Long-term effects of losartan on proteinuria and renal function in patients with renal amyloidosis

French practical guidelines for the diagnosis and management of AA amyloidosis

AA amyloidosis is secondary to the deposit of excess insoluble Serum Amyloid A (SAA) protein fibrils. AA amyloidosis complicates chronic inflammatory diseases, especially chronic inflammatory rheumatisms such as rheumatoid arthritis and spondyloarthritis; chronic infections such as tuberculosis, bronchectasia, chronic inflammatory bowel diseases such as Crohn's disease; and auto-inflammatory diseases including familial Mediterranean fever. This work consists of the French guidelines for the diagnosis workup and treatment of AA amyloidosis. We estimate in France between 500 and 700 cases in the whole French population, affecting both men and women. The most frequent organ impaired is kidney which usually manifests by oedemas of the lower extremities, proteinuria, and/or renal failure. Patients are usually tired and can display digestive features anf thyroid goiter. The diagnosis of AA amyloidosis is based on detection of amyloid deposits on a biopsy using Congo Red staining with a characteristic green birefringence in polarized light. Immunohistochemical analysis with an antibody directed against Serum Amyloid A protein is essential to confirm the diagnosis of AA amyloidosis. Peripheral inflammatory biomarkers can be measured such as C Reactive protein and SAA. We propose an algorithm to guide the etiological diagnosis of AA amyloidosis. The treatement relies on the etiologic treatment of the undelying chronic inflammatory disease to decrease and/or normalize Serum Amyloid A protein concentration in order to stabilize amyloidosis. In case of renal failure, dialysis or even a kidney transplant can be porposed. Nowadays, there is currently no specific treatment for AA amyloidosis deposits which constitutes a therapeutic challenge for the future.

Secondary, AA, Amyloidosis

Secondary, AA, amyloidosis is a rare systemic complication that can develop in any long-term inflammatory disorder, and is characterized by the extracellular deposition of fibrils derived from serum amyloid A (SAA) protein. SAA is an acute-phase reactant synthetized largely by hepatocytes under the transcriptional regulation of proinflammatory cytokines. The kidney is the major involved organ with proteinuria as first clinical manifestation; renal biopsy is the commonest diagnostic investigation. Targeted anti-inflammatory treatment promotes normalization of circulating SAA levels preventing amyloid deposition and renal damage. Novel therapies aimed at promoting clearance of existing amyloid deposits soon may be an effective treatment approach.

Clinical outcomes and survival in AA amyloidosis patients

AIM

Amyloid A amyloidosis is a rare complication of chronic inflammatory conditions. Most patients with amyloid A amyloidosis present with nephropathy and it leads to renal failure and death. We studied clinical characteristics and survival in patients with amyloid A amyloidosis.

METHODS

A total of 81 patients (51 males, 30 females) with renal biopsy proven amyloid A amyloidosis were analyzed retrospectively. The patients were divided into good and poor outcomes groups according to survival results.

RESULTS

Most of the patients (55.6%) had nephrotic range proteinuria at diagnosis. Most frequent underlying disorders were familial Mediterranean fever (21.2%) and rheumatoid arthritis (10.6%) in the good outcome group and malignancy (20%) in the poor outcome group. Only diastolic blood pressure in the good outcome group and phosphorus level in the poor outcome group was higher. Serum creatinine levels increased after treatment in both groups, while proteinuria in the good outcome group decreased. Increase in serum creatinine and decrease in estimated glomerular filtration rate of the poor outcome group were more significant in the good outcome group. At the time of diagnosis 18.5% and 27.2% of all patients had advanced chronic kidney disease (stage 4 and 5, respectively). Median duration of renal survival was 65±3.54 months. Among all patients, 27.1% were started dialysis treatment during the follow-up period and 7.4% of all patients underwent kidney transplantation. Higher levels of systolic blood pressure [hazard ratios 1.03, 95% confidence interval: 1-1.06, p=0.036], serum creatinine (hazard ratios 1.25, 95% confidence interval: 1.07-1.46, p=0.006) and urinary protein excretion (hazard ratios 1.08, 95% confidence interval: 1.01-1.16, p=0.027) were predictors of end-stage renal disease. Median survival of patients with organ involvement was 50.3±16 months.

CONCLUSION

Our study indicated that familial Mediterranean fever constituted a large proportion of cases and increased number of patients with idiopathic amyloid A amyloidosis. Additionally, it was observed that patient survival was not affected by different etiological causes in amyloid A amyloidosis.

Hereditary amyloidosis caused by R554L fibrinogen Aα-chain mutation in a Spanish family and review of the literature

BACKGROUND

Hereditary amyloidosis with predominant renal disease can be caused by mutations in the gene encoding the fibrinogen Aα-chain (AFib). Here, we describe the clinical course of AFib amyloidosis associated with the rare R554L mutation, and the significance of extrarenal amyloid deposits and their possible influence on cardiovascular morbidity.

METHODS

We report on 101 members of a family after having conducted patient interviews, chart review, genetic testing, renal biopsies and assessment for extrarenal amyloid deposition.

RESULTS

Ten family members had chronic kidney disease with late-onset gross proteinuria and a variable course of declining renal function, starting in the fourth decade of life. In two affected living members, we identified the AFib R554L mutation. Renal biopsies from two affected members revealed almost complete obliteration of the mesangial glomerular architecture, although kidney function was only moderately impaired. There was neither evidence of extrarenal amyloidosis nor accelerated atherosclerosis.

CONCLUSIONS

Renal amyloidosis associated with the R554L AFib variant dominated the clinical picture in this family, which was similar to that associated with the much more prevalent E526V mutation. Although it has been hypothesized that vascular deposits of fibrinogen amyloid may be associated with accelerated atherosclerosis, there was no suggestion of this in this particular kindred.

The relation between urinary angiotensinogen and proteinuria in renal AA amyloidosis patients

OBJECTIVE

The aim of this study was to evaluate the relationship of local intrarenal renin angiotensin system (RAS) with proteinuria in patients with renal AA amyloidosis.

METHODS

Thirty-two patients with renal AA amyloidosis (19 male, mean age: 45 ± 13 years) and sixteen healthy controls (5 male, mean age: 32 ± 5 years) were included in this study. Spot urine samples were obtained to measure urinary angiotensinogen (AGT) using human AGT-ELISA, urinary creatinine and protein levels. Logarithmic transformations of urinary AGT-creatinine ratio log(UAGT/Ucre) and urinary protein-to-creatinine ratio (UPCR) were done to obtain the normal distributions of these parameters.

RESULTS

Log(UAGT/UCre) was significantly higher in patients compared with the controls (1.88 ± 0.92 µg/g vs. 1.25 ± 0.70 µg/g; p = 0.023). Importantly a significantly positive correlation was found between log(UAGT/Ucre) and logUPCR in patients (r = 0.595, p = 0.006).

CONCLUSIONS

Urinary AGT levels are higher in renal AA amyloidosis patients than in controls. Also, there is a significant positive correlation between urinary AGT and proteinuria in renal AA amyloidosis.

Fifteen years of losartan: what have we learned about losartan that can benefit chronic kidney disease patients?

Losartan, the first AT1 receptor blocker (ARB), was FDA approved 15 years ago. During those years, researchers and clinicians have developed a growing base of knowledge on the benefits of losartan, particularly for hypertension and renal disease. These benefits include decreasing proteinuria, slowing the progression of diabetic nephropathy, controlling hypertension, and decreasing stroke risk in patients with left ventricular hypertrophy. Although many of the benefits of losartan represent a class effect for ARBs, losartan has pharmacokinetic and pharmacodynamic characteristics and effects that are unique and are not a class effect. For example, a shorter duration of action is seen with this first ARB compared with other more recently approved ARBs. Losartan also has a uricosuric effect not seen in other ARBs and attenuates platelet aggregation, which is not seen or is seen to a lesser extent with the other ARBs. This review presents the physiological effects of losartan on the kidney and discusses relevant clinical outcomes.

Comparison of higher dose of losartan treatment with losartan plus carvedilol and losartan plus ramipril in patients with glomerulonephritis and proteinuria

BACKGROUND

Proteinuria may cause a worsening of accompanying renal disease or even lead to glomerulosclerosis. There is no data about the effect of carvedilol on patients with proteinuric (>0.5 g/day) glomerulonephritis. This study aimed to compare the effects of carvedilol with ramipril and losartan in patients with proteinuric glomerulonephritis.

METHODS

Twenty-one glomerulonephritis patients were followed for 12 months. Patients were divided into three groups. All patients were treated with losartan 50 mg once daily for two weeks. After two weeks (baseline), patients were given additional medications: 50 mg losartan, 5 mg ramipril, and 25 mg carvedilol were given additionally to the patients in groups 1, 2, and 3 respectively.

RESULTS

Baseline mean proteinuria values of patients in groups 1, 2 and 3 were 1.6 +/- 1.1 g/day, 2.1 +/- 1.3 g/day, and 1.4 +/- 1.2 g/day, respectively. These values decreased to 0.5 +/- 0.7 g/day, 0.6 +/- 0.7 g/day, and 0.9 +/- 0.9 g/day, respectively, at the end of the 12th month. These results were statistically significant only in group 1 (p = 0.04). The rational variation of proteinuria between the first and 12th month of losartan, ramipril, and carvedilol were -61%, -62%, and -27%, respectively. The decreases in blood pressures between baseline and the first, sixth, and twelfth-month measurements were significant in all groups.

CONCLUSIONS

Thee results showed that angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (AT1ras) provide marked decreases in proteinuria, making their use indisputable in patients with glomerulonephritis. Carvedilol was not found to be as effective as ACEIs and AT1ras in decreasing proteinuria and preserving renal function.

Effect of indomethacin and selective cyclooxygenase-2 inhibitors on proteinuria and renal function in patients with AA type renal amyloidosis

AIMS

Because the cardiovascular system (CVS) side-effects of cyclooxygenase-2 (COX-2) selective inhibitors have recently been questioned, we aimed to compare the renal and haemodynamic effects of cyclooxygenase selective (celecoxib and rofecoxib) and non-selective non-steroidal anti-inflammatory drugs (NSAIDs) (indomethacin) in patients with renal amyloidosis secondary to rheumatological diseases who required anti-inflammatory agents and are taking maximum tolerable dose of angiotensin-converting enzyme inhibitors.

METHODS

The present study was performed on 11 patients with stable proteinuria who were diagnosed as AA amyloidosis secondary to rheumatological diseases confirmed by renal biopsies. The study had three consecutive stages (celecoxib 200 mg/day; indomethacin 100 mg/day; rofecoxib 25 mg/day.) Each was given for 4 weeks and a wash-out phase of 3 weeks was allowed between consecutive stages.

RESULTS

Although the decrease of proteinuria in the celecoxib period was higher than in the rofecoxib and indomethacin periods, the difference was not statistically significant. No statistically significant differences were found between serum urea, creatinine, creatinine clearance and urinary sodium excretion.

CONCLUSION

In this study, no differences were found between indomethacin and the two selective COX-2 inhibitors in respect to proteinuria and renal functions in 11 patients with renal amyloidosis secondary to rheumatological diseases with varying degrees of proteinuria. Routine doses of NSAIDs brought no additional benefit to the ACE inhibitor use in terms of proteinuria and renal functions. The use of selective COX-2 inhibitors should be limited to their anti-inflammatory and analgesic effects in this population.