Chronic Renal Failure Serum Research Articles

Relationship between kidney ultrasound data and blood creatinine and urea levels in cats with autosomal dominant polycystic kidney disease

The results of studying the influence of structural changes in the kidneys on their filtration in cats with polycystic kidney disease are given. The study was conducted on 10 domestic cats, which were divided into two experimental groups based on the results of creatinine determination according to the IRIS (International Renal Interest Society) classification – 5 animals with moderate renal azotemia (group 1) and 5 animals with severe renal azotemia (group 2). Ultrasound examination of the kidneys of cats in both groups was performed using a Mindray device with a microconvection transducer with a frequency of 7.5–10 MHz in B-mode. Both kidneys were examined in each animal. Scanning was performed in the sagittal plane so that the kidney gate was visible. The length, width of the kidney, and thickness of the cortical layer, as well as the number of cysts and their diameter, were counted. The renal area (RA), cyst area (CA), and the ratio of cyst area to renal area (RA/Cyst) were calculated. According to the results of the study of serum creatinine and urea content, the animals were divided into two groups depending on the level of azotemia. 5 cats with stage III chronic renal failure (CRF), serum creatinine levels were 326.40 ± 23.59 μmol/l, and 5 animals with stage IV chronic renal failure serum creatinine – 887.00 ± 61.81 µmol/l, which is 2.7 times higher (P ≤ 0.001) than the creatinine level in cats with stage III CKD. The urea content in the serum was significantly increased compared to the norm and amounted to 22.82 ± 2.09 mol/l in cats with stage III CKD and 42.45 ± 1.05 mol/l in cats with stage IV CKD, which was 2.2 times higher (P ≤ 0.01) compared to stage III. In animals with polycystic kidney disease and stage IV chronic renal failure according to the results of ultrasound examination an increase in the length of the kidney by 6.5 mm (p≤0.001) and a thickening of the cortical layer by 0.8 mm (P ≤ 0.01) was revealed, compared to animals with polycystic kidney disease and stage III chronic renal failure. There was no correlation between the area of cysts in the kidneys and the level of creatinine in the blood serum of animals. Ultrasound signs of chronic renal failure in cats of stage III are enlargement of the kidney in the length of more than 51 mm and cortical thickness of more than 5.5 mm, of stage IV is an increase in kidney length of more than 59 mm and cortical thickness of more than 6.0 mm. According to the results of ultrasonography, the number of cysts or their area cannot be used to assess the degree of renal functional failure.

Hydroxysafflor Yellow A inhibits the viability and migration of vascular smooth muscle cells induced by serum from rats with chronic renal failure via inactivation of the PI3K/Akt signaling pathway.

It has been reported that the viability and migration of vascular smooth muscle cells contributes to arteriovenous fistula stenosis. Hydroxysafflor Yellow A (HSYA) has been demonstrated to inhibit the viability and migration of VSMCs by regulating Akt signaling. The present study aimed to investigate the role of HSYA on the viability and migration of human umbilical vein smooth muscle cells (HUVSMCs) following stimulation using serum from rats with chronic renal failure (CRF), and to determine the effects of HSYA on PI3K/Akt signaling. Wistar rats were randomly divided into two groups, control and CRF groups. Serum from each group was collected to stimulate the HUVSMCs. Cell Counting Kit-8 and wound healing assays were performed to assess cell viability and migration, respectively. Flow cytometry analysis was performed to assess apoptosis, and western blot analysis was performed to detect protein expression levels of PI3K and Akt. Nitric oxide (NO) production was measured using the Nitrate/Nitrite assay kit. The results demonstrated that serum from CRF rats significantly enhanced cell viability, migration and apoptosis, the effects of which were reversed following treatment with HSYA. In addition, CRF serum decreased NO and endothelial NO synthase expression, whilst increasing the protein expression levels of PI3K and phosphorylated-Akt in HUVSMCs. Notably, treatment with HSYA markedly restored NO production and inactivated the PI3K/Akt signaling pathway. Furthermore, the PI3K/Akt inhibitor, AMG511, exerted similar effects to HSYA. Taken together, the results of the present study suggest that HSYA suppresses cell viability and migration in the presence of CRF serum by inactivating the PI3K/Akt signaling pathway.

Protective role of PERK-eIF2α-ATF4 pathway in chronic renal failure induced injury of rat hippocampal neurons

Purpose Chronic renal failure (CRF) is associated with impairment of hippocampal neurons. This study investigated the effect of PERK-eIF2α-ATF4 pathway in CRF. Methods Rat CRF model was established and rat hippocampal neurons were separated. Xanthine Oxidase method, fluorescence spectrophotometry and flow cytometry were applied to detect superoxide dismutase (SOD) content, reactive oxygen species (ROS) level and apoptosis in hippocampal neurons, respectively. The levels of phosphorylated (p)-PERK, phosphorylated (p)-eIF2α, CHOP, Bax, C-Caspase-3 and Bcl-2 in rats were measured using Western blot. Then, the neurotoxicity of serum from CRF rats was assessed in rat hippocampal neurons after treatment with rat CRF serum and transfection with or without PERK overexpression or knockdown plasmid. Results SOD activity was reduced, while ROS level and apoptosis rate were increased in hippocampal tissues of CRF rats. PERK-eIF2α-ATF4 and apoptosis pathways were activated in CRF rats. Cells treated with serum from CRF rats showed increases in apoptosis rate and LDH and ROS levels, and decreases in cell viability and SOD activity. However, overexpressed PERK could reverse the cytotoxic effect of serum from CRF rats. PERK overexpression could enhance the activation of PERK-eIF2α-ATF4 pathway in hippocampal neurons induced by serum from CRF rats. Furthermore, PERK overexpression could alleviate the increases in CHOP, Bax, C-Caspase-3 expressions and the reduction of Bcl-2 expression in hippocampal neurons induced by serum from CRF rats. Conclusion PERK-eIF2α-ATF4 pathway induced by increased endoplasmic reticulum stress may alleviate CRF-induced hippocampal neuronal damage.

Hirudin prevents vascular endothelial cell apoptosis and permeability enhancement induced by the serum from rat with chronic renal failure through inhibiting RhoA/ROCK signaling pathway.

Endothelial cells injury and activation contribute to arteriovenous fistula (AVF) stenosis. Hirudin (Hiru) can inhibit the activity of thrombin, which was reported to enhance endothelial cell permeability and promote vascular inflammatory responses. RhoA/ROCK signaling pathway is also important in regulating vascular endothelial permeability. This study aimed to investigate the role of Hiru on the viability and permeability of human umbilical vein endothelial cells (HUVECs) following stimulation of serum from rat with chronic renal failure (CRF) and illustrated the effects of Hiru on RhoA/ROCK signaling. Wistar rats were randomly divided into control group and CRF group. Serum from each group was collected to stimulate HUVECs. Proliferation capability was estimated with Cell Count Kit-8 (CCK-8) assay. Transwell assay was performed to determine permeability. Cell apoptosis was examined using Tunel staining. Telomere length and telomerase activity were determined by qPCR. Moreover, the expression of RhoA, ROCK1 and ROCK2 was estimated via western blot. Results showed that the serum from CRF rat significantly inhibited cell viability while enhanced cell permeability and apoptosis. Different concentrations of Hiru prevented the above effects caused by CRF serum. Additionally, Hiru recovered the CRF serum-induced decreased telomere length and telomerase activity. Hiru also inhibited the protein expression of RhoA, ROCK1 and ROCK2, which were activated by CRF serum. Moreover, the ROCK inhibitor, Y27632, exhibited similar effects with Hiru. In conclusion, Hiru-restored HUVECs cell viability, telomere length and telomerase activity, suppressed permeability and apoptosis in the presence of CRF serum might depend on inactivating the RhoA/ROCK signaling.

Effects of Chronic Renal Failure on Brain Cytochrome P450 in Rats.

Chronic renal failure (CRF) impedes renal excretion of drugs and their metabolism by reducing the expression of liver cytochrome P450 (P450). Uremic serum contains factors, such as parathyroid hormone (PTH), that decrease liver P450s. The P450s are also involved in the metabolism of xenobiotics in the brain. This study investigates: 1) the effects of CRF on rat brain P450, 2) the role of PTH in the downregulation of brain P450s in CRF rats, and 3) the effects of PTH on P450s in astrocytes. Protein and mRNA expression of P450s were assessed in the brain of CRF and control (CTL) rats, as well as from CTL or CRF rats that underwent parathyroidectomy (PTX) 1 week before nephrectomy. CYP3A activity was measured using 3-[(3, 4-difluorobenzyl) oxy]-5, 5-dimethyl-4-[4-methylsulfonyl) phenyl] furan-2(5H)-1 metabolism in brain microsomal preparation. CYP3A protein expression was assessed in primary cultured astrocytes incubated with serum obtained from CRF or CTL rats or with PTH. Significant downregulations (≥40%) of CYP1A, CYP2C11, and CYP3A proteins were observed in microsomes from CRF rat brains. CYP3A activity reduction was also observed. CYP3A expression and activity were unaffected in PTX-pretreated CRF rats. Serum of PTX-treated CRF rats had no impact on CYP3A levels in astrocytes compared with that of untreated CRF rats. Finally, PTH addition to normal calf serum induced a reduction in CYP3A protein similar to CRF serum, suggesting that CRF-induced hyperparathyroidism is associated with a significant decrease in P450 drug-metabolizing enzymes in the brain, which may have implications in drug response.

Effect of chronic renal failure medium on the ubiquitin-proteasome pathway of arterial muscle cells

The ubiquitin‑proteasome pathway (UPP) is involved in the occurrence and development of atherosclerosis through inhibitor of κB (IκB) degradation which activates nuclear factor-κB (NF‑κB). However, the correlation between UPP and vascular complications of uramia remains unknown. The aim of the present study was to determine whether the UPP is activated in aortic smooth muscle cells (ASMCs) when cultured with uremic serum and to examine the role of the UPP on the dysfunction of ASMCs in uremia. ASMCs were cultured with pooled normal sera or chronic renal failure sera. The mRNA expression levels for ubiquitin (Ub) and Ub-activating enzyme (E1) were analyzed using reverse transcription PCR and levels of the ubiquitinated proteins E1 and IκBα were measured using western blot analysis. The enzymatic activities of three 20S proteasomes were examined using specific fluorogenic peptide substrates. Compared with normal serum, chronic renal serum increased E1 mRNA and protein expression of rabbit ASMCs (both P<0.01). In addition, the mRNA expression of Ub also increased and the expression of IκBα was observed to decrease significantly (both P<0.01). Ubiquitinated proteins in the normal and chronic renal failure groups were not found to be significantly different, but the activity of proteasomes increased significantly (P<0.01). Chronic renal failure medium induced the activation of the UPP in ASMCs.

Effects of Chronic Renal Failure on Brain Drug Transporters in Rats

Studies demonstrated that chronic renal failure (CRF) affects the expression and activity of intestinal, hepatic, and renal drug transporters. Such drug transporters are expressed in brain cells and at the blood-brain barrier (BBB), where they limit the entry and distribution of drugs in the brain. Perturbations in brain drug transporter equilibrium by CRF could lead to central drug toxicity. This study evaluates how CRF affects BBB drug transporters using a 5/6 nephrectomized rat model. Protein and mRNA expression of influx transporters [organic anion-transporting polypeptide (Oatp), organic anion transporter (Oat)] and efflux transporters [P-glycoprotein (P-gp), multidrug resistance-related protein (Mrp), breast cancer resistance protein (Bcrp)] were measured in CRF and control rat brain. Intracerebral accumulation of radiolabeled benzylpenicillin, digoxin, doxorubicin, and verapamil was used to evaluate BBB drug permeability. Protein expression of the transporters was evaluated in rat brain endothelial cells (RBECs) and astrocytes incubated with control and CRF rat serum. We demonstrated significant decreases (30-50%) in protein and mRNA levels of Bcrp, Mrp2 to -4, Oat3, Oatp2 and -3, and P-gp in CRF rat brain biopsies, as well as in astrocytes and RBECs incubated with CRF serum. These decreases did not correlate with in vivo changes because BBB permeability of benzylpenicillin was decreased by 30% in CRF rats, whereas digoxin, doxorubicin, and verapamil permeabilities were unchanged. It thus seems that even with decreased drug transporters, BBB integrity and function is conserved in CRF.

Improvement in Chronic Renal Failure after Mycophenolate Mofetil Introduction and Cyclosporine Dose Reduction: Four-Year Results From a Cohort of Heart Transplant Recipients

Chronic renal failure (CRF) due to calcineurin inhibitor (CNI) nephrotoxicity is a frequent complication among heart transplant (HT) recipients. Small studies have suggested that the introduction of mycophenolate mofetil (MMF) can help to reduce CNI doses thereby to maintaining or improving renal function. We conducted a 4-year, prospective, multicenter study in 89 maintenance HT recipients at 5.6 ± 2.7 years postgrafting who displayed CRF (serum creatinine > 1.4 mg/dL) and were undergoing treatment with cyclosporine and prednisone ± azathioprine. We introduced MMF and reduced cyclosporine to level below 100 ng/mL. Creatinine clearance (CrCl), acute rejection episodes, and survival were through retrospectively compared with a contemporary cohort of HT recipients who were not treated with MMF (control group; n = 38). After conversion to MMF, a rapid increase was observed in the CrCl, which was maintained over the follow-up: namely, CrCl at month 6 and at 4 years were 51.0 ± 15.6 and 54.1 ± 15.6 mL/min versus 41.9 ± 11.1 mL/min at baseline ( P < .0001). No renal function changes were observed among the control group. Acute rejection rates were 5.6% and 2.6% in the MMF versus control groups ( P = NS) with 4-year survivals >85%. In conclusion, the introduction of MMF allowed a safe reduction of cyclosporine and significantly improved renal function after 4 years.

Serum Hydroxyl Radical Scavenging Capacity as Quantified with Iron-Free Hydroxyl Radical Source

We have developed a simple ESR spin trapping based method for hydroxyl (OH) radical scavenging-capacity determination, using iron-free OH radical source. Instead of the widely used Fenton reaction, a short (typically 5 seconds) in situ UV-photolysis of a dilute hydrogen peroxide aqueous solution was employed to generate reproducible amounts of OH radicals. ESR spin trapping was applied to quantify OH radicals; the decrease in the OH radical level due to the specimen’s scavenging activity was converted into the OH radical scavenging capacity (rate). The validity of the method was confirmed in pure antioxidants, and the agreement with the previous data was satisfactory. In the second half of this work, the new method was applied to the sera of chronic renal failure (CRF) patients. We show for the first time that after hemodialysis, OH radical scavenging capacity of the CRF serum was restored to the level of healthy control. This method is simple and rapid, and the low concentration hydrogen peroxide is the only chemical added to the system, that could eliminate the complexity of iron-involved Fenton reactions or the use of the pulse-radiolysis system.

Downregulation of hepatic acetylation of drugs in chronic renal failure.

Drug metabolism can be affected by chronic renal failure (CRF). Although it is known that several drugs that are known to be acetylated accumulate in CRF, the effect of CRF on N-acetyltransferase (NAT), the enzyme responsible for this acetylation, is unknown. Herein is reported that protein and gene expression of both Nat isoforms in the liver was reduced by >30% and Nat2 activity was reduced by 50% in rats with CRF compared with control rats. Incubation of hepatocytes with serum from rats with CRF suggested that a circulating factor is responsible for the decrease in protein and gene expression. For testing the hypothesis that parathyroid hormone may be this factor, CRF was induced in parathyroidectomized rats; downregulation of Nat expression and activity was not observed in these rats. Furthermore, addition of parathyroid hormone to cultured hepatocytes induced a decrease in Nat2 protein and gene expression. In conclusion, liver acetylation of drugs in a rat model of CRF is reduced by a downregulation of Nat1 and Nat2 isoforms, secondary to decreased gene expression. Parathyroid hormone seems to be an important mediator of this phenomenon.

Effects of Chronic Renal Failure on Liver Drug Transporters

Chronic renal failure (CRF) is associated with a decrease in liver drug metabolism, particularly mediated by the cytochrome P450. CRF also impedes intestinal drug transporters [mainly P-glycoprotein (P-gp) and multidrug resistance protein (MRP)]. However, very few studies have evaluated the effects of CRF on liver drug transport. The present study aimed to investigate the repercussions of CRF on liver drug transporters involved in hepatic uptake [organic anion transporting polypeptide (Oatp) 2] and in drug extrusion (P-gp and MRP2). Two groups of rats were studied: control and CRF. Oatp2, P-gp, and MRP2 protein expressions and mRNA levels, as well as some of their metabolic activity, were assessed. The effects of CRF serum on drug transporters were also evaluated in cultured hepatocytes. Compared with control, creatinine clearance was reduced by 70% (p < 0.01) in rats with CRF. Protein expression and mRNA levels of P-gp were increased by 25 and 40% (p < 0.01), respectively, in liver from rats with CRF. MRP2 protein expression was identical in both groups, whereas its mRNA levels were increased by 35% (p < 0.01) in CRF rats. Finally, Oatp2 protein expression was reduced by 35%, whereas its mRNA levels remained unchanged. Similar results were obtained when hepatocytes were incubated with uremic serum. In conclusion, CRF is associated with a decrease in liver transporters involved in drug absorption and an increase in those involved in drug extrusion. Uremic mediators appear to be responsible for these modifications.

Role of Parathyroid Hormone in the Downregulation of Liver Cytochrome P450 in Chronic Renal Failure

Chronic renal failure (CRF) is associated with a decrease in drug metabolism secondary to a decrease in liver cytochrome P450 (P450). The predominant theory to explain this decrease is the presence of factors in the blood of uremic patients. This study tested the hypothesis that parathyroid hormone (PTH) could be this factor. The objectives of this study were to determine (1) the role of PTH in the downregulation of hepatocyte P450 induced by rat uremic serum, (2) the role of PTH in the downregulation of liver P450 in rats with CRF, and (3) the effects of PTH on P450 in hepatocytes. For this purpose, (1) hepatocytes were incubated with serum from rat with CRF that was depleted with anti-PTH antibodies or with serum from parathyroidectomized (CRF-PTX) rat with CRF, (2) the effect of PTX on liver P450 was evaluated in rats with CRF, and (3) the effects of PTH on P450 in hepatocytes were determined. The depletion of PTH from CRF serum completely reversed the downregulating effect of CRF serum on P450 in hepatocytes. Addition of PTH (10(-9) M) to depleted CRF serum induced a decrease in P450 similar to nondepleted CRF serum. The serum of CRF-PTX rats had no effect on P450 in hepatocytes compared with CRF serum. Adding PTH to CRF-PTX serum induced a similar decrease in P450 as obtained with CRF serum. Finally, PTX prevented the decrease of liver P450 in rats with CRF. In summary, PTH is the major mediator implicated in the downregulation of liver P450 in rats with CRF.

Forgotten Ureteral Stents Causing Renal Failure: Multimodal Endourologic Treatment

To report our experience in managing nine patients with forgotten ureteral stents that resulted in chronic renal failure (CRF). We reviewed our stent records from January 1994 to January 2004 to analyze cases of forgotten indwelling ureteral stents in solitary kidneys that had led to CRF (serum creatinine 4-14 mg/dL). These patients had normal renal function prior to the interventions at which stents were placed. They were subjected to multimodal endourologic management, including cystolithotripsy and ureteroscopic and percutaneous lithotripsy, to make them stent and stone free in a single operative session. The median dwell time of the retained stents was 39 months. Three patients were not aware of the stent, while six chose to ignore it. All patients underwent a temporizing percutaneous nephrostomy with an 8F pigtail catheter and were operated on 2 to 4 weeks later. All nine patients were rendered stone and stent free; however, one patient succumbed to septic complications 3 weeks after the operation. At last follow-up (6-56 months), two patients are on the transplant waiting list, while six are living with mild to moderate renal failure on conservative treatment. Chronic renal failure caused by encrusted stents in a functionally solitary kidney is a disastrous complication of forgotten stents. Prevention is, of course, ideal, but such cases are still seen despite increasing awareness. Temporizing percutaneous nephrostomy, renal support, and skilled endourologists are the cornerstones of management of such high-risk cases.

The Natural History of Chronic Renal Failure: Results From an Unselected, Population-Based, Inception Cohort in Sweden

Mortality rates in patients with chronic renal failure (CRF) are high both before and after start of renal replacement therapy (RRT). However, few studies of mortality and progression have been performed in an unselected CRF population. We followed up a population-based inception cohort of 920 men and women aged 18 to 74 years who had CRF (serum creatinine level > 3.4 mg/dL [>300 micromol/L] for men and >2.8 mg/dL [>250 micromol/L] for women) for 55 to 79 months. Relationships between the outcomes (death and start of RRT) and independent variables under study (age, sex, primary renal disease, body mass index [BMI], and glomerular filtration rate [GFR] at entry) were explored by using Cox regression models. Seven hundred thirty-nine patients (80%) started RRT during the follow-up period. As expected, GFR at entry was clearly linked to the incidence of RRT (P < 0.0001). Age was related inversely to incidence of RRT (adjusted relative risk for patients > or =65 years relative to patients <45 years, 0.72; 95% confidence interval, 0.57 to 0.90). Men progressed to RRT more often than women (adjusted relative risk, 1.59; 95% confidence interval, 1.35 to 1.88). BMI was unrelated to RRT incidence. By the end of follow-up, 389 patients with CRF (42%) had died, 89 of them (10%) before the start of RRT. The most common primary cause of death was cardiovascular disease (37.5%). Characteristics significantly related to a greater mortality rate included older age, diagnoses of diabetic nephropathy and nephrosclerosis, and low BMI. Preuremic characteristics (age, sex, primary renal diagnosis, BMI, and GFR) are predictive of prognosis in unselected patients with CRF.

Effects of serum from patients with chronic renal failure on rat hepatic cytochrome P450

1. In humans, chronic renal failure (CRF) is associated with decreased hepatic drug metabolism, particularly that mediated by the cytochrome P450 (P450). The mechanisms remain poorly understood. The present study aimed to investigate the effects of the serum of patients with CRF on liver P450, and to evaluate whether renal replacement therapies (dialysis or transplantation) impede the inhibition of CRF serum on P450. 2. Rat hepatocytes were incubated for 24 h with serum from patients with severe CRF and from controls to measure (1) P450 level, (2) protein expression and mRNA levels of P450 isoforms and (3) metabolic activities of CYP3A and CYP1A. Similar experiments were performed with serum of patients once on chronic hemodialysis and after kidney transplantation. 3. In rat hepatocytes incubated for 24 h with serum from patients with CRF, P450 level and protein expression, as well as mRNA levels of P450 isoforms (CYP1A2, 2C6, 2C11, 2D1/2D2, 3A2 and 4A1/4A3), were decreased by more than 45% (P<0.001) compared to control serum, while the levels of CYP2E1 were not modified. CYP3A and CYP1A activities were decreased by 51 and 59% (P<0.001), respectively. The inhibitory effect of serum obtained from patients before first dialysis was similar after 1 or 6 months on chronic hemodialysis but was lost after successful kidney transplantation. In CRF serum, the fraction containing proteins between 10 and 15 kDa decreases P450. 4. Human uremic serum contains mediator(s) that decreases rat hepatic P450 activity and expression secondary to reduced gene expression. The inhibitory effect of serum persists even after initiation of dialysis, but disappears after normalization of renal function following kidney transplantation.

Growth hormone/insulin-like growth factor system in children with chronic renal failure

Disturbances of the somatotropic hormone axis play an important pathogenic role in growth retardation and catabolism in children with chronic renal failure (CRF). The apparent discrepancy between normal or elevated growth hormone (GH) levels and diminished longitudinal growth in CRF has led to the concept of GH insensitivity, which is caused by multiple alterations in the distal components of the somatotropic hormone axis. Serum levels of IGF-I and IGF-II are normal in preterminal CRF, while in end-stage renal disease (ESRD) IGF-I levels are slightly decreased and IGF-II levels slightly increased. In view of the prevailing elevated GH levels in ESRD, these serum IGF-I levels appear inadequately low. Indeed, there is both clinical and experimental evidence for decreased hepatic production of IGF-I in CRF. This hepatic insensitivity to the action of GH may be partly the consequence of reduced GH receptor expression in liver tissue and partly a consequence of disturbed GH receptor signaling. The actions and metabolism of IGFs are modulated by specific high-affinity IGFBPs. CRF serum has an IGF-binding capacity that is increased by seven- to tenfold, leading to decreased IGF bioactivity of CRF serum despite normal total IGF levels. Serum levels of intact IGFBP-1, -2, -4, -6 and low molecular weight fragments of IGFBP-3 are elevated in CRF serum in relation to the degree of renal dysfunction, whereas serum levels of intact IGFBP-3 are normal. Levels of immunoreactive IGFBP-5 are not altered in CRF serum, but the majority of IGFBP-5 is fragmented. Decreased renal filtration and increased hepatic production of IGFBP-1 and -2 both contribute to high levels of serum IGFBP. Experimental and clinical evidence suggests that these excessive high-affinity IGFBPs in CRF serum inhibit IGF action in growth plate chondrocytes by competition with the type 1 IGF receptor for IGF binding. These data indicate that growth failure in CRF is mainly due to functional IGF deficiency. Combined therapy with rhGH and rhIGF-I is therefore a logical approach.

Effect of Daily Hemodialysis on Monocytes Apoptosis

Uremia is associated with a state of immune dysfunction with increased susceptibility to infection and malignancy possibly related to dysregulation of immune system cell apoptosis. Peritoneal dialysis can restore plasma apoptosis activity on monocytes compared to intermittent hemodialysis. Whether the continuous modality or diverse clearance mechanisms involved are responsible is unknown. Apoptosis rates correlate with phagocytic function highlighting the benefit of efficient toxin clearance. The plasma of 16 patients on daily hemodialysis (D-HD) was incubated with U937 monocytes and compared to 18 hemodialysis (HD) patients, 5 chronic renal failure (CRF) subjects and 5 healthy volunteers (controls). Apoptosis was evaluated by immunofluorescence microscopy dyes (Hoechst 33342, propidium iodide) and annexin V cytoflowmetry at 96 h. Plasma-induced U937 apoptosis (mean values) was significantly enhanced in D-HD (18.8 ± 4.1), HD (19.67 ± 5.5) and CRF patients (20.8 ± 4.7) compared to controls (9.6 ± 3.6; p < 0.05 for CRF vs. controls, HD vs. controls and D-HD vs. controls). No significant differences were observed between D-HD, HD and CRF sera on apoptosis rate, caspase-3 activity and phagocytic capacity of U937 monocytes. This study demonstrates that the plasma of various HD schedules was unable to reduce monocyte apoptosis induced by uremia.

Growth impairment of primary chondrocyte cells by serum of rats with chronic renal failure.

Insulin-like growth factor (IGF)/IGF binding protein (IGFBP) abnormalities may be important in the pathogenesis of growth failure in chronic renal failure (CRF). We induced experimental CRF by 5/6 nephrectomy in Sprague Dawley rats (100 g) and observed for 2 weeks comparing with sham-operated pair-fed control rats (Sham- C). CRF rats gained 30% less height than Sham- C rats (P < 0.01). Serum IGFBP profiles by Western ligand blot revealed that IGFBP4 was elevated two fold in CRF rats (P < 0.01 vs. Sham-C). However, IGFBP4 mRNA levels in liver or skeletal muscle were not different in two groups. To determine if the increase of serum IGFBP4 in CRF retarded the growth of cartilage, epiphyseal chondrocytes were isolated from CRF or control rats and cultured in the presence of control or CRF rat sera. Incubation with 10% CRF serum reduced proliferations of normal chondrocytes and L6 rat skeletal muscle cells. In contrast, 10% CRF serum did not inhibit the growth of CRF chondrocytes. Rat sera from two groups were separated into two different fractions, high (>10 kDa, containing IGFBPs) and low (<10 kDa, containing free IGF) molecular weight fractions using a gel filtration column. Both fractions obtained from CRF sera decreased the growth of control chondrocytes up to 40% compared with those from control sera. We suggest that the pathogenesis of growth failure in CRF may be involved in the increase of circulating IGFBP4 as well as the unidentified small molecular weight uremic serum factors which block the growth of chondrocytes in growth plate.

Effect of heme oxygenase-1 inducer hemin on chronic renal failure rats.

The role of HO-1 inducer, hemin, in chronic renal failure (CRF) rats and its possible mechanism of action was studied. 5/6 subtotal nephrectomy was performed to establish chronic renal failure model. Rats were randomly assigned to 4 groups: sham-operated group, CRF group, ferrous gluconate group and hemin group. At the 10th week after operation, serum creatinine, BUN, RBC, HGB and HCT were measured. Renal pathologic changes were observed. RT-PCR and immunohistochemistry were used to detect the expression and distribution of HO-1. RT-PCR and radioimmunoassay was used to determine the expression of ET-1 in the kidney and plasma. The results showed that as compared with CRF group, serum creatinine and BUN in hemin group were reduced significantly and nephrogenic anemia was improved markedly. Glomerular mesangial proliferation and interstitial lesion were also ameliorated significantly. Hemin not only increased the expression of HO-1 but also reduced the expression of ET-1 in the kidney. The level of ET-1 protein in the plasma was also reduced after hemin treatment. Most of these indexes were not obviously changed in ferrous gluconate group. It was suggested that through inducing the expression of HO-1 and reducing the level of ET-1 in the kidney and plasma, hemin plays an important protective role in 5/6 subtotal nephrectomized rats.

Lipoprotein (a) in CRF: Effect of Maintenance Hemodialysis

Coronary artery disease is a major cause of morbidity and mortality in patients with chronic renal failure (CRF). Besides the higher prevalence of traditional risk factors, several uremia-related factors may play a role. Although lipoprotein (a)[Lp (a)] is largely determined by genetic factors, there is some evidence to suggest elevated levels of Lp (a) in patients with CRF. However, the effect of maintenance hemodialysis (MHD) on Lp (a) levels has not been studied. Objective: To evaluate the profile of serum Lp (a) and carotid intima-media thickness (IMT) in patients with various grades of CRF and to study the effect of MHD on Lp (a) levels in patients with advanced CRF. Methods: The study group comprised of patients with mild to moderate CRF (n = 15) and advanced CRF (n = 15). Fifteen healthy controls were also enrolled. Serum Lp (a) level was measured and carotid doppler study was done in all cases. In patients with advanced CRF serum Lp (a) level was again measured after one month of MHD. Results: Serum Lp (a) showed a progressive rise with increase in severity of CRF. As against 20% controls, 60% of patients with mild-moderate CRF and 73% of patients with advanced CRF had Lp (a) levels more than 30 mg/dl. In patients with advanced CRF, repeat Lp (a) levels after 4 weeks of MHD showed a decline by 23.6% with a range of 2.5%–50%(p < 0.001)(Figure) However there was no significant difference in the carotid IMT amongst the three groups. Conclusion: Patients with CRF have significant elevation of Lp (a) level. This lipid abnormality starts early during the course of CRF and shows progressive worsening with increase in severity of CRF. In patients with advanced CRF, MHD results in significant decline in Lp (a) levels.