Statins stabilize the renal function of IgA nephropathy

Targeting the Liver with Nucleic Acid Therapeutics for the Treatment of Systemic Diseases of Liver Origin

Systemic diseases of liver origin (SDLO) are complex diseases in multiple organ systems, such as cardiovascular, musculoskeletal, endocrine, renal, respiratory, and sensory organ systems, caused by irregular liver metabolism and production of functional factors. Examples of such diseases discussed in this article include primary hyperoxaluria, familial hypercholesterolemia, acute hepatic porphyria, hereditary transthyretin amyloidosis, hemophilia, atherosclerotic cardiovascular diseases, α-1 antitrypsin deficiency-associated liver disease, and complement-mediated diseases. Nucleic acid therapeutics use nucleic acids and related compounds as therapeutic agents to alter gene expression for therapeutic purposes. The two most promising, fastest-growing classes of nucleic acid therapeutics are antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs). For each listed SDLO disease, this article discusses epidemiology, symptoms, genetic causes, current treatment options, and advantages and disadvantages of nucleic acid therapeutics by either ASO or siRNA drugs approved or under development. Furthermore, challenges and future perspectives on adverse drug reactions and toxicity of ASO and siRNA drugs for the treatment of SDLO diseases are also discussed. In summary, this review article will highlight the clinical advantages of nucleic acid therapeutics in targeting the liver for the treatment of SDLO diseases. SIGNIFICANCE STATEMENT: Systemic diseases of liver origin (SDLO) contain rare and common complex diseases caused by irregular functions of the liver. Nucleic acid therapeutics have shown promising clinical advantages to treat SDLO. This article aims to provide the most updated information on targeting the liver with antisense oligonucleotides and small interfering RNA drugs. The generated knowledge may stimulate further investigations in this growing field of new therapeutic entities for the treatment of SDLO, which currently have no or limited options for treatment.

Enumerating the role of properdin in the pathogenesis of IgA nephropathy and its possible therapies

BACKGROUND

IgA nephropathy (IgAN) has become the most prevalent form of glomerulonephritis affecting almost 1.3% of the total population worldwide. It is an autoimmune disorder where the host autoantibody forms an immune complex with the defective galactose-deficient IgA1 and gets deposited at the mesangium and endocapillary region of glomeruli. IgA has the capability to activate alternative and lectin complement cascades which even aggravates the condition. Properdin is directly associated with IgAN by activating and stabilising the alternative complement pathway at the mesangium, thereby causing progressive renal damage.

OBJECTIVE

The present review mainly focuses on correlating the influence of properdin in activating the complement cascade at glomeruli which is the major cause of disease exacerbation. Secondly, we have described the probable therapies and new targets that are under trials to check their efficacy in IgAN.

METHODS

An in-depth research was carried out from different peer-reviewed articles till December 2020 from several renowned databases like PubMed, Frontier, and MEDLINE, and the information was analysed and written in a simplified manner.

RESULTS

Co-deposition of properdin is observed along with IgA and C3 in 75%-100% of the patients. It is not yet fully understood whether properdin inhibition can attenuate IgAN, as many conflicting reports have revealed worsening of IgAN after impeding properdin.

CONCLUSION

With no specific cure still available, the treatment strategies are of great concern to find a better target to restrict the disease progression. More research and clinical trials are required to find out a prominent target to combat IgAN.

Progress of research on dyslipidemia accompanied by nephrotic syndrome

Nephrotic syndrome is a relatively common clinical disease. Associated dyslipidemia is a risk factor for the occurrence and development of cardiovascular and renal diseases that might gradually develop into atherosclerosis, glomerulosclerosis or tubulointerstitial injury. It also confers an elevated risk of complications such as thromboembolism. If not properly controlled over the long term, dyslipidemia will become a key factor in a poor prognosis. Furthermore, dyslipidemia correlates with an increase in hepatic compensatory synthetic lipoprotein levels and a decrease in lipoprotein clearance, which can be sourced to the downregulation of hepatic and lipoprotein lipase activities in endothelial cells, muscle, and adipose tissue, and clinically characterized as hypertriglyceridemia or hypercholesterolemia. However, further investigations into the mechanism(s) of dyslipidemia are needed, with the resultant detailed perspectives and analyses substantially aiding the further development of treatment guidelines. Currently, statins represent the most popular type of pharmaceutical intervention because they lower hepatic cholesterol production and promote the absorption of low-density lipoprotein-cholesterol from the bloodstream, followed by second-line and other potential therapies to regulate the expression of specific receptors.

Mortality in IgA Nephropathy: A Nationwide Population-Based Cohort Study

BACKGROUND

The clinical course of IgA nephropathy (IgAN) varies from asymptomatic nonprogressive to aggressive disease, with up to one in four patients manifesting ESRD within 20 years of diagnosis. Although some studies have suggested that mortality appears to be increased in IgAN, such studies lacked matched controls and did not report absolute risk.

METHODS

We conducted a population-based cohort study in Sweden, involving patients with biopsy-verified IgAN diagnosed in 1974-2011; main outcome measures were death and ESRD. Using data from three national registers, we linked 3622 patients with IgAN with 18,041 matched controls; we also conducted a sibling analysis using 2773 patients with IgAN with 6210 siblings and a spousal analysis that included 2234 pairs.

RESULTS

During a median follow-up of 13.6 years, 577 (1.1%) patients with IgAN died (10.67 per 1000 person-years) compared with 2066 deaths (0.7%) in the reference population during a median follow-up of 14.1 years (7.45 per 1000 person-years). This corresponded to a 1.53-fold increased risk and an absolute excess mortality of 3.23 per 1000 person-years (equaling one extra death per 310 person-years) and a 6-year reduction in median life expectancy. Similar increases in risk were seen in comparisons with siblings and spouses. IgAN was associated with one extra case of ESRD per 54 person-years. Mortality preceding ESRD was not significantly increased compared with controls, spouses, or siblings. Overall mortality did not differ significantly between patients with IgAN-associated ESRD and patients with ESRD from other causes.

CONCLUSIONS

Patients with IgAN have an increased mortality compared with matched controls, with one extra death per 310 person-years and a 6-year reduction in life expectancy.

Clinical and histological features and therapeutic strategies for IgA nephropathy

Chronic glomerulonephritis is the second most common reason, after diabetic nephropathy, for initiation of dialysis in Japan and IgA nephropathy (IgAN) is the most prevalent form of chronic glomerulonephritis. In the half century since IgAN was initially reported, our understanding of the long-term prognosis, clinical and histological features, pathogenesis of onset and progression, risk factors for progression, and appropriate treatment under different clinical and histological conditions, has steadily increased. Strong experimental and clinical evidence, the Clinical Practice Guidelines for IgA Nephropathy in Japan, the Oxford Classification, and the Kidney Disease Improving Global Outcomes guidelines have all contributed to the appropriate treatment of IgAN. Several intensive therapies, such as tonsillectomy, steroid therapy, and their combinations, can result in clinical remission, and prevent the progression to end stage renal disease (ESRD). However, some IgAN patients still progress to ESRD even when treated with intensive therapies. In this review, we discuss the clinical and histological features of IgAN, focusing primarily on our previous reports, and our opinions on therapeutic strategies for IgAN.

Analysis of the differential urinary protein profile in IgA nephropathy patients of Uygur ethnicity

Background

IgA nephropathy (IgAN) is one of the most common forms of idiopathic glomerular diseases and might lead to end-stage kidney disease. Accurate and non-invasive biomarkers for early diagnosis are required for early intervention and consequent therapy for IgAN patients. Because variance in the disease incidence and predisposing genes of IgAN has been detected among different ethnicities, the ethnicity factor should be considered in IgAN biomarker discovery. The differences in the protein profiles and pathological mechanisms of IgAN in patients of Uygur ethnicity need to be clearly illustrated.

Methods

In this study, we used urinary proteomics to discover candidate biomarkers of IgAN in patients of Uygur ethnicity. The urinary proteins from Uygur normal control and Uygur IgAN patients were extracted and analyzed using 2D-LC-MS/MS and isobaric tags for relative and absolute quantitation (iTRAQ) analysis.

Results

A total of 277 proteins were found to be differentially represented in Uygur IgAN compared with the respective normal controls. The bioinformatics analysis revealed that the immune response, cell survival, and complement system were activated in Uygur IgAN. Many differentially expressed proteins were found to be related to nephropathy and kidney injuries. Four candidate biomarkers were validated by Western blot, and these results were consistent with the iTRAQ results. ICAM1, TIMP1, SERPINC1 and ADIPOQ were upregulated in Uygur IgAN. Bioinformatic analysis revealed that the increase of ICAM1 and TIMP1 might be caused by IgAN, but the increase of SERPINC1 and ADIPOQ might be caused by proteinuria. SERPINC1 and ICAM1 were identified as the candidate biomarkers with excellent area-under-the-curve (AUC) values (0.84) for distinguishing Uygur IgAN from normal controls.

Conclusions

Using urinary proteomic analysis, we identified several candidate biomarkers for IgAN in patients of Uygur ethnicity. These results will prove helpful for exploring the pathological mechanism of IgAN in patients of Uygur ethnicity and for developing better treatments for these patients.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1139-3) contains supplementary material, which is available to authorized users.

Primary IgA nephropathy: current challenges and future prospects

IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide, exhibiting a variable clinical and pathological course and significantly contributing to the global burden of chronic kidney disease and end-stage renal disease. Current standards of care focus on optimization of antihypertensive and antiproteinuric therapies (typically renin- angiotensin system blockade) to reduce disease progression. Much recent attention has focused on whether additional immunosuppression confers better outcomes than supportive management alone, and indeed, several trials have demonstrated renoprotective effects following the use of oral corticosteroids. However, results have been inconsistent, and perceived benefits must be balanced against risks and adverse effects associated with generalized immunosuppression, as highlighted by the high-profile STOP-IgAN and TESTING clinical trials. Recent translational research in vitro and animal models of IgAN have generated greater insight into potential therapeutic targets for this complex autoimmune disease. Deeper understanding of the roles of the mucosal immune barrier, complement activation and deposition, T-cell dependent and independent mechanisms of B cell activation, and of the deposition and downstream inflammatory signaling pathways of nephritogenic polymeric IgA1 complexes (e.g., signaling of immune receptors via spleen tyrosine kinase) has formed the rationale for the development of novel agents and clinical trials of more targeted therapies. However, translating findings into clinical practice is challenging, with many immunopathological features of IgAN specific to humans. Recent comprehensive reviews outline current understanding of mechanisms of IgAN as well as ongoing and future clinical trials; it is not our aim to replicate this here. Instead, we take a mechanistic approach to current treatment strategies, outlining advantages and limitations of each before exploring ongoing research with potential translation into future targeted therapies for this complex disease.

Update on immunoglobulin a nephropathy. Part II: Clinical, diagnostic and therapeutical aspects

Immunoglobulin A nephropathy (IgAN) is characterized by different clinical manifestations and by long-term different outcomes. Major problem for the physicians is to understanding which patients are at risk of a disease evolution and to prescribe the right therapy to the right patients. Indeed, in addition to patients with a stable disease with no trend to evolution or even with a spontaneous recovery, patients with an active disease and patients with a rapidly evolving glomerulonephritis are described. Several histopathological, biological and clinical markers have been described and are currently used to a better understanding of patients at risk, to suggest the right therapy and to monitor the therapy effect and the IgAN evolution over time. The clinical markers are the most reliable and allow to divide the IgAN patients into three categories: The low risk patients, the intermediate risk patients and the high risk patients. Accordingly, the therapeutic measures range from no therapy with the only need of repeated controls, to supportive therapy eventually associated with low dose immunosuppression, to immunosuppressive treatment in the attempt to avoid the evolution to end stage renal disease. However the current evidence about the different therapies is still matter of discussion. New drugs are in the pipeline and are described. They are object of randomized controlled trials, but studies with a number of patients adequately powered and with a long follow up are needed to evaluate efficacy and safety of these new drugs.

The Treatment of IgA Nephropathy

BACKGROUND

IgA nephropathy (IgAN) is a very common glomerulonephritis worldwide. Nevertheless, treatment options for primary IgAN are still largely based on opinion or weak evidence. There is a lack of large randomized controlled trials (RCT) that provide a definitive immunosuppressive protocol for IgAN. The recent KDIGO Clinical Practice Guidelines for Glomerulonephritis have assigned low levels of evidence for almost all recommendations and suggestions related to this nephropathy.

SUMMARY

In this article, we review different treatment options and emphasize that the key to therapeutic decision-making is the assessment of an individual's prognosis. The risk of disease progression is closely related to clinical parameters such as proteinuria, hypertension, and impaired glomerular filtration rate. For patients with minor urinary abnormalities, the mainstay of treatment is long-term regular follow-up to detect renal progression and hypertension. Optimized supportive care aiming to maintain proteinuria <1 g/day is preferred in the typical patient presenting with microhematuria, significant but nonnephrotic proteinuria, hypertension, and variable degrees of renal failure. The atypical patient with overt nephritic syndrome or rapidly progressive kidney injury that represents a vasculitic form of IgAN should be treated with immunosuppression. Finally, the variant of overlapping syndrome of IgAN and lipoid nephrosis that runs a good prognosis should be treated as lipoid nephrosis.

KEY MESSAGE

The treatment of IgAN should be structured according to the clinical scenario.

Prognosis in IgA nephropathy: 30-year analysis of 1,012 patients at a single center in Japan

Background

Little is known about the long-term prognosis of patients with IgA nephropathy (IgAN).

Methods

This retrospective cohort analysis evaluated clinical and histological findings at the time of renal biopsy, initial treatment, patient outcomes over 30 years, and risk factors associated with progression in 1,012 patients diagnosed with IgAN at our center since 1974.

Results

Of the 1,012 patients, 40.5% were male. Mean patient age was 33±12 years and mean blood pressure was 122±17/75±13 mmHg. Mean serum creatinine concentration was 0.89±0.42 mg/dL, and mean estimated glomerular filtration rate (eGFR) was 78.5±26.2 ml/min/1.73 m². Mean proteinuria was 1.19±1.61 g/day, and mean urinary red blood cells were 36.6±35.3/high-powered field. Histologically, mesangial hypercellularity was present in 47.6% of patients, endothelial hypercellularity in 44.3%, segmental sclerosis in 74.6%, and tubular atrophy/interstitial fibrosis in 28.8% by Oxford classification. Initial treatment consisted of corticosteroids in 26.9% of patients, renin-angiotensin-aldosterone system inhibitor in 28.9%, and tonsillectomy plus steroids in 11.7%. The 10-, 20-, and 30-year renal survival rates were 84.3, 66.6, and 50.3%, respectively. Tonsillectomy plus steroids dramatically improved renal outcome. Cox multivariate regression analysis showed that higher proteinuria, lower eGFR, and higher uric acid at the time of renal biopsy were independent risk factors for the development of end stage renal disease (ESRD).

Conclusions

IgAN is not a benign disease, with about 50% of patients progressing to ESRD within 30 years despite treatment.