Can we personalize treatment for kidney diseases?

Influence of uridine diphosphate-glucuronosyltransferases (1A9) polymorphisms on mycophenolic acid pharmacokinetics in patients with renal transplant

Background: There are differences in pharmacokinetic of mycophenolic acid among individuals. The UGT1A9 enzyme is of special interest since it is the main enzyme involved in the glucuronidation of MPA. Single nucleotide polymorphisms in the UGT1A9 gene may be responsible for individual differences in the pharmacokinetics of MPA. The aim of this study was to explain MPA pharmacokinetics in UGT1A9 1399 C > T polymorphisms in Turkish renal transplant patients.

Patients and methods: One hundred and twenty-five living-donor transplant recipients and 100 healthy control subjects underwent UGT1A9 1399 C > T genotyping using polymerase chain reaction–restriction fragment length polymorphism. Concentrations of MPA were determined with Cloned Enzyme Donor Immunoassay (CEDIA). Besides that, all the patients were monitored for acute rejection and graft function during the study period.

Results: The UGT1A9 1399 C > T CC, CT, and TT genotype frequencies among patients were, respectively, 68.0%, 23.2%, and 8.8%. The CC, CT, and TT genotype frequencies among controls were, respectively, 63.0%, 23.0%, and 14.0%. There was no significant difference between patients and controls (p = .480, p = .999, p = .286, respectively). At first month, respectively, through blood concentrations of MPA were significantly higher in UGT1A9 1399 C > T TT carriers than in CT and CC carriers (p = .046). The doses for these patients were lower at first month (p = .021). Acute rejection episodes were not associated with the CC vs CT or TT genotypes (p = .064).

Conclusions: Our results demonstrated a correlation between the UGT1A9 1399 C > T polymorphism and MPA pharmacokinetics among renal transplant patients. Determination of UGT1A9 polymorphism may help to achieve target of MPA blood concentrations.

Preventing the development of SLE: identifying risk factors and proposing pathways for clinical care

Although challenging, developing evidence-based approaches to an early and accurate diagnosis of systemic lupus erythematosus is a key approach to preventing disease and lupus-associated morbidity and mortality. Advances in our understanding of preclinical and incomplete lupus erythematosus have enabled the identification of risk factors that may predict disease and the development of potential strategies aimed at primary prevention. Emerging data support the notion that there is a temporal disease progression from initial asymptomatic autoimmunity (preclinical lupus) through early clinical features of the disease (incomplete lupus erythematosus) to finally becoming fully classifiable systemic lupus erythematosus (complete lupus erythematosus). Here, we review the demographic, clinical, biomarker as well as genetic and environmental features that are reported to increase the risk of disease progression. Based on these risk factors, we propose a clinical care pathway for patients with early disease. We envisage that such a pathway, through early identification of disease, may improve patient outcomes, while reducing health care costs.

Genetics of Lupus Nephritis: Clinical Implications

Systemic lupus erythematosus is a heterogeneous autoimmune disease marked by the presence of pathogenic autoantibodies, immune dysregulation, and chronic inflammation that may lead to increased morbidity and early mortality from end-organ damage. More than half of all systemic lupus erythematosus patients will develop lupus nephritis. Genetic-association studies have identified more than 50 polymorphisms that contribute to lupus nephritis pathogenesis, including genetic variants associated with altered programmed cell death and defective immune clearance of programmed cell death debris. These variants may support the generation of autoantibody-containing immune complexes that contribute to lupus nephritis. Genetic variants associated with lupus nephritis also affect the initial phase of innate immunity and the amplifying, adaptive phase of the immune response. Finally, genetic variants associated with the kidney-specific effector response may influence end-organ damage and the progression to end-stage renal disease and death. This review discusses genetic insights of key pathogenic processes and pathways that may lead to lupus nephritis, as well as the clinical implications of these findings as they apply to recent advances in biologic therapies.

Therapeutic variability in adult minimal change disease and focal segmental glomerulosclerosis

Background

Variability in the management of glomerulonephritis may negatively impact efficacy and safety. However, there are little/no data on actual variability in the treatment of minimal change disease (MCD)/focal segmental glomerulosclerosis (FSGS) in adults. We assessed Spanish practice patterns for the management of adult nephrotic syndrome due to MCD or FSGS. The absence of reasonably good evidence on treatment for a disease often increases the variability substantially. Identification of evidence–practice gaps is the first necessary step in the knowledge-to-action cyclical process. We aim to analyse the real clinical practice in adults in hospitals in Spain and compare this with the recently released Kidney Disease: Improving Global Outcomes clinical practice guideline for glomerulonephritis.

Methods

Participating centres were required to include all adult patients (age >18 years) with a biopsy-proven diagnosis of MCD or FSGS from 2007 to 2011. Exclusion criteria included the diagnosis of secondary nephropathy.

Results

We studied 119 Caucasian patients with biopsy-proven MCD (n = 71) or FSGS (n = 48) from 13 Spanish hospitals. Of these patients, 102 received immunosuppressive treatment and 17 conservative treatment. The initial treatment was steroids, except in one patient in which mycophenolate mofetil was used. In all patients, the steroids were given as a single daily dose. The mean duration of steroid treatment at initial high doses was 8.7 ± 13.2 weeks and the mean global duration was 38 ± 32 weeks. The duration of initial high-dose steroids was <4 weeks in 41% of patients and >16 weeks in 10.5% of patients. We did find a weak and negative correlation between the duration of whole steroid treatment in the first episode and the number of the later relapses (r = −0.24, P = 0.023). There were 98 relapses and they were more frequent in MCD than in FSGs patients (2.10 ± 1.6 versus 1.56 ± 1.2; P = 0.09). The chosen treatment was mainly steroids (95%). Only seven relapses were treated with another drug as a first-line treatment: two relapses were treated with mycophenolate and five relapses were treated with anticalcineurinics. A second-line treatment was needed in 29 patients (24.4%), and the most frequent drugs were the calcineurin inhibitors (55%), followed by mycophenolate mofetil (31%). Although cyclophosphamide is the recommended treatment, it was used in only 14% of the patients.

Conclusions

We found variation from the guidelines in the duration of initial and tapered steroid therapy, in the medical criteria for classifying a steroid-resistant condition and in the chosen treatment for the second-line treatment. All nephrologists started with a daily dose of steroids as the first-line treatment. The most frequently used steroid-sparing drug was calcineurin inhibitors. Cyclophosphamide use was much lower than expected.

Moderator's view: Cyclophosphamide in lupus nephritis

Mycophenolate mofetil was recently accepted as the effective induction treatment of lupus nephritis, with the potential to replace cyclophosphamide or at least expand our therapeutic armamentarium in patients with this lifelong disease often requiring repeated induction treatment of its relapses. Compared with cyclophosphamide, mycophenolate may be more effective in black patients, and the risk of gonadotoxicity may be significantly lower in mycophenolate-treated subjects. However, experience with mycophenolate in severe lupus nephritis is still limited and we also have insufficient data on the long-term outcome of mycophenolate-treated patients. Treatment with mycophenolate is more expensive than with cyclophosphamide, which may limit its use, especially in low- and middle-income countries. The efficacy of mycophenolate mofetil may be more dependent on the patient's compliance compared with intravenous cyclophosphamide pulses. Low-dose cyclophosphamide remains an effective and relatively safe induction treatment of active lupus nephritis, but to decrease its cumulative toxicity, repeated exposure to cyclophosphamide in relapsing patients should be (if possible) avoided.

Unmet medical needs in lupus nephritis: solutions through evidence-based, personalized medicine

Lupus nephritis (LN) remains a kidney disease with significant unmet medical needs despite extensive clinical and translational research over the past decade. These include the need to (i) predict the individual risk for LN in a patient with systemic lupus erythematosus, (ii) identify the best therapeutic option for an individual patient, (iii) distinguish chronic kidney damage from active immunologic kidney injury, (iv) develop efficient treatments with acceptable or no side effects and improve the design of randomized clinical trials so that effective drugs demonstrate efficacy. This review discusses the underlying reasons for these unmet medical needs and options of how to overcome them in the future.

Training the next generation's nephrology workforce

The subspecialty of nephrology faces several critical challenges, including declining interest among medical students and internal medicine residents and worrisome declines in the number of applicants for nephrology fellowships. There is an urgent need to more clearly define the subspecialty and its scope of practice, reinvigorate meaningful research training and activities among trainees, and ensure that fellows who complete training and enter the practice of nephrology are experts in the broad scope of nephrology. This need requires a critical look at fellowship training programs and training requirements. A new workforce analysis is also needed that is not focused on primarily meeting estimated future clinical needs but rather, ensuring that there is alignment of supply and demand for nephrology trainees, which will ensure that those entering nephrology fellowships are highly qualified and capable of becoming outstanding nephrologists and that there are desirable employment opportunities for them when they complete their training.

Genetic testing in renal disease

A revolution is happening in genetics! The decoding of the first genome in 2003 was a large international collaborative effort that took about 13 years at a cost of around $2.7 billion. Now, only a few years later, new technology allows the sequencing of an entire genome within a few weeks--and at a cost of less than $10,000. The vaunted $1000 genome is within reach. These extraordinary advances will undoubtedly transform the way we practice medicine. But, like any new technology, it carries risks, as well as benefits. As physicians, we need to understand the implications in order to best utilise these advances for our patients and to provide informed advice. In this review, our aim is to explain these new technologies, to separate the hype from the reality and to address some of the resulting questions and implications. The practical objective is to provide a simple overview of the available technologies and of purpose to which they are best suited.

Characterization of glomerular diseases using proteomic analysis of laser capture microdissected glomeruli

The application of molecular techniques to characterize clinical kidney biopsies has the potential to provide insights into glomerular diseases that cannot be revealed by traditional renal pathology. The present work is a proof-of-concept approach to test whether proteomic analysis of glomeruli isolated from clinical biopsies by laser capture microdissection can provide unique information regarding differentially expressed proteins relevant to disease pathogenesis. The proteomes of glomeruli isolated by laser capture microdissection from biopsies of normal kidneys (living-related donor kidneys) were compared with those from patients with diabetic nephropathy, lupus nephritis, and fibronectin glomerulopathy. Glomerular proteins were extracted, trypsin digested, and subjected to liquid chromatography-tandem mass spectrometry for identification and quantitation. Relative to normal glomeruli, all disease-associated glomeruli showed an increased presence of complement components, a marked decline in podocyte-associated proteins, and a decrease in proteins associated with cellular metabolism. Additionally, fibronectin glomerulopathy glomeruli differed from all the other glomeruli because of a significant accumulation of fibronectin and fibulin. This study demonstrates that our method acquires reproducible and quantitative proteomic information from laser capture microdissection isolates that can be used to characterize the molecular features of glomerular diseases.

Treatment of proliferative lupus nephritis: a slowly changing landscape

Proliferative lupus nephritis is the most severe form of lupus nephritis. Outcomes of this disease are affected by ethnicity, clinical characteristics, irreversible damage on renal biopsy, initial response to treatment and future disease course (for example, the occurrence of renal flares). Initial intensive (induction) treatment of proliferative lupus nephritis is aimed at achieving remission, but optimal duration and intensity are not well defined. A combination of intravenous cyclophosphamide and corticosteroids have been shown to decrease the risk of end-stage renal disease, but are associated with substantial acute toxic effects (such as infections) and chronic toxic effects (such as ovarian failure). In white populations, low-dose cyclophosphamide is a reasonable alternative to high-dose cyclophosphamide as it is similarly effective and associated with less toxicity. Mycophenolate mofetil is as effective as high-dose intravenous cyclophosphamide in terms of inducing remission and similar in terms of safety. Although most patients respond to induction treatment, remission is often only achieved after patients are switched to maintenance treatment. As maintenance treatment, mycophenolate mofetil is superior to azathioprine and azathioprine is similarly effective to ciclosporin in terms of prevention or reducing the risk of relapse. Rituximab should be reserved for patients with refractory disease. Treatment of lupus nephritis should be individually tailored to patients, with more aggressive therapy reserved for patients at high risk of renal dysfunction and progression of renal disease.