Sirt1 activation prevents high glucose-induced angiotensin converting enzyme 2 downregulation in renal tubular cells by regulating the TIMP3/ADAM17 pathway.

BACKGROUND: Angiotensin converting enzyme 2 (ACE2) exerts renoprotective effects in diabetic kidney disease (DKD) by converting angiotensin (Ang) II into Ang (1-7). Previous studies have demonstrated that ACE2 expression in renal tubules is downregulated in DKD, but the mechanism is not fully understood. Sirtuin-1 (Sirt1) is a protein deacetylase that may regulate the activity of the renin-angiotensin system. The present study investigated the effects of Sirt1 on ACE2 expression under high glucose (HG) conditions and the underlying signaling pathway. METHODS AND RESULTS: Rats with DKD and NRK-52E cells cultured with HG were employed in this study. Western blotting, immunohistochemistry detection and qRT-PCR were performed for protein and mRNA expression analyses. Rats subjected to DKD displayed downregulated expression of Sirt1 and ACE2 in kidneys. Resveratrol, an activator of Sirt1, restored ACE2 expression and ameliorated renal injuries. Similarly, pharmacological activation of Sirt1 with SRT1720 markedly upregulated ACE2 in NRK-52E cells cultured with HG, while Sirt1 small interfering RNA (siRNA) further suppressed ACE2 expression. In addition, A disintegrin and metalloproteinase (ADAM) 17 was observed to be upregulated, and its inhibitor, tissue inhibitor of metalloproteinase 3 (TIMP3), was downregulated in the kidneys of diabetic rats and NRK-52E cells incubated with HG. The TIMP3/ADAM17 pathway was involved in the regulation of ACE2 expression, as evidenced by decreased ACE2 expression levels after TIMP3-siRNA pretreatment. SRT1720 ameliorated the imbalance of TIMP3/ADAM17 induced by HG and consequently enhanced the expression of ACE2. Notably, the above effect of SRT1720 on ACE2 was interrupted by TIMP3-siRNA. CONCLUSIONS: Our findings suggest that Sirt1 activation may prevent HG-induced downregulation of renal tubular ACE2 by modulating the TIMP3/ADAM17 pathway. Sirt1 stimulation might be a potential strategy for the treatment of DKD.

Clinical characteristics and management of hemodialysis patients with pre-dialysis hypertension: a multicenter observational study.

BACKGROUND: Hypertension is a leading preventable risk factor for cardiovascular disease in hemodialysis patients. Pre-dialysis systolic blood pressure (SBP) more than 160 mmHg was thought to be associated with increased risk of cardiovascular events and all-cause mortality. The present study was performed to explore the clinical characteristics and management of hemodialysis patients with pre-dialysis SBP ≥ 160 mmHg. METHODS: A total of 1233 patients undergoing hemodialysis from nine hemodialysis centers were enrolled. Pre-dialysis and home BP were measured and clinical data were collected. The characteristics of patients with pre-dialysis SBP ≥ 160 mmHg were explored. Clinical parameters between hypertensive and non-hypertensive patients were compared. The partial correlation analyses performed to identify the associations between BP and clinical parameters. RESULTS: There were 24.6% of the hemodialysis patients had pre-dialysis SBP ≥ 160 mmHg and the average SBP was 173.8 ± 10.9 mmHg. Only 21.4% of the patients achieved dry weight after dialysis and up to 30.2% of patients were not given combination therapies of antihypertensive drugs. Compared to patients with pre-hemodialysis SBP < 160 mmHg, patients with pre-dialysis SBP ≥ 160 mmHg had lower target-reaching rate of Kt/v and higher incidences of intradialytic hypotension and muscle spasm. Most patients (96%) with pre-dialysis SBP ≥ 160 mmHg had home SBP≥ 135 mmHg. Patients with home SBP ≥ 160 mmHg had higher left ventricular weight index and lower hemoglobin levels when compared to their counterparts with home SBP <160 mmHg. CONCLUSIONS: Pre-dialysis SBP ≥ 160 mmHg is common in clinical practice and most of the patients could diagnosed to be hypertensive according to their home SBP. Patients with pre-dialysis SBP ≥ 160 mmHg are more likely to be subjected to dialysis insufficiency and intradialytic complications. Achieving dry weight and sufficient pharmacologic interventions should be strengthened to improve BP control in the hemodialysis population.

Soluble epoxide hydrolase inhibition ameliorates proteinuria-induced epithelial-mesenchymal transition by regulating the PI3K-Akt-GSK-3ß signaling pathway.

Soluble epoxide hydrolase (sEH) plays an essential role in chronic kidney disease by hydrolyzing renoprotective epoxyeicosatrienoic acids to the corresponding inactive dihydroxyeicosatrienoic acids. However, there have been few mechanistic studies elucidating the role of sEH in epithelial-mesenchymal transition (EMT). The present study investigated, in vitro and in vivo, the role of sEH in proteinuria-induced renal tubular EMT and the underlying signaling pathway. We report that urinary protein (UP) induced EMT in cultured NRK-52E cells, as evidenced by decreased E-cadherin expression, increased alpha-smooth muscle actin (α-SMA) expression, and the morphological conversion to a myofibroblast-like phenotype. UP incubation also resulted in upregulated sEH, activated phosphatidylinositol 3-kinase (PI3K)-protein kinase B (PKB/Akt) signaling and increased phosphorylated glycogen synthase kinase-3ß (GSK-3ß). The PI3K inhibitor LY-294002 inhibited phosphorylation of Akt and GSK-3ß as well as blocking EMT. Importantly, pharmacological inhibition of sEH with 12-(3-adamantan-1-yl- ureido)-dodecanoic acid (AUDA) markedly suppressed PI3K-Akt activation and GSK-3ß phosphorylation. EMT associated E-cadherin suppression, α-SMA elevation and phenotypic transition were also attenuated by AUDA. Furthermore, in rats with chronic proteinuric renal disease, AUDA treatment inhibited PI3K-Akt activation and GSK-3ß phosphorylation, while attenuating levels of EMT markers. Overall, our findings suggest that sEH inhibition ameliorates proteinuria-induced renal tubular EMT by regulating the PI3K-Akt-GSK-3ß signaling pathway. Targeting sEH might be a potential strategy for the treatment of EMT and renal fibrosis.

Urinary angiotensin converting enzyme 2 increases in patients with type 2 diabetic mellitus.

BACKGROUND/AIMS: Angiotensin converting enzyme 2 (ACE2) is highly expressed in the kidney and recognized to be renoprotective by degrading Angiotensin II to Angiotensin (1-7) in diabetic nephropathy. However, little is known about the role of urinary ACE2 (UACE2) in diabetes. The present study was performed to evaluate UACE2 levels in type 2 diabetic patients with various degrees of albuminuria and its associations with metabolic parameters. The effect of RAS inhibitors on UACE2 excretion was also assessed. METHODS: A total of 132 type 2 diabetic patients with different degrees of albuminuria and 34 healthy volunteers were studied. UACE2 levels and activity were measured. RESULTS: Compared to healthy controls, UACE2 to creatinine (UACE2/Cr) levels were significantly increased in both albuminuric and non-albuminuric diabetic patients. UACE2/Cr levels were much higher in hypertensive diabetic patients compared with their normotensive counterparts and treatment with RAS inhibitors markedly attenuated the augmentation. Furthermore, UACE2/Cr was positively correlated with fasting blood glucose, hemoglobin A1C (HbA1C), triglyceride, and total cholesterol. In multiple regression analysis, UACE2/Cr was independently predicted by HbA1C and RAS inhibitors treatment. CONCLUSIONS: UACE2 increased in type 2 diabetic patients with various degrees of albuminuria and RAS inhibitors suppresses UACE2 excretion. UACE2 might potentially function as a marker for monitoring the metabolic status and therapeutic response of RAS inhibitors in diabetes.

[Up-regulation of intrarenal renin-angiotensin system contributes to renal damage in high-salt induced hypertension rats].

OBJECTIVE: To test the hypothesis that in a high-salt induced hypertension in normal rats, whether the changes of intrarenal renin-agiotensin system (RAS) play a critical role in renal damage and could be reflected by urinary angiotensinogen (AGT). METHODS: In the study, 27 normotensive male Wistar-Kyoto rats were divided into control group [0.3% (mass faction) NaCl in chow, n=9, NS], high-salt diet group [8% (mass faction) NaCl in chow, n=9, HS] and high-salt diet with Losartan group [8% (mass faction) NaCl in chow and 20 mg/(kg×d) Losartan in gavages, n=9, HS+L)], and were fed for six weeks. The blood pressure was monitored and urine samples were collected every 2 weeks. AGTs in plasma, kidney and urine were measured by ELISA kits. The renal cortex expression of mRNA and protein of AGT were measured by Real-time PCR and immunohistochemistry (IHC). The renin activity and ANG II were measured by radioimmunoassay (RIA) kits. RESULTS: Compared with NS, the systolic blood pressure (SBP) [(156 ± 2) mmHg vs. (133 ± 3) mmHg, P<0.05] increased significantly at the end of the 2nd week, and the urinary protein [(14.07 ± 2.84) mg/24 h vs. (7.62 ± 3.02) mg/24 h, P<0.05] increased significantly at the end of the 6th week in HS. Compared with HS, there was no significant difference in SBP (P>0.05) but the proteinuria [(9.69 ± 2.73) mg/24 h vs. (14.07 ± 2.84) mg/24 h, P<0.01] decreased significantly in HS+L. Compared with NS, there was no significant difference in the plasma renin activity, angiotensinogen and ANG II level in HS (P>0.05), but the renal cortex renin content [(8.72 ± 1.98) ng/(mL × h) vs. (4.37 ± 1.26) ng/(mL × h), P<0.05], AGT formation [(4.02 ± 0.60) ng/mg vs. (2.59 ± 0.42) ng/mg, P<0.01], ANG II level [(313.8 ± 48.76) pmol/L vs. (188.9 ± 46.95) pmol/L, P<0.05] were increased significantly in HS, and the urinary AGT and ANG II excretion rates increased significantly (P<0.05). Compared with HS, the plasma renin activity, angiotensinogen and ANG II level were significantly increased (P<0.05), but the renal cortex renin content, AGT formation, ANG II level significantly decreased (P<0.05), and the urinary AGT and ANG II excretion rates decreased significantly in HS+L (P<0.05). The urinary AGT excretion rates were positively correlated with the AGT level in the renal cortex (P<0.05). CONCLUSION: Up-regulation of intarenal RAS may contribute to renal damage in high-salt induced hypertension rats. Urinary AGT may reflect the status of intrarenal RAS.

Prophylactic angiotensin type 1 receptor antagonism confers neuroprotection in an aged rat model of postoperative cognitive dysfunction.

Postoperative cognitive dysfunction (POCD) is a common geriatric complication, although its exact neuropathogenesis remains elusive. Blockers of the renin-angiotensin system (RAS) ameliorate cognitive deficits in inflammatory brain disorders, with its effects on POCD not yet fully elucidated. The aim of the present study was to investigate regulation of the brain RAS and the effect of angiotensin II receptor type 1 (AT1) inhibition on surgery-induced cognitive impairment in a well-established rat POCD model. We observed upregulation of angiotensin II protein expression and AT1 subtype B transcript levels in the hippocampus after laparotomy, suggesting surgical stress activates the hippocampal RAS in aged rats. Chronic pretreatment with 0.1 mg/kg/day candesartan, an AT1 antagonist, significantly attenuated surgery-induced cognitive deficits in the Morris water maze task without altering blood pressure. Candesartan also decreased hippocampal blood-brain barrier (BBB) permeability. Concomitant with these functional benefits, we observed significant inhibition of hippocampal neuroinflammation, evidenced by decreased glial reactivity and phosphorylation of the NF-κB p65 subunit, as well as marked reductions in interleukin-1ß, tumor necrosis factor-α, and cyclooxygenase-2. Our results are the first to show that activation of the brain RAS after surgery contributes to POCD in aged rats. Chronic treatment with low doses of candesartan may elicit blood pressure-independent neuroprotective effects in POCD by improving BBB function and promoting resolution of neuroinflammation.

Up-regulation of intrarenal renin-agiotensin system contributes to renal damage in high-salt induced hypertension rats.

BACKGROUND/AIMS: To investigate the change of intrarenal renin-agiotensin system (RAS) and its role in high-salt induced hypertension. METHODS: Wistar rats were divided into normal-salt (NS), high-salt diet (HS) and high-salt diet with Losartan group (HS+L), for 6 weeks. Systolic blood pressure (SBP) was monitored. Blood and urine samples were collected every 2 weeks. Angiotensinogen (AGT) was measured by ELISA. AGT mRNA and protein were measured by real-time PCR and immunohistochemistry. Renin activity and angiotensin II (Ang II) were measured by radioimmunoassay. RESULTS: HS versus NS group, SBP increased from 2(nd) week (P<0.05), urinary protein increased at 6(th) week (P<0.05). Although plasma renin, AGT and Ang II had no significant changes (P>0.05), renal cortex renin, AGT, and Ang II increased significantly in HS (P<0.05). In HS+L, Losartan failed to reduce SBP (P>0.05) but abolished the increase of proteinuria (P<0.01), renal cortex renin, AGT, Ang II and urinary AGT reduced (P<0.05) while plasma renin, AGT and Ang II enhanced (P<0.05) when compared with HS. Urinary AGT was positively correlated with renal AGT (r=0.592, P <0.01) and Ang II (r=0.726, P <0.01). CONCLUSION: Inappropriate response of the renal RAS to a high salt diet may contribute to hypertension and renal damage, and urinary AGT could reflect intrarenal RAS activity.

Isoflurane preconditioning ameliorates renal ischemia-reperfusion injury through antiinflammatory and antiapoptotic actions in rats.

Renal ischemia-reperfusion (I/R) injury is a major cause of acute kidney injury via inflammation and cell apoptosis. Volatile anesthetics have been shown to exert organ-protective effects against kidney damage in vivo and in vitro. In the present study, we investigated the effects of isoflurane, a commonly used volatile anesthetic, on renal I/R injury and the underlying mechanisms. Rats subjected to renal I/R displayed higher serum creatinine and blood urea nitrogen levels than sham rats as well as severe histopathological damage. Renal I/R also resulted in a nuclear factor-κB (NF-κB)-mediated inflammatory response and dysfunction of the p53-Bax-caspase-3 apoptotic pathway. Rats preconditioned with 1.5% isoflurane for 2 h had better renal function and less tubular apoptosis 24 h after I/R injury than control rats. Pretreatment with isoflurane suppressed renal NF-κB activation, leading to a reduction in proinflammatory molecules (high-mobility group box 1, interleukin-1ß, and tumor necrosis factor-α) both in the kidneys and circulation. In addition, rats subjected to isoflurane preconditioning had a higher Bcl-2/Bax ratio and less cleaved caspase-3. Our findings suggest that preconditioning with a clinically relevant concentration of isoflurane attenuates renal I/R injury, based at least in part on its ability to modulate renal inflammation and apoptosis.

Coexistence of Light- and Heavy-Chain Deposition Disease and Immunotactoid Glomerulopathy in a Patient with Multiple Myeloma: A Case Report.

Multiple myeloma is a malignant neoplasm leading to a variety of renal diseases. Although most patients have only one pattern of renal pathology, two or more patterns can exist in some patients. Here, we report a 61-year-old man with multiple myeloma developed proteinuria, hematuria, hypertension, and renal insufficiency. A combined presentation of light- and heavy-chain deposition disease and immunotactoid glomerulopathy was proved by kidney biopsy. Treatment of multiple myeloma resulted in a complete resolution of the renal manifestations. This case illustrates the complexity of paraprotein associated renal lesions and emphasizes that further studies examining the physiologic properties and pathologic effects of monoclonal immunoglobulin are needed.

Expression of immunoglobulin G in human proximal tubular epithelial cells.

Proximal tubular epithelial cells (PTECs) have innate immune characteristics, and produce proinflammatory factors, chemokines and complement components that drive epithelial­mesenchymal transition (EMT). Our previous studies revealed that human mesangial cells and podocytes were able to synthesize and secrete immunoglobulin (Ig)A and IgG, respectively. The aim of the present study was to evaluate the expression of Igs in PTECs. Firstly, IgG was detected in the cytoplasm, the cell membrane and the lumen of PTECs in the normal renal cortex by immunohistochemistry. Secondly, Igγ gene transcription and V(D)J recombination were detected in single PTECs by nested PCR and Sanger sequencing. Thirdly, Igγ, Igκ and Igλ were clearly detected in an immortalized PTEC line (HK­2) by immunostaining and western blotting, in which RP215 (an antibody that predominantly binds to non­B cell­derived IgG) was used. In addition, Igγ, Igκ and Igλ gene transcripts, conservative V(D)J recombination in the Igγ variable region, recombination activating gene 1/2 and activation­induced cytidine deaminase were all detected in HK­2 cells. These data suggested that PTECs may express IgG in a similar manner to B cells. Furthermore, IgG expression was upregulated by TGF­ß1 and may be involved in EMT.

The Non-peptide Angiotensin-(1-7) Mimic AVE 0991 Attenuates Delayed Neurocognitive Recovery After Laparotomy by Reducing Neuroinflammation and Restoring Blood-Brain Barrier Integrity in Aged Rats.

Delayed neurocognitive recovery (dNCR) after surgery is a common postoperative complication in older adult patients. Our previous studies have demonstrated that cognitive impairment after surgery involves an increase in the brain renin-angiotensin system (RAS) activity, including overactivation of the angiotensin 2/angiotensin receptor-1 (Ang II/AT1) axis, which provokes the disruption of the hippocampal blood-brain barrier (BBB). Nevertheless, the potential role of the counter-regulatory RAS axis, the Ang-(1-7)/Mas pathway, in dNCR remains unknown. Using an aged rat model of dNCR, we dynamically investigated the activity of both axes of the RAS following laparotomy. AVE 0991, a nonpeptide analog of Ang-(1-7), was administered intranasally immediately after laparotomy. We found that the elevation of Ang II, induced by surgery was accompanied by a decrease of Ang-(1-7) in the hippocampus, but not in the circulation. Surgery also significantly downregulated hippocampal Mas receptor expression at 24 h postsurgery. Mas activation with intranasal AVE 0991 treatment significantly improved hippocampus-dependent learning and memory deficits induced by surgery. Furthermore, it attenuated hippocampal neuroinflammation, as shown by the decreased level of the microglial activation marker cluster of differentiation 11b (CD11b) and the decreased production of several inflammatory molecules. Along with these beneficial effects, the AVE 0991 treatment also alleviated the imbalance between matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-3 (TIMP-3), modulated the expression of occludin, and alleviated the IgG extravasation, thereby restoring the integrity of the BBB. In conclusion, these data indicate that activation of Mas by AVE 0991 attenuates dNCR after surgery by reducing neuroinflammation and restoring BBB integrity. Our findings suggest that the Ang-(1-7)/Mas pathway may be a novel therapeutic target for treating dNCR after surgery in older adult patients.

Expression of immunoglobulin A in human mesangial cells and its effects on cell apoptosis and adhesion.

IgA nephropathy (IgAN) is characterized by predominant IgA deposition in the glomerular mesangium. It has been considered that the deposited IgA is synthesized by B cells, although recent reports have suggested the implication of other cell types. Therefore, the present study investigated whether glomerular mesangial cells could produce IgA by themselves. Semi­quantitative reverse transcription-polymerase chain reaction, and immunostaining analysis revealed that the IgA protein and gene transcripts were expressed in primary human renal mesangial cells (HRMCs). Furthermore, the IgA heavy chain (α1 and α2) and the light chain (κ and λ) were localized in the cytoplasm or were located on the cell membranes of human mesangial cells (HMCs). Mass spectrometry results indicated that Ig α1 and Ig α2 were secreted in the culture media of HMCs. The transcripts of Ig α, Ig κ and Ig λ constant regions were detected. The predominant rearrangement pattern of the variable region of Ig κ, was Vκ3­20*01/Jκ1*01 in HMCs and Vκ1­12*01/Jκ4*01 in HRMCs. In addition, knockdown of Ig α1 expression by small interfering RNA (siRNA) inhibited cell adhesion and promoted apoptosis. Our findings demonstrate that HMCs can express IgA, and that this expression is associated with cell functions, which may contribute to the deposition of IgA in patients with IgAN.

Expression of immunoglobulin G in human podocytes, and its role in cell viability and adhesion.

Podocyte injury occurs during the initiation and development of numerous forms of glomerular disease, and antibodies targeting podocytes have become a biomarker for diagnosis and monitoring treatment response. Accumulating evidence has suggested that immunoglobulin (Ig) is expressed in non­B lineage cells, including epithelial cancer cells, myeloid cells and several types of normal cells. The main aim of the present study was to ascertain the expression of IgG in human podocytes and to determine its potential role in cellular bioactivity. The present study detected positive staining for IgG heavy chain (Igγ) and its subtype γ4, and the light chains κ and λ in the cytoplasm or on the membrane by immunofluorescence. In addition, positive bands were detected for Igγ, γ1, γ3, γ4, κ and λ in the lysates of a podocyte cell line by western blotting. Mass spectrometry confirmed IgG1 as an intact tetramer in the culture supernatant. Constant region transcripts of Igγ, γ1, γ3, γ4, κ and λ were identified by reverse transcription­polymerase chain reaction, and DNA sequencing of these transcripts revealed 96­99% similarity with Ig mRNAs in the National Center for Biotechnology Information database. Compared with the diverse gene rearrangements from B cell-derived Ig, podocyte­derived Ig exhibited conservative V(D)J patterns in the variable regions of Igγ and κ chains. Furthermore, the present study investigated the mechanism underlying IgG production in these cells by examining the expression of recombination activating gene (RAG)1, RAG2 and activation­induced cytidine deaminase. The expression levels of these proteins suggested that podocyte­derived Ig and traditional Ig may be generated in a similar manner. Furthermore, small interfering RNA­mediated downregulation of IgG expression reduced podocyte viability and adhesive capabilities. These findings suggested that IgG is expressed in podocytes and that this expression may be associated with podocyte function. Due to its potential biological and clinical significance, this phenomenon warrants further investigation.

Monoclonal gammopathy in rheumatic diseases.

To analyze the clinical spectrum, laboratory characteristics, and outcomes of monoclonal gammopathy (MG) in patients with rheumatic diseases. Screening for the presence of MG was performed in 872 inpatients with rheumatic diseases from January 2010 to July 2017. A total of 41 patients were enrolled. Their clinical and biological features in addition to outcomes were described. For each patient with primary Sjögren syndrome (pSS), 2 age- and sex-matched pSS patients without MG were selected as controls. Risk factors for the presence of MG and malignant hematological neoplasias were assessed. MG was observed in patients with SS, rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis, primary biliary cirrhosis, polymyositis, hypomyopathic dermatomyositis, psoriatic arthritis, ANCA-associated vasculitis, polyarteritis nodosa, and polymyalgia rheumatic, with SS the most frequent type. Serum M protein was detected in 37 patients. The monoclonal bands identified in serum were 16 IgG (5 κ, 11 λ), 11 IgA (6 κ, 5 λ), 6 IgM (5 κ, 1 λ), and 4 free λ chains. M components were observed in urine in the other 4 patients. High ESR, albumin/globulin inversion, rheumatoid factor positivity, hypergammaglobulinemia, and hypocomplementemia were common features, presented in more than half of the 41 patients. Patients with pSS, when complicated with MG, showed a higher rate of abnormal urine NAG (71.4 vs 15.8%, P = 0.025), higher levels of ESR [55.0 (53.5) mm/h vs 21.0 (31.8) mm/h, P = 0.001], ESSDAI [26.0 (25.0) vs 12.0 (9.0), P = 0.006], and ClinESSDAI scores [24.0 (25.0) vs 10.5 (10.0), P = 0.011]. Multivariate analysis revealed that the disease activity, assessed by either ESSDAI [adjusted OR 1.127 (95%CI 1.015-1.251), P = 0.025] or ClinESSDAI [adjusted OR 1.121 (95%CI 1.011-1.242), P = 0.030], was the only independent risk factor for the presence of MG. During the follow-up, 2 patients had transient serum M protein, 2 had isotype switch, 1 progressed to multiple myeloma (MM), and another 2 experienced renal injuries attributed by monoclonal or polyclonal plasma cell interstitial infiltration. Seven (17.1%) of the 41 MG patients presented hematological neoplasias, 4 with MM, 2 with smoldering multiple myeloma, and 1 with B cell lymphoma of mucosa-associated lymphoid tissue (MALT) type. The presence of light-chain MG was associated with the development of MM [OR 17.5 (95%CI 1.551-197.435), P = 0.041], but not with an increased risk of lymphoma or SMM. MG was observed in patients with various rheumatic disorders, with SS being the most common type. The presence of MG might be associated with higher disease activity. The development of hematological neoplasias including MM and lymphoma was seen in this setting. Therefore, we recommend the screening for MG and close monitoring for potential malignant transformation in patients with rheumatic diseases as needed.

Hemodialysis is associated with higher serum FGF23 level when compared with peritoneal dialysis.

BACKGROUND: Considering the growing relevance of fibroblast growth factor-23 (FGF23) and increased cardiovascular mortality in dialysis population, an analysis was performed to assess the influence of dialysis modality (peritoneal dialysis and hemodialysis) on level of FGF23. METHODS: A cross-sectional study was performed in 80 continuous ambulatory peritoneal dialysis (CAPD) and 65 hemodialysis (HD) patients without residual renal function. Levels of calcium, phosphate, parathyroid hormone and FGF23 were measured, and their correlations were analyzed. Data on demographics, dialysis modality and FGF23 level were also analyzed. RESULTS: A significant correlation was found between FGF23 and serum calcium, serum phosphate and dialysis vintage in dialysis patients. Level of FGF23 was significantly higher in hemodialysis patients than that in peritoneal dialysis population. Multivariable regression revealed that, compared to CAPD, hemodialysis was found to be a predictor for higher FGF23 level, which was independent of serum calcium and phosphate level (P < 0.05). CONCLUSIONS: These findings demonstrate that FGF23 levels are significantly higher in hemodialysis patients than that in peritoneal dialysis patients. We demonstrate an important association between dialysis modality (HD vs CAPD) and higher FGF23, independent of classical determinants (serum calcium and phosphate level).

Surgery-Induced Hippocampal Angiotensin II Elevation Causes Blood-Brain Barrier Disruption via MMP/TIMP in Aged Rats.

Reversible blood-brain barrier (BBB) disruption has been uniformly reported in several animal models of postoperative cognitive dysfunction (POCD). Nevertheless, the precise mechanism underlying this occurrence remains unclear. Using an aged rat model of POCD, we investigated the dynamic changes in expression of molecules involved in BBB disintegration, matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9), as well as three of their endogenous tissue inhibitors of MMP (TIMP-1, -2, -3), and tried to establish the correlation between MMP/TIMP balance and surgery-induced hippocampal BBB disruption. We validated the increased hippocampal expression of angiotensin II (Ang II) and Ang II receptor type 1 (AT1) after surgery. We also found MMP/TIMP imbalance as early as 6 h after surgery, together with increased BBB permeability and decreased expression of Occludin and zonula occludens-1 (ZO-1), as well as increased basal lamina protein laminin at 24 h postsurgery. The AT1 antagonist candesartan restored MMP/TIMP equilibrium and modulated expression of Occludin and laminin, but not ZO-1, thereby improving BBB permeability. These events were accompanied by suppression of the surgery-induced canonical nuclear factor-κB (NF-κB) activation cascade. Nevertheless, AT1 antagonism did not affect nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ) expression. Collectively, these findings suggest that surgery-induced Ang II release impairs BBB integrity by activating NF-κB signaling and disrupting downstream MMP/TIMP balance via AT1 receptor.

Changes of urinary angiotensinogen concentration and its association with urinary proteins in diabetic rats.

OBJECTIVE: It had been reported that angiotensinogen might be a marker for activation of renin-angiotensin system, which was associated with the development of diabetic nephropathy. The purpose of this study was to investigate the functional roles of AGT in DN in vitro. METHODS: Diabetic rat models were built by single intraperitoneal injection of streptozotocin. The diabetic rats were divided into three groups, two of the three groups were treated with different doses of losartan, the other diabetic group was as control and normal rats acted as healthy control. In a 12-week investigation, we detected the changes of AGT in all rats' blood and urine and the association between AGT concentration and RAS activation and urinary proteins were analyzed in this study. RESULTS: The serum AGT of rats had no significant differences (P>0.05 for all). The urinary AGT of the diabetic rats was significantly different from the control group, moreover, the urinary AGT of the diabetic rats under different treatments was also obviously different (P<0.05 for all). Besides, the results of immunohistochemical assay indicated that AGT expression level was correlated with renal tissues damage. The level of AGT was positively associated with urinary protein (r=0.493, P<0.01) and negatively correlated with CCr (r=-0.474, P=0.007) and the dose of ARB (r=-0.575, P=0.001). Moreover, the dose of ARB was independently associated with urinary AGT (B=-2.963, P=0.024) in diabetic rats. CONCLUSION: Urinary AGT may be a marker for the activation of local RAS in kidney and independently associated with ARB.

Increased urinary angiotensinogen precedes the onset of albuminuria in normotensive type 2 diabetic patients.

It was previously reported that intrarenal renin angiotensin system (RAS) plays a pivotal role in the onset and progression of diabetic nephropathy (DN). Urinary angiotensinogen (UAGT) was employed as a special index of the intrarenal RAS status and enhanced significantly at a very early stage of chronic kidney disease and type 1 diabetes. On the basis of these findings, the present study was performed to test the hypothesis that UAGT levels are increase even before the development of DN in type 2 diabetic patients without hypertension. 102 patients with type 2 diabetes mellitus (T2DM) and 18 healthy volunteers were studied cross-sectionally. Clinical data were collected and morning spot urine samples were obtained from all participants. UAGT levels were detected by an enzyme-linked immunosorbent assay (ELISA). As a result, UAGT to creatinine ratio (UAGT/Cr) was significantly enhanced in T2DM patients before the appearance of urinary albumin (UALB) and further increased to a greater degree in albuminuric patients. UAGT/Cr levels were positively correlated with Log (UALB to creatinine ratio) and diastolic blood pressure, but negatively correlated with estimated glomerular filtration rate. These data indicate that elevated UAGT levels precede the onset of albuminuria in normotensive T2DM patients. UAGT might potentially serve as an early marker to determine intrarenal RAS activity and predict progressive kidney disease in T2DM patients without hypertension.

Duration-dependent regulation of autophagy by isoflurane exposure in aged rats.

Current evidence suggests a central role for autophagy in many inflammatory brain disorders, including Alzheimer's disease (AD). Furthermore, it is also well accepted that some inhalation anesthetics, such as isoflurane, may cause AD-like neuropathogenesis and resultant postoperative cognitive dysfunction, especially in the elderly population. However, the impact of inhalation anesthetics on autophagic components in the brain remains to be documented. Hence, our objective was to investigate the effects of different durations of isoflurane exposure on hippocampus-dependent learning and hippocampal autophagy in aged rats. Aged Sprague-Dawley rats (20 months old) were randomly exposed to 1.5% isoflurane or 100% oxygen for 1 or 4 h. Animals were then trained in the Morris water maze (4 trials/day for 5 consecutive days). Hippocampal phagophore formation markers, beclin 1 and protein microtubule-associated protein 1 light chain-3B (LC3B), as well as p62, an indicator of autophagic flux, were quantified by western blotting. There was no significant difference in the escape latencies and time spent in the target quadrant, as well as hippocampal expression of beclin 1, LC3B-II, and p62 at 24 h post-anesthesia between the 1-h isoflurane-exposed rats and their controls (P >0.05). Four-hour exposure to isoflurane resulted in spatial learning and memory deficits, as evidenced by prolonged escape latencies on days 4 and 5 post-anesthesia and less time spent in the target quadrant than sham-exposed animals (P <0.05). These events were accompanied by a decline in hippocampal expression of LC3B-I, LC3B-II, and beclin 1 24 h after isoflurane (P <0.01 and P <0.05). Nevertheless, no significant change in p62 expression was found. Further kinetics study of autophagic changes induced by 4 h of isoflurane showed a transient upregulation of LC3B-I, LC3B-II, and beclin 1 at the end of exposure and a subsequent striking decrease within 12-24 h post-anesthesia (P <0.05). Hippocampal p62 peaked at 6 h but subsequently resolved. These results from our pilot in vivo study support a duration-dependent relationship between 1.5% isoflurane exposure, and spatial cognitive function as well as hippocampal phagophore formation.