA biofilm development.

[Corticosteroid treatment for a first episode of steroid-sensitive nephrotic syndrome (SSNS) in children: guideline from the Italian Society of Nephrology]

BACKGROUND

The current 3rd edition of the Italian Society of Nephrology guidelines has been drawn up to summarize evidence of key intervention issues on the basis of systematic reviews (SR) of randomized trials (RCT) or RCT data only. In the present guideline, evidence of the use of corticosteroid treatment for a first episode of steroid-sensitive nephrotic syndrome (SSNS) in children is presented.

METHODS

SR of RCT and RCT on SSNS therapeutic interventions were identified referring to a Cochrane Library and Renal Health Library search (2005 update). Results. One SR including 15 RCT was available on this topic. Methodological quality of available RCT was suboptimal according to current methodological standards.

RESULTS

In children with a first episode of SSNS, corticosteroids administered for 3 months or more compared with 2 months' administration are associated with a significant reduction in the risk of relapse at 6, 12 and 24 months, and in frequent relapsing rates, even though complications did not seem significantly increased (psychological, ocular, gastrointestinal disorders, hypertension, growth delay, Cushingoid syndrome, infection and osteoporosis) (evidence from SR). 6-month compared to 3-month treatment regimens are associated with a significant reduction in the risk of relapse at 12-24 months (evidence from SR). Increasing steroids cumulative doses are associated with increasing improvements in the risk of relapse (evidence from RCT). The risk of relapse at 12-24 months correlates inversely with duration of treatment (evidence from SR).

CONCLUSION

In SSNS children, current available evidence supports the hypothesis that primary intervention should be a high dose of corticosteroids administered for 3 months or more. Further studies are necessary to test this hypothesis in adult patients.

[Treating lupus nephritis: guideline from the Italian Society of Nephrology]

BACKGROUND

The current 3rd edition of the Italian Society of Nephrology guidelines has been drawn up to summarize evidence of key intervention issues on the basis of systematic reviews (SR) of randomized trials (RCT) or RCT data only. In the present guideline, evidence of lupus nephritis (LN) treatment is presented.

METHODS

SR of RCT and RCT on different therapeutic options for LN were identified referring to a Cochrane Library and Renal Health Library search (2005 update).

RESULTS

One SR of 25 RCT and 6 further RCT were available to address this issue. Methodological quality of available RCT was suboptimal according to current methodological standards. In LN patients, combining cyclophosphamide (CyA) and steroids as induction therapy results in a reduced risk of serum creatinine doubling compared to steroids alone, although there is no evidence of significant survival advantage and risk of ovarian failure was demonstrated (evidence from SR). The association of azathioprine (Aza) and steroids significantly reduces the risk of all-cause mortality compared to steroids alone (evidence from SR). No significant survival advantages from the association of plasma exchange and CyA or Aza are proven (evidence from SR). No significant differences on renal and survival endpoints are demonstrated with different dosing of CyA (evidence from RCT).

CONCLUSION

In LN patients available evidence supports the hypothesis that immunosuppressive agents reduce the risk of all-cause mortality and the risk of progressive renal disease. Further studies are necessary to test new immunosuppressive agents such as mycophenolate mofetil in severe LN patients.

[Therapeutic strategies for membranous nephropathy: guideline from the Italian Society of Nephrology]

BACKGROUND

The current 3rd edition of the Italian Society of Nephrology guidelines has been drawn up to summarize evidence of key intervention issues on the basis of systematic reviews (SR) of randomized trials (RCT) or RCT data only. In the present guideline, evidence of interventions for idiopathic membranous nephropathy (MN) is presented.

METHODS

SR of RCT and RCT on interventions for MN were identified referring to a Cochrane Library and Renal Health Library search (2005 update).

RESULTS

Three SR and 18 RCT were available to address this issue. Methodological quality of available RCT was suboptimal according to current methodological standards. In patients with MN, nephrotic syndrome and normal renal function, methylprednisolone and chlorambucil or cyclophosphamide for 6 months alternately increase the probability of nephritic syndrome remission (evidence from SR) and long-term renal protection (evidence from RCT). Other drugs (ACTH and cyclosporine) are associated with nephrotic syndrome remission, but there is no evidence of significant effects on renal function (evidence from RCT). In patients with impaired renal function, association of corticosteroids and cytotoxic agents is proven to cause a short-term delay of renal damage progression, even though benefits are counterbalanced by complications (evidence from RCT).

CONCLUSION

In patients with MN, nephrotic syndrome and normal renal function, current available evidence supports the hypothesis that primary intervention should be the association of corticosteroids and cytotoxic agents. Secondary therapeutic choices include ACTH and cyclosporine. Further studies are necessary to test new immunosuppressive agents such as mycophenolate mofetil.

[Immunosuppressive and non-immunosuppressive agents for patients with IgA nephropathy: guideline from the Italian Society of Nephrology]

BACKGROUND

The current 3rd edition of the Italian Society of Nephrology guidelines has been drawn up to summarize evidence of key intervention issues on the basis of systematic reviews (SR) of randomized trials (RCT) or RCT data only. In the present guideline, evidence of the use of immunosuppressive and non-immunosuppressive treatments in IgA nephropathy (IgAN) is presented.

METHODS

SR of RCT and RCT on treatment in patients with IgAN were identified referring to a Cochrane Library and Renal Health Library search (2005 update). Quality of SR and RCT was assessed according to current methodological standards.

RESULTS

Two SR of RCT (13 and 3 RCT, respectively), and 18 further RCT were available to address this issue. Methodological quality of available trials was suboptimal. In patients with IgAN and normal or mildly impaired renal function, steroids significantly delay the progression to end stage kidney disease (evidence from SR) and improve proteinuria. Associating steroids and cytotoxic agents (cyclophosphamide followed by oral azathioprine) proves effective in patients with rapidly progressive renal disease (evidence from RCT). Angiotensin converting enzyme inhibitors and angiotensin II receptor blockers significantly improve proteinuria (evidence from RCT), but there are no conclusive data on efficacy on hard patient level endpoints. There are no conclusive data available on the use of a therapy combining these agents.

CONCLUSION

In IgAN patients current evidence supports the hypothesis that immunosuppressive agents delay the progression to end stage renal disease. Further studies are necessary to test this hypothesis in selected patient populations.

Non-essential KDO biosynthesis and new essential cell envelope biogenesis genes in the Escherichia coli yrbG–yhbG locus

In Escherichia coli and most Gram-negative bacteria, KDO (3-deoxy-D-manno-octulosonate), a component of the lipopolysaccharide inner core, is essential for outer membrane biogenesis and cell viability. Two recently identified genes involved in KDO biosynthesis, kdsD and kdsC, belong to the yrbG-yhbG locus where four additional ORFs (yrbG, yrbK, yhbN and yhbG) with unknown function are located. We have constructed six conditional expression mutants in which the arabinose-inducible araBp promoter is respectively located upstream of each gene of the locus. Complementation analysis of these mutants indicates that the locus is organized in at least three operons and that the three distal genes (yrbK, yhbN and yhbG) are essential for E. coli viability. Surprisingly, kdsD and kdsC (encoding a D-arabinose 5-phosphate isomerase and a KDO 8-phosphate phosphatase, respectively) were shown to be non-essential, indicating genetic redundancy for these two functions. A preliminary characterization of the arabinose-dependent mutants under permissive conditions and upon depletion revealed increased sensitivity to hydrophobic toxic chemicals, suggesting that the mutants have a defective outer membrane. These genes may thus be implicated in cell envelope integrity.

A reconsideration of the domestication geography of tetraploid wheats

The domestication of tetraploid wheats started from their wild progenitor Triticum dicoccoides. In this paper, the geographical distribution of this progenitor is revised to include more sampling locations. The paper is based on a collection of wild and domesticated lines (226 accessions in total) analyzed by AFLP at 169 polymorphic loci. The collection includes the 69 wild lines considered by Mori et al. (2003) in their study on chloroplast DNA haplotypes of T. dicoccoides. The goal of the experiment was to reconsider which location thought to have generated the domesticated germplasm has the highest chance of being the actual site from which wild progenitors were sampled during domestication. Phylogenetic analysis of the nuclear AFLP databases indicates that two different genetic taxa of T. dicoccoides exist, the western one, colonizing Israel, Syria, Lebanon and Jordan, and the central-eastern one, which has been frequently sampled in Turkey and rarely in Iran and Iraq. It is the central-eastern race that played the role of the progenitor of the domesticated germplasm. This is supported by the cumulative results of the AFLP data from the collections of Ozkan et al. (2002) and of Mori et al. (2003), which indicate that the Turkish Karacadag population, intermixed with some Iraq-Iran lines, has a tree topology consistent with that of the progenitor of domesticated genotypes. The Turkish Kartal population belongs genetically to the central-eastern T. dicoccoides race but at the nuclear DNA level is less related to the domesticated gene pool. A general agreement between published work on tetraploid wheat domestication emerges from these results. A disagreement is nevertheless evident at the local geographical scale; the chloroplast DNA data indicate the Kartal mountains while AFLP fingerprinting points to the Karacadag Range as the putative site of tetraploid wheat domestication.

[Prevalence of Bartonella henselae in stray and domestic cats in different Italian areas: evaluation of the potential risk of transmission of Bartonella to humans]

Bartonella henselae is the major etiological agent of Cat Scratch Disease in humans. Cats act as the natural reservoir of B. henselae and can transmit the infection to humans by bite or scratch. The diffusion of B. henselae was evaluated by seroprevalence and bacteremic status in different stray cat populations located in nine areas of Northern Italy. A total of 1585 cats were tested by blood culture and 361 (23%) resulted bacteremic; 1416 out off 1585 cats were also tested for Bartonella henselae antibodies and 553 (39%) resulted seropositive. The molecular typing of the isolates showed that 26% of bacteremic cats were infected with B. henselae type I, 52% with B. henselae type II, 16% were co-infected with both and 5% infected with B. Clarridgeiae. Moreover 165 domestic cats were tested by blood culture and serological test (IFA test cut-off: 1:64). 35 cats (21%) resulted bacteremic and 49 (43.5%) were seropositive. The molecular typing of the Bartonella isolates of the domestic cats showed that 45% of bacteremic cats were infected with B. henselae type I, 36.5% with B. henselae type II, 12% were coinfected with both and 6% infected with B. Clarridgeiae. For a completely evaluation of health status of the cat for B. henselae infection, the authors suggest both blood culture and serological tests. Nevertheless a nonbacteremic cat with positive serology result should be reevaluated for possible recurrent bacteremia.

Integration of a barley (Hordeum vulgare) molecular linkage map with the position of genetic loci hosting 29 developmental mutants

The first step in positional gene cloning is the integration into available molecular maps of genetic loci for which mutant alleles exist. We report the placement of 29 barley developmental mutants on a restriction fragment length polymorphism-amplified fragment length polymorphism (RFLP-AFLP) map. The mapping procedure used homozygous mutant F(2) plants in an iterative process: once a mutant linked AFLP was found, primer combinations were successively selected to generate AFLP fragments more tightly linked to the mutant locus. The mutants considered were adp, als, aur-a1, aur-a2, br1, br2, bra-d7, cul3, cul5, cul15, cul16, den6, den8, dub1, hex-v3, hex-v4, int-c5, K, li, lig-a2, lk2, lk5, sld1, sld4, tr, trd, unc, uc2 and uz. The 29 mutant loci were linked to the closest molecular markers by distances ranging from 0 to 23 cM, with an average value of 3.8 cM away. Since the efficiency of the mapping procedure is a function of the density of molecular markers, the RFLP-AFLP map of Castiglioni et al was further integrated with new AFLPs using 87 doubled haploid lines derived from the barley cross Igri x Danilo. A total of 819 mapped AFLP marker loci are now available in the combined map.

Molecular linkage maps of Vitis vinifera L. and Vitis riparia Mchx

Two linkage maps for grape (Vitis spp.) have been developed based on 81 F(1) plants derived from an interspecific cross between the wine cultivar Moscato bianco (Vitis vinifera L.) and a Vitis riparia Mchx. accession, a donor of pathogen resistance traits. The double pseudotest-cross mapping strategy was applied using three types of molecular markers. The efficiency of SSRs to anchor homologous linkage groups from different Vitis maps and the usefulness of AFLPs in saturating molecular linkage maps were evaluated. Moreover, the SSCP technique was developed based on sequence information in public databases concerning genes involved in flavonoid and stilbene biosynthesis. For the maternal genetic map a total of 338 markers were assembled in 20 linkage groups covering 1,639 cM, whereas 429 loci defined the 19 linkage groups of the paternal map which covers 1,518 cM. The identification of 14 linkage groups common to both maps was possible based on 21 SSR and 19 AFLP loci. The position of SSR loci in the maps presented here was consistent with other published mapping experiments in Vitis.

[Immunosuppressive therapy in IgA glomerulonephritis with chronic renal failure: case study presentation and literature review]

Immunosuppressive treatment of IgA Nephropathy (IgAN) with chronic renal failure (CRF) is still a controversial issue, because of scepticism on expected results and possible side effects of therapy. There is a "point of no return" (serum creatinine of 3 mg/dL), after which the deterioration of renal function becomes inevitable. We report the case of a 24-year-old woman, with advanced IgAN (serum creatinine > 3 mg/dL), who experienced remission of proteinuria and long-lasting stabilisation of renal function, after treatment with a 6-month steroid course. Literature information on the therapy for advanced phases of IgAN is inadequate. Our multicenter randomised controlled trial, aimed at evaluating the effects of a 6-month steroid course, included 18 patients with mild CRF at baseline. The ten patients that we treated experienced better renal survival than the eight patients who received no steroids, with an expected renal survival of 29.5 and 6.5 years, respectively. In a prospective study of patients with serum creatinine of 1.6 - 2.9 mg/dl, Ballardie and Roberts compared 19 patients treated with immunosuppressive drugs and 19 control patients: renal survival at 5 years was 72% in treated and 5% in control patients. Goumenos et al. retrospectively evaluated 39 patients treated with steroids and azathioprine and 22 untreated patients: a non-progressive course was observed in 79.5% of treated patients and in 36% of untreated patients. Tsuruya et al. retrospectively examined 26 patients treated with steroids and cyclophosphamide and 19 untreated patients: the expected renal survival was of 5.2 years in treated and 4.8 years in untreated patients, respectively. Prospective controlled trials are essential for evaluating the real effectiveness of immunosuppressive therapy in IgAN patients with impaired renal function. We have recently proposed a study to compare steroids alone and steroids plus azathioprine, because it is mandatory to look for safe and effective therapies that delay as much as possible the start of dialysis, also in patients with already established CRF.

[Rhabdomyolysis as a complication of Parkinson's disease]

BACKGROUND

Rhabdomyolysis is known as one of the possible causes of acute renal failure and can be triggered by different situations. In recent years, Parkinson's disease emerged as a condition that can be complicated by the development of rhabdomyolysis and consequently, in some cases, of acute renal failure. We report two cases of rhabdomyolysis, one of which complicated by an oligo-anuric renal failure, which occurred in patients affected by Parkinson's disease and admitted to our Division.

METHODS AND RESULTS

The first case occurred in a 90-year-old Parkinsonian woman, under treatment with Levodopa-Benserazide and Bornaprine. She developed rhabdomyolysis (CPK 1746 U/L with MB isoenzyme 3.5 ng/ml, LDH 610 U/L, GOT 78 U/L) after she had been found lying on the floor, in a state of mental confusion, after 24 hours in which her relatives had not heard from her. During the first two days of hospitalization, the patient also had a fever (axillary temperature between 37 degrees C and 38 degrees C), accompanied by mild leukocytosis (WBC 13000/mm3) on entrance. The second case occurred in a 78-year-old Parkinsonian woman, under treatment with Levodopa-Carbidopa, Levodopa-Benserazide and Pramipexol. She developed a severe rhabdomyolysis (CPK 34800 U/L with MB isoenzyme 771 ng/ml, LDH 2133 U/L, GOT 785 U/L) complicated by acute renal failure with anuria, after two days characterized by several episodes of vomit and diarrhea. In the following days we learned that in the last 20 days before admission to hospital the patient had increased the dose of her anti-Parkinson therapy and was almost always disturbed by severe choreiform and dystonic movements.

CONCLUSIONS

Regarding the first case, the clinical conditions in which the patient was found, the simultaneous presence of fever and leukocytosis and the absence of any reasonable explanation for a hypothetical fall to the floor induced us to think that this was a case of rhabdomyolysis in the context of an akinetic hyperthermic crisis. This is a syndrome that can develop in Parkinsonian patients after discontinuance or simply reduction of therapy with dopaminergic agents and is characterized also by rhabdomyolysis. The fact that the patient was living alone would confirm this hypothesis. On the other hand, the second case of rhabdomyolysis must probably be related to the severe choreiform and dystonic movements that the patient developed in the days just prior to admission. These movements were surely caused by the increase of the substitutive therapy with Levodopa by the patient herself. In conclusion, these two clinical cases, together with others previously reported by other Authors, show how the circumstances leading to the development of acute episodes of rhabdomyolysis in Parkinson's disease can be different and, at the same time, how these circumstances are always somehow related to the treatment of the basic disease with dopaminergic drugs.

Patterns and symmetries in leaf development

The leaf is a coordinated mosaic of developmental domains, which are evident from leaf inception on the flanks of the apical meristem. The subdivision of the meristem into molecularly defined domains is regulated by the interactions of a number of gene products and by receptor kinase-mediated signals. The acquisition of symmetry axes in the emerging leaf is a process coordinated by hormones (such as auxin and cytokinins) and the expression of classes of genes (such as the knox and the ARP, as1/rs2/phan, genes). As with simple leaves, the architecture of compound leaves is defined by spatial/temporal gradients of regulatory gene functions: complexity results from the interplay between leaf differentiation processes and genes maintaining a partial level of indeterminacy in the developing primordium. Boundaries between regions with different molecular 'addresses' are considered, in plants as in Drosophila, as organizing centres for lateral organ development.