The anemia of chronic renal failure: in vitro response of bone marrow to erythropoietin.

Bone marrow cells of patients with chronic renal failure were studied in short-term in vitro cultures to determine erythropietin responsiveness. Seven normals and fourtheen patients on hemodialysis were studied. Bone marrow cells of normal subjects and of patients with chronic renal failure responded similarly to erythropoietin. Total heme synthesis was significantly lower in cultures prepared with uremic serum than normal serum. We conclude that there is a substance in the serum of uremic patients which suppresses general heme synthesis and that this "uremic toxin" may be responsible, in part, for the clinically severe anemia seen in these patients.     

Excretion of inhibitors of calcification in urine Part II. Findings in patients with chronic renal failure.

By means of a semiquantitative method incorporating the rachitic rat cartilage technique, the total urinary inhibitory activity with respect to calcification was compared in 11 control subjects and 20 patients with renal failure. The patients had significantly lower mean values of inhibiting units per day than did the control subjects. Both groups showed a significant positive correlation between the number of inhibiting units per day and urine volume. When urine volume was taken into account in the comparison, the numbers of inhibiting units for patients continued to be lower than the numbers for controls. These findings are consistent with the hypothesis that the increase of inhibitory activity observed in uremic serum is secondary to a decrease in excretion of the responsible factor (or factors) in the urine, and that the factor (or factors) in serum responsible for the inhibition are identical to those in the urine.     

The Association of Uremic Toxins and Inflammation in Hemodialysis Patients

Background

Cardiovascular disease is the leading cause of mortality in hemodialysis patients and is associated with chronic inflammation. Elevation of uremic toxins, particular protein-bound uremic toxins, is a possible cause of hyper-inflammation in hemodialysis patients. But the association between uremic toxins and inflammatory markers in hemodialysis is still unclear.

Methods

We conducted a cross-sectional study to evaluate the association of the serum uremic toxins and inflammatory markers in hemodialysis patients.

Results

The uremic toxins were not associated with inflammatory markers- including high sensitivity C-reactive protein, IL(Interleukin) -1β, IL-6, tumor necrosis factor-α. In multiple linear regression, serum levels of total p-cresol sulfate (PCS) were independently significantly associated with serum total indoxyl sulfate (IS) (standardized coefficient: 0.274, p<0.001), and co-morbidity of diabetes mellitus (DM) (standardized coefficient: 0.342, p<0.001) and coronary artery disease (CAD) (standardized coefficient: 0.128, p = 0.043). The serum total PCS levels in hemodialysis with co-morbidity of DM and CAD were significantly higher than those without co-morbidity of DM and CAD (34.10±23.44 vs. 16.36±13.06 mg/L, p<0.001). Serum levels of total IS was independently significantly associated with serum creatinine (standardized coefficient: 0.285, p<0.001), total PCS (standardized coefficient: 0.239, p = 0.001), and synthetic membrane dialysis (standardized coefficient: 0.139, p = 0.046).

Conclusion

The study showed that serum levels of total PCS and IS were not associated with pro-inflammatory markers in hemodialysis patients. Besides, serum levels of total PCS were independently positively significantly associated with co-morbidity of CAD and DM.     

Glutathione and its associated enzymes in peripheral blood cells in different stages of chronic renal insufficiency

Summary Reduced glutathione (GSH) levels and glutathione reductase (GR) and glutathione S-transferase (GST) activities were investigated in the erythrocytes and lymphocytes of non-dialyzed patients with varying degrees of chronic renal insufficiency, and also of patients on regular hemodialysis treatment. GSH, GR and GST levels were higher in erythrocytes and lymphocytes of examined patients as compared to their corresponding age-matched healthy controls. A correlation was found between the degree of renal insufficiency and the above parameters tested. A routine hemodialysis did not significantly affect erythrocyte and lymphocyte GSH content and activities of its associated enzymes. The increased GSH levels as well as GSH-linked enzyme activities of blood cells in uremia may be a protective mechanism for the cells due to the accumulation of toxic, oxidizing, wastes in the blood as a result of the uremic state. This view is supported by the results ofin vitro experiments, which have shown that GR and GST activities of normal human lymphocytes are increased when incubated with plasma from uremic patients.     

A Novel Mechanism of Bacterial Toxin Transfer within Host Blood Cell-Derived Microvesicles

Shiga toxin (Stx) is the main virulence factor of enterohemorrhagic Escherichia coli, which are non-invasive strains that can lead to hemolytic uremic syndrome (HUS), associated with renal failure and death. Although bacteremia does not occur, bacterial virulence factors gain access to the circulation and are thereafter presumed to cause target organ damage. Stx was previously shown to circulate bound to blood cells but the mechanism by which it would potentially transfer to target organ cells has not been elucidated. Here we show that blood cell-derived microvesicles, shed during HUS, contain Stx and are found within patient renal cortical cells. The finding was reproduced in mice infected with Stx-producing Escherichia coli exhibiting Stx-containing blood cell-derived microvesicles in the circulation that reached the kidney where they were transferred into glomerular and peritubular capillary endothelial cells and further through their basement membranes followed by podocytes and tubular epithelial cells, respectively. In vitro studies demonstrated that blood cell-derived microvesicles containing Stx undergo endocytosis in glomerular endothelial cells leading to cell death secondary to inhibited protein synthesis. This study demonstrates a novel virulence mechanism whereby bacterial toxin is transferred within host blood cell-derived microvesicles in which it may evade the host immune system.     

Male Fertility in Uremia: Restoration by Renal Allografts

Spermatogenesis has been studied in eight chronic uremic patients on hemodialysis and in 11 recipients of well-functioning renal allografts. Sexual activity, semen analysis and testicular biopsy are abnormal in chronic uremic patients. Spermatogenesis remains “arrested” even when uremia is well controlled by intermittent hemodialysis. Marked improvement occurs in sexual performance, semen analysis and testicular biopsy after successful kidney transplantation. Immunosuppressive treatment, at dosages used six months after allografting, does not appear to affect male fertility adversely.     

Thrombotic Role of Blood and Endothelial Cells in Uremia through Phosphatidylserine Exposure and Microparticle Release

The mechanisms contributing to an increased risk of thrombosis in uremia are complex and require clarification. There is scant morphological evidence of membrane-dependent binding of factor Xa (FXa) and factor Va (FVa) on endothelial cells (EC) in vitro. Our objectives were to confirm that exposed phosphatidylserine (PS) on microparticle (MP), EC, and peripheral blood cell (PBC) has a prothrombotic role in uremic patients and to provide visible and morphological evidence of PS-dependent prothrombinase assembly in vitro. We found that uremic patients had more circulating MP (derived from PBC and EC) than controls. Additionally, patients had more exposed PS on their MPs and PBCs, especially in the hemodialysis group. In vitro, EC exposed more PS in uremic toxins or serum. Moreover, reconstitution experiments showed that at the early stages, PS exposure was partially reversible. Using confocal microscopy, we observed that PS-rich membranes of EC and MP provided binding sites for FVa and FXa. Further, exposure of PS in uremia resulted in increased generation of FXa, thrombin, and fibrin and significantly shortened coagulation time. Lactadherin, a protein that blocks PS, reduced 80% of procoagulant activity on PBC, EC, and MP. Our results suggest that PBC and EC in uremic milieu are easily injured or activated, which exposes PS and causes a release of MP, providing abundant procoagulant membrane surfaces and thus facilitating thrombus formation. Blocking PS binding sites could become a new therapeutic target for preventing thrombosis.     

尿毒症血液透析患者血清Lp-PLA2、FGF-23与自体动静脉内瘘成熟不良的关系研究

摘要 目的：探讨尿毒症血液透析患者血清脂蛋白相关磷脂酶A2（Lp-PLA2）、成纤维细胞生长因子-23（FGF-23）与自体动静脉内瘘（AVF）成熟不良的关系。方法：选取2021年2月～2022年12月联勤保障部队第908医院肾内科收治的170例接受血液透析的尿毒症患者,根据AVF成熟情况分为成熟不良组57例和成熟组113例。采用酶联免疫吸附法检测血清Lp-PLA2、FGF-23水平。通过多因素Logistic回归分析尿毒症血液透析患者AVF成熟不良的影响因素,受试者工作特征（ROC）曲线分析血清Lp-PLA2、FGF-23水平对尿毒症血液透析患者AVF成熟不良的预测效能。结果：成熟不良组血清Lp-PLA2、FGF-23水平高于成熟组（P＜0.05）。多因素Logistic回归分析显示,血磷、低密度脂蛋白胆固醇（LDL-C）、Lp-PLA2、FGF-23升高为尿毒症血液透析患者AVF成熟不良的独立危险因素（P＜0.05）。ROC曲线分析显示,血清Lp-PLA2、FGF-23水平单独和联合预测尿毒症血液透析患者AVF成熟不良的曲线下面积（AUC）分别为0.725、0.763、0.822,血清Lp-PLA2、FGF-23水平联合预测的AUC最大。结论：尿毒症血液透析患者血清Lp-PLA2、FGF-23水平升高与AVF成熟不良独立相关,血清Lp-PLA2、FGF-23水平联合对AVF成熟不良的预测效能良好。     

A comparison of calcium binding inCallinectes sapidus premolt and postmolt cuticle homogenates: Implications for regulation of biomineralization

Cuticle tissue homogenates (CTHs) fromCallinectes sapidus premolt cuticle bound approximately 367% more Ca²⁺ ions than did those from the postmolt cuticle. ThepH-stat assay which was used to comparein vitro CaCO₃ nucleation times confirmed that the premolt CTHs had greater inhibitory activity than did the postmolt CTHs. This inhibitory activity was indicated by CaCO₃ nucleation times in excess of control values. Premolt nucleation times exceeded those of postmolt samples by approximately 340%. A positive correlation was observed between Ca²⁺ binding and calcification inhibitory activity for both premolt and postmolt CTHs. Heat pretreatment of CTHs at 70°C for a 24-hr period had no significant effect on their Ca²⁺ binding. However, this heat pretreatment decreased their calcification inhibitory activity. Pretreatment of CTHs with Ca²⁺ diminished their calcification inhibitory activity. These results are consistent with a mechanism for inhibition of biocalcification by these proteins which involves their initial reversible binding to nascent calcite nuclei growth steps and kinks, rather than theirin vivo interaction with free Ca²⁺ ions in solution.     

Oxidative phosphorylation promotes vascular calcification in chronic kidney disease

Metabolism has been reported to associate with the progression of vascular diseases. However, how vascular calcification in chronic kidney disease (CKD) is regulated by metabolic status remains poorly understood. Using a model of 5/6 nephrectomy, we demonstrated that the aortic tissues of CKD mice had a preference for using oxidative phosphorylation (OXPHOS). Both high phosphate and human uremic serum-stimulated vascular smooth muscle cells (VSMCs) had enhanced mitochondrial respiration capacity, while the glycolysis level was not significantly different. Besides, 2-deoxy-d-glucose (2-DG) exacerbated vascular calcification by upregulating OXPHOS. The activity of cytochrome c oxidase (COX) was higher in the aortic tissue of CKD mice than those of sham-operated mice. Moreover, the expression levels of COX15 were higher in CKD patients with aortic arch calcification (AAC) than those without AAC, and the AAC scores were correlated with the expression level of COX15. Suppressing COX sufficiently attenuated vascular calcification. Our findings verify the relationship between OXPHOS and calcification, and may provide potential therapeutic approaches for vascular calcification in CKD.Subject terms: Calcification, End-stage renal disease     

血清Sclerostin、OPN、Klotho蛋白、BMP-7水平与维持性血液透析患者血管钙化的关系研究

目的:探讨血清骨硬化蛋白(Sclerostin)、骨桥蛋白(OPN)、Klotho蛋白、骨形态发生蛋白7(BMP-7)水平与维持性血液透析患者血管钙化的关系。方法:选取2018年4月~2020年4月期间我院收治的109例维持性血液透析患者,经CT检查患者的血管钙化情况分为钙化组(48例)和非钙化组(61例),另选同期在我院进行体检的健康志愿者50例为对照组,对各组血清Sclerostin、OPN、Klotho蛋白、BMP-7水平进行检测对比。分析维持性血液透析患者血管钙化的影响因素。结果:钙化组、非钙化组血清Sclerostin、OPN水平高于对照组且钙化组以上指标水平高于非钙化组(P<0.05),钙化组、非钙化组血清Klotho蛋白、BMP-7水平低于对照组且钙化组以上指标水平低于非钙化组(P<0.05)。经单因素分析显示,维持性血液透析患者血管钙化与血清Sclerostin、OPN、Klotho蛋白、BMP-7有关(P<0.05)。经多因素Logistic回归分析显示,血清Sclerostin、OPN、Klotho蛋白、BMP-7是维持性血液透析患者血管钙化发生的影响因素(P<0.05)。结论:维持性血液透析患者通常伴随着血清Sclerostin、OPN水平升高,Klotho蛋白、BMP-7水平降低,且血清Sclerostin、OPN、Klotho蛋白、BMP-7是其血管钙化的影响因素,临床工作中应结合以上因素对此类患者进行针对性干预,预防其血管钙化的发生。     

CRP、PTH、Alb及Hb水平变化与尿毒症周围神经病变程度的相关性

摘要 目的：探讨C反应蛋白（CRP）、甲状旁腺素（PTH）、血清白蛋白（Alb）及血红蛋白（Hb）水平变化与尿毒症周围神经病变程度的相关性。方法：选取我院2019年4月到2022年4月收治的340例需要进行维持性血液透析治疗的尿毒症患者作为研究对象,依照是否存在周围型神经病变的情况分为非神经病变组（n=132）和神经病变组（n=208）。对比两组患者的临床相关资料,CRP、PTH、Alb及Hb水平变化,其他血清指标变化,并分析CRP、PTH、Alb及Hb水平变化与尿毒症周围神经病变程度的相关性。结果：两组患者高血压患病人数对比无差异（P＞0.05）,两组患者的糖尿病患病人数、血液透析频率以及血液透析时间对比差异显著（P<0.05）;神经病变组患者的CRP、PTH水平明显高于非神经病编组（P＜0.05）,神经病变组患者的Alb、Hb水平明显低于非神经病变组（P＜0.05）;两组患者血浆胆固醇（CHO）、红细胞（RBC）、三酰甘油（TG）、血肌酐（SCr）水平对比无显著差异（P＞0.05）,神经病变组患者血清前白蛋白（PA）、二氧化碳结合力（CO2CP）水平低于非神经病变组,神经病变组患者血清BUN、FBG水平高于非神经病变组（P＜0.05）;Spearman相关分析结果显示：CRP、PTH与尿毒症周围神经病变程度呈正相关（P＜0.05）,Alb、Hb与尿毒症周围神经病变程度呈负相关（P＜0.05）。结论：CRP、PTH、Alb及Hb水平变化与尿毒症周围神经病变程度具有明显关系,可以用于判断尿毒症患者的周围神经病变程度。而且尿毒症周围神经病变患者多数原发疾病为糖尿病,血液透析频率较低,维持血液透析时间较长。     

Highlighting Levels of Indoxyl Sulphate among Critically Ill Patients with Acute Nephrotoxicity; Correlations Between Indoxyl Sulphate Levels and Patients’ Characteristics

Background:Many animal studies suggested that the uremic toxin indoxyl sulphate can add to renal damage following induced nephrotoxicity and this effect has not been proved in patients with such complication. Methods:This is a prospective, case-control, and an observational study conducted on 74 critically ill patients with acute nephrotoxicity. It was designed to measure serum levels of indoxyl sulphate on the day of enrollment and over the course of their illness using high performance liquid chromatography (HPLC-UV) and to test the correlation between these levels and patient’s demographics, clinical characteristics, physiological variables, and their outcomes.Results:Critically ill patients with acute nephrotoxicity had significantly higher total (tIS) and free (fIS) indoxyl sulphate than healthy controls and significantly lower than patients with end-stage renal disease (ESRD). Although, no correlation was found between tIS or fIS and mortality, among survivors, tIS, fIS, creatinine and eGFR were independently associated with no renal recovery.Conclusion:Serum indoxyl sulphate levels were elevated in critically ill patients with acute nephrotoxicity. There is an association between high levels of indoxyl sulphate and no renal-recovery outcome among survivors of acute nephrotoxicity. Early removal of indoxyl sulphate from patients’ blood may improve their outcomes.Key Words: HPLC, Indoxyl sulphate, Mortality, Prognosis, Toxic acute kidney injury     

血液灌流联合血液透析治疗尿毒症的临床价值分析

目的:探讨血液灌流联合血液透析治疗尿毒症的临床价值。方法:选取我院2014年5月~2016年4月接收血液透析的尿毒症患者90例,全部患者均采用血液透析进行维持性治疗,将其分为对照组(45例)与治疗组(45例)两组。对照组进行单纯的血液透析,而治疗组则在血液透析的基础上联合血液灌流进行治疗。观察和比较两组患者治疗前后血清肌酐(Cr)、β2微球蛋白(β2-MG)、血液尿素氮(BUN)、甲状旁腺激素(PTH)、球蛋白、白蛋白、血常规、电解质的变化情况以及治疗后临床症状的改善情况。结果:治疗前,两组患者的血清Cr、β2-MG、BUN、PTH水平比较差异无统计学意义(P0.05);治疗后,治疗组患者的血清β2-MG、PTH水平较治疗前明显下降(P0.05),对照组患者各项指标无明显变化(P0.05)。两组患者治疗前后的球蛋白、白蛋白、血常规、电解质均无明显变化。治疗后,治疗组的临床不良反应改善率明显高于对照组(P0.05)。结论:与单纯的血液透析相比,血液灌注联合血液透析能够更有效清除尿毒症患者体内Cr、β2-MG、BUN、PTH的蓄积,改善不良反应,且不会引起球蛋白、白蛋白、血常规、电解质的变化而破坏内平衡。     

不同血液净化方法对维持性血液透析尿毒症动脉粥样硬化患者血清microRNA-144和microRNA-155水平的影响及其临床意义

摘要 目的：探讨不同血液净化方法对维持性血液透析（MHD）尿毒症动脉粥样硬化患者血清microRNA-144和microRNA-155水平的影响及其临床意义。方法：选取2019年6月~2020年6月川北医学院附属医院收治的98例MHD尿毒症动脉粥样硬化患者为研究组,另选取98例同期本院体检健康的志愿者为健康对照组,比较两组血清microRNA-144和microRNA-155、血清炎症因子[白细胞介素-6（IL-6）、单核细胞趋化蛋白-1（MCP-1）、超敏C反应蛋白（hs-CRP）]水平。采用Pearson分析法分析血清microRNA-144、microRNA-155水平与MHD尿毒症动脉粥样硬化患者内膜中层厚度（IMT）值、斑块面积及血清炎症因子的相关性。采用多因素Logistic回归分析MHD尿毒症动脉粥样硬化患者IMT增厚的影响因素。将研究组按随机数字表法分为血液透析滤过组和血液灌流组,各49例。血液透析滤过组给予血液透析滤过联合血液透析治疗,血液灌流组给予血液灌流联合血液透析治疗。比较两组血清microRNA-144和microRNA-155、血清炎症因子水平、IMT值和斑块面积。结果：研究组血清microRNA-144、microRNA-155、IL-6、MCP-1、hs-CRP水平明显高于健康对照组（P<0.05）;Pearson相关性结果显示,血清microRNA-144、microRNA-155均与MHD尿毒症动脉粥样硬化患者IMT值、斑块面积及IL-6、MCP-1、hs-CRP均呈正相关（P<0.05）;多因素Logistic回归分析结果显示,血清microRNA-144、microRNA-155、IL-6、MCP-1、hs-CRP水平均是导致MHD尿毒症动脉粥样硬化患者IMT增厚的危险因素（P<0.05）。治疗后,血液灌流组血清microRNA-144和microRNA-155水平均明显低于血液透析滤过组（P<0.05）,IL-6、MCP-1、hs-CRP水平均明显低于血液透析滤过组（P<0.05）,IMT值和斑块面积均明显低于血液透析滤过组（P<0.05）。结论：血清microRNA-144、microRNA-155水平与IMT值、斑块面积及IL-6、MCP-1、hs-CRP水平呈正相关,均是MHD尿毒症动脉粥样硬化患者IMT增厚的危险因素。血液灌流联合血液透析治疗可减轻机体炎症反应,延缓动脉粥样硬化进程,可能与下调患者血清microRNA-144、microRNA-155水平有关。     

Quercetin Attenuates Warfarin-induced Vascular Calcification in Vitro Independently from Matrix Gla Protein

Warfarin can stimulate vascular calcification in vitro via activation of β-catenin signaling and/or inhibition of matrix Gla protein (MGP) carboxylation. Calcification was induced in vascular smooth muscle cells (VSMCs) with therapeutic levels of warfarin in normal calcium and clinically acceptable phosphate levels. Although TGF/BMP and PKA pathways are activated in calcifying VSMCs, pharmacologic analysis reveals that their activation is not contributory. However, β-catenin activity is important because inhibition of β-catenin with shRNA or bioflavonoid quercetin prevents calcification in primary human VSMCs, rodent aortic rings, and rat A10 VSMC line. In the presence of quercetin, reactivation of β-catenin using the glycogen synthase kinase-3β (GSK-3β) inhibitor LiCl restores calcium accumulation, confirming that quercetin mechanism of action hinges on inhibition of the β-catenin pathway. Calcification in VSMCs induced by 10 μm warfarin does not associate with reduced levels of carboxylated MGP, and inhibitory effects of quercetin do not involve induction of MGP carboxylation. Further, down-regulation of MGP by shRNA does not alter the effect of quercetin. These results suggest a new β-catenin-targeting strategy to prevent vascular calcification induced by warfarin and identify quercetin as a potential therapeutic in this pathology.     

Model for skeletal resistance to vitamin D in renal failure.

Chronic renal disease in man and animals is associated with disturbances in calcium homeostasis which are resistant to vitamin D-therapy. Partially nephrectomized and intact rats were used to evaluate the effect of uremia on the response of bone to vitamin D. Serum calcium, serum phosphorus and blood urea nitrogen levels were higher in uremic rats than in intact rats, both given vitamin D. Metaphyseal bone in uremic rats was resistant to vitamin D-induced bone resorption; osteoblasts and osteocytes appeared less active ultrastructurally and osteoclass were infrequent. Calcitonin synthesis and release evaluated electron microscopically was greater in uremic rats. It is suggested that the altered response of bone to vitamin D in uremic rats was due in part to elevated serum phosphorus and increased calcitonin release. The present model does not refute experimental and clinical data that metabolism of vitamin D is altered in renal disease. It does, however, emphasize that in chronic renal failure other parameters (phosphorus levels, calcitonin release, uremia) are operating which may influence end organ response to pharmacologic doses of vitamin D. The partially nephrectomized rat may be a useful model for evaluating end-organ resistance to vitamin D in uremia.     

Selenium status indices,laboratory data,and selected biochemical parameters in end-stage renal disease patients

We investigated the relations between selenium status (SeS) parameters, indexes of nutrition, erythropoiesis, and uremic toxemia, serum electrolytes, and other biochemical markers in end-stage renal disease (ESRD) patients, as no multivariate statistical analysis concerning all of these parameters was performed so far. SeS was evaluated by plasma Se concentration (plSe) and glutathione peroxidase (plGSHPx) activity in 69 uremic patients treated with hemodialysis (HD) and 40 healthy controls. The hierarchical multivariate partial least squares model (PLS2) was employed to establish data structure and correlations between parameters investigated. plSe and plGSHPx activity were significantly lower in patients when compared with controls (p=0.000). plSe was positively associated with indexes of erythropoiesis and nutritional status, as well as serum electrolytes and parameters of uremic toxemia. plGSHPx was inversely dependent on the pair of parameters: intact parathyroid hormone (iPTH) and aluminum plasma concentration (Al). We conclude that (1) ESRD strongly decreases selenium status and (2) the PLS2 approach revealed the existence of significant interactions among plSe, plGSHPx, and selected biochemical parameters or groups of such parameters; some of these associations need further studies to be clarified.