Management of chronic renal insufficiency in lupus nephritis: role of proteinuria, hypertension and dyslipidemia in the progression of renal disease

Immunohistochemical detection of intravascular platelet microthrombi in patients with lupus nephritis and anti-phospholipid antibodies

OBJECTIVES

To evaluate whether the use of platelet immunohistochemistry (IHC) markers improves the sensitivity of histological methods to detect microthrombosis in SLE nephritis and aPLs and to analyse the clinicopathological correlations of microthrombosis in this setting.

METHODS

Kidney biopsy specimens from 65 patients with SLE, including 36 with positive aPLs, were studied by IHC using antibodies against platelet glycoproteins CD41 and CD61. Clinical data at the time of kidney biopsy and during a mean follow-up of 7.5 years after biopsy were recorded and analysed with regard to histological or IHC data.

RESULTS

Histological lesions previously defined as APS nephropathy were found in 33% of the SLE kidney biopsies and were not associated with positive aPLs. Microthrombi detected as intravascular CD61(+) platelet deposits were present in 43% of the tissues and were significantly associated with positive aPLs, but not with histological APS nephropathy, nephritis manifestations nor with renal outcome. Histological APS lesions but not CD61(+) microthrombi correlated with an older age at nephritis presentation, previous cardiovascular risk factors and worse renal outcome.

CONCLUSIONS

Immunodetection of intravascular CD61(+) platelet aggregates is more sensitive than histological evaluation to detect acute microthrombosis and provides a better correlation with aPLs in SLE patients. In contrast, histological lesions consistent with APS nephropathy were not associated with aPLs but with cardiovascular risk factors and worse renal outcome.

Beyond immunosuppression – challenges in the clinical management of lupus nephritis

Lupus nephritis remains the most common severe manifestation of SLE with increased risk of death and end-stage renal disease. Although, recent research has focused on the choice of immunosuppressive in its treatment, other factors, including the quality and delivery of healthcare, the management of glucocorticoids and co-morbidity are probably of more importance. There has been significant progress in induction regimes with the successful use of mycophenolate mofetil, low dose intravenous cyclophosphamide and development of sequential regimens whereby cyclophosphamide is followed by an alternative immunosuppressive. However, the attention on the day-to-day management of lupus nephritis in the clinic has merited less attention. In this article, we aim to address more widely the major issues which are encountered regularly in the long-term management of these patients. The overall goals are the reduction of mortality and preservation of renal function.

[Treatment of lupus nephritis]

Lupus nephritis is a relevant source of morbidity and mortality in patients with systemic lupus erythematosus. The standard therapy of remission induction in severe lupus nephritis is based on the use of monthly intravenous cyclophosphamide. Recent data have established that the maintenance of remission in lupus nephritis can be achieved with azathioprine or mycophenolate mofetil, with less adverse effects than quarterly intravenous cyclophosphamide. In recent years, a number of controlled randomized clinical trials have been published, opening new therapeutic options in the induction of remission in lupus nephritis, such as less aggressive regimens of intravenous cyclophosphamide or mycophenolate mofetil. Further studies are needed for establishing the optimal therapy of lupus nephritis patients.

Association between serum total cholesterol level and renal outcome in systemic lupus erythematosus

OBJECTIVE

To determine whether an elevated serum total cholesterol level in a first-available sample obtained at a systemic lupus erythematosus (SLE) clinic is associated with worse renal outcome in patients with SLE.

METHODS

Survival analysis methods were used on prospectively gathered data on 1,060 patients with SLE who were registered in the University of Toronto Lupus Databank. The effect of total cholesterol and 15 additional variables on the outcomes of renal deterioration, end-stage renal disease (ESRD), and death was assessed using Cox proportional hazards methods.

RESULTS

In 474 (45%) of the 1,060 patients, the total cholesterol level exceeded 5.2 mmoles/liter. In the entire study group, the median total cholesterol level was 5.1 mmoles/liter (range 1.6-17.1). During a mean followup period of 8.8 years, 93 patients (9%) experienced renal deterioration, 42 patients (4%) had ESRD, and 161 deaths occurred, 48 (30%) of which were associated with renal dysfunction (renal death), and 113 (70%) of which were not associated with renal dysfunction (nonrenal death). Kaplan-Meier survival estimates for each outcome were statistically significantly different between patients with normal versus those with elevated total cholesterol levels (cutoff 5.2 mmoles/ liter), with a worse outcome observed among those with an elevated total cholesterol concentration. In multivariate analyses, total cholesterol level (hazard ratio [HR] 1.17, 95 confidence interval [95% CI] 1.01-1.36), serum creatinine level (HR 1.06, 95% CI 1.04-1.07), proteinuria (HR 2.44, 95% CI 1.25-4.76), the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (HR 1.44, 95% CI 1.16-1.80), and corticosteroid dose (HR 1.01, 95% CI 1.00-1.02) were associated with renal deterioration. Significant predictors of ESRD were baseline proteinuria (HR 6.24, 95% CI 1.96-19.88) and serum creatinine level (HR 1.15, 95% CI 1.08-1.22). The total cholesterol level was correlated with death (HR 1.20, 95% CI 1.11-1.29), retaining statistical significance for renal death (HR 1.33, 95% CI 1.20-1.47) but not for nonrenal death (HR 1.12, 95% CI 0.99-1.25).

CONCLUSION

Those results indicate that an elevated serum total cholesterol level in a first-available sample obtained at an SLE clinic is associated with adverse renal outcomes and mortality.

An overview of statin-associated proteinuria

Statins are an established therapeutic modality for the treatment of hypercholesterolemia. Although they generally exhibit a good efficacy and tolerability profile, their reputation has been tarnished as a result of reports of myotoxicity and, more recently, observations of proteinuria. The increased incidence of proteinuria with rosuvastatin was of particular concern, and raised questions about the renoprotective actions of statins. Different hypotheses have been put forward to explain the mechanisms of statin-induced proteinuria. The multifarious effects of statins, independent of their effects on cholesterol-lowering, form the basis of such hypotheses. However, rosuvastatin-associated proteinuria is transient and reversible and even at the highest dose did not affect renal function after prolonged treatment. It would appear that clinically relevant proteinuria is not associated solely with rosuvastatin and might represent a minor class effect of statins with a fairly low incidence. However, definitive proof of this assertion will need to be provided by rigorous testing.

Preventing renal failure in patients with severe lupus nephritis

BACKGROUND AND METHODS

Advances in immunosuppressive treatment regimens, with increased efficacy, while minimizing the treatment-related toxicities, and better prevention and treatment of complications, have resulted in improved patient and renal survival in subjects with severe proliferative lupus nephritis over the past few decades. This review discusses the issues that are pertinent to the preservation of renal function in these patients.

RESULTS AND CONCLUSION

Treatment of severe proliferative lupus nephritis can be divided into an initial phase of induction followed by a prolonged maintenance phase, both of which impact upon the long-term renal and patient survival. The immunosuppressive potency of the treatment required for disease control varies according to the disease activity during the different phases. Despite variations in the choice, duration, and route of administration of antiproliferative agents, data to date suggest that immunosuppressive treatments combining cyclophosphamide or mycophenolate mofetil with corticosteroid appear to have similar efficacy in terms of inducing immunologic remission. In this regard, the immunologic efficacy of treatment is prerequisite to the prevention of irreversible loss of nephrons, but long-term renal outcome is also dependent on factors other than treatment efficacy, such as preexisting renal parenchymal damage and blood pressure control. Prompt diagnosis, early effective therapy, and reducing the risk of relapses are the disease specific measures that are essential to long-term renal preservation and the prevention of renal failure in subjects with severe proliferative lupus nephritis.

Predictors of poor renal outcome in patients with lupus nephritis treated with combined pulses of cyclophosphamide and methylprednisolone

Lupus nephritis remains a major cause of morbidity and mortality in patients with systemic lupus erythematosus. Although the renal prognosis has improved, the optimal therapeutic regime has not been definitively established, and significant challenges remain in the management of disease progression and recurrent renal relapse. We performed a prospective study to evaluate the outcome of 38 patients with severe lupus nephritis treated with standard cyclophosphamide and methylprednisolone pulse therapy, and to determine the variables associated with poor outcome. Five patients developed end-stage renal disease (ESRD) (13%), 10 (26%) developed persistent proteinuria (> 1 g/24h) and 15 (39%) suffered at least one relapse after 8 years of follow-up. A high chronicity index, interstitial fibrosis (P = 0.04), persistent hypertension (P < 0.0001) and hypocomplementaemia (P = 0.002) after treatment were the major variables associated with ESRD. Tubular atrophy (P = 0.01), persistent hypertension (P = 0.0001) and hypocomplementaemia after treatment (P = 0.0281) were associated with persistent proteinuria. Persistence of anti-dsDNA antibodies and hypocomplementaemia after treatment (P = 0.0118) were associated with renal relapse. Our data suggest that the group of patients with persistence of hypocomplementaemia and raised anti-dsDNA antibodies titres are at high risk of renal relapse and may be candidates for continuation of immunosuppressive treatment. Patients with persistent proteinuria alone or a high chronicity index are less likely to respond to immunosuppression, and strict control of the hypertension may be the best approach.

Treatment of lupus nephritis

Renal involvement in systemic lupus erythematosus (SLE) is a serious complication of the disease. However, the prognosis of patients with lupus nephritis is continually improving with 10-year survival rates now greater than 75%. This improvement reflects earlier diagnosis due to more sensitive and specific diagnostic tests, better clinical appreciation of the natural history, and improved treatment of SLE and its manifestations. This review of the treatment of lupus nephritis has graded the level of evidence of specific treatment using the guidelines of the US Preventive Service Task Force. Although many new treatments have been advocated, the best evidence for treating proliferative lupus nephritis relies on a strategy combining specific treatment of the SLE as well as generalised treatment of the associated comorbidities. This strategy involves a combination of corticosteroids and cytotoxic agents plus or minus the adjunctive use of antimalarials, coordinated aggressive management of hypertension, proteinuria, infections, dyslipidaemia, thrombotic coagulopathy and potential renal replacement therapies.

Importance of blood pressure reduction for prevention of progression of renal disease

Despite reduction of stroke and coronary mortality rates, progression of renal disease to end stage continues to occur with increasing frequency. Recent studies emphasize common pathways of elevated arterial pressures that produce increased glomerular capillary pressures and increase filtered proteins in the urinary space. Such proteinuria, along with activation of the intrarenal renin-angiotensin system, endothelin, and inflammatory cytokines, magnifies progressive renal injury and fibrosis. Malignant forms of hypertension with severe arteriolar injury and proteinuria can be treated effectively with current antihypertensive regimens with improved patient survival. Several recent studies indicate improved renal outcomes in proteinuric diseases, generally regardless of the specific antihypertensive agent. Recent trials of hypertensive subjects with minimal proteinuria demonstrate slower rates of disease progression than that seen in subjects with proteinuria above 1 gram per day. Reduction of arterial pressures, particularly when it leads to reduced proteinuria, can slow the progression of many renal diseases.