Rise In Plasma Creatinine Research Articles

Western diet exacerbates aristolochic acid-induced nephropathy in mice

Aristolochic acid (AA) ingestion causes Balkan nephropathy, characterized by tubular injury and progression to chronic kidney disease (CKD). AA is taken up by proximal tubule cells via organic anion transport (OAT3) and induces p53-mediated DNA damage, but little is known about modulating factors. The Western diet (WD) is rich in saturated fats, sugars, and salt and contributes to the development of metabolic disorders such as obesity and diabetes, but also to the progression of CKD. The aim of this study was to elucidate the impact of WD on AA-induced kidney injury. 5-week-old male C57BL6 mice were fed with WD or normal chow (NC) for 8 weeks, followed by administration of AA every 3 days at a dose of 3 mg/kg for 3 weeks. Samples were collected after a 3-week recovery period (n=4/group for vehicle; n=7-8/group for AA). The AA-induced increase in plasma creatinine and the reduction of hematocrit were significantly greater in WD vs NC. This was associated with increased kidney gene expression in WD vs NC of markers of DNA damage ( p53), injury ( Kim1 and Ngal), and inflammation ( Tnfa). The WD group had a greater body weight and, therefore, received a higher total dose of AA (0.73 and 0.6 mg), which may have worsened kidney injury. Therefore, in a second series, the same total dose of AA (0.9 mg) was administered to WD and NC groups. WD similarly increased the AA-induced fall in hematocrit and rise in plasma creatinine and renal p53, Kim1, Ngal, and Tnfa mRNA expression compared to the NC group. Moreover, WD increased renal mRNA expression of Oat3. These findings suggest that WD increases the susceptibility to AA nephrotoxicity, possibly through upregulation of OAT3. This model may be useful for studying the mechanistic impact of Western diet on the development and progression of CKD caused by nephrotoxic agents. Supported by National Institutes of Health (NIH) Grants RF1AG061296 (PM, VV), R01DK132690 (VV), and P30 DK079337 (VV), the Department of Veterans Affairs, and a fellowship of the Manpei Suzuki Diabetes Foundation (YO). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Neutrophil Gelatinase-Associated Lipocalin (NGAL) and cystatin C are early biomarkers of acute kidney injury associated with cardiac surgery

Acute kidney injury (AKI) is a serious complication in as much as half of the patients undergoing cardiac surgery, and early diagnosis and treatment are of the utmost importance. There is a need for robust biomarkers that can detect cardiac surgery-associated AKI (CSA-AKI) prior to rise in plasma creatinine, which typically occurs at least 48 h postoperatively. We compared pre- and 4, 12 and 48 h postoperative plasma (P) neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, urea and creatinine, and urine (U) NGAL, as markers of AKI, in 49 patients (67% men, median age 65 years) scheduled for elective cardiac surgery (e.g. coronary artery bypass graft and/or valve replacement surgery) with the use of extracorporeal circulation. Patients with preoperative sepsis, renal replacement therapy, or estimated glomerular filtration rate <30 mL/min/1.73m2 were excluded. P- and U-NGAL were measured using the Roche Modular P (Roche Diagnostics®) NGAL immunoassay. According to AKIN/KDIGO criteria, nine patients (18%) were diagnosed with CSA-AKI. Compared to patients without CSA-AKI, these patients had significantly higher P-NGAL and P-cystatin C values 4 h (p-values .002 and <.001) and 12 h (p-values <.001 and <.001) postoperatively. The same differences were not observed for U-NGAL. Patients with AKI also had significantly higher P-creatinine 4 and 12 h postoperatively (p-values .001 and <.001), however the rise in P-creatinine was just above the upper reference limit. In conclusion, plasma NGAL and cystatin C seem to detect CSA-AKI earlier than the more commonly used biomarkers creatinine and urea.

Aristolochic acid-induced nephropathy is attenuated in mice lacking the neutral amino acid transporter B0AT1 (Slc6a19).

B0AT1 (Slc6a19) mediates absorption of neutral amino acids in the small intestine and in the kidneys, where it is primarily expressed in early proximal tubules (S1-S2). To determine the role of B0AT1 in nephropathy induced by aristolochic acid (AA), which targets the proximal tubule, littermate female B0AT1-deficient (Slc6a19-/-), heterozygous (Slc6a19+/-), and wild-type (WT) mice were administered AA (10 mg/kg ip) or vehicle every 3 days for 3 wk, and analyses were performed after the last injection or 3 wk later. Vehicle-treated mice lacking Slc6a19 showed normal body and kidney weight and plasma creatinine versus WT mice. The urinary glucose-to-creatinine ratio (UGCR) and urinary albumin-to-creatinine ratio (UACR) were two to four times higher in vehicle-treated Slc6a19-/- versus WT mice, associated with lesser expression of early proximal transporters Na+-glucose cotransporter 2 and megalin, respectively. AA caused tubular injury independently of B0AT1, including robust increases in cortical mRNA expression of p53, p21, and hepatitis A virus cellular receptor 1 (Havcr1), downregulation of related proximal tubule amino acid transporters B0AT2 (Slc6a15), B0AT3 (Slc6a18), and Slc7a9, and modest histological tubular damage and a rise in plasma creatinine. Absence of B0AT1, however, attenuated AA-induced cortical upregulation of mRNA markers of senescence (p16), inflammation [lipocalin 2 (Lcn2), C-C motif chemokine ligand 2 (Ccl2), and C-C motif chemokine receptor 2 (Ccr2)], and fibrosis [tissue inhibitor of metallopeptidase 1 (Timp1), transforming growth factor-β1 (Tgfb1), and collagen type I-α1 (Col1a1)], associated with lesser fibrosis staining, lesser suppression of proximal tubular organic anion transporter 1, restoration of Na+-glucose cotransporter 2 expression, and prevention of the AA-induced fivefold increase in the urinary albumin-to-creatinine ratio observed in WT mice. The data suggest that proximal tubular B0AT1 is important for the physiology of renal glucose and albumin retention but potentially deleterious for the kidney response following AA-induced kidney injury.NEW & NOTEWORTHY Based on insights from studies manipulating glucose transport, the hypothesis has been proposed that inhibiting intestinal uptake or renal reabsorption of energy substrates has unique therapeutic potential to improve metabolic disease and kidney outcome in response to injury. The present study takes this idea to B0AT1, the major transporter for neutral amino acids in the intestine and kidney, and shows that its absence attenuates aristolochic acid-induced nephropathy.

Renal Water Conservation and Plasma Creatinine in Colorectal Cancer Surgery: A Single-Group Clinical Study.

Elevation of plasma creatinine after surgery is associated with postoperative morbidity and mortality. We studied whether lengthy surgery might induce renal conservation of water strong enough to exceed the renal capacity to excrete creatinine. Colorectal cancer surgery was performed via laparoscopy in 126 patients. Blood and urine were sampled before surgery, in the postoperative care unit, and 1 day after surgery. The Fluid Retention Index (FRI), which is a composite index of renal water conservation, was calculated. The mean FRI before surgery was 2.4, indicating that patients were well-hydrated. The FRI increased to 2.8 after surgery, and further to 3.5 on the first postoperative day. Plasma creatinine increased in 66 (52%) of the patients while plasma proteins were diluted by 15%. Patients with urinary creatinine > 8.5 mmol/L before surgery were more likely to later show elevation of plasma creatinine (68 vs. 46%, P < 0.04). The final FRI was higher in those with perioperative elevation of plasma creatinine (median 3.7 vs. 3.4; P < 0.01) and a similar difference was found for the final urinary creatinine concentration (8.5 vs. 7.2 mmol/L; P < 0.01). The gastrointestinal recovery time was prolonged when >2 L of Ringer's had been infused during the surgery. We conclude that colorectal surgery initiated a process of renal water conservation that extended into the postoperative period. The water conservation was more intense and the urinary concentration of creatinine was higher in those who had a perioperative rise in plasma creatinine.

Absolute quantification of donor-derived cell-free DNA as a marker of rejection and graft injury in kidney transplantation: Results from a prospective observational study.

Donor‐derived cell‐free DNA (dd‐cfDNA) is a noninvasive biomarker for comprehensive monitoring of allograft injury and rejection in kidney transplantation (KTx). dd‐cfDNA quantification of copies/mL plasma (dd‐cfDNA[cp/mL]) was compared to dd‐cfDNA fraction (dd‐cfDNA[%]) at prespecified visits in 189 patients over 1 year post KTx. In patients (N = 15, n = 22 samples) with biopsy‐proven rejection (BPR), median dd‐cfDNA(cp/mL) was 3.3‐fold and median dd‐cfDNA(%) 2.0‐fold higher (82 cp/mL; 0.57%, respectively) than medians in Stable Phase patients (N = 83, n = 408) without rejection (25 cp/mL; 0.29%). Results for acute tubular necrosis (ATN) were not significantly different from those with biopsy‐proven rejection (BPR). dd‐cfDNA identified unnecessary biopsies triggered by a rise in plasma creatinine. Receiver operating characteristic (ROC) analysis showed superior performance (P = .02) of measuring dd‐cfDNA(cp/mL) (AUC = 0.83) compared to dd‐cfDNA(%) (area under the curve [AUC] = 0.73). Diagnostic odds ratios were 7.31 for dd‐cfDNA(cp/mL), and 6.02 for dd‐cfDNA(%) at thresholds of 52 cp/mL and 0.43%, respectively. Plasma creatinine showed a low correlation (r = 0.37) with dd‐cfDNA(cp/mL). In a patient subset (N = 24) there was a significantly higher rate of patients with elevated dd‐cfDNA(cp/mL) with lower tacrolimus levels (<8 μg/L) compared to the group with higher tacrolimus concentrations (P = .0036) suggesting that dd‐cfDNA may detect inadequate immunosuppression resulting in subclinical graft damage. Absolute dd‐cfDNA(cp/mL) allowed for better discrimination than dd‐cfDNA(%) of KTx patients with BPR and is useful to avoid unnecessary biopsies.

Increased migration of antigen presenting cells to newly-formed lymphatic vessels in transplanted kidneys by glycol-split heparin.

BackgroundChronic renal transplant dysfunction is characterized by loss of renal function and tissue remodeling, including chronic inflammation and lymph vessel formation. Proteoglycans are known for their chemokine presenting capacity. We hypothesize that interruption of the lymphatic chemokine–proteoglycan interaction interferes with the lymphatic outflow of leukocytes from the renal graft and might decrease the anti-graft allo-immune response.MethodsIn a rat renal chronic transplant dysfunction model (female Dark-Agouti to male Wistar Furth), chemokines were profiled by qRT-PCR in microdissected tubulo-interstitial tissue. Disruption of lymphatic chemokine–proteoglycan interaction was studied by (non-anticoagulant) heparin-derived polysaccharides in vitro and in renal allografts. The renal allograft function was assessed by rise in plasma creatinine and urea.ResultsWithin newly-formed lymph vessels of transplanted kidneys, numerous CD45+ leukocytes were found, mainly MHCII+, ED-1-, IDO-, HIS14-, CD103- antigen presenting cells, most likely representing a subset of dendritic cells. Treatment of transplanted rats with regular heparin and two different (non-)anticoagulant heparin derivatives revealed worsening of kidney function only in the glycol-split heparin treated group despite a two-fold reduction of tubulo-interstitial leukocytes (p<0.02). Quantitative digital image analysis however revealed increased numbers of intra-lymphatic antigen-presenting cells only in the glycol-split heparin group (p<0.01). The number of intra-lymphatic leukocytes significantly correlates with plasma creatinine and urea, and inversely with creatinine clearance.ConclusionsTreatment of transplanted rats with glycol-split heparin significantly increases the number of intra-lymphatic antigen presenting cells, by increased renal diffusion of lymphatic chemokines, thereby increasing the activation and recruitment of antigen presenting cells towards the lymph vessel. This effect is unwanted in the transplantation setting, but might be advantageous in e.g., dendritic cell vaccination.

Proenkephalin, Renal Dysfunction, and Prognosis in Patients With Acute Heart Failure: A GREAT Network Study

BackgroundProenkephalin A (PENK) and its receptors are widely distributed. Enkephalins are cardiodepressive and difficult to measure directly. PENK is a stable surrogate analyte of labile enkephalins that is correlated inversely with renal function. Cardiorenal syndrome is common in acute heart failure (HF) and portends poor prognosis. ObjectivesThis study assessed the prognostic value of PENK in acute HF, by identifying levels that may be useful in clinical decisions, and evaluated its utility for predicting cardiorenal syndrome. MethodsThis multicenter study measured PENK in 1,908 patients with acute HF (1,186 male; mean age 75.66 ± 11.74 years). The primary endpoint was 1-year all-cause mortality; secondary endpoints were in-hospital mortality, all-cause mortality or HF rehospitalization within 1 year, and in-hospital worsening renal function, defined as a rise in plasma creatinine ≥26.5 μmol/l or 50% higher than the admission value within 5 days of presentation. ResultsDuring 1-year follow-up, 518 patients died. Measures of renal function were the major determinants of PENK levels. PENK independently predicted worsening renal function (odds ratio: 1.58; 95% confidence interval [CI]: 1.24 to 2.00; p < 0.0005) with a model receiver-operating characteristic area of 0.69. PENK was associated with the degree of worsening renal function. Multivariable Cox regression models showed that PENK level was an independent predictor of 1-year mortality (p < 0.0005) and 1-year death and/or HF (hazard ratio: 1.27; 95% CI: 1.10 to 1.45; p = 0.001). PENK levels independently predicted outcomes at 3 or 6 months and were independent predictors of in-hospital mortality, predominantly down-classifying risk in survivors when added to clinical scores; levels <133.3 pmol/l and >211.3 pmol/l detected low-risk and high-risk patients, respectively. ConclusionsPENK levels reflect cardiorenal status in acute HF and are prognostic for worsening renal function and in-hospital mortality as well as mortality during follow-up.

Impact of Glucose Management Team on Outcomes of Hospitalization in Patients With Type 2 Diabetes Admitted to the Medical Service

To improve glycemic control of hospitalized patients with diabetes and hyperglycemia, many medical centers have established dedicated glucose management teams (GMTs). However, the impact of these specialized teams on clinical outcomes has not been evaluated. We conducted a retrospective study of 440 patients with type 2 diabetes admitted to the medical service for cardiac or infection-related diagnosis. The primary endpoint was a composite outcome of several well-recognized markers of morbidity, consisting of: death during hospitalization, transfer to intensive care unit, initiation of enteral or parenteral nutrition, line infection, new in-hospital infection or infection lasting more than 20 days of hospitalization, deep venous thrombosis or pulmonary embolism, rise in plasma creatinine, and hospital re-admissions. Medical housestaff managed the glycemia in 79% of patients (usual care group), while the GMT managed the glycemia in 21% of patients (GMT group). The primary outcome was similar between cohorts (0.95 events per patient versus 0.99 events per patient in the GMT and usual care cohorts, respectively). For subanalysis, the subjects in both groups were stratified into those with average glycemia of <180 mg/dL versus those with glycemia >180 mg/dL. We found a significant beneficial impact of glycemic management by the GMT on the composite outcome in patients with average glycemia >180 mg/dL during their hospital stay. The number of patients who met primary outcome was significantly higher in the usual care group (40 of 83 patients, 48%) than in the GMT-treated cohort (8 of 33 patients, 25.7%) (P<.02). Our data suggest that GMTs may have an important role in managing difficult-to-control hyperglycemia in the inpatient setting. BG = blood glucose GMT = glucose management team HbA1c = hemoglobin A1c ICU = intensive care unit POC = point of care T2D = type 2 diabetes.

Sphingosine 1-Phosphate Receptor 3-Deficient Dendritic Cells Modulate Splenic Responses to Ischemia-Reperfusion Injury.

The plasticity of dendritic cells (DCs) permits phenotypic modulation ex vivo by gene expression or pharmacologic agents, and these modified DCs can exert therapeutic immunosuppressive effects in vivo through direct interactions with T cells, either inducing T regulatory cells (T(REG)s) or causing anergy. Sphingosine 1-phosphate (S1P) is a sphingolipid and the natural ligand for five G protein-coupled receptors (S1P1, S1P2, S1P3, S1P4, and S1P5), and S1PR agonists reduce kidney ischemia-reperfusion injury (IRI) in mice. S1pr3(-/-)mice are protected from kidney IRI, because DCs do not mature. We tested the therapeutic advantage of S1pr3(-/-) bone marrow-derived dendritic cell (BMDC) transfers in kidney IRI. IRI produced a rise in plasma creatinine (PCr) levels in mice receiving no cells (NCs) and mice pretreated with wild-type (WT) BMDCs. However, S1pr3(-/-) BMDC-pretreated mice were protected from kidney IRI. S1pr3(-/-) BMDC-pretreated mice had significantly higher numbers of splenic T(REG)s compared with NC and WT BMDC-pretreated mice. S1pr3(-/-) BMDCs did not attenuate IRI in splenectomized, Rag-1(-/-), or CD11c(+) DC-depleted mice. Additionally, S1pr3(-/-) BMDC-dependent protection required CD169(+)marginal zone macrophages and the macrophage-derived chemokine CCL22 to increase splenic CD4(+)Foxp3(+) T(REG)s. Pretreatment with S1pr3(-/-) BMDCs also induced T(REG)-dependent protection against IRI in an allogeneic mouse model. In summary, adoptively transferred S1pr3(-/-) BMDCs prevent kidney IRI through interactions within the spleen and expansion of splenic CD4(+)Foxp3(+) T(REG)s. We conclude that genetically induced deficiency of S1pr3 in allogenic BMDCs could serve as a therapeutic approach to prevent IRI-induced AKI.

Administration of hydrogen sulfide protects ischemia reperfusion-induced acute kidney injury by reducing the oxidative stress.

Renal ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury. Hydrogen sulfide (H2S) has been known as a novel gaseous signaling molecule. The aim of this study was to investigate whether the efficacy of H2S in protecting against renal IRI is through its antioxidative effect. In this study, rats were randomized into Sham, IR, or sodium hydrosulfide (NaHS, an H2S donor) groups. To establish a model of renal IRI, both renal arteries were occluded for 55min and then declamped to allow reperfusion for 24h. Rats in the NaHS group received intraperitoneal injections of 75μmol/kg NaHS 10min before the onset of ischemia and immediately after the onset of reperfusion. Sham group underwent laparotomy without cross-clamping of renal pedicles. After reperfusion, plasma and renal tissue samples were collected for functional, histological, and oxidative stress evaluation. The IR group exhibited significant rise in plasma creatinine, blood urea nitrogen (BUN), renal malondialdehyde (MDA) concentration, and significant reduction of renal superoxide dismutase (SOD) activity. Treatment with NaHS reduced the levels of plasma creatinine, BUN, renal MDA concentration, and increased SOD activity in the kidneys. NaHS improved renal histological changes in comparison to IR group. Our data demonstrated that H2S can protect against renal IRI and that its therapeutic effects may be mediated by reducing oxidative stress.

English

Aim: The research was primarily set to assess the stages at which acute kidney injuries (AKI) are presented for clinical appraisal. Methods: The research was carried out in southwest Nigeria. A total of 151 participants were included, 101 were AKI patients. The remaining 50 were apparently healthy individuals who had no history of AKI, who served as control. Estimation of plasma creatinine was carried out on the subjects’ blood sample. Values were then subjected to statistical analysis using SPSS 17. The diagnosis and staging of AKI was based on history taken and a rise in plasma creatinine to set cut off points. AKI patients were therefore grouped into three with respect to the plasma creatinine content of the first blood sample collected on presentation. The three stages were titled 1, 2, and 3; 1 and 3 being mild and severe respectively. Result: A significant rise in plasma creatinine was observed when the AKI patients were compared with control. The frequencies of patients at each AKI stage were 17, 5, and 79 for stages 1, 2, and 3 respectively. The age groups and frequency of AKI were: up to 10 years (31), 11 to 20years (6), 21 to 30 years (27), 31 to 4 years (33), 41 to 50 years (4), 51 to 60 years (5), and 60 years and above (6). Conclusion: It appears that in the absence of etabolic diseases, the frequency of AKI is higher in children and between the age group of 21 to 40. Key words: Acute kidney injury, Staging, Creatinine, Nephrotoxic substances

Glycemic Control and Outcomes of Hospitalization in Noncritically Ill Patients With Type 2 Diabetes Admitted With Cardiac Problems or Infections

Although the importance of glycemic control is well established for patients with diabetes hospitalized for surgical problems, it has not been supported by clinical studies for patients with diabetes hospitalized on the medical floors. We conducted a retrospective study of 378 patients with type 2 diabetes admitted for cardiac or infectious disease (ID) diagnosis between September 1, 2011, and August 1, 2012. Exclusion criteria included type 1 diabetes, admission to the intensive care unit (ICU), hospital stay shorter than 3 days, and daily glucocorticoid dose >20 mg of methylprednisolone. The primary composite outcome included death during hospitalization, ICU transfer, initiation of enteral or parenteral nutrition, line infection, deep vein thrombosis, pulmonary embolism, rise in plasma creatinine by 1 or >2 mg/dL, new infection, an infection lasting for more than 20 days, and readmission within 30 days and between 1 and 10 months after discharge. Patients were stratified by mean blood glucose (BG) level: group 1 had mean BG of <180 mg/dL (n = 286; mean BG, 142 ± 23 mg/dL), whereas group 2 had mean BG levels >181 mg/dL (n = 92; mean BG, 218 ± 34 mg/dL; P<.0001). Group 2 had a 46% higher occurrence of the primary outcome (P<.0004). The rate of unfavorable events was greater in cardiac and ID patients with worse glycemic control (group 2). Our data strongly support a positive influence of better glycemic control (average glycemia <180 mg/dL or 10 mmol/L) on outcomes of hospitalization in patients with type 2 diabetes.

G377(P) Early renal transplant biopsies in children: rejection or calcineurin inhibitor toxicity?

AimsAn increase in transplant biopsy rate in the first month following renal transplantation (RT) was observed in our centre following implementation of an early steroid withdrawal (ESW) immunosuppression (IS) protocol...

Slit2 Prevents Neutrophil Recruitment and Renal Ischemia-Reperfusion Injury

Neutrophils recruited to the postischemic kidney contribute to the pathogenesis of ischemia-reperfusion injury (IRI), which is the most common cause of renal failure among hospitalized patients. The Slit family of secreted proteins inhibits chemotaxis of leukocytes by preventing activation of Rho-family GTPases, suggesting that members of this family might modulate the recruitment of neutrophils and the resulting IRI. Here, in static and microfluidic shear assays, Slit2 inhibited multiple steps required for the infiltration of neutrophils into tissue. Specifically, Slit2 blocked the capture and firm adhesion of human neutrophils to inflamed vascular endothelial barriers as well as their subsequent transmigration. To examine whether these observations were relevant to renal IRI, we administered Slit2 to mice before bilateral clamping of the renal pedicles. Assessed at 18 hours after reperfusion, Slit2 significantly inhibited renal tubular necrosis, neutrophil and macrophage infiltration, and rise in plasma creatinine. In vitro, Slit2 did not impair the protective functions of neutrophils, including phagocytosis and superoxide production, and did not inhibit neutrophils from killing the extracellular pathogen Staphylococcus aureus. In vivo, administration of Slit2 did not attenuate neutrophil recruitment or bacterial clearance in mice with ascending Escherichia coli urinary tract infections and did not increase the bacterial load in the livers of mice infected with the intracellular pathogen Listeria monocytogenes. Collectively, these results suggest that Slit2 may hold promise as a strategy to combat renal IRI without compromising the protective innate immune response.

Plasma homocysteine and the risk of venous thromboembolism: insights from the FIELD study

The lipid-lowering effect of fenofibrate is accompanied by a rise in plasma homocysteine (HCY), a potential risk factor for venous thromboembolism (VTE).This study investigated the relationship between HCY and the risk of VTE in patients treated with fenofibrate. The relationship between HCY and deep-vein thrombosis or pulmonary embolism was investigated in 9522 participants of the 5-year Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial. All subjects received fenofibrate during a 6-week active run-in phase before randomization.A Cox proportional-hazards model was used to assess the effect of HCY on risk of venous thromboembolic events. During active-drug run-in, HCY rose on average by 6.5 μ mol/L, accompanied by a substantial rise in plasma creatinine ( + 12 % ). Fenofibrate-induced changes in HCY and creatinine were fully reversible in the placebo group but persisted in the treatment group until reversing at the end of therapy. During follow-up, 1.8 % had at least one episode of deep-vein thrombosis or pulmonary embolism: 103 on fenofibrate and 68 on placebo (log-rank p = 0.006). In multivariate analysis, every 5 μ mol/L higher baseline HCY was associated with 19 % higher risk of VTE. Fenofibrate treatment was associated with 52 % higher risk, but the change in HCY with fenofibrate was not significantly associated with VTE after adjustment for baseline HCY. Hyperhomocysteinemia is prospectively associated with VTE. Fenofibrate may predispose individuals with high pretreatment HCY towards VTE. The fenofibrate induced increase in HCY did not, however, explain the risk associated with fenofibrate therapy.

Some biomarkers of acute kidney injury are increased in pre-renal acute injury

Pre-renal acute kidney injury (AKI) is assumed to represent a physiological response to underperfusion. Its diagnosis is retrospective after a transient rise in plasma creatinine, usually associated with evidence of altered tubular transport, particularly that of sodium. In order to test whether pre-renal AKI is reversible because injury is less severe than that of sustained AKI, we measured urinary biomarkers of injury (cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), γ-glutamyl transpeptidase, IL-18, and kidney injury molecule-1 (KIM-1)) at 0, 12, and 24 h following ICU admission. A total of 529 patients were stratified into groups having no AKI, AKI with recovery by 24 h, recovery by 48 h, or the composite of AKI greater than 48 h or dialysis. Pre-renal AKI was identified in 61 patients as acute injury with recovery within 48 h and a fractional sodium excretion <1%. Biomarker concentrations significantly and progressively increased with the duration of AKI. After restricting the AKI recovery within the 48 h cohort to pre-renal AKI, this increase remained significant. The median concentration of KIM-1, cystatin C, and IL-18 were significantly greater in pre-renal AKI compared with no-AKI, while NGAL and γ-glutamyl transpeptidase concentrations were not significant. The median concentration of at least one biomarker was increased in all but three patients with pre-renal AKI. Thus, the reason why some but not all biomarkers were increased requires further study. The results suggest that pre-renal AKI represents a milder form of injury.

High-risk diabetic nephropathy patients: The outcome of evidence-based clinical practice in an outpatient clinic

Objective A retrospective audit to assess the impact of a combined diabetes–renal consultant clinic over 10 years, on slowing the progression of diabetic nephropathy, using recognised markers of renal disease progression, including creatinine clearance and proteinuria. Methods 44 high-risk patients with diabetic nephropathy defined as having significant proteinuria (an elevated albumin creatinine ratio greater than 30 mg/mmol), and hypertension, a progressive rise in plasma creatinine or other evidence of diabetic microvascular disease or macrovascular disease, were identified. Sufficient follow up was defined as at least two data sets over a 12-month period prior to referral to the combined clinic, and at least 18 months of combined clinic follow up thereafter. Results In this high risk group, GFR was falling at an average of 7.97 m/min/year (95% CI 9.83–6.10 ml/min/year) at the time of referral and following clinic intervention this was significantly reduced to 3.17 ml/min/year (95% CI 4.47–1.87 ml/min/year) over the duration of follow up. Blood pressure, glycaemic control and lipid status remained stable and close to current recommended guidelines. Conclusions A combined diabetes–renal consultant clinic is an effective intervention to improve the outcome of high-risk diabetics with progressive diabetic nephropathy.

Stability of plasma creatinine concentrations in acute complex long-stay admissions to a general medical service

Assessment of glomerular filtration rate (GFR) is essential for calculating safe dosages of renally cleared drugs. Formulae for estimating reliable GFRs assume that plasma creatinine concentrations are stable. This study evaluates the variability of plasma creatinine (PCr) concentrations in patients admitted acutely to hospital. From 2,293 newly admitted patients, those in whom a subsequent clinically significant change (> 20%) in PCr had occurred were identified. Median age was 81.1 years. Median baseline PCr was 90 umol/l (eGFR 60 ml/min). In total, 46.3% of the patients had a PCr that varied > 20% from baseline three to seven days following admission. A 10-year increase in age increased the odds of a rise in PCr over the next week by 11.1% (odds ratio = 1.11, 95% confidence interval = 1.03, 1.20; p = 0.007). Overall, baseline creatinine was a poor predictor of subsequent variation in PCr. GFR formulae for calculating renally-cleared drug dosages should be used with caution in elderly patients admitted acutely to hospital.

Pharmacokinetic and biodistribution studies of Amphotericin B microspheres

The pharmacokinetics of Amphotericin B (AmB) from polyethylene glycol 2000 (PEG 2000) entrapped cross-linked bovine serum albumin (BSA) microsphere formulations were investigated and compared with solution formulation. The microsphere preparations were characterized for particle size using electron microscopy, zeta potential and encapsulation efficiency. The microsphere formulations demonstrated a sustained release of AmB for a longer period of time, with no rise in plasma creatinine and potassium levels. The enhanced AmB accumulation in lungs was observed which could be of importance since lungs are the primary target in most fungal infections. The stealth property of submicron cross-linked BSA microspheres in formulations containing PEG 2000 (formulation F-2N) and without PEG 2000 (formulation F-1N) was also evaluated. There was no evidence that microspheres embedded with PEG remained longer in circulation; however, it was noticed that the internalization of formulation F-2N microspheres was delayed when compared with microspheres from formulation F-1N.

Digital image analysis of cytoskeletal F‐actin disintegration in renal microvascular endothelium following ischemia/reperfusion

Damaged and/or dysfunctional microvascular endothelium has been implicated in the pathogenesis of ischemic acute renal failure (ARF). Rapidly occurring changes in the endothelial F-actin cytoskeleton as observed in vitro might be responsible, but have been proven difficult to measure accurately in situ. Therefore, the purpose of this study was to examine several methods of digital image analysis in order to quantify the alterations of endothelial F-actin after renal ischemia and reperfusion (I/R), and to relate these to deterioration of renal function. Frozen sections of Sham and I/R rat kidneys were fixed in 4% formaldehyde and stained with rhodamine-phalloïdin. Microvascular structures were captured using a 3i Marianastrade mark digital imaging fluorescence microscope workstation. Images were analyzed using 3i SlideBooktrade mark software, employing several masking techniques and line-scans. Digital image analysis demonstrated a decrease in the mean intensity of rhodamine-phalloïdin fluorescence after I/R from 1030 +/- 187 to 735 +/- 121 a.u. (arbitrary units, mean +/- SD, n = 7). The number of F-actin fragments per pixel increased from (15.8 +/- 4.9) x 10(-5) to (20.7 +/- 3.5) x 10(-5) (n = 7), indicating cytoskeletal fragmentation. In addition, line-scan analysis demonstrated a disturbed spatial orientation of the F-actin cytoskeleton after I/R. Finally, the loss of F-actin correlated with a rise in plasma creatinine. The methods of digital image analysis described in the present study demonstrate that renal I/R induces profound changes in the F-actin cytoskeletal structure of microvascular endothelial cells, implicating an injured and dysfunctional microvascular endothelium, which may contribute to acute renal failure (ARF).