The protease inhibitor E64d might attenuate the development of experimental anti-glomerular basement membrane disease through regulating the activation of Th1 cells.

BACKGROUND: Cathepsins have been recently identified as a regulator in the activation of Th1 and Th17 cells, which play an important role in the pathogenesis of anti-glomerular basement membrane (GBM) disease. Whether cathepsins contribute to the development of anti-GBM disease through regulating the activation of CD4+ T cell is still unclear. METHODS: Rats with experimental anti-GBM disease was established by immunization with the nephritogenic T cell epitope α3127-148. E64d, a cysteine cathepsin inhibitor, was administered in vitro and vivo to evaluate the effect of cathepsins on regulating the activation of antigen specific T cells and the development of anti-GBM disease. RESULTS: In rats with experimental anti-GBM diseases, E64d treatment not only reduced the levels of proteinuria, serum creatinine and anti-GBM antibody, but also ameliorated the kidney injury with less glomerular IgG deposition, a lower percentage of crescents and less infiltration of CD4+ T cells, CD8+ T cells and macrophages, as well as a lower percentage of splenic Th1 cells. In vitro, E64d treatment could significantly reduce the production of IFN-γ in the supernatant which might be produced by the activation of Th1 cells after being recalled with the autoantigen α3127-148. We also found the CD4+ T cells of rats with anti-GBM disease had an increased expression of cathepsin L (Cts-L), and the percentage of CD4+ T cells with extracellular expression of Cts-L was obviously higher, indicating it as a potential key regulator. CONCLUSIONS: E64d might attenuate the development of anti-GBM disease by participating in the activation of Th1 cells, indicating it as a potential drug for anti-GBM disease in the future.

Significance of thyroid dysfunction in the patients with primary membranous nephropathy.

BACKGROUND: Thyroid dysfunction is common in patients with nephrotic syndrome, especially patients with primary membranous nephropathy (pMN). In view of both MN and thyroid dysfunction are associated with autoimmunity, the current study aimed to elucidate the significance of thyroid dysfunction in patients with pMN. METHODS: Four hundred and twenty patients with biopsy-proven pMN from 2018-2021 were retrospectively enrolled. Clinical and pathological parameters, and treatment response of patients with and without thyroid dysfunction were analyzed. RESULTS: Ninety-one (21.7%) patients with pMN suffered from thyroid dysfunction, among which subclinical hypothyroidism (52.7%) was the main disorder. Compared to patients with normal thyroid function, patients with thyroid dysfunction presented with a higher level of proteinuria, a lower level of serum albumin, a higher level of serum creatinine and more severe tubulointerstitial injury at the time of biopsy. But the positive rate and level of circulating anti-phospholipase A2 receptor (PLA2R) antibody were comparable between these two groups. Though following the similar treatment, the percentage of no response to treatment were significantly higher in the patients with thyroid dysfunction (38.6 vs. 20.0%, P = 0.003). Similar to the urinary protein and the positivity of anti-PLA2R antibody, multivariate COX analysis showed thyroid dysfunction was also identified as an independent risk factor for the failure to remission (HR = 1.91, 95%CI, 1.07-3.40, P = 0.029). CONCLUSION: In conclusion, thyroid dysfunction is common in the patients with pMN and might predict a severe clinical manifestation and a poor clinical outcome, which indicated that the thyroid dysfunction might be involved in the disease progression of pMN.

The potential pathogenic roles of S100A8/A9 and S100A12 in patients with MPO-ANCA-positive vasculitis.

BACKGROUND: The significance of S100A8/A9 and S100A12 in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has not been clarified. This study was dedicated to exploring the potential pathogenic roles of S100A8/A9 and S100A12 in patients with myeloperoxidase (MPO)-ANCA-positive vasculitis. METHODS: Serum and urine concentrations of S100A8/A9 and S100A12 of forty-two AAV patients were evaluated. The influence of S100A8/A9 and S100A12 on the chemotaxis, the apoptosis, the release of IL-1ß, the complement activation, the respiratory burst, as well as the neutrophil extracellular traps (NETs) formation of MPO-ANCA-activated neutrophils was investigated. RESULTS: The serum and urine S100A8/A9 and S100A12 of active MPO-AAV significantly increased (compared with inactive AAV and healthy controls, p < 0.001) and were correlated with the severity of the disease. In vitro study showed that S100A8/A9 and S100A12 activated the p38 MAPK/NF-κB p65 pathway, increased the chemotaxis index (CI) and the release of IL-1ß, extended the life span, and enhanced the complement activation ability of MPO-ANCA-activated neutrophils. The Blockade of TLR4 and RAGE inhibited the effects of S100A8/A9 and S100A12. All above-mentioned effects of S100A8/A9 and S100A12 were ROS-independent because neither S100A8/A9 nor S100A12 enhanced the ROS formation and NETs formation of MPO-ANCA-activated neutrophils. CONCLUSION: S100A8/A9 and S100A12 serve as markers for assessing the disease severity, and they may also play a role in MPO-AAV pathogenesis.

Monomeric C-reactive protein promotes platelets to release mitochondrial DNA in anti-neutrophil cytoplasmic antibody-associated vasculitis.

Although high level of circulating C-reactive protein (pCRP) is considered as a biomarker for disease activity, the significance of CRP in the pathogenesis of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has not been clarified. We once reported in AAV, pentameric CRP (pCRP) could dissociate into monomeric CRP (mCRP) and activate platelets. Recent studies have demonstrated that the activated platelets can release mitochondrial DNA (mtDNA). The purpose of this study was to further study the relationship between mCRP and platelets in AAV. We found the plasma level of mCRP in AAV patients was significantly higher than that of normal control and positively correlated with the proportion of mCRP-positive platelets. Platelets isolated from one normal donor could be activated by plasma from 5 AAV patients and this effect could be attenuated when mCRP had been removed. Only 0.1 µg/mL of recombinant mCRP was needed for inducing platelets to release mtDNA via interaction with lipid raft and through p38 MAPK/NF-κB pathway. The mCRP binding on platelets depended on the C-terminal octapeptide (aa 199-206). The released mtDNA did not induce respiratory burst alone, but enhanced the ANCA-induced neutrophils respiratory burst after binding Toll-like receptor 9 (TLR9). The mtDNA released by mCRP-activated platelets also enhanced thrombin generation of plasma. In conclusion, our data demonstrate that mCRP can bind platelets via interaction with lipid raft and induce the release of mtDNA. The released mtDNA can enhance the pathogenicity of ANCA and promote activation of coagulation system in AAV.

Circulating nicotinamide adenine dinucleotide-ubiquinone oxidoreductase chain 6 is associated with disease activity of anti-neutrophil cytoplasmic antibody-associated vasculitis.

BACKGROUND: Increased serum and urinary mitochondrial DNA have been demonstrated in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Here we investigated the significance of serum nicotinamide adenine dinucleotide-ubiquinone oxidoreductase chain 6 (ND6), which is encoded by mtDNA and can attract neutrophils, in AAV. METHODS: Thirty-seven AAV patients (32 patients with positive myeloperoxidase-ANCA and 5 patients with proteinase 3-ANCA) were enrolled. Relationship between serum ND6 and clinico-laboratory characteristics were analyzed. RESULTS: The ND6 level of patients was higher than normal people (46.56 ± 23.67 pg/mL vs. 4.95 ± 2.45 pg/mL, P < 0.001) The ND6 levels of patients who needed hemodialysis at disease onset and who had pulmonary hemorrhage (PH) were higher than that of the corresponding controls (P = 0.004 and 0.044 respectively). The ND6 level negatively correlated with the percentages of normal glomeruli in kidney biopsy. The AUC of ROC curve to diagnose hemodialysis and PH was 0.804 and 0.750 respectively. ND6 level positively correlated with Birmingham Vasculitis Activity Score in active disease, and returned to normal after remission. Patients with higher serum ND6 had higher mortality (P = 0.023). CONCLUSIONS: Serum ND6 increases in active AAV, and its level correlates with the severity of disease. High ND6 level is associated with severe organ injury and predicts poor prognosis of AAV.

Urinary mitochondrial DNA is a useful biomarker for assessing kidney injury of antineutrophil cytoplasmic antibody -associated vasculitis.

BACKGROUND: The value of urinary mitochondrial DNA (mtDNA) for assessing kidney injury of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) was investigated. METHODS: Thirty-nine kidney biopsy-proved myeloperoxidase (MPO)-ANCA associated AAV patients were enrolled and analyzed. RESULTS: The average urinary mtDNA of patients was significantly higher than that of normal controls (3372.74 ± 1859.72 vs. 474.90 ± 123.59 copy/nmol creatinine, p < 0.001). The patients who needed dialysis at disease onset had the highest levels of urinary mtDNA (5072.23 ± 1302.87 copy/nmol creatinine). Urinary mtDNA positively correlated with urinary neutrophil gelatinase-associated lipocalin (R = 0.661, P < 0.001) and negatively correlated with estimated glomerular filtration rate (R = -0.515, P = 0.001). The urinary mtDNA level of crescentic class (4703.08 ± 1744.31 copy/nmol creatinine) was higher than that of mixed class (3258.14 ± 1158.99 copy/nmol creatinine) and focal class (2268.15 ± 1897.63 copy/nmol creatinine). Univariate correlation analysis showed urinary mtDNA positively correlated with interstitial neutrophils (R = 0.471, P = 0.048) and glomerular neutrophils (R = 0.673, P = 0.002) in kidney biopsy. Among 13 patients who needed hemodialysis at disease onset, 10 patients who got renal recovery had higher urinary mtDNA than 3 patients who remained dialysis dependent (5455.20 ± 1174.64 vs. 3795.67 ± 893.34 copy/nmol creatinine, p = 0.047). CONCLUSIONS: Urinary mtDNA increases in AAV with kidney injury, and its levels correlate with the severity of kidney injury and neutrophils infiltration in pathology.

Pathological severity determines the renal recovery for anti-myeloperoxidase antibody-associated vasculitis requiring dialysis at disease onset: a retrospective study.

BACKGROUND: Many patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) need dialysis at disease onset due to severe kidney injury. Determining whether they can become dialysis independent is an important clinical assessment. METHODS: Forty kidney biopsy-proved myeloperoxidase (MPO)-ANCA associated AAV patients who required dialysis at disease onset were enrolled. Relationships between laboratory and pathological characteristics and prognoses were analyzed. RESULTS: Twenty-five patients obtained dialysis independence within 3 months, while the other 15 patients remained dialysis dependent. No sclerotic class was identified among the 40 patients. Only two biopsies exhibited focal class diagnoses and both these patients recovered their renal function. The renal recovery rate of the 20 patients with mixed class was significantly lower than that of the 18 patients with crescentic class (40.0% vs. 83.3%, p = 0.006). Receiver operating characteristics (ROC) curves showed fibrous crescent+global glomerulosclerosis greater than 32.6% was a strong predictor of dialysis dependence with a sensitivity of 93.3% and specificity of 88.0%. When the percentage of fibrous crescent+global glomerulosclerosis exceeded 47.9%, dialysis independence was not possible. Correlation analysis indicated that platelet counts were negatively correlated with the percentage of fibrous crescent+global glomerulosclerosis (R = -0.448, p = 0.004). Most patients with increased platelets (84.62%) obtained renal recovery. Compared with methylprednisolone pulse therapy, plasma exchange accelerated renal recovery (29.4 ± 15.6 vs. 41.4 ± 11.7 days, p = 0.039). CONCLUSIONS: For MPO-ANCA AAV who required dialysis at disease onset, crescentic and mixed classes accounted for the majority of patients in our cohort. The renal outcome of mixed class patients was worse than that of crescentic class. A high proportion of fibrous crescent+global glomerulosclerosis is a predictor of dialysis dependence. Increased platelet count is associated with active and reversible renal lesions.

High serum hepcidin is associated with the occurrence of anemia in anti-myeloperoxidase antibody-associated vasculitis with normal kidney function: a cross-sectional study.

The etiology of anemia in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has not been elucidated. In this cross-sectional study, we tried to investigate the relationship between serum hepcidin and anemia in myeloperoxidase (MPO)-ANCA-AAV. Data of 64 newly diagnosed AAV patients who did not have kidney dysfunction or hemorrhage were analyzed. Serum hepcidin was measured with enzyme linked immunosorbent assay. Twenty-three of 64 patients had anemia. Compared with patients without anemia, patients with anemia had higher Birmingham vasculitis activity score [10 (3, 23) vs. 5 (3, 17), p = 0.020], lower levels of serum iron (5.83 ± 1.63 vs. 9.76 ± 1.54, p < 0.001) and higher levels of ferrtin [358.00 (59.85, 1314.10) vs. 151.05 (43.00, 645.30), p = 0.006]. All 64 patients had increased levels of serum hepcidin compared with normal controls, while patients with anemia had higher serum hepcidin than patients without anemia (85.30 ± 16.92 ng/mL vs. 53.48 ± 13.32 ng/mL, p < 0.001). In the multivariable analysis, the level of hemoglobin correlated with the levels of serum iron (r = 0.344, p = 0.026) and hepcidin (r = - 0.353, p = 0.022). Low level of serum iron was related to high level of serum hepcidin (r = - 0.472, p = 0.001). Immunosuppressive treatment induced rapid decrease of hepcidin and increase of serum iron on the 1st month, while the recovery of hemoglobin was relatively slow. This study indicated that in MPO-AAV without kidney dysfunction or hemorrhage, the existence of anemia is associated with high level of hepcidin which induces low serum iron and the abnormality of iron utilization.

Severe acute interstitial nephritis induced by valsartan: A case report.

RATIONALE: Angiotensin receptor blocker (ARB) can increase serum creatinine or potassium levels in patients with renal insufficiency, renal artery stenosis, heart failure or hypovolemia, but hardly cause severe kidney injury in patients without any risk factors. A case of severe acute interstitial nephritis (AIN) induced by valsartan was reported here. PATIENT CONCERNS: A 62-year-old female with nausea for 1 month and acute deterioration of kidney function for 2 weeks was admitted. She had a history of hypertension for 5 months and had taken valsartan 40 mg daily for 4 months. Although the valsartan had been stopped for 2 weeks, the serum creatinine continuously increased after admission. Kidney biopsy demonstrated the eosinophils infiltration in interstitium. DIAGNOSES: AIN induced by valsartan. INTERVENTIONS: The patient was treated with glucocorticoid. OUTCOMES: The serum creatinine decreased gradually and got back to normal level 5 months later. Then therapy of glucocorticoid was stopped. Renal artery stenosis was excluded by computed tomography angiography (CTA). LESSONS: Although valsartan-induced allergy has been reported previously, AIN was firstly recognized as a severe complication of this drug. We suggest when there is a ARB-associated continuous deterioration of kidney function for patients without renal insufficiency, renal artery stenosis, heart failure or hypovolemia, AIN should be thought of and therapy with glucocorticoid should be considered if necessary.

Clinical and pathologic characteristics of pauci-immune anti-myeloperoxidase antibody associated glomerulonephritis with nephrotic range proteinuria.

BACKGROUND: Heavy proteinuria in antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (GN) is usually considered to be associated with immune deposits in renal biopsy. Nephrotic ANCA GN without immune deposits (pauci-immune) is rare and has not been studied specially. In this study characteristics of these patients are to be investigated. METHODS: Clinical and pathological characteristics from 20 kidney biopsy-proven pauci-immune anti-myeloperoxidase antibody-associated GN patients with nephrotic proteinuria were analyzed and were compared with ANCA GN patients without nephrotic proteinuria. RESULTS: Acute kidney injury (AKI) and gross hematuria were much prevalent but extra-renal involvement was less prevalent in pauci-immune ANCA GN with nephrotic proteinuria than in pauci-immune ANCA GN without nephrotic proteinuria. No more severe hypoalbuminemia, hypercoagulability, hyperlipidemia or higher thrombosis incidence were found between two groups. Compared with patients without nephrotic proteinuria, patients with nephrotic proteinuria had more prevalent crescentic category in histopathology. Proteinuria decreased quickly after treatment but much poorer renal prognosis was found in pauci-immune ANCA GN with nephrotic proteinuria. The results of urinary albumin to total protein ratio and urinary protein electrophoresis showed pauci-immune ANCA GN with nephrotic proteinuria had obvious non-selective proteinuria. CONCLUSIONS: Pauci-immune ANCA GN with nephrotic proteinuria do not have more severe hypoalbuminemia, hypercoagulability or hyperlipidemia than patients without nephrotic proteinuria. Non-selective proteinuria might be the reason. However, pauci-immune ANCA GN with nephrotic proteinuria have more prevalent crescentic category in histopathology, higher incidence of AKI, gross hematuria and poorer renal prognosis despite of good sensitivity to therapy of proteinuria.

Hypoalbuminaemia in antineutrophil cytoplasmic antibody-associated vasculitis: incidence and significance.

OBJECTIVES: Hypoalbuminaemia has been proved to be a biomarker of poor prognosis in many diseases. The objective of this study was to investigate the significance of hypoalbuminaemia in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). METHODS: Data of 117 AAV patients were analysed retrospectively. The relationship between hypoalbuminaemia and disease severity were studied. The influence of albumin on the pathogenetic role of ANCA was investigated in vitro. RESULTS: Among all patients, 52 had light hypoalbuminaemia (30g/L<=albumin<35g/L) and 40 had nephrotic hypoalbuminaemia (albumin <30g/L). Patients with hypoalbuminaemia had higher inflammation levels and more severe kidney injury than patients without hypoalbuminaemia, but no significant difference of the urinary protein levels were found between patients with nephrotic and light hypoalbuminaemia. Multivariate analysis showed serum albumin correlated with age (r=-0.566, p=0.018), C-reactive protein (r=-0.521, p=0.032) and haemoglobin (r=0.512, p=0.036). Patients with nephrotic hypoalbuminaemia had higher incidence of infection, end stage renal disease and all cause mortality during treatment than patients with light hypoalbuminaemia or normal serum albumin. In vitro study indicated albumin could inhibit the binding between ANCA and neutrophils in a concentration dependent manner. Albumin also inhibited the ANCA-induced respiratory burst and neutrophil extracellular traps formation. CONCLUSIONS: Serum albumin have an inhibitory effect on the binding between ANCA and its antigen. The incidence of hypoalbuminaemia in AAV with kidney involvement is high but is not caused by heavy proteinuria. Hypoalbuminaemia is correlated with the high inflammation level and poor prognosis of AAV. Therapy targeting hypoalbuminaemia might benefit patients with AAV.

Myeloperoxidase-antineutrophil cytoplasmic antibody (ANCA)-associated systemic vasculitis developed from ANCA negative renal limited vasculitis: A case report.

RATIONALE: The relationship between antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) and ANCA-negative vasculitis has not been elucidated. PATIENT CONCERNS: A 64-year-old female with edema and proteinuria was admitted. A kidney biopsy indicated focal proliferative nephritis with crescents in 25% of glomeruli. Serum ANCA was negative. Eighteen months later, systemic symptoms emerged and acute kidney injury occurred. Serum ANCA against myeloperoxidase (MPO) turned positive. Repeated kidney biopsy showed more severe lesion than last time. Immunoglobulin (Ig)G was purified from serum obtained before the first kidney biopsy. Weak ANCA which could not be detected in serum was found in IgG. DIAGNOSES: MPO-ANCA-associated AAV developed from ANCA-negative renal-limited AAV. INTERVENTIONS: The patient was treated with glucocorticoid. OUTCOMES: The serum creatinine decreased to 2.17 mg/dL a week later. MPO-ANCA turned negative when re-examined 3 weeks later. No relapse has been observed during follow-up for 6 months. LESSONS: This is the first reported case about the spontaneous transformation from ANCA-negative renal-limited AAV to ANCA-positive systemic vasculitis. There might be a slow process of epitope spreading in the pathogenesis of disease. Physicians should try their best to detect the ANCA in the diagnose and treatment of ANCA-negative AAV.

C-reactive protein enhances activation of coagulation system and inflammatory response through dissociating into monomeric form in antineutrophil cytoplasmic antibody-associated vasculitis.

BACKGROUND: C-reactive protein (CRP) exerts prothrombotic effects through dissociating from pentameric CRP (pCRP) into modified or monomeric CRP (mCRP). However, although the high prevalence of venous thromboembolism (VTE) in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has been identified, it remains unclear whether the high levels of circulating pCRP potentially contribute to this hypercoagulable state in AAV. ANCA can induce the generation of neutrophil extracellular traps (NETs). In this study, the NETs-dependent generation of mCRP from pCRP and the influences of mCRP on the activation of coagulation system and inflammatory response in AAV were investigated. RESULTS: NETs were induced after TNF-α primed neutrophils were incubated with ANCA-containing IgG. After ANCA-induced netting neutrophils were incubated statically with platelet-rich plasma (PRP) containing mCRP (60 µg/mL), the proportion of platelets expressing CD62p increased significantly, while no increased CD62p expression of platelets was observed after static incubation with PRP containing pCRP (60 µg/mL). Under flow conditions, perfusing immobilized ANCA-induced netting neutrophils with pCRP-containing PRP caused platelets activation and mCRP deposition. The newly generated mCRP induced platelets activation on ANCA-induced netting neutrophils, enhanced D-dimer formation, and enhanced high mobility group box 1 secretion by platelets. CONCLUSIONS: Under flow conditions, ANCA-induced netting neutrophils can activate platelets and then prompt the formation of mCRP on activated platelets. Then the newly generated mCRP can further enhance the activation of platelets, the process of thrombogenesis, and the inflammatory response. So the high level of circulating pCRP is not only a sensitive marker for judging the disease activity, but also a participant in the pathophysiology of AAV.

Urinary kidney injury molecule-1 is related to pathologic involvement in IgA nephropathy with normotension, normal renal function and mild proteinuria.

BACKGROUND: IgA nephropathy (IgAN) may progress to renal failure for some patients without any clinical risk factors and it is not unusual to find severe pathologic damage in clinically mild IgAN. We therefore investigated whether urinary kidney injury molecule-1 (KIM-1) was related to pathologic involvement in clinically mild IgAN. METHODS: Urinary KIM-1/creatinine of 51 IgAN patients with normotension, normal renal function and proteinuria < 1.0 g/24 h were tested. Relationships between urinary KIM-1 and pathologic features were analyzed. RESULTS: Eighteen of the 51 patients had elevated urinary KIM-1. The tubular atrophy/interstitial fibrosis was more severe in patients with elevated urinary KIM-1 than that in patients with normal urinary KIM-1 (T0/T1/T2, 13/5/0 vs. 33/0/0, P = 0.004). Proportion of glomeruli containing cresecents was higher in patients with elevated urinary KIM-1 than that in patients with normal urinary KIM-1 (50% vs. 18%, P = 0.026). Urinary KIM-1 correlated with the proportion of total crescents (R = 0.303, p = 0.031) and fibrous crescents (R = 0.456, p = 0.001), but did not correlate with the proportion of cellular crescents or fibrocellular crescents. Although the proportion of vascular lesions was higher in patients with elevated urinary KIM-1 (44.4%) than that in patients with normal urinary KIM-1 (18.1%), the difference was not significant (p = 0.057). There was no difference of the response to treatment between patients with and without elevated urinary KIM-1 during a short-term follow-up. CONCLUSIONS: Urinary KIM-1 is a reflection of tubularinstitial injury. For patients with clinically mild IgAN, high urinary KIM-1 is related to relatively severe pathologic involvement on renal biopsy.

IgG4-related membranous nephropathy with high blood and low urine IgG4/IgG ratio: a case report and review of the literature.

Membranous nephropathy (MN) is a rare manifestation of IgG4-related disease. Interestingly, the significance of IgG4 has also been documented in idiopathic MN (IMN). Previous studies reported that urine IgG4/IgG ratios were significantly higher in IMN compared with other kinds of nephropathy, indicating that impairment of charge selectivity barrier seemed to be an obvious characteristic of IMN. Although high blood concentration of IgG4 is very common in IgG4-related MN, no study about the urine IgG4 has been described before. Here, we present a 55-year-old male with IgG4-related MN. Complete remission of proteinuria was promptly achieved by glucocorticoid treatment without immunosuppressant. Consistent with previous reports, the serum antibody against M-type phospholipase A2 receptor was negative. Surprisingly, although the blood concentration of IgG4/IgG reached as high as 36 %, the urine concentration of IgG4/IgG was only 5 %. The calculated ratio of the renal clearance of IgG4 to IgG of this patient (0.15) was obviously lower than that of five patients with IMN (0.53∼0.81). We speculated that this phenomenon might be a clue of the different pathogenesis between IgG4-related MN and IMN.

[The histological changes in radial artery in uremia and their effects on arterial stiffness].

OBJECTIVE: To examine the changes of histological parameters of radial artery in uremia, and to explore their effects on arterial stiffness. METHODS: Sixty uremic patients underwent arteriovenous fistula surgery for hemodialysis and 20 healthy subjects received healthy examination were collected as uremia group and control group, respectively. Segments of radial arteries were obtained from all of uremic subjects and were evaluated by HE, Masson, van Kossa staining and electron microscopy. The expressions of osteopontin (OPN), α-SMA and elastin in arterial wall were detected by immunostaining, and apoptotic cells were determined by TUNEL assay. All of the subjects in the two groups received brachial ankle pulse wave velocity (baPWV) examination and the results were compared. The associations among histological parameters and baPWV were analyzed. RESULTS: More than one half (34/60) of artery samples presented uniformly thickening intima, in which most of cells expressed α-SMA and a few cells underwent apoptosis. The subendothelial matrix was abundant in collagen fibers, and no calcium deposition was found. The media thickened obviously, with increased collagen fibers, reduced elastin, unchanged α-SMA expression, and a few apoptotic smooth muscle cells. Two thirds uremic arteries expressed OPN, of which only one half had significant calcium deposition. The adventitia thickened and no calcium deposition was found. The baPWV level in uremic subjects was (18.5±3.2) m/s, far greater than that in control subjects (P<0.001). Statistical analysis showed that baPWV value was correlated with media thickness, calcification degree, and collagen content positively, and with elastin expression negatively. For diabetic uremic subjects, the OR values of vascular calcium deposition and remarkably-elevated baPWV value were 3.1, 2.3, respectively. CONCLUSIONS: Radial arterial intima often presents hyperplasia which is not related with baPWV increment in uremia. Arterial media calcification and collagen content incremental are the most two protuberant characteristics in uremia, especially in ones accompanied with diabetes. Medical calcification, collagen accumulation, and elastin reduction may contribute to the increased arterial stiffness in uremia.