Ping Fu

Chronic kidney disease (CKD) is estimated to affect 10-14% of global population. Kidney fibrosis, characterized by excessive extracellular matrix deposition leading to scarring, is a hallmark manifestation in different progressive CKD; However, at present no antifibrotic therapies against CKD exist. Kidney fibrosis is identified by tubule atrophy, interstitial chronic inflammation and fibrogenesis, glomerulosclerosis, and vascular rarefaction. Fibrotic niche, where organ fibrosis initiates, is a complex interplay between injured parenchyma (like tubular cells) and multiple non-parenchymal cell lineages (immune and mesenchymal cells) located spatially within scarring areas. Although the mechanisms of kidney fibrosis are complicated due to the kinds of cells involved, with the help of single-cell technology, many key questions have been explored, such as what kind of renal tubules are profibrotic, where myofibroblasts originate, which immune cells are involved, and how cells communicate with each other. In addition, genetics and epigenetics are deeper mechanisms that regulate kidney fibrosis. And the reversible nature of epigenetic changes including DNA methylation, RNA interference, and chromatin remodeling, gives an opportunity to stop or reverse kidney fibrosis by therapeutic strategies. More marketed (e.g., RAS blockage, SGLT2 inhibitors) have been developed to delay CKD progression in recent years. Furthermore, a better understanding of renal fibrosis is also favored to discover biomarkers of fibrotic injury. In the review, we update recent advances in the mechanism of renal fibrosis and summarize novel biomarkers and antifibrotic treatment for CKD.

BACKGROUND: Treatment of lupus nephritis (LN) remains challenging. OBJECTIVE: To assess the efficacy and safety of a multitarget therapy consisting of tacrolimus, mycophenolate mofetil, and steroid compared with intravenous cyclophosphamide and steroid as induction therapy for LN. DESIGN: 24-week randomized, open-label, multicenter study. (ClinicalTrials.gov: NCT00876616). SETTING: 26 renal centers in China. PATIENTS: Adults (aged 18 to 65 years) with biopsy-proven LN. INTERVENTION: Tacrolimus, 4 mg/d, and mycophenolate mofetil, 1.0 g/d, versus intravenous cyclophosphamide with a starting dose of 0.75 (adjusted to 0.5 to 1.0) g/m2 of body surface area every 4 weeks for 6 months. Both groups received 3 days of pulse methylprednisolone followed by a tapering course of oral prednisone therapy. MEASUREMENTS: The primary end point was complete remission at 24 weeks. Secondary end points included overall response (complete and partial remission), time to overall response, and adverse events. RESULTS: After 24 weeks of therapy, more patients in the multitarget group (45.9%) than in the intravenous cyclophosphamide group (25.6%) showed complete remission (difference, 20.3 percentage points [95% CI, 10.0 to 30.6 percentage points]; P < 0.001). The overall response incidence was higher in the multitarget group than in the intravenous cyclophosphamide group (83.5% vs. 63.0%; difference, 20.4 percentage points [CI, 10.3 to 30.6 percentage points]; P < 0.001), and the median time to overall response was shorter in the multitarget group (difference, -4.1 weeks [CI, -7.9 to -2.1 weeks]). Incidence of adverse events did not differ between the multitarget and intravenous cyclophosphamide groups (50.3% [91 of 181] vs. 52.5% [95 of 181]). LIMITATION: The study was limited to 24 weeks of follow-up. CONCLUSION: Multitarget therapy provides superior efficacy compared with intravenous cyclophosphamide as induction therapy for LN. PRIMARY FUNDING SOURCE: National Basic Research Program of China, National Key Technology R&D Program.

BACKGROUND: Diabetic nephropathy is a major global health problem. Progression to renal failure is common; however, the mechanisms are unknown. Experimental models suggest a role for macrophages. Therefore, macrophage accumulation and its relationship to the subsequent clinical course were studied. METHODS: A retrospective study of baseline histology and the subsequent clinical course over at least 5 years involving 20 consecutive patients with a histological and clinical diagnosis of diabetic nephropathy was performed. The relationship between macrophage accumulation in renal biopsy tissue (KP-1/anti-CD68+ cells), baseline measures of known predictors of progression (proteinuria, tubulointerstitial damage, myofibroblast accumulation) and progression over 5 years (plot of reciprocal of serum creatinine) was quantified. RESULTS: Accumulation of macrophages was apparent in the glomeruli (2.8 + 0.7/gcs vs 1.0 + 0.2 for normals, P = not significant) and interstitium (296.9 + 63.3/mm(2) vs 19.0 + 1.3/mm(2) for normals, P = 0.002) of patients with diabetic nephropathy. Glomerular macrophage number correlated with baseline serum creatinine (r = 0.548, P = 0.012) but not with progression of renal failure as glomerular macrophages were prevalent in early, but not advanced diabetic nephropathy. Interstitial macrophage accumulation correlated strongly with serum creatinine (r = 0.649, P = 0.002), proteinuria (r = 0.779, P < 0.0001), interstitial fibrosis (r = 0.774, P < 0.0001) and inversely with the slope of 1/serum creatinine (r = -0.531, P = 0.023). CONCLUSION: Macrophages accumulate within glomeruli and the interstitium in diabetic nephropathy and the intensity of the interstitial infiltrate is proportional to the rate of subsequent decline in renal function. These human data support animal studies that suggest a pathogenic role for the macrophage in diabetic nephropathy.

Our intent is to examine the predictive role of Charlson comorbidity index (CCI) on mortality of patients with type 2 diabetic nephropathy (DN). Based on the CCI score, the severity of comorbidity was categorized into three grades: mild, with CCI scores of 1-2; moderate, with CCI scores of 3-4; and severe, with CCI scores ≥5. Factors influencing mortality and differences between groups stratified by CCI were determined by logistical regression analysis and one-way analysis of variance (ANOVA). The impact of CCI on mortality was assessed by the Kaplan-Meier analysis. A total of 533 patients with type 2 DN were enrolled in this study, all of them had comorbidity (CCI score >1), and 44.7% (238/533) died. The mortality increased with CCI scores: 21.0% (50/238) patients with CCI scores of 1-2, 56.7% (135/238) patients with CCI scores of 3-4, and 22.3% (53/238) patients with CCI scores ≥5. Logistical regression analysis showed that CCI scores, hemoglobin, and serum albumin were the potential predictors of mortality (P<0.05). One-way ANOVA analysis showed that DN patients with higher CCI scores had lower levels of hemoglobulin, higher levels of serum creatinine, and higher mortality rates than those with lower CCI scores. The Kaplan-Meier curves showed that survival time decreased when the CCI scores and mortality rates went up. In conclusion, CCI provides a simple, readily applicable, and valid method for classifying comorbidities and predicting the mortality of type 2 DN. An increased awareness of the potential comorbidities in type 2 DN patients may provide insights into this complicated disease and improve the outcomes by identifying and treating patients earlier and more effectively.