Huiping Wang

Rapamycin Prevents Early Steps of the Development of Diabetic Nephropathy in Rats

Background/Aims: Recent studies suggested the involvement of the Akt/mammalian target of rapamycin (mTOR) pathway in the pathogenesis of diabetic nephropathy. The effect of mTOR blockade by rapamycin in diabetic nephropathy was investigated, but in vivo study of rapamycin treatment in the course of early diabetes is still insufficient. This study was designed to determine the therapeutic effects of rapamycin on diabetic nephropathy at an early stage. Methods: Diabetes was induced in Sprague-Dawley rats with streptozotocin, and rapamycin (1 mg/kg) was administered by daily gavage for 4 weeks. Renal structural changes and some factors involved in the early pathogenesis of diabetic nephropathy were tested. The activation level of the Akt/mTOR pathway was also determined. Results: Rapamycin treatment reduced albuminuria, glomerular enlargement, glomerular basement membrane thickening, renal macrophage recruitment, and levels of renal mRNA expression of proliferating cell nuclear antigen, transforming growth factor-β1, vascular endothelial growth factor, and monocyte chemoattractant protein-1 without change in blood glucose level and blood pressure in experimental diabetic rats. In addition, treatment with rapamycin also down-regulated the enhanced levels of renal p-Akt, phospho-p70S6 kinase, and phospho-ribosomal S6 protein in diabetic rats. Conclusions: Rapamycin treatment can prevent the early renal structural changes of diabetes in experimental rats, and thus halt the early steps of the development of diabetic nephropathy. mTOR blockade might be beneficial for the treatment of diabetic nephropathy.

The significance of BOLD MRI in differentiation between renal transplant rejection and acute tubular necrosis

BACKGROUND Blood oxygen level-dependent MRI (BOLD MRI) can be used to assess intra-renal oxygen bioavailability by measuring the R2(*) level, which reflects tissue deoxyhaemoglobin levels. This study was designed to identify the significance of BOLD MRI in differentiation of acute rejection (AR) and acute tubular necrosis (ATN) in patients within 6 months after kidney transplantation. METHODS Eighty-two patients with normal graft function and 28 patients with biopsy-proven AR (n = 21) or ATN (n = 7) were enrolled. Patients with normal functioning allograft underwent BOLD MRI within 2 to 3 weeks post-transplantation, while patients with AR and ATN underwent BOLD MRI within 6 days before or after kidney transplant biopsy. Cortical R2(*) (CR2(*)) and medullary R2(*) (MR2(*)) levels were measured. RESULTS The mean CR2(*) level was significantly higher in the ATN group (15.25 +/- 1.03/s) compared to the normal group (13.35 +/- 2.31/s, P = 0.028) and AR group (12.02 +/- 1.72/s, P = 0.001). There was a significant difference also between the AR group and normal group on CR2(*) levels (P = 0.013). The mean MR2(*) level was significantly lower in the AR group (14.02 +/- 2.68/s) compared to the normal group (16.66 +/- 2.82/s, P < 0.001) and ATN group (19.47 +/- 1.62/s, P < 0.001). There was also a significant difference between the ATN group and normal group on MR2(*) levels (P = 0.011). There were no correlations between characteristics such as patient age, post-operation time, post-biopsy time, Scr level, HB level, urine output volume, MAP level, CNI trough concentration and R2(*) levels, except between MAP level and CR2(*) level (P = 0.029). CONCLUSIONS BOLD MRI could be a valuable method to discriminate between AR and ATN by measuring tissue oxygen bioavailability in early kidney allograft dysfunction.

Urinary fractalkine is a marker of acute rejection

Chemokines and their receptors play an important role in the development of allograft rejection through directing mononuclear cell invasion of the graft. To study whether chemokine assays in the urine could prove to be predictive of acute rejection, we measured the urinary excretion of several chemokines, including fractalkine, chemokine monokine induced by interferon-gamma, interferon-gamma-inducible protein 10, macrophage inflammatory protein-3 alpha, granzyme B, and perforin in 215 allograft recipients and in 80 healthy control subjects. The 67 patients with acute rejection had significantly higher levels of all urinary chemokines compared to the healthy controls or patients having chronic allograft nephropathy but with stable renal function. Only changes in urinary fractalkine differentiated patients with acute rejection from those with acute tubular necrosis. The 7 patients who lost their grafts had greater urinary fractalkine, interferon-gamma, and macrophage inflammatory protein-3 alpha concentrations than those patients with reversible acute rejection. The area under the receiver operating characteristic curve for fractalkine was the best indicator among all of the markers differentiating 39 patients diagnosed with steroid-resistant from the 28 patients with steroid-sensitive acute rejection and in predicting graft loss. Our study shows that measuring urinary fractalkine levels is a noninvasive approach for detecting acute rejection where high levels were associated with steroid-resistance and poor outcome.

Effects of Mycophenolate Mofetil Combined with Corticosteroids for Induction Therapy of Microscopic Polyangiitis

Aims: We prospectively compared the effects of oral mycophenolate mofetil (MMF) or intravenous cyclophosphamide (IVC) combined with corticosteroids for induction therapy of microscopic polyangiitis (MPA) with renal involvement over a follow-up period of 6 months. Methods: 41 MPA patients were randomly assigned to either the open-label MMF group or the IVC group. Patients in the MMF group (n = 19) received oral MMF 1.0 g/day (1.5 g/day for patients with a body weight >70 kg) and patients in the IVC group (n = 22) received IVC in monthly pulses of 1.0 g per pulse (0.8 g per pulse for patients with a body weight <50 kg). Both groups received intravenous methylprednisolone 360–500 mg/day for 3 days, followed by oral prednisone 0.6–0.8 mg/kg/day and gradual tapering. Results: There was no significant difference of estimated glomerular filtration rate (eGFR) level between the IVC and MMF groups at baseline. At 6 months, the eGFR level increased significantly in both groups, but there was no significant difference between the two. Three patients in the IVC group and 1 in the MMF group received maintenance dialysis within 6 months (p = 0.36). The remission rate was 63.6% in the IVC group and 78.9% in the MMF group (p = 0.23). Conclusion: MMF is effective for inducing remission in Chinese MPA patients and may represent an alternative therapy to monthly impulses of IVC.

Evaluation of sphingolipid metabolism in renal cortex of rats with streptozotocin-induced diabetes and the effects of rapamycin

BACKGROUND Abnormal lipid metabolism contributes to the pathogenesis of diabetes, but it is uncertain whether it plays a role in the development of diabetic nephropathy (DN). While rapamycin was shown to prevent DN development in streptozotocin (STZ)-induced diabetic rats in our previous studies, it is unknown if it intervenes with lipid metabolism. METHODS We divided the rats into four groups: normal control rats, rapamycin-treated normal rats, diabetic rats and rapamycin-treated DN rats. The apoptosis was evaluated by immunohistochemistry. The crude lipid and sphingolipid were extracted from rat renal cortex and analysed by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The expression of the three key enzymes in sphingolipid metabolism including serine palmitoyltransferase, acid sphingomyelinase and sphingomyelin synthase was measured by western blot and immunohistochemistry in rat renal cortex. RESULTS The level of apoptosis was increased in diabetic rats, and rapamycin treatment reduced apoptosis. STZ treatment significantly increased formation of many sphingolipids species through elevated de novo synthesis. These changes were inhibited by treatment with rapamycin. CONCLUSIONS Accumulation of sphingolipids contributes to STZ-induced diabetes, and the therapeutic effect of rapamycin on diabetic nephropathy is partly through suppression of sphingolipid abnormality.

Acute renal allograft rejection is associated with increased levels of vascular endothelial growth factor in the urine

Aim:  The purpose of this study was to assess whether measurement of urinary vascular endothelial growth factor (VEGF) could be adopted as a new non‐invasive diagnostic tool for acute rejection following renal transplantation.

Low Prevalence of Human Papillomavirus (HPV) in Chinese Patients with Breast Cancer

This retrospective study investigated the presence of human papillomavirus (HPV) in Chinese women with breast cancer, and the correlation between HPV infection and carcinogenesis. Tumour and non-cancerous breast tissue samples were obtained from 62 female patients with breast cancer; normal breast tissue samples were obtained from 46 women without breast cancer. HPV DNA was detected by nested polymerase chain reaction using consensus primers; HPV subtypes were determined by reverse dot blot and pyrosequencing analyses. HPV was found in tumour tissue samples from four of the 62 patients (6.5%), while no HPV DNA was detected in either the non-cancerous samples from patients with breast cancer or from the normal breast tissue controls. Of the four HPV-positive cases, three were HPV 16 positive (75%) and one was HPV 18 positive (25%). The low frequency of HPV detected in this study suggests that this infection is not a major risk factor in breast cancer development.

C4d deposition in allograft renal biopsies is an independent risk factor for graft failure.

Aim:  Association between C4d deposition and renal allograft survival is still uncertain. We retrospectively evaluated the clinical outcome of C4d deposition in allograft renal biopsies.

Pre-transplant serum concentrations of anti-endothelial cell antibody in panel reactive antibody negative renal recipients and its impact on acute rejection

Abstract Background: Endothelial cell antigens are important targets in acute rejection (AR). Our goal was to measure the serum concentrations of pre-transplant anti-endothelial cell antibody (AECA) in panel reactive antibody (PRA) negative recipients and its impact on AR within 6 months following renal transplantation. Methods: We retrospectively examined pre-transplant sera from 392 patients using cellular enzyme linked immunosorbent assay (ELISA) with substrate from a permanent endothelial cell line EAhy926. Equal volumes of serum from 40 healthy volunteers were mixed and used as the negative control. Results: The positive rate of AECA was 15.8%. There were no significant differences with respect to age, gender, original disease, dialysis history, immune suppressive regimen, cytomegalovirus (CMV) antigen positive rate, complement dependent cytotoxicity (CDC) level and soluble CD30 (sCD30) levels between the AECA positive group and AECA negative group. AR rate in the AECA positive group was higher than that in the AECA negative group (35.5% vs. 22.4%, p=0.023). The AECA positive patients had significantly higher rates of acute grade II T-cell mediated rejection (TMR) and acute antibody mediated rejection (AMR) compared with AECA negative patients. The concentrations of sCD30, and AECA were independent risk factors for AR within 6 months; the odds ratios were 7.005 and 2.469, respectively. Conclusions: Positive AECA was an independent risk factor for AR and appeared to correlate with relatively severe rejection subtypes. Clin Chem Lab Med 2009;47:1265–9.

Non-invasive Detection of Acute Renal Allograft Rejection by Measurement of Vascular Endothelial Growth Factor in Urine

Urinary vascular endothelial growth factor (VEGF) was determined by enzyme-linked immunosorbent assay in 199 renal allograft recipients and 80 healthy controls. Urinary VEGF level did not change significantly during the first 8 weeks after transplantation in 119 patients with stable renal function and there were no abnormal histological findings (No-AR). In 67 patients with acute rejection, urinary VEGF was significantly higher (28.57 ± 6.21 pg/μmol creatinine) than in the No-AR patients (3.05 ± 0.45 pg/μmol creatinine) and healthy controls (2.87 ± 0.35 pg/μmol creatinine). At a cut-off point of 3.26 pg/μmol creatinine, sensitivity and specificity for diagnosis of acute rejection were 86.6 and 71.4%, respectively. The 13 patients with subclinical rejection excreted urinary VEGF (16.14 ± 4.09 pg/μmol creatinine) at a significantly higher level than No-AR patients (3.05 ± 0.45 pg/μmol creatinine). At a cut-off point of 4.69 pg/μmol creatinine, sensitivity and specificity for diagnosis of subclinical rejection were 84.6 and 79.8%, respectively. In conclusion, monitoring VEGF in urine might offer a new non-invasive way to detect acute and subclinical rejection in renal transplant recipients.