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1.
J Clin Invest ; 132(24)2022 12 15.
Article in English | MEDLINE | ID: mdl-36326820

ABSTRACT

The Hippo pathway nuclear effector Yes-associated protein (YAP) potentiates the progression of polycystic kidney disease (PKD) arising from ciliopathies. The mechanisms underlying the increase in YAP expression and transcriptional activity in PKD remain obscure. We observed that in kidneys from mice with juvenile cystic kidney (jck) ciliopathy, the aberrant hyperactivity of mechanistic target of rapamycin complex 1 (mTORC1), driven by ERK1/2 and PI3K/AKT cascades, induced ER proteotoxic stress. To reduce this stress by reprogramming translation, the protein kinase R-like ER kinase-eukaryotic initiation factor 2α (PERK/eIF2α) arm of the integrated stress response (ISR) was activated. PERK-mediated phosphorylation of eIF2α drove the selective translation of activating transcription factor 4 (ATF4), potentiating YAP expression. In parallel, YAP underwent K63-linked polyubiquitination by SCF S-phase kinase-associated protein 2 (SKP2) E3 ubiquitin ligase, a Hippo-independent, nonproteolytic ubiquitination that enhances YAP nuclear trafficking and transcriptional activity in cancer cells. Defective ISR cellular adaptation to ER stress in eIF2α phosphorylation-deficient jck mice further augmented YAP-mediated transcriptional activity and renal cyst growth. Conversely, pharmacological tuning down of ER stress/ISR activity and SKP2 expression in jck mice by administration of tauroursodeoxycholic acid (TUDCA) or tolvaptan impeded these processes. Restoring ER homeostasis and/or interfering with the SKP2-YAP interaction represent potential therapeutic avenues for stemming the progression of renal cystogenesis.


Subject(s)
S-Phase Kinase-Associated Proteins , Ubiquitin-Protein Ligases , Mice , Animals , Mechanistic Target of Rapamycin Complex 1/genetics , Mechanistic Target of Rapamycin Complex 1/metabolism , S-Phase Kinase-Associated Proteins/metabolism , Ubiquitin-Protein Ligases/genetics , Ubiquitin-Protein Ligases/metabolism , SKP Cullin F-Box Protein Ligases/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Eukaryotic Initiation Factor-2/genetics , Activating Transcription Factor 4/metabolism , Phosphorylation , Kidney/metabolism
2.
J Hypertens ; 40(7): 1394-1405, 2022 07 01.
Article in English | MEDLINE | ID: mdl-35703228

ABSTRACT

OBJECTIVE: Hypertension is associated with vascular injury, which contributes to end-organ damage. MicroRNAs regulating mRNAs have been shown to play a role in vascular injury in hypertensive mice. We aimed to identify differentially expressed microRNAs and their mRNA targets in small arteries of hypertensive patients with/without chronic kidney disease (CKD) to shed light on the pathophysiological molecular mechanisms of vascular remodeling. METHODS AND RESULTS: Normotensive individuals and hypertensive patients with/without CKD were recruited ( n  = 15-16 per group). Differentially expressed microRNAs and mRNAs were identified uniquely associated with hypertension (microRNAs: 10, mRNAs: 68) or CKD (microRNAs: 68, mRNAs: 395), and in both groups (microRNAs: 2, mRNAs: 32) with a P less than 0.05 and a fold change less than or greater than 1.3 in subcutaneous small arteries ( n  = 14-15). One of the top three differentially expressed microRNAs, miR-338-3p that was down-regulated in CKD, presented the best correlation between RNA sequencing and reverse transcription-quantitative PCR (RT-qPCR, R2  = 0.328, P  < 0.001). Profiling of human aortic vascular cells showed that miR-338-3p was mostly expressed in endothelial cells. Two of the selected top nine up-regulated miR-338-3p predicted targets, glutathione peroxidase 3 ( GPX3 ) and protein tyrosine phosphatase receptor type S ( PTPRS ), were validated with mimics by RT-qPCR in human aortic endothelial cells ( P  < 0.05) and by a luciferase assay in HEK293T cells ( P  < 0.05). CONCLUSION: A distinct transcriptomic profile was observed in gluteal subcutaneous small arteries of hypertensive patients with CKD. Down-regulated miR-338-3p could contribute to GPX3 and PTPRS up-regulation via the canonical microRNA targeting machinery in hypertensive patients with CKD.http://links.lww.com/HJH/C27.


Subject(s)
Hypertension , MicroRNAs , Renal Insufficiency, Chronic , Vascular System Injuries , Animals , Aorta/metabolism , Endothelial Cells/metabolism , Glutathione Peroxidase/genetics , Glutathione Peroxidase/metabolism , HEK293 Cells , Humans , Hypertension/complications , Hypertension/genetics , Mice , MicroRNAs/genetics , MicroRNAs/metabolism , Phosphoric Monoester Hydrolases/genetics , Phosphoric Monoester Hydrolases/metabolism , RNA, Messenger , Receptor-Like Protein Tyrosine Phosphatases, Class 2/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 2/metabolism , Renal Insufficiency, Chronic/complications , Renal Insufficiency, Chronic/genetics , Renal Insufficiency, Chronic/metabolism , Transcriptome
3.
Case Rep Endocrinol ; 2021: 7320217, 2021.
Article in English | MEDLINE | ID: mdl-33628532

ABSTRACT

[This corrects the article DOI: 10.1155/2019/8639629.].

4.
Ren Fail ; 42(1): 294-301, 2020 Nov.
Article in English | MEDLINE | ID: mdl-32506997

ABSTRACT

Context: Patients treated with maintenance hemodialysis experience significant symptom burden resulting in impaired quality of life. However, the association of patient reported symptom burden and the risk of healthcare use for patients with end stage kidney disease on hemodialysis has not been fully explored.Objectives: To investigate if higher symptom burden, assessed by the Edmonton Symptom Assessment System-revised (ESASr), is associated with increased healthcare use in patients with end stage kidney disease on hemodialysis.Methods: Prospective, single-center, study of adult patients on HD. Participants completed the ESASr questionnaire at enrollment. Baseline demographic, clinical information as well as healthcare use events during the 12-month following enrollment were extracted from medical records. The association between symptom burden and healthcare use was examined with a multivariable adjusted negative binomial model.Results: Mean (SD) age of the 80 participants was 71 (13) years, 56% diabetic, and 70% male. The median (IQR) dialysis vintage was 2 (1-4) years. In multivariable adjusted models, higher global [incident rate ratio (IRR) 1.02, 95% confidence interval (CI) 1.00-1.04, p = .025] and physical symptom burden score [IRR 1.03, CI 1.00-1.05, p = .034], but not emotional symptom burden score [IRR 1.05, CI 1.00-1.10, p = .052] predicted higher subsequent healthcare use.Conclusions: Our preliminary evidence suggests that higher symptom burden, assessed by ESASr may predict higher risk of healthcare use amongst patients with end stage kidney disease on hemodialysis. Future studies need to confirm the findings of this preliminary study and to assess the utility of ESASr for systematic symptom screening.


Subject(s)
Health Services Accessibility , Kidney Failure, Chronic/therapy , Renal Dialysis , Aged , Aged, 80 and over , Delivery of Health Care , Female , Humans , Male , Middle Aged , Prospective Studies , Quality of Life , Symptom Flare Up
5.
Am J Hypertens ; 33(6): 505-513, 2020 05 21.
Article in English | MEDLINE | ID: mdl-32115655

ABSTRACT

BACKGROUND: Hypertension (HTN) is associated with target organ damage such as cardiac, vascular, and kidney injury. Several studies have investigated circulating microRNAs (miRNAs) as biomarkers of cardiovascular disease, but few have examined them as biomarker of target organ damage in HTN. We aimed to identify circulating miRNAs that could serve as biomarkers of HTN-induced target organ damage using an unbiased approach. METHODS AND RESULTS: Fifteen normotensive subjects, 16 patients with HTN, 15 with HTN associated with other features of the metabolic syndrome (MetS), and 16 with HTN or chronic kidney disease (CKD) were studied. Circulating RNA extracted from platelet-poor plasma was used for small RNA sequencing. Differentially expressed (DE) genes were identified with a threshold of false discovery rate <0.1. DE miRNAs were identified uniquely associated with HTN, MetS, or CKD. However, only 2 downregulated DE miRNAs (let-7g-5p and miR-191-5p) could be validated by reverse transcription-quantitative PCR. Let-7g-5p was associated with large vessel stiffening, miR-191-5p with MetS, and both miRNAs with estimated glomerular filtration rate (eGFR) and neutrophil and lymphocyte fraction or number and neutrophil-to-lymphocyte ratio. Using the whole population, stepwise multiple linear regression generated a model showing that let-7g-5p, miR-191-5p, and urinary albumin/creatinine ratio predicted eGFR with an adjusted R2 of 0.46 (P = 8.5e-7). CONCLUSIONS: We identified decreased circulating let-7g-5p and miR-191-5p as independent biomarkers of CKD among patients with HTN, which could have pathophysiological and therapeutic implications.


Subject(s)
Circulating MicroRNA/blood , Hypertension/blood , MicroRNAs/blood , Renal Insufficiency, Chronic/blood , Adult , Aged , Albuminuria/blood , Albuminuria/diagnosis , Albuminuria/etiology , Albuminuria/physiopathology , Blood Pressure , Case-Control Studies , Down-Regulation , Female , Glomerular Filtration Rate , Humans , Hypertension/complications , Hypertension/diagnosis , Hypertension/physiopathology , Kidney/physiopathology , Male , Middle Aged , Predictive Value of Tests , Prognosis , Renal Insufficiency, Chronic/diagnosis , Renal Insufficiency, Chronic/etiology , Renal Insufficiency, Chronic/physiopathology
7.
Case Rep Endocrinol ; 2019: 8639629, 2019.
Article in English | MEDLINE | ID: mdl-31275667

ABSTRACT

BACKGROUND: Sodium glucose cotransport (SGLT)-2 inhibitors are the newest class of antihyperglycemic agents used as second- or third-line treatment in the management of type 2 diabetes. Although the use of SGLT-2 inhibitors has not been shown to cause nephrotoxicity, there have been case reports of SGLT-2 inhibitor use being associated with acute kidney injury. CASE PRESENTATION: A 72-year-old woman with a history of type 2 diabetes and no known chronic renal insufficiency presented to the emergency room with a 3-day history of nausea, vomiting, and increased somnolence. She was found to have potassium level of 7.4 (normal: 3.5-5.5) mmol/L and a markedly elevated creatinine level at 1154 (normal: 45-95) µmol/L. Imaging of the abdomen and pelvis did not reveal any findings of obstruction. Urine microscopy showed many granular casts. In the absence of other causes for her clinical presentation, the patient was diagnosed with acute kidney injury secondary to ischemic acute tubular necrosis, with canagliflozin use likely an important contributing factor. CONCLUSIONS: Physicians should inform patients to stop the use of SGLT-2 inhibitors when patients are unable to maintain hydration or during acute illness. Use of SGLT-2 inhibitors in managing type 2 diabetes should be done with caution among more vulnerable populations, including individuals with cognitive impairment and the elderly.

8.
Psychosomatics ; 60(4): 385-392, 2019.
Article in English | MEDLINE | ID: mdl-30396686

ABSTRACT

BACKGROUND: End-stage renal disease is associated with significant morbidity, high-symptom burden, and health care use. Studies have not yet assessed psychosocial distress and health care utilization in this population. OBJECTIVE: This study examines psychosocial distress and its association with hospitalization and emergency room (ER) visits in patients on maintenance hemodialysis (HD). METHODS: The Distress Assessment and Response Tool (DART) was administered to 80 adults on HD in a single treatment center. The DART assessed for anxiety, depression, and social distress. Health care utilization data were extracted prospectively from electronic medical charts. The time between psychosocial distress and hospitalization or ER visits during 12-month follow-up was examined using Cox proportional hazard models. RESULTS: Overall 46% of the sample reported psychosocial distress, with 33% screening above the threshold for depression, 14% for anxiety, and 36% for significant social distress. In multivariable regression adjusting for age, sex, and comorbidity, the presence of psychosocial distress was associated with shorter time to hospitalization (hazard ratio: 2.4 [1.1, 5.0], p = 0.03) during 12-month follow-up. Psychosocial distress was not significantly associated with ER visits in either univariable (hazard ratio: 1.3 [0.7, 2.3], p = 0.5) or multivariable (hazard ratio: 1.4 [0.8, 2.6], p = 0.3) analyses. CONCLUSION: Psychosocial distress is frequent in patients undergoing maintenance HD and is associated with shorter time to hospitalization. Future longitudinal studies should examine if health service use can be reduced through routine distress screening and psychosocial distress intervention.


Subject(s)
Kidney Failure, Chronic/psychology , Kidney Failure, Chronic/therapy , Patient Acceptance of Health Care/psychology , Patient Acceptance of Health Care/statistics & numerical data , Psychological Distress , Renal Dialysis/psychology , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Prospective Studies
9.
Can J Diabetes ; 42(2): 118-123, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29602404

ABSTRACT

Cardiovascular disease is the principal cause of morbidity and mortality in patients with diabetes mellitus. The incidence or progression of kidney disease is also common in these patients. Several clinical trials have established the efficacy of angiotensin receptor blockers for the prevention of adverse cardiovascular and renal outcomes in this population and are summarized in this review article. Head-to-head comparison of angiotensin receptor blockers with angiotensin-converting enzyme inhibitors has shown similar cardioprotective and renoprotective properties of both medication classes. However, angiotensin receptor blockers have an improved safety profile with fewer episodes of cough and angioedema and may be the agent of choice in patients with diabetes and hypertension. Novel therapeutic strategies, such as those that include a mineralocorticoid receptor blocker or a selective sodium-glucose cotransporter type 2 inhibitor, may further protect patients with diabetes from cardiovascular and renal complications.


Subject(s)
Angiotensin Receptor Antagonists/therapeutic use , Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Diabetes Mellitus, Type 2/drug therapy , Hypertension/drug therapy , Adult , Diabetes Mellitus, Type 2/complications , Humans , Hypertension/etiology , Prognosis
10.
BMC Nephrol ; 19(1): 4, 2018 01 08.
Article in English | MEDLINE | ID: mdl-29310600

ABSTRACT

BACKGROUND: There is conflicting evidence of benefit versus harm for warfarin anticoagulation in hemodialysis patients with atrial fibrillation. This equipoise may be explained by suboptimal Time in Therapeutic Range (TTR), which correlates well with thromboembolic and bleeding complications. This study aimed to compare nephrologist-led management of warfarin therapy versus that led by specialized anticoagulation clinic. METHODS: In a retrospective cohort of chronic hemodialysis patients from two institutions (Institution A: Nephrologist-led warfarin management, Institution B: Anticoagulation clinic-led warfarin management), we identified patients with atrial fibrillation who were receiving warfarin for thromboembolic prophylaxis. Mean TTRs, proportion of patients achieving TTR ≥ 60%, and frequency of INR testing were compared using a logistic regression model. RESULTS: In Institution A, 16.7% of hemodialysis patients had atrial fibrillation, of whom 36.8% were on warfarin. In Institution B, 18% of hemodialysis patients had atrial fibrillation, and 55.5% were on warfarin. The mean TTR was 61.8% (SD 14.5) in Institution A, and 60.5% (SD 15.8) in Institution B (p-value 0.95). However, the proportion of patients achieving TTR ≥ 60% was 65% versus 43.3% (Adjusted OR 2.22, CI 0.65-7.63) and mean frequency of INR testing was every 6 days versus every 13.9 days in Institutions A and B respectively. CONCLUSIONS: There was no statistical difference in mean TTR between nephrologist-led management of warfarin and that of clinic-led management. However, the former achieved a trend toward a higher proportion of patients with optimal TTR. This improved therapeutic results was associated with more frequent INR monitoring.


Subject(s)
Anticoagulants/therapeutic use , Atrial Fibrillation/drug therapy , Drug Monitoring/trends , Nephrologists/trends , Renal Dialysis/trends , Warfarin/therapeutic use , Aged , Atrial Fibrillation/diagnosis , Cohort Studies , Disease Management , Drug Monitoring/standards , Female , Humans , Male , Nephrologists/standards , Retrospective Studies , Treatment Outcome
11.
Am J Physiol Renal Physiol ; 314(6): F1046-F1061, 2018 06 01.
Article in English | MEDLINE | ID: mdl-29357413

ABSTRACT

Vascular calcification increases the risk of cardiovascular disease and death in patients with chronic kidney disease (CKD). Increased activity of mammalian target of rapamycin complex 1 (mTORC1) and endoplasmic reticulum (ER) stress-unfolded protein response (UPR) are independently reported to partake in the pathogenesis of vascular calcification in CKD. However, the association between mTORC1 activity and ER stress-UPR remains unknown. We report here that components of the uremic state [activation of the receptor for advanced glycation end products (RAGE) and hyperphosphatemia] potentiate vascular smooth muscle cell (VSMC) calcification by inducing persistent and exaggerated activity of mTORC1. This gives rise to prolonged and excessive ER stress-UPR as well as attenuated levels of sestrin 1 ( Sesn1) and Sesn3 feeding back to inhibit mTORC1 activity. Activating transcription factor 4 arising from the UPR mediates cell death via expression of CCAAT/enhancer-binding protein (c/EBP) homologous protein (CHOP), impairs the generation of pyrophosphate, a potent inhibitor of mineralization, and potentiates VSMC transdifferentiation to the osteochondrocytic phenotype. Short-term treatment of CKD mice with rapamycin, an inhibitor of mTORC1, or tauroursodeoxycholic acid, a bile acid that restores ER homeostasis, normalized mTORC1 activity, molecular markers of UPR, and calcium content of aortas. Collectively, these data highlight that increased and/or protracted mTORC1 activity arising from the uremic state leads to dysregulated ER stress-UPR and VSMC calcification. Manipulation of the mTORC1-ER stress-UPR pathway opens up new therapeutic strategies for the prevention and treatment of vascular calcification in CKD.


Subject(s)
Aortic Diseases/enzymology , Endoplasmic Reticulum Stress , Mechanistic Target of Rapamycin Complex 1/metabolism , Muscle, Smooth, Vascular/enzymology , Unfolded Protein Response , Uremia/complications , Vascular Calcification/enzymology , Activating Transcription Factor 4/genetics , Activating Transcription Factor 4/metabolism , Animals , Aorta/drug effects , Aorta/enzymology , Aorta/pathology , Aortic Diseases/drug therapy , Aortic Diseases/etiology , Aortic Diseases/pathology , Cell Death , Cell Proliferation , Cell Transdifferentiation , Disease Models, Animal , Endoplasmic Reticulum Stress/drug effects , Extracellular Signal-Regulated MAP Kinases/metabolism , HEK293 Cells , Humans , Mechanistic Target of Rapamycin Complex 1/antagonists & inhibitors , Mechanistic Target of Rapamycin Complex 1/genetics , Mice, Mutant Strains , Muscle, Smooth, Vascular/drug effects , Muscle, Smooth, Vascular/pathology , Osteogenesis , Phosphorylation , Receptor for Advanced Glycation End Products/genetics , Receptor for Advanced Glycation End Products/metabolism , S100 Proteins/genetics , S100 Proteins/metabolism , Signal Transduction , Sirolimus/pharmacology , Taurochenodeoxycholic Acid/pharmacology , Unfolded Protein Response/drug effects , Vascular Calcification/drug therapy , Vascular Calcification/etiology , Vascular Calcification/pathology
12.
J Am Soc Nephrol ; 28(7): 2241-2248, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28302754

ABSTRACT

It is unclear whether warfarin is protective or harmful in patients with ESRD and atrial fibrillation. This state of equipoise raises the question of whether alternative anticoagulants may have a therapeutic role. We aimed to determine apixaban pharmacokinetics at steady state in patients on hemodialysis. Seven patients received apixaban 2.5 mg twice daily for 8 days. Blood samples were collected before and after apixaban administration on days 1 and 8 (nondialysis days). Significant accumulation of the drug was observed between days 1 and 8 with the 2.5-mg dose. The area under the concentration-time curve from 0 to 24 hours increased from 628 to 2054 ng h/ml (P<0.001). Trough levels increased from 45 to 132 ng/ml (P<0.001). On day 9, after a 2.5-mg dose, apixaban levels were monitored hourly during dialysis. Only 4% of the drug was removed. After a 5-day washout period, five patients received 5 mg apixaban twice daily for 8 days. The area under the concentration-time curve further increased to 6045 ng h/ml (P=0.03), and trough levels increased to 218 ng/ml (P=0.03), above the 90th percentile for the 5-mg dose in patients with preserved renal function. Apixaban 2.5 mg twice daily in patients on hemodialysis resulted in drug exposure comparable with that of the standard dose (5 mg twice daily) in patients with preserved renal function and might be a reasonable alternative to warfarin for stroke prevention in patients on dialysis. Apixaban 5 mg twice daily led to supratherapeutic levels in patients on hemodialysis and should be avoided.


Subject(s)
Factor Xa Inhibitors/pharmacokinetics , Pyrazoles/pharmacokinetics , Pyridones/pharmacokinetics , Renal Dialysis , Factor Xa Inhibitors/administration & dosage , Female , Humans , Male , Middle Aged , Pyrazoles/administration & dosage , Pyridones/administration & dosage , Time Factors
14.
BMC Nephrol ; 16: 136, 2015 Aug 13.
Article in English | MEDLINE | ID: mdl-26268579

ABSTRACT

BACKGROUND: Observational data suggest that serum magnesium (Mg) concentration is inversely related to vascular calcification and hyperparathyroidism among patients with end-stage renal disease (ESRD). In recent years, there have been several case reports of hypomagnesemia due to use of proton-pump inhibitors (PPI), with the hypomagnesemia attributed to inappropriate gastrointestinal (GI) Mg loss. We hypothesized that the tendency to GI Mg loss is more common than is currently reported. Since patients with ESRD have little to no renal Mg loss to affect serum Mg concentration, dialysis patients are an interesting population in whom to study the relationship between PPI use and serum Mg levels. METHODS: Using a single-center cross-sectional design, we studied 155 prevalent hemodialysis (HD) patients. Serum Mg concentration for each patient was determined based on the mean of 3 consecutive serum Mg levels drawn at 6 week intervals. PPI use at the time of the blood tests was documented. The relationship between PPI use and Mg concentration was determined in unadjusted analyses, as well as after adjustment for age, gender, race, cause of ESRD, diabetes, time on HD and dialysate Mg concentration. RESULTS: 55 % of patients were on PPIs at the time of the study. The majority of patients (62 %) used a dialysate Mg (in mmol/L) of 0.5, and the remainder (38 %) used a dialysate Mg of 0.375. Serum Mg levels were significantly lower among PPI users vs. non-users (0.93 vs. 1.02 mmol/L, p < 0.001). This finding persisted after stratifying for dialysate Mg concentration, and after multivariable adjustment (p < 0.001). In addition, more PPI users vs. non-users had a Mg level < 1 mmol/L (79 % vs. 43 %) and a Mg level < 0.8 mmol/L (16 % vs. 4 %). There was a non-significant trend toward increased time on PPI being associated with lower serum Mg levels (p = 0.067). CONCLUSION: Among HD patients, PPI users have lower serum Mg levels as compared with non-users. Further research is required to determine whether the magnitude of change in Mg levels among PPI users is associated with adverse outcomes.


Subject(s)
Kidney Failure, Chronic/blood , Magnesium/blood , Proton Pump Inhibitors/therapeutic use , Renal Dialysis , Aged , Aged, 80 and over , Cross-Sectional Studies , Dialysis Solutions/chemistry , Female , Humans , Kidney Failure, Chronic/therapy , Male , Middle Aged , Proton Pump Inhibitors/adverse effects , Time Factors
15.
Transplantation ; 98(7): 745-53, 2014 Oct 15.
Article in English | MEDLINE | ID: mdl-24879386

ABSTRACT

BACKGROUND: Delayed graft function (DGF) and slow graft function (SGF) are a continuous spectrum of ischemia-reperfusion-related acute kidney injury (AKI) that increases the risk for acute rejection and graft loss after kidney transplantation. Regulatory T cells (Tregs) are critical in transplant tolerance and attenuate murine AKI. In this prospective observational cohort study, we evaluated whether pretransplantation peripheral blood recipient Treg frequency and suppressive function are predictors of DGF and SGF after kidney transplantation. METHODS: Deceased donor kidney transplant recipients (n=53) were divided into AKI (n=37; DGF, n=10; SGF, n=27) and immediate graft function (n=16) groups. Pretransplantation peripheral blood CD4CD25FoxP3 Treg frequency was quantified by flow cytometry. Regulatory T-cell suppressive function was measured by suppression of autologous effector T-cell proliferation by Treg in co-culture. RESULTS: Pretransplantation Treg suppressive function, but not frequency, was decreased in AKI recipients (P<0.01). In univariate and multivariate analyses accounting for the effects of cold ischemic time and donor age, Treg suppressive function discriminated DGF from immediate graft function recipients in multinomial logistic regression (odds ratio, 0.77; P<0.01), accurately predicted AKI in receiver operating characteristic curve (area under the curve, 0.82; P<0.01), and predicted 14-day estimated glomerular filtration rate in linear regression (P<0.01). CONCLUSION: Our results indicate that recipient peripheral blood Treg suppressive function is a potential independent pretransplantation predictor of DGF and SGF.


Subject(s)
Delayed Graft Function/immunology , Kidney Transplantation/adverse effects , T-Lymphocytes, Regulatory/cytology , T-Lymphocytes, Regulatory/immunology , Acute Kidney Injury/etiology , Aged , CD4-Positive T-Lymphocytes/cytology , Cell Proliferation , Female , Glomerular Filtration Rate , Graft Rejection , Graft Survival , Humans , Interleukin-2 Receptor alpha Subunit/metabolism , Male , Middle Aged , Multivariate Analysis , Odds Ratio , Prospective Studies , Regression Analysis , Renal Insufficiency/complications , Renal Insufficiency/surgery
16.
Clin Kidney J ; 7(1): 68-70, 2014 Feb.
Article in English | MEDLINE | ID: mdl-25859355

ABSTRACT

A 67-year-old man known for metastatic colon cancer received treatment with oxaliplatin and developed severe acute kidney injury requiring dialysis. Renal biopsy revealed severe acute tubular necrosis. Acute kidney injury is a rare but severe adverse effect of oxaliplatin administration.

17.
J Am Heart Assoc ; 2(2): e000128, 2013 Apr 12.
Article in English | MEDLINE | ID: mdl-23584809

ABSTRACT

BACKGROUND: Recent studies have raised concern about the safety of erythropoiesis-stimulating agents because of evidence of increased risk of hypertension and cardiovascular morbidity and mortality in chronic kidney disease (CKD) patients. In the present study, we investigated the effects of recombinant human erythropoietin (EPO) on endothelial function of gluteal subcutaneous resistance arteries isolated from 17 stage 4 patients (estimated glomerular filtration rate 21.9±7.4 mL/min per 1.73 m(2)) aged 63±13 years. METHODS AND RESULTS: Arteries were mounted on a pressurized myograph. EPO impaired endothelium-dependent relaxation in a concentration-dependent manner. The maximal response to acetylcholine with EPO at 1, 10, and 20 IU/mL was reduced by 12%, 34%, and 43%, respectively, compared with the absence of EPO (P<0.001). EPO-induced endothelial dysfunction was significantly associated with carotid stiffness and history of cardiovascular events. EPO had no effect on norepinephrine-induced vasoconstriction or sodium nitroprusside-induced relaxation. ABT-627, an endothelin type A receptor antagonist, and tempol, a superoxide dismutase mimetic, partially reversed the altered endothelial function in the presence of EPO (P<0.01). Increased expression of endothelin-1 was found in the vessel wall after incubation with EPO. CONCLUSIONS: EPO alters endothelial function of resistance arteries in CKD patients via a mechanism involving in part oxidative stress and signaling through an endothelin type A receptor. EPO-induced endothelial dysfunction could contribute to deleterious effects of EPO described in large interventional trials.


Subject(s)
Anemia/drug therapy , Arteries/drug effects , Endothelium, Vascular/drug effects , Erythropoietin/pharmacology , Hematinics/pharmacology , Recombinant Proteins/pharmacology , Renal Insufficiency, Chronic/complications , Acetylcholine/pharmacology , Aged , Anemia/etiology , Arteries/metabolism , Buttocks/blood supply , Carotid Arteries/diagnostic imaging , Carotid Intima-Media Thickness , Endothelin-1/drug effects , Endothelin-1/metabolism , Endothelium, Vascular/metabolism , Erythropoietin/therapeutic use , Female , Hematinics/therapeutic use , Humans , Male , Middle Aged , Pulse Wave Analysis , Recombinant Proteins/therapeutic use , Vasodilator Agents/pharmacology
18.
J Pharm Pharm Sci ; 16(5): 665-75, 2013.
Article in English | MEDLINE | ID: mdl-24393550

ABSTRACT

PURPOSE: The purpose of this study was to develop an artificial neural network (ANN) model to predict drug removal during dialysis based on drug properties and dialysis conditions. Nine antihypertensive drugs were chosen as model for this study. METHODS: Drugs were dissolved in a physiologic buffer and dialysed in vitro in different dialysis conditions (UFRmin/UFRmax, with/without BSA). Samples were taken at regular intervals and frozen at -20ºC until analysis. Extraction methods were developed for drugs that were dialysed with BSA in the buffer. Drug concentrations were quantified by high performance liquid chromatography (HPLC) or mass spectrometry (LC/MS/MS). Dialysis clearances (CLDs) were calculated using the obtained drug concentrations. An ANOVA with Scheffe's pairwise adjustments was performed on the collected data in order to investigate the impact of drug plasma protein binding and ultrafiltration rate (UFR) on CLD. The software Neurosolutions was used to build ANNs that would be able to predict drug CLD (output). The inputs consisted of dialysis UFR and the herein drug properties: molecular weight (MW), logD and plasma protein binding. RESULTS: Observed CLDs were very high for the majority of the drugs studied. The addition of BSA in the physiologic buffer statistically significantly decreased CLD for carvedilol (p= 0.002) and labetalol (p<0.001), but made no significant difference for atenolol (p= 0.100). In contrast, varying UFR does not significantly affect CLD (p>0.025). Multiple ANNs were built and compared, the best model was a Jordan and Elman network which showed learning stability and good predictive results (MSEtesting = 129). CONCLUSION: In this study, we have developed an ANN-model which is able to predict drug removal during dialysis. Since experimental determination of all existing drug CLDs is not realistic, ANNs represent a promising tool for the prediction of drug CLD using drug properties and dialysis conditions.


Subject(s)
Adrenergic beta-Antagonists/pharmacokinetics , Angiotensin-Converting Enzyme Inhibitors/pharmacokinetics , Antihypertensive Agents/pharmacokinetics , Neural Networks, Computer , Renal Dialysis , Humans , Membranes, Artificial , Serum Albumin, Bovine/metabolism
19.
J Pharm Pharm Sci ; 16(5): 657-64, 2013.
Article in English | MEDLINE | ID: mdl-24393549

ABSTRACT

PURPOSE: In order to update our data on drug dialyzability using the high-permeability dialysis membranes, atenolol elimination by an in vitro dialysis model was compared to that observed in six patients during high-permeability hemodialysis (HD), and the predictive value of the model was evaluated. METHODS: Atenolol clearance was evaluated in six patients undergoing chronic HD. They were considered as eligible candidates if they were between 18 and 80 years of age, had a body mass index between 19 and 30 kg/m2, underwent HD and were taking atenolol on a regular basis in oral tablet form for at least 1 month before the study started. Atenolol clearance was also evaluated in three in vitro dialysis sessions with high-permeability polysulfone membrane. Atenolol was dissolved in 6 L of Krebs-Henseleit buffer with bovine serum albumin. Dialysis parameters were set to mirror as much as possible the patients' parameters (flow rate: 300 mL/min, dialyzate flow: 500 mL/min). After sample collection, drug concentrations were measured with high performance liquid chromatography. The comparison between in vivo and in vitro atenolol elimination kinetics was performed by drawing the curve fittings of concentrations vs. time on SigmaPlot 12, and adding a 95% prediction interval to each elimination curve fitting. RESULTS: Mean dialysis clearance of atenolol in vitro and in vivo was 198 ± 4 and 235 ± 53 mL/min, respectively. Atenolol was significantly removed within the study time period in both in vitro and in vivo experiments. By the end of in vitro dialysis, atenolol remaining in the drug reservoir was less than 2% of initial arterial concentration. CONCLUSION: Our study has indicated that atenolol is almost entirely cleared during high-permeability hemodialysis. Furthermore, the in vitro prediction interval of the drug elimination curve fitting could forecast its in vivo elimination especially at the end of dialysis.


Subject(s)
Adrenergic beta-1 Receptor Antagonists/pharmacokinetics , Atenolol/pharmacokinetics , Models, Biological , Renal Dialysis , Adrenergic beta-1 Receptor Antagonists/blood , Adult , Aged , Atenolol/blood , Female , Humans , Male , Membranes, Artificial , Middle Aged , Permeability
20.
Curr Cardiol Rep ; 14(6): 651-9, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22903734

ABSTRACT

There appears to be a broad consensus among professional health organizations that a blood pressure (BP) of 130/80 mm Hg or less is the recommended therapeutic BP target for subjects with diabetes mellitus. This review focuses on key studies that have examined the relationship between BP reduction and its impact on diabetic complications. An attempt is being made to identify the BP level at which maximum protection against diabetic complications is conferred, and below which further reduction no longer delivers a benefit that exceeds risk. Specific attention has been accorded to data contributing to establishing ideal BP goals in diabetic patients with nephropathy. On the basis of recent studies, it would appear that a BP below 140/90 mm Hg should be recommended for all diabetic individuals, and around 135/85 mm Hg for most. BP should be closer to, but not below, 130/80 mm Hg for those subjects at the highest cardiovascular risk. For those diabetic subjects at highest risk for stroke, lower BP may provide greater protection against stroke as shown in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. In younger individuals with diabetes and hypertension of shorter duration, it may be possible to lower BP below 130/80 mm Hg without untoward side effects and in fact with cardiovascular benefit, but this remains to be demonstrated. The ideal BP goal in diabetic patients with nephropathy remains questionable, and for now, the recommended target must be considered the same as that for the general diabetic population.


Subject(s)
Antihypertensive Agents/therapeutic use , Diabetes Mellitus, Type 2/complications , Diabetic Nephropathies/complications , Hypertension , Blood Pressure , Diabetes Mellitus , Humans , Hypertension/complications , Hypertension/drug therapy , Patient Care Planning
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