Can the nephrologist prevent dialysis-related amyloidosis?

213 Elderly Uremic Patients over 75 Years of Age Treated with Long Term Peritoneal Dialysis: A French Multicenter Study

We report our experience in 213 elderly patients over 75 years treated by peritoneal dialysis (PC) as first and exclusive dialysis therapy. The mean age at start of PC was 79.4t3.6 years, and the cumulative time on PC was 4551 months (mean time: 21.4 %19.8 months). Twenty-six patients lived in institutions and 187 1ived at home. Thirty patients had an effective autonomy with the ability to carry on normal activities. One hundred and two patients were cared for by a private nurse at home, and 46 patients were cared for in a family environment. Most cases were treated by three exchanges per day (152 cases) and used a nondisconnect system (175 cases) on account of absence of autonomy. The rate of peritonitis per patient month was one episode per 16.8 patient-months. Patient survival (Kaplan-Meier curves) was 74%,59%,45%, and 19% at one, two, three, and five years, respectively. The causes of death were various with a higher frequency of cardiovascular causes (48.3% of the 116 deaths). Thirtythree patients died in less than six months including 18 patients in less than three months. In conclusion: elderly uremic patients can be treated with long-term PC with relatively good results. Mortality is high but essentially due to age and poor general status -the dedication of private home nursing is very important in treating elderly PC patients. This fact often is a necessary condition in maintaining these elderly patients at home.

Successful Self-Care Home Dialysis in the Elderly: A Single Center's Experience

Objective

This study was designed to prospectively review our experience with self-care home dialysis in the 60-years-and-older age group since the commencement of continuous ambulatory peritoneal dialysis (CAPD) in our center in 1989.

Design

Data on mortality, morbidity, dialysis technique and complications, quality of life, and rehabilitation were collected prospectively.

Setting

A regional dialysis unit providing full renal replacement services for a population of 292 000.

Patients

Twenty-five patients (16 male) with an average age of 64.4 years (range: 58.25-76.5 years) at commencement of dialysis.

Results

All patients were on self-care home dialysis. Patient survival rates were comparable with the national average at 12 months (90% vs 89%) and two years (84% vs 80%). Dialysis therapy was well tolerated and technique survival rates were comparable for both hemodialysis and CAPD. There was a very low peritonitis rate of 1 episode per 28.5 patient-months.

Conclusions

Self-care home dialysis is a viable therapeutic option with a high degree of technique success and a good quality of life in the older population.

Do Different Dialysis-Membranes Affect Beta 2-Microglobulin Kinetics during Chronic Hemodialysis?

Hemodialysis is not an absolute prerequisite for the formation of β2-microglobulin amyloidosis, but it enhances the progression of this complication related to long-standing renal failure. Thus the clearance and turnover of β2-microglobulin seems to play a major role in this disease. In a prospective multicenter study the β2-microglobulin clearance was studied in 87 patients starting hemodialysis. Serum samples were taken prior to and after the first dialysis session and also before and after dialysis at 4, 6, 12, 16, 26 and 52 weeks. Patients were either treated by cuprophane or a polyacrylonitril membrane. At the start, the mean serum β2-microglobulin level was about 18 mg/L in patients treated with a cuprophane membrane, but the levels increased after hemodialysis and reached a plateau, which was always higher than in those treated with polyacrylonitril, which cleared β2-microglobulin from the serum. However, after 12 months the difference was no longer significant. Thus β2-microglobulin excretion during dialysis differs between the two membranes, but seems to lose its significance for the β2-microglobulin serum level in chronic hemodialysis treatment.

Behavior of Beta 2-microglobulin (B2-m) serum levels in uremic patients

This Study Was Performed In 97 Hemodialysis Patients (85 On Hd And 12 On Capd) To Investigate The Possible Correlation Between B2-M And Hemodialysis-Related Amyloidosis Syndromes (Hra-S); Differences In B2-M And Hra Behavior Between Patients Hemodialysed With Cellulose And Synthetic Membranes Were Also Included In The Present Study. Data Indicate That B2-M Levels Are Not Correlated With Dialysis Length Or With The Type Of Membrane Used For The Dialysis. On The Contrary, In 16 Patients With The Carpal Tunnel Syndrome, A Significant Correlation Was Found Between The Cts, The Dialysis Length And The Type Of Membrane (Greater Incidence With Cellulosic Membranes).

Mesenchymal Stem Cells as Therapeutic Candidates for Halting the Progression of Diabetic Nephropathy

Mesenchymal stem cells (MSCs) possess pleiotropic properties that include immunomodulation, inhibition of apoptosis, fibrosis and oxidative stress, secretion of trophic factors, and enhancement of angiogenesis. These properties provide a broad spectrum for their potential in a wide range of injuries and diseases, including diabetic nephropathy (DN). MSCs are characterized by adherence to plastic, expression of the surface molecules CD73, CD90, and CD105 in the absence of CD34, CD45, HLA-DR, and CD14 or CD11b and CD79a or CD19 surface molecules, and multidifferentiation capacity in vitro. MSCs can be derived from many tissue sources, consistent with their broad, possibly ubiquitous distribution. This article reviews the existing literature and knowledge of MSC therapy in DN, as well as the most appropriate rodent models to verify the therapeutic potential of MSCs in DN setting. Some preclinical relevant studies are highlighted and new perspectives of combined therapies for decreasing DN progression are discussed. Hence, improved comprehension and interpretation of experimental data will accelerate the progress towards clinical trials that should assess the feasibility and safety of this therapeutic approach in humans. Therefore, MSC-based therapies may bring substantial benefit for patients suffering from DN.

Effect of Antifibrotic MicroRNAs Crosstalk on the Action of N-acetyl-seryl-aspartyl-lysyl-proline in Diabetes-related Kidney Fibrosis

N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) is an endogenous antifibrotic peptide. We found that suppression of AcSDKP and induction of dipeptidyl peptidase-4 (DPP-4), which is associated with insufficient levels of antifibrotic microRNA (miR)s in kidneys, were imperative to understand the mechanisms of fibrosis in the diabetic kidneys. Analyzing streptozotocin (STZ)-induced diabetic mouse strains, diabetic CD-1 mice with fibrotic kidneys could be differentiated from less-fibrotic diabetic 129Sv mice by suppressing AcSDKP and antifibrotic miRs (miR-29s and miR-let-7s), as well as by the prominent induction of DPP-4 protein expression/activity and endothelial to mesenchymal transition. In diabetic CD-1 mice, these alterations were all reversed by AcSDKP treatment. Transfection studies in culture endothelial cells demonstrated crosstalk regulation of miR-29s and miR-let-7s against mesenchymal activation program; such bidirectional regulation could play an essential role in maintaining the antifibrotic program of AcSDKP. Finally, we observed that AcSDKP suppression in fibrotic mice was associated with induction of both interferon-γ and transforming growth factor-β signaling, crucial molecular pathways that disrupt antifibrotic miRs crosstalk. The present study provides insight into the physiologically relevant antifibrotic actions of AcSDKP via antifibrotic miRs; restoring such antifibrotic programs could demonstrate potential utility in combating kidney fibrosis in diabetes.

Clinical Education and Postgraduate Training Opportunities in Nephrology Pharmacy

All colleges of pharmacy in the United States were surveyed to assess the availability of didactic and clinical pharmacotherapy education in the field of nephrology. Forty-four of the 54 (81.5%) colleges with PharmD programs responded to the survey. Of these programs, 64% (28/44) teach nephrology as a separate module during the PharmD curriculum. The content of the nephrology curriculum varied from 2 lecture hours to 30 lecture hours. The pharmacokinetic concepts that relate to pharmacotherapeutic management of nephrology patients are taught in a separate nephrology course in only 9% of these 28 programs. In 57% of these PharmD programs, pharmacokinetic concepts inherent to nephrology are taught as part of a separate pharmacokinetic course. There are 34% of the programs that teach these pharmacokinetic principles in both the nephrology course and as part of a separate pharmacokinetic course. Of the 44 PharmD programs that responded to the survey, 23 (52%) have elective nephrology clerkships. Ten postgraduate training opportunities in nephrology are offered by nine individuals in association with eight colleges of pharmacy. Seven programs have a primary focus in nephrology, three residencies and four fellowships, while three programs identify nephrology as a secondary focus: one residency and two fellowships. An additional eight postgraduate training opportunities with a significant nephrology component were identified. Some of these transplantation residencies and fellowships provide a focused experience in renal transplantation while others include liver, lung, heart, and/or bone marrow experiences. The newest nephrology postgraduate educational opportunity is the American Society of Hospital Pharmacists (ASHP) Clinical Pharmacy Dialysis Service Traineeship Program, which was established in 1992. Implementation of the program was directed by the ASHP Research and Education Foundation with funding from Amgen, Inc. This postgraduate training experience is designed to prepare a pharmacist practitioner to establish and maintain a specialized service for the pharmacotherapeutic management of patients undergoing dialysis.

Chronic administration of EP4-selective agonist exacerbates albuminuria and fibrosis of the kidney in streptozotocin-induced diabetic mice through IL-6

Diabetic nephropathy is currently the most common cause of end-stage renal disease in the western world. Exacerbated inflammation of the kidney is known to contribute acceleration of nephropathy. Despite increased COX-2-mediated production of prostanoid metabolite PGE2, knowledge on its involvement in the progression of diabetic kidney disease is not complete. Here, we show the cross talk of the PGE2-EP4 pathways and IL-6 in inducing albuminuria and fibrosis in an animal model of type 1 diabetes. Hyperglycemia causes enhanced COX-2 expression and PGE2 production. Administration of PGE2 receptor EP4-selective agonist ONO-AE1-329 for 12 weeks exacerbated fibrosis and albuminuria. Diabetes-induced expression of inflammatory cytokines TNFα and TGFβ1 was enhanced in EP4 agonist-treated mice kidney. In addition, urinary excretion of cytokines (TNFα and IL-6) and chemokines (MCP-1 and IP-10) were significantly more in EP4-treated mice than vehicle-treated diabetes. Diabetes-induced collagen I and CTGF expression were also significantly higher in EP4-treated mice. However, EP4 agonist did not alter macrophage infiltration but increased cytokine and chemokine production in RAW264.7 cells. Interestingly, EP4-induced IL-6 expression in the kidney was localized in proximal and distal tubular epithelial cells. To confirm further whether EP4 agonist increases fibrosis and albuminuria through an increase in IL-6 expression, IL-6-knockout mice were administered with EP4 agonist. IL-6-knockout mice were resistant to EP4-induced exacerbation of albuminuria and diabetes and EP4-induced fibrosis. Our data suggest that EP4 agonist through IL-6 induces glomerulosclerosis and interstitial fibrosis, and IL-6 represents a new factor in the EP4 pathway.

What the radiologist needs to know about the diabetic patient

Diabetes mellitus (DM) is recognised as a major health problem. Ninety-nine percent of diabetics suffer from type 2 DM and 10% from type 1 and other types of DM. The number of diabetic patients worldwide is expected to reach 380 millions over the next 15 years. The duration of diabetes is an important factor in the pathogenesis of complications, but other factors frequently coexisting with type 2 DM, such as hypertension, obesity and dyslipidaemia, also contribute to the development of diabetic angiopathy. Microvascular complications include retinopathy, nephropathy and neuropathy. Macroangiopathy mainly affects coronary arteries, carotid arteries and arteries of the lower extremities. Eighty percent of deaths in the diabetic population result from cardiovascular incidents. DM is considered an equivalent of coronary heart disease (CHD). Stroke and peripheral artery disease (PAD) are other main manifestations of diabetic macroangiopathy. Diabetic cardiomyopathy (DC) represents another chronic complication that occurs independently of CHD and hypertension. The greater susceptibility of diabetic patients to infections completes the spectrum of the main consequences of DM. The serious complications of DM make it essential for physicians to be aware of the screening guidelines, allowing for earlier patient diagnosis and treatment.

The role of vascular endothelial growth factor +405 G/C polymorphism and albuminuria in patients with type 2 diabetes mellitus

Observations on the association between the vascular endothelial growth factor (VEGF) gene polymorphism and nephropathy have been inconsistent, which might be due to ethnic and geographical variations. Furthermore, the relationship between +405 G/C polymorphism and albuminuria in the diabetic population has not been sufficiently studied. The aim of this study was to evaluate for the first time the possible association between +405 G/C polymorphism and albuminuria in an population from Tehran of Iran. A total of 255 consecutive patients with type 2 diabetes and microalbuminuria (Group A) and 235 patients with type 2 diabetes and normoalbuminuria (Group B) were included. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were used to detect the VEGF alleles. In univariate analysis, the groups were statistically similar in all variables except for HbA1c (8.53 ± 1.7 in Group A vs. 8.2 ± 1.73 in Group B; P = 0.034), 24-h urinary albumin (201.33 ± 84.8 in Group A vs. 22.88 ± 3.5 in Group B; P < 0.001), and the frequency of GG genotype (31% in Group A vs. 18.7% in Group B; P = 0.006). The GG genotype was the independent predictor of albuminuria [P = 0.014, OR = 1.771, 95% confidence interval (CI) = 1.124-2.790]. Our study showed that the G allele was not associated with albuminuria, but the GG genotype in the VEGF gene is independently associated with development of nephropathy in the our diabetic population.

FVB mouse genotype confers susceptibility to OVE26 diabetic albuminuria

OVE26 (OVE) diabetic mice on the inbred strain FVB are a valuable model of diabetic nephropathy that excretes the highest amount of urine albumin of all diabetic mouse models. Crossing of OVE mice to C57BL6 or DBA2 mice reduced albuminuria 17-fold in F1 diabetic offspring without reducing diabetes. When comparing renal histology of OVE mice on the FVB background to F1 C57BL6 crosses, we found that the F1 kidneys had significantly smaller glomeruli, much less albumin accumulation in tubules, reduced mesangial matrix expansion, and less interstitial fibrosis. A genome scan of 108 OVE-positive N2 offspring for albuminuria revealed one significant peak on chromosome 11 and nearly significant peaks on chromosomes 9, 13, and 19. Homozygosity for the FVB genotype for peaks on chromosomes 11, 13, or 19 increased albuminuria. Homozygosity for the chromosome 9 peak reduced albuminuria. Combined homozyogosity for the peaks on chromosomes 11, 13, and 19 increased albuminuria over 12-fold and accounted for >70% of the difference between OVE mice on the FVB vs. the F1 background. These loci contain sequences important to susceptibility to diabetic albuminuria.

Renal effects of plant-derived oleanolic acid in streptozotocin-induced diabetic rats

Previous studies from our laboratories indicate that the anti-diabetic effects of Syzygium cordatum (Hochst.) [Myrtaceae] leaf extract in streptozotocin-induced diabetic rats may be attributed in part to mixtures of triterpenes, oleanolic acid (3ss-hydroxy-olea-12-en-28-oic acid, OA) and ursolic acid (3ss -hydroxyl-urs-12-en-28-oic acid, UA). For the bioactive compounds to have potential in diabetes management, they should alleviate or prevent complications of diabetes mellitus, kidney function, and cardiovascular disorders. This study was, therefore, designed to assess whether S. cordatum leaf derived OA influenced renal function evaluated by the ability to increase urinary Na(+) outputs parameters and creatinine clearance (Ccr) of streptozotocin (STZ)-induced diabetic rats. Extraction and fractionation of S. cordatum powdered leaf ethyl acetate-solubles (EAS) yielded mixtures of OA/UA and methyl maslinate/methyl corosolate. Recrystallization of OA/UA mixture using ethanol afforded OA, the structure of which was confirmed by NMR spectroscopy ((1)H & (13)C). Acute effects of OA on kidney function and mean arterial blood pressure (MAP) were investigated in anesthetized rats challenged with hypotonic saline after a 3.5-h equilibration for 4h of 1 h control, 1.5 h treatment, and 1.5 h recovery periods. OA was added to the infusate during the treatment period. Chronic effects of OA were studied in individually caged rats treated twice daily with OA (60 mg/kg, p.o.) for five weeks. By comparison with respective control animals administration, OA significantly increased Na(+) excretion rates of non-diabetic and STZ-induced diabetic rats without affecting urine flow, K(+) and Cl(-) rates. At the end of five weeks, OA treatment significantly (p < 0.05) increased Ccr in non-diabetic (2.88 +/- 0.14 vs. 3.71 +/- 0.30 ml/min) and STZ-diabetic rats (1.81 +/- 0.32 vs. 3.07 +/- 0.16 ml/min) with concomitant reduction of plasma creatinine concentration (n = 6 in all groups). OA also caused significant decreases in MAP in non-diabetic and STZ-induced diabetic rats. These findings suggest that OA may have beneficial effects on some processes associated with renal derangement of STZ-induced diabetic rats.

Protective effects of morroniside isolated from Corni Fructus against renal damage in streptozotocin-induced diabetic rats

In our previous study, we reported the renoprotective effect of Hachimi-jio-gan, a Chinese traditional prescription consisting of eight medicinal plants, and also reported the effect of Corni Fructus (Cornus officinalis SIEB. et ZUCC.), a component of Hachimi-jio-gan, on diabetic nephropathy using diabetic rats. In this study, we investigated the effects of morroniside isolated from Corni Fructus on renal damage in streptozotocin-treated diabetic rats. Oral administration of morroniside at a dose of 20 or 100 mg/kg body weight/d for 20 d to diabetic rats resulted in significant decreases in increasing serum glucose and urinary protein levels. Moreover, the decreased levels of serum albumin and total protein in diabetic rats were significantly increased by morroniside administration at a dose of 100 mg/kg body weight/d. In addition, morroniside significantly reduced the elevated serum urea nitrogen level and showed a tendency to reduce creatinine clearance. Morroniside also significantly reduced the enhanced levels of serum glycosylated protein, and serum and renal thiobarbituric acid-reactive substances. Protein expressions related to the advanced glycation endproduct (AGE) level and actions, oxidative stress such as N(epsilon)-(carboxyethyl)lysine, as well as receptors for AGE and heme oxygenase-1 were increased in diabetic rats, but the levels were also significantly decreased by the administration of morroniside. This suggests that morroniside exhibits protective effects against diabetic renal damage by inhibiting hyperglycemia and oxidative stress. These results indicate that morroniside is one component partly responsible for the protective effects of Corni Fructus and Hachimi-jio-gan against diabetic renal damage.

The pathogenesis of diabetic nephropathy

Between 20% and 40% of patients with diabetes ultimately develop diabetic nephropathy, which in the US is the most common cause of end-stage renal disease requiring dialysis. Diabetic nephropathy has several distinct phases of development and multiple mechanisms contribute to the development of the disease and its outcomes. This Review provides a summary of the latest published data dealing with these mechanisms; it focuses not only on candidate genes associated with susceptibility to diabetic nephropathy but also on alterations in various cytokines and their interaction with products of advanced glycation and oxidant stress. Additionally, the interactions between fibrotic and hemodynamic cytokines, such as transforming growth factor beta1 and angiotensin II, respectively, are discussed in the context of new information concerning nephropathy development. We touch on the expanding clinical data regarding markers of nephropathy, such as microalbuminuria, and put them into context; microalbuminuria reflects cardiovascular and not renal risk. If albuminuria levels continue to increase over time then nephropathy is present. Lastly, we look at advances being made to enable identification of genetically predisposed individuals.

Protective effect of heat-processed American ginseng against diabetic renal damage in rats

We investigated the effects of American ginseng (AG) and heat-processed American ginseng (H-AG) on diabetic renal damage using streptozotocin (STZ)-induced diabetic rats in this study. The diabetic rats showed a loss of body weight gain, and increases in kidney weight, food intake, water intake, and urine volume, whereas the oral administration of H-AG at a dose of 100 mg/kg of body weight per day for 20 days attenuated these diabetes-induced physiological abnormalities. Among the renal function parameters, the elevated urinary protein levels in diabetic control rats were significantly decreased by the AG or H-AG administrations, and the decreased creatinine clearance level was significantly increased in H-AG-administered rats. In addition, the markedly high serum levels of glucose and glycosylated protein in diabetic control rats were significantly decreased by the administration of H-AG, implying that H-AG might prevent the pathogenesis of diabetic complications caused by impaired glucose metabolism and glycosylation of serum proteins. Although no significant ameliorations were shown in overexpressed protein expressions related to diabetic oxidative stress by the AG or H-AG administrations, the accumulation of N (epsilon)-(carboxymethyl)lysine and receptors for advanced glycation endproduct (AGE) expressions were significantly reduced by the administration of H-AG. On the basis of these results, we found that AG and H-AG inhibit AGE accumulation in diabetic rat kidney by their hypoglycemic and renal function ameliorating effects, and this effect was stronger in the H-AG-administered group than in the AG-administered group. These findings indicate that H-AG may have beneficial effect on pathological conditions associated with diabetic nephropathy.

An association between vascular endothelial growth factor gene promoter polymorphisms and diabetic retinopathy

BACKGROUND

Diabetic retinopathy is a highly prevalent cause of visual loss in Western countries. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor implicated in the development of the proliferative stage of this disease. Reports have suggested that polymorphisms at positions -460 and -634 of the 5' untranslated region of the VEGF gene increase its basal promoter activity.

METHODS

To investigate whether polymorphisms are associated with diabetic retinopathy, 215 patients with type 2 diabetes mellitus (T2DM) were enrolled. Among them, 82 subjects had proliferative diabetic retinopathy (PDR), 72 had non-proliferative diabetic retinopathy (NPDR), and 61 individuals without retinopathy served as controls. Two polymorphisms of the VEGF gene, a G-->C transversion at -634 (the G/C polymorphism) and a C-->T transition at -460 (the C/T polymorphism), were investigated by restriction fragment length polymorphism PCR and allele-specific PCR respectively.

RESULTS

We did not find any association between the C/T polymorphism and diabetic retinopathy. However, the G/C polymorphism genotype distribution and the frequency of the C allele were significantly higher in the NPDR group than in control patients (OR = 1.69, 95% CI = 1.03-2.79). Analysis of the distribution of combined genotypes of the VEGF gene revealed the prevalence of the C/C-C/C genotype in NPDR patients (OR = 8.26, 95% CI = 1.79-37.99) and C/G-CC in PDR patients (OR = 3.36, 95% CI = 1.39-8.12).

CONCLUSIONS

Occurrence of the -634C allele appears to be associated with increased VEGF gene promoter activity, and the G/C polymorphism might serve as a predictive factor for the development of diabetic retinopathy.

Effect of improvement in anemia on electroneurophysiological markers (P300) of cognitive dysfunction in chronic kidney disease

Our aim is to study the effect of improvement in anemia on event-related potentials (ERPs; P300) as markers of cognitive dysfunction in predialysis and dialysis patients of chronic kidney disease (CKD). Thirty anemic patients of CKD (hemoglobin [Hb] < 9 g%), 15 in the predialysis group (Group A), and 15 patients on biweekly hemodialysis (Group B) were recruited for the study. Patients of uremic encephalopathy, dyselectrolytemia, and those with hearing problems were excluded. Both groups were given recombinant human erythropoietin (rhuEPO) 100 IU/kg biweekly for 6 weeks by the subcutaneous route. No intervention was performed in the third control group (Group C), which consisted of 30 normal healthy volunteers. The improvement in Hb was assessed every 2 weeks, and the amplitude and latency of the P300 component of the ERPs were studied before initiating treatment and after 6 weeks of rhuEPO administration. There was a significant increase in Hb in both the study groups without any significant alteration in kidney functions. A significant reduction in P300 latency was noted in both the study groups after intervention. Similarly, the amplitude of P300 also increased in both study groups, but attained statistical significance for the dialysis group only. No significant changes were observed in the control group. Administration of EPO in patients of anemia with CKD resulted in a significant improvement in the electrophysiological markers of cognitive function in the form of increased amplitudes and decreased latencies of P300 in both predialysis and dialysis patients.

Protective Effect of Sun Ginseng against Diabetic Renal Damage

The effect of sun ginseng (SG, heat-processed Panax ginseng C. A. MEYER at 120 degrees C) on diabetic renal damage was investigated using streptozotocin-induced diabetic rats. The diabetic rats showed loss of body weight gain, and increases in food and water intake and urine volume, while the oral administration of SG at a dose of 50 or 100 mg/kg body weight/d for 15 d attenuated water intake and urine excretion induced by diabetes. In addition, the diabetic rats given SG at a dose of 100 mg/kg body weight showed significant decreases in serum glucose, serum glycosylated protein and urinary protein levels, suggesting that SG improves the abnormal conditions that lead to oxidative stress. Furthermore, SG significantly reduced advanced glycation endproduct (AGE) formation and thiobarbituric acid-reactive substance levels elevated in the kidneys of diabetic rats. This implies that SG would alleviate the oxidative stress under diabetes through the inhibition of lipid peroxidation. SG also reduced the overexpression of cyclooxygenase-2 and inducible nitric oxide synthase in the kidney induced by hyperglycemia via deactivation the activation of nuclear factor-kappa B. Furthermore, treatment with SG decreased the levels of 3-nitrotyrosine, carboxymethyllysine and receptors for AGE which increase under diabetes. These findings indicate that oxidative stress is increased in the diabetic rat kidney and that SG can prevent renal damage associated with diabetes by attenuating the oxidative stress.

Quo vadis dialysis membrane?

The development of dialysis membranes is closely related to the development of dialysis as a routine therapy for patients with kidney failure. Without having membranes and dialyzers available as commodity products, the treatment of more than 1 million uremic patients worldwide would be impossible. Several transition periods can be identified: a change in membrane geometry from flat sheet to capillaries, a shift in market appreciation from cellulose to synthetic polymers, and from low-flux to high-flux dialyzers. This shift is supported by the notion that convective therapies using high-flux membranes allow the removal of large-molecular-weight solutes. From a historical background, three eras of perception can be identified for both membrane and dialysis development. First, the period of survival when nephrologists had to focus on techniques for blood access and availability of membranes. Second, the period of issues dedicated to rather specific features of membranes and dialysis therapy such as dose of dialysis, reuse, sterilization, and membrane biocompatibility. And third, the period of quality tops this sequence with a complicated approach: the principal area of interest from the medical community has switched to issues such as quality of life, morbidity, mortality, therapy standards, and cost-effectiveness. New membrane developments should focus on this situation.

Nontransplant therapy for dialysis-related amyloidosis

There is no specific treatment for dialysis-related amyloidosis (DRA). Available therapy is directed at removal of large quantities of beta(2)-microglobulin (beta(2)M) and palliation of symptoms. Plasma concentrations of beta(2)M in end-stage renal disease (ESRD) depend on the degree of residual renal function, the type of blood purification therapy, and properties of the dialysis filtration membrane. Retention of beta(2)M appears to be a necessary, although not sufficient, condition for DRA. While preserving residual renal function is important, dialysis modality largely determines beta(2)M removal. Convective dialysis treatments (hemofiltration and hemodiafiltration) remove beta(2)M more efficiently than diffusive treatments (conventional dialysis). In addition, column adsorption of beta(2)M can extensively remove the molecule, as can nocturnal hemodialysis. Hemodialysis membrane properties that are particularly important with regard to beta(2)M removal include permeability, adsorptive capacity, and biocompatibility. As such, beta(2)M removal with highly permeable biocompatible membranes such as polysulfone and polyacrylonitrile is relatively large. Several studies have suggested that use of such membranes can significantly delay DRA development and may be useful in ameliorating DRA-associated symptoms. Non-dialysis-related therapy for DRA is palliative and includes both medical and surgical therapies. Medical therapy includes low-dose corticosteroids and nonsteroidal anti-inflammatory drugs (NSAIDs). Surgical therapy consists of relief of carpal tunnel syndrome, or palliation of shoulder pain, destroyed weight-bearing joints, or spinal cord compression. DRA is a serious complication of long-term dialysis. It is important for nephrologists to recognize the condition and attempt to slow its progression.

Polytetrafluoroethylene hemoaccess site infections

The advent of permanent hemodialysis access has made possible the use of chronic hemodialysis in patients with end-stage renal disease. Although autogenous arteriovenous fistulae remain the conduit of choice, their construction is not always feasible. Prosthetic grafts made of polytetrafluoroethylene (PTFE) are typically the second-line choice for hemoaccess. However, these grafts suffer from decreased rates of patency and an increased number of complications. Although thrombosis is the most common complication, infection of PTFE grafts accounts for a significant number of hospitalizations and uses a large amount of healthcare resources. In this monograph, we address infectious complications of PTFE hemoaccess grafts and present a review of the recent literature.

Effects of simulated hyperglycemia, insulin, and glucagon on endothelial nitric oxide synthase expression

Diabetes is associated with endothelial dysfunction and increased risk of hypertension, cardiovascular disease, and renal complications. Earlier studies have revealed that hyperglycemia impairs nitric oxide (NO) production and diabetes causes endothelial dysfunction in humans and experimental animals. This study was designed to test the effects of altered concentrations of glucose, insulin, and glucagon, the principal variables in types I and II diabetes, on NO production and endothelial NO synthase (eNOS) expression in cultured human coronary endothelial cells. Cultured endothelial cells were incubated in the presence of glucose at either normal (5.6 mM) or high (25 mM) concentrations for 7 days. The rates of basal and bradykinin-stimulated NO production (nitrate + nitrite) and eNOS protein expression (Western blot) were then determined at the basal condition and in the presence of insulin (10(-8) and 10(-7) M), glucagon (10(-8) and 10(-7) M), or both. Incubation with a high-glucose concentration for 7 days significantly downregulated, whereas insulin significantly upregulated, basal and bradykinin-stimulated NO production and eNOS expression in cultured endothelial cells. The stimulatory action of insulin was mitigated by high-glucose concentration and abolished by cotreatment of cells with glucagon. Thus hyperglycemia, insulinopenia, and hyperglucagonemia, which frequently coexist in diabetes, can work in concert to suppress NO production by human coronary artery endothelial cells.

In search of ideal hemodialysis: is prolonged frequent dialysis the answer?

Advances in technology have made it possible to deliver a high Kt/V in a shorter time. The realization that duration of dialysis may be an important predictor of survival independent of dialysis dose has resulted in the popularity of prolonged slow dialysis (PHD). The longer duration and increased frequency of dialysis achieve excellent small- and middle-molecular weight solute clearance and also attenuate the peak concentration of uremic toxins. The slow dialysis process enables the equilibration of tissue and vascular compartments, resulting in better clearance and decreased postdialysis rebound increase in solutes. Gentle, persistent ultrafiltration allows the control of hypertension with minimal antihypertensive use. The intense and more frequent dialysis improves appetite and permits liberalization of diet. This greater dietary protein intake results in a progressive increase in serum albumin level and dry weight. Nocturnal hemodialysis achieves control of hyperphosphatemia without phosphate binders and a significant reduction in serum beta(2)-microglobulin levels. Normalization of extracellular volume, better clearance of uremic toxins, and improved nutrition result in a significant improvement in survival. The flexible time schedule with home hemodialysis and improvement of sleep and neurocognitive function allow better rehabilitation. The available evidence indicates PHD may be closer to the concept of an ideal dialysis, but there is lingering uncertainty about the consequence of prolonged immune stimulation, catabolism, and loss of essential solutes with these therapies.

Outcome of renal transplantation in ninety-seven cyclosporine-era patients with systemic lupus erythematosus and matched controls

OBJECTIVE

To evaluate the effectiveness of renal transplantation in systemic lupus erythematosus (SLE).

METHODS

A total of 97 SLE patients who underwent renal transplantation between January 1984 and September 1996 were selected for study and were matched with a group of non-SLE controls (1 control for each SLE patient) who also received transplants during that period. SLE patients and controls were matched on 6 covariates: age, sex, race, type of allograft (cadaveric versus living-related), number of previous transplants, and year of transplantation. All study subjects received either cyclosporine or FK-506/tacrolimus as part of their immunosuppressive regimen. In a rigorous medical records review, the status of each allograft and the cause of each graft loss was determined. Using a stratified Cox proportional hazards model, the transplantation outcomes of the SLE patients were compared with those of the controls. The effects of 9 individual variables on transplantation outcomes were also examined, and the statistically significant variables were compared in a stratified, multivariate Cox proportional hazards model.

RESULTS

The control group included patients with 20 different causes of end-stage renal disease (ESRD). The mean followup times for the SLE patients and controls were 323 weeks and 320 weeks, respectively. During the followup period, 52 SLE patients and 37 controls lost their allografts. The 1-, 2-, 5-, and 10-year allograft survival probabilities for the 2 groups (SLE versus controls) were as follows: 81.7% versus 88.2% (1-year); 74.7% versus 84.4% (2-year); 45.9% versus 75.0% (5-year); and 18.5% versus 34.8% (10-year). In the multivariate model, the relative hazard of allograft loss associated with SLE as the cause of ESRD was 2.1 (95% confidence interval 1.06-4.06, P = 0.0328). The total number of HLA mismatches, smoking status, and delayed allograft function were also associated with allograft loss in the multivariate model.

CONCLUSION

Compared with matched controls, renal transplant patients with SLE had inferior transplantation outcomes, with more than twice the risk of allograft loss.

Beta2-microglobulin and low-flux synthetic dialyzers

The aim of this study was to compare the effect on beta2-microglobulin (beta2-M) plasma levels of dialyzers with 3 low-flux synthetic membranes and regenerated cellulose (Cuprophan) in 12 chronic dialysis patients. The synthetic membrane materials chosen were low-flux polymethylmethacrylate (PMMA), low-flux polysulfone (PS 400), and polycarbonate-polyether (Gambrane). Adequate and comparable removal of small solutes was provided by dialyzers with all 4 membrane materials used under similar conditions. A significant reduction of beta2-M plasma levels was seen only with Gambrane while the other 2 synthetic membrane materials gave rise to increases similar to those known to occur with Cuprophan. After correction for the hemoconcentration caused by ultrafiltration, dialysis with Gambrane showed a 24% lower plasma beta2-M level while the beta2-M concentrations with the other 3 membrane materials were practically unchanged. In addition, the efficiency of Gambrane dialyzers in beta2-M removal was able to significantly lower the predialysis plasma beta2-M levels after only 5 dialysis sessions. The hemocompatibility of the 3 synthetic low-flux membranes as judged by the white blood cell (WBC) count and complement activation was similar and therefore cannot be used to explain the different beta2-M plasma levels. In anticipation of gaining further insight into the mechanisms of accumulation and deposition of beta2-M in dialysis patients, a worthwhile approach may be to use a low-flux membrane such as Gambrane which combines removal with protection against potential activating factors in the dialysis fluid.

Beta 2-microglobulin associated amyloidosis: a vanishing complication of long-term hemodialysis?

Beta 2-microglobulin associated amyloidosis (A beta 2m amyloidosis) is considered an inevitable complication of chronic hemodialysis, particularly in hemodialysis with cellulose based membranes. We performed a single center study to assess the prevalence of A beta 2m amyloidosis in 1988 versus 1996. Randomly selected patients, studied in 1988, were matched for time on hemodialysis (mean 71 months, range 3 to 207) and age (mean 51 years, range 22 to 80) with patients of the 1996 population. Compared to 1988 patients, the 1996 patients exhibited a lower prevalence of carpal tunnel syndrome (7 of 43 in 1988 vs. 1 of 43 in 1996; P < 0.001) and radiological evidence of A beta 2m amyloidosis (13 of 34 patients vs. 3 of 34 patients positive; P < 0.001; and 33 of 272 possible sites affected in 1988 vs. 7 of 272 sites in 1996 patients; P < 0.05). Compared to the 1988 population, the 1996 population exhibited significantly lower serum aluminum levels, lower average serum creatinine (but not urea) levels, more frequent therapy with erythropoietin, less home hemodialysis, longer hemodialysis time using high-flux synthetic dialysis membranes (mean of 13% vs. 6% of the total hemodialysis time in the 1988 group), and more frequent usage of reverse osmosis water plus bicarbonate buffer for dialysate preparation. We conclude that the prevalence and severity of A beta 2m amyloidosis unexpectedly decreased by about 80% in our center between 1988 and 1996. Given the relatively short times spent on high flux hemodialysis in both groups, increased beta 2-microglobulin removal is unlikely to account for this phenomenon. Rather, other factors, for example, dialysate composition and purity, may be involved.

Dialysis-related amyloidosis of the tongue in long-term hemodialysis patients

Dialysis-related amyloidosis (DRA) predominantly occurs in the osteoarticular structures. However, according to studies in the increasing number of long-term hemodialysis patients, DRA has also been systemically found to appear in the other tissues and organs as well. In this study, we investigated lingual amyloidosis in relation to systemic DRA. A total of 472 patients were studied who were on regular hemodialysis for more than 10 years, including 103 patients for more than 20 years. Eight of these patients (7 males and 1 female, mean age 59 +/- 8 years, range 46 to 68 years) developed lingual amyloidosis, seemingly as a result of beta2-microglobulin (beta2m) deposits. All patients demonstrating lingual amyloidosis had been treated with regular hemodialysis for more than 20 years (mean HD duration 23.6 +/- 1.4 years), and its morbidity was 7.8% in the 103 patients and 20% (6 patients) in the 30 patients treated for more than 23 years with hemodialysis. Hemodialysis (HD) duration with bioincompatible unsubstituted cellulose membranes in the 8 patients was longer than that in the control group without lingual amyloidosis (P < 0.05). Lingual amyloid nodules were whitish-yellow in color and varied in size, at least over 1 mm in diameter. Their consistency was firmer than the intact tongue. The location of the amyloid nodules could be classified into two types: (1) diffuse type (diffusely distributed over the tongue), and (2) lateral type (localized only in the lateral side of the tongue). Five of the eight patients with lingual amyloidosis complained of functional disturbances in the tongue, such as abnormal taste, or difficulty in mobility and articulation. No macroglossia was observed in any of these cases. It was thus concluded that DRA of the tongue is a very rare complication, occurring in the late stage of long-term hemodialysis patients, that disturbs their quality of life.

Renal osteodystrophy

Renal osteodystrophy is a general complication of chronic renal failure and end-stage renal disease. The nature of renal osteodystrophy has changed since osteomalacia due to aluminum intoxication has become less prevalent. Osteomalacia has been replaced by the adynamic bone disorder. Suppression of osteitis fibrosa, calcitrol and control of secondary hyperparathyroidism has been shown to produce the adynamic bone disorder. Thus, many other factors besides secondary hyperparathyroidism and calcitrol deficiency contribute to the pathogenesis of renal osteodystrophy. Some of these factors, according to our current state of knowledge, are discussed in this chapter along with the presentation and treatment of renal osteodystrophy.

Long term effect of renal transplantation on dialysis-related amyloid deposits and symptomatology

We report the five year outcome of nine patients with dialysis-related amyloid (DRA) who underwent successful renal transplantation (RT) and six patients who remained on hemodialysis (HD). Amyloid bone cysts, a radiologic feature of DRA, and scintigraphy with 123I-labeled serum amyloid P component (SAP), a specific technique for evaluating amyloid deposits in vivo, were monitored and compared with clinical features. In all HD patients there was clinical, scintigraphic and/or radiologic evidence that DRA progressed. In contrast, eight of the RT patients experienced profound early relief of DRA symptoms following transplantation that persisted throughout follow-up, despite the reduction or withdrawal of corticosteroids. Amyloid bone cysts improved in four patients and SAP scans demonstrated regression of articular amyloid in eight out of nine cases. The modest radiographic improvement suggests that amyloid is mobilized more slowly in bone cysts than elsewhere or that cystic bone is remodeled poorly. This is the first objective evidence that DRA regresses following renal transplantation, and suggests that this may contribute to the long-term relief of DRA symptoms in transplant recipients who discontinue corticosteroids.

Treatment of amyloidosis

Amyloidosis is the extracellular deposition of normally soluble autologous protein in a characteristic abnormal fibrillar form. Systemic amyloidosis and some local forms are progressive, cause major morbidity, and are often fatal. No treatment specifically causes the resolution of amyloid deposits, but therapy that reduces the supply of amyloid fibril precursor proteins can improve survival and preserve organ function. Major regression of amyloid occurs in at least a proportion of such cases, suggesting that the clinical improvement reflects mobilization of amyloid. The clearest evidence for regression of amyloid has been obtained in juvenile rheumatoid arthritis patients with AA amyloidosis treated with chlorambucil. This drug suppresses the acute phase production of serum amyloid A protein, the precursor of AA amyloid fibrils, and is associated with remission of proteinuria and greatly improved survival. In many such patients, scintigraphy with serum amyloid P component shows major regression of amyloid over 12 to 36 months and frequently reveals a discrepancy between the local amyloid load and organ dysfunction. Measurement of target organ function is therefore not an adequate method for monitoring treatment aimed at promoting the resolution of amyloid. In monoclonal immunoglobulin light chain (AL) amyloidosis the aim of treatment is to suppress the underlying B-cell clone and, therefore, production of the amyloid fibril precursor protein. This can be difficult to achieve or sustain and, since the prognosis is so poor, many patients die before benefits of therapy are realized. A recent development has been the introduction of liver transplantation as treatment for familial amyloid polyneuropathy caused by transthyretin gene mutations. This leads to the disappearance of variant transthyretin from the plasma and halts progression of the neurologic disease. Features of autonomic neuropathy frequently ameliorate, and improvement in peripheral motor nerve function has been recently reported. Serum amyloid P component scans show regression of associated visceral amyloidosis. This surgical form of gene therapy holds much promise for patients with familial amyloid polyneuropathy and has been widely adopted. The only other form of amyloidosis in which the supply of the fibril precursor protein can be sharply reduced is beta 2M amyloidosis in long-term hemodialysis patients. Renal transplantation lowers the plasma concentration of beta 2M to normal levels and is associated with rapid improvement of the osteoarticular symptoms. Preliminary observations suggest that the beta 2M amyloid deposits also can regress in some patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Amyloidosis

Amyloidosis is the generic term for a heterogeneous group of disorders characterised by the common finding of amyloid deposition. The various acquired and hereditary syndromes are classified according to the identity of the respective amyloid fibril sub-unit protein. Systemic amyloidosis and some local forms are progressive diseases that are frequently fatal. The diagnosis of systemic amyloidosis is only occasionally suspected on clinical grounds alone, and is more often considered when an associated disorder such as a chronic inflammatory disease or monoclonal gammopathy is present. No blood test is diagnostic of amyloidosis but routine haematological and biochemical investigations have important roles in defining the underlying metabolic disturbance and evaluating function of affected organs. The diagnosis can only be confirmed by demonstrating the presence of tissue amyloid deposits. Traditionally this required histology but the recent introduction of labelled serum amyloid P component scintigraphy is a specific alternative that provides a quantitative macroscopic whole body survey of amyloid deposits. No treatment specifically causes the resolution of amyloid but therapy which reduces the supply of amyloid fibril precursor proteins can improve survival and preserve organ function. Major regression of amyloid occurs in at least a proportion of such cases suggesting that clinical improvement reflects mobilisation of amyloid.

Membrane adsorption of beta 2-microglobulin: equilibrium and kinetic characterization

Enhanced extracorporeal removal of beta 2-microglobulin (beta 2m) may prevent the development of dialysis-related amyloidosis (DRA). One mechanism of beta 2m removal is membrane adsorption. Therefore, we fundamentally characterized beta 2m adsorption to the highly permeable polyacrylonitrile (PAN) membrane. Porous and nonporous PAN fragments were incubated in buffer containing 125I-beta 2m. Over a concentration range of 8 to 60 mg/liter, the equilibrium adsorption isotherm was linear (r = 0.99) for porous PAN while the isotherm for nonporous PAN suggested either multilayer binding or adsorption of proteins with differing orientations. In kinetic analyses, the approach to equilibrium versus (time)1/2 was evaluated. For both porous and nonporous PAN, this relationship was linear (r = 0.99), consistent with a diffusion-controlled process. Adsorption reversibility was assessed by comparing the amount bound at varying residence times (0 to 4 hr) to the amount remaining adsorbed after a subsequent incubation in buffer. The fractions remaining bound at 60, 120, and 240 minutes (0.34 +/- 0.02, 0.36 +/- 0.06, and 0.44 +/- 0.03; mean +/- SEM) were significantly greater (P < 0.05) than the value at five minutes (0.23 +/- 0.01). This suggests membrane-induced conformational changes in adsorbed beta 2m. This investigation permits the comparison of beta 2m adsorptive properties of PAN to those of other membrane-based and nonmembrane-based therapies designed to prevent DRA.

In vivo effect of beta 2-microglobulin on bone resorption

beta 2-Microglobulin (beta 2-M) deposits have been found in the destructive bone lesions associated with dialysis-related amyloidosis. To examine whether beta 2-M can cause bone resorption in vivo, doses of beta 2-M alone were compared with parathyroid hormone (PTH), aluminum, and vehicle alone. Eleven injections of 10 micrograms each were made over a period of 56 hours into the subcutaneous tissue overlying the occipital region of mice. Using a computerized image analysis system we measured (1) periosteal and inner bone length, (2) bone marrow interface length, and (3) the extent of resorption along these surfaces expressed as percentage of total length. Injections of either beta 2-M or PTH were associated with 22% +/- 4% and 25% +/- 4% resorption of periosteal surface, respectively, and 15.9% +/- 2% and 19.9% +/- 5% resorption of marrow bone surfaces, respectively, compared with control. In contrast, aluminum did not increase bone resorption over controls. The simultaneous injection of calcitonin, an osteoclast inhibitor, with beta 2-M or PTH did not increase periosteal resorption over controls. The resorption of inner bone surface was similar in all groups. These studies show that beta 2-M and PTH cause bone resorption in the bone surfaces proximate to the site of injection. This suggests that beta 2-M may contribute to the development of the bone cysts in dialysis-related amyloidosis.

Dialysis-associated spondylarthropathy. Report of 10 cases

Ten patients undergoing long-term renal dialysis for end-stage renal failure developed a destructive, non-infectious spondylarthropathy. All 10 patients had biopsy-proven dialysis-associated spondylarthropathy and subsequent spinal instability secondary to beta 2-microglobulin deposition in the vertebrae, intervertebral disc spaces, and support structures of the spine. Nine patients had cervical spinal instability and one had thoracolumbar spinal instability, with resultant neural compression. In at least one patient, the spinal instability was rapidly progressive. All had received renal dialysis for 34 months or longer (mean 109 months, range 34 to 154 months). Each patient required spinal stabilization (external in seven patients, internal in three). Nine of the 10 patients underwent neural decompression and spinal stabilization and fusion procedures. One patient's neurological condition was worse following surgery due to a postoperative cervical epidural hematoma; in the other nine patients, the presenting symptoms and signs improved. Three of these chronically ill patients did not survive their hospitalization, for a perioperative mortality rate of 30%. Death was due to cardiopulmonary arrest in two patients on Day 5 and 9 postoperatively and to sepsis in the third on Day 14. Of the seven early survivors, two additional patients died: one on Day 59 due to congestive heart failure and the other on Day 273 due to a cerebrovascular accident. Four of five patients who were followed for 8 months or longer (mean 14 months, range 8 to 20 months) had successful neural decompression and spinal stabilization procedures with evidence of stable bone fusion, indicating that these chronically ill, difficult-to-manage patients can be successfully treated. Clinicians who treat patients with renal disease and neurosurgeons who treat spinal disorders should be aware of dialysis-associated spondylarthropathy as a potential cause of degenerative vertebral column instability.

Clinical Pharmacology in Aged Intensive Care Unit Patients

Elderly patients are presenting themselves for advanced critical care services in ever-increasing numbers due to changing population demographics coupled with advances in medical technology and pharmacology. Medical management of the elderly in critical care settings is complicated by pre-existing multisystem chronic disease, polypharmacy, and age-related changes in pharmacokinetics and pharmacodynamics. Three principles in the management of the elderly in an intensive care unit (ICU) setting are discussed: (1) the protection of renal function from common nephrotic drugs; (2) the necessity of altered drug dosing due to changes in pharmacokinetics and pharmacodynamics; and (3) the necessity of avoiding polypharmacy. Strategies for the prevention of acute renal failure in ICU contrast studies are described. A review of pharmacodynamics and pharmacokinetics in the elderly is presented with examples of commonly seen ICU medication problems.

Southwestern Internal Medicine Conference: bone disease in kidney failure: diagnosis and management

Recent technologic and therapeutic advances have improved the life of the patient with end-stage renal disease. High efficiency and high-flux hemodialyzer membranes have shortened the time required to dialyze, and recombinant erythropoietin has all but eliminated anemia as a major cause of morbidity, but the problem of renal osteodystrophy remains. The following discussion examines the spectrum of bone and joint disease in the patient with end-stage renal disease. The diagnostic and therapeutic strategies currently being tried in the management of these disorders are discussed.

Clinical Nephrology and Dialysis in the 1990s

End-stage renal disease (ESRD) afflicts more than 200,000 patients in the United States today, and they undergo chronic dialysis or transplantation in order to sustain life. The primary causes of treated ESRD today are diabetes mellitus, hypertension, and glomerulonephritis. Hemodialysis remains the mainstay of therapy for patients, primarily due to the chronic shortage of organs available for transplantation. Technological advances have led to numerous improvements in hemodialysis therapy during the last 30 years. Dialysis is now provided in a variety of settings, including hospitals, outpatient dialysis units, and the home. Despite these advances, morbidity and mortality remain high for patients with ESRD. Patients with diabetes have the highest mortality rates primarily due to cardiac and infectious complications. Patients undergoing continuous ambulatory peritoneal dialysis (CAPD) are generally younger and healthier than their hemodialysis counterparts. Mortality is lower in the CAPD group for younger patients, whereas mortality is lower among older hemodialysis patients. Various methods have been described to assess adequacy of dialysis in order to develop the optimal dialysis prescription. Although these may ultimately prove beneficial, recent observations indicate an increased mortality in American hemodialysis patients compared with their European counterparts. These differences may be due in part to variances in reimbursement rates for dialysis therapy, and a reduction in dialysis time among U.S. centers. In light of the increasing number of patients and the complexity of their therapy, multiple opportunities exist for pharmacists to become actively involved in the comprehensive care of the ESRD patient.

Clinical evaluation of a new dialyzer, FLX-12 GW, with a polyester-polymer alloy membrane

The performance of a membrane in renal failure therapy is determined by its structure, its overall mass transfer properties, and its blood compatibility. In this regard, removal of beta 2-microglobulin (beta 2M) has become a major objective of dialysis therapy. In the present study, a newly developed high-flux membrane composed of a polyester-polymer alloy (PEPA) with the components of polyarylate and polyethersulfone (dialyzer FLX-12 GW; Nikkiso Co., Japan) has been evaluated with regard to both biocompatibility and elimination capacity for beta 2M during hemodialysis of 8 stable chronic uremic patients. The clearance values of low molecular weight solutes were in the same range as those reported for high-flux dialyzers of comparable surface area. There was no drop in leukocyte counts and only a minimal fall in platelet counts nearly in the same range as has been observed by other investigators using polyamide membrane. C3a Des Arg generation was low, and C5a Des Arg formation was not significantly influenced. There was a sharp drop in the serum beta 2M level (-35%) during dialysis with a clearance between 59.7 +/- 5.6 ml/min (QB 200 ml/min) and 70.1 +/- 9.7 ml/min (QB 300 ml/min), respectively. Accordingly, the sieving coefficient was calculated to be 0.2 at 30 min after start of dialysis and 0.6 1 h later. The membrane was able to remove 184.0 +/- 22.3 mg/4 h due to an apparent rate of adsorption during the first hour of treatment in combination with high transmembrane transfer in the following time.

The effect of dialyzer reprocessing on performance and beta 2-microglobulin removal using polysulfone membranes

Increased biocompatibility and lower cost are the two major arguments favoring routine dialyzer reprocessing. The impact of longer-term reprocessing is critical to the practical use of polysulfone membranes (PMs), because of the possibility of decreasing efficiency and performance, especially in the removal of beta 2-microglobulin (beta 2M), a protein that has been implicated in the development of dialysis-associated amyloidosis (DDA). In this study, we examine urea clearance (Kd), urea mass transfer coefficient (h0), ultrafiltration coefficient (K(uf)), and percent removal of beta 2M up to 24 uses. The study involved 11 patients on hemodialysis for 5.27 +/- 4.6 years, with a mean age of 62.5 +/- 9.7 years and average run-time treatment of 2.78 +/- 0.3 hours. PMs were tested after being reprocessed manually using bleach and formaldehyde. The efficacy of the dialyzer was examined on uses 1, 5, 10, 15, 20, and 24, and the percent removal of beta 2M was determined except in the twentieth use and corrected for ultrafiltration. The Kd obtained through 24 uses showed no significant change, although h0 was significantly increased in the fifteenth use, and K(uf) was significantly increased in the 10th and 20th use (P < 0.05). The percent removal of beta 2M increased significantly from 44.1 +/- 2.8 (mean +/- SEM) in the first use to 59.4 +/- 2.19 (P < 0.05) in the 10th use, and 62.1 +/- 4.07 and 63.1 +/- 4.27 in the 15th and 24th uses, respectively (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Kinetics of 125I-beta 2-microglobulin turnover in dialyzed patients

The kinetics of beta 2-microglobulin (beta 2m) were studied in 17 anephric or functionally anephric hemodialyzed patients and five healthy subjects as controls. Highly purified beta 2m was radiolabeled with 125I and infused into patients. The radioactivity in plasma and dialysis fluids was measured during a week including two or three dialysis sessions. Patients were classified in four groups according to treatment: hemodialysis on Cuprophan (N = 5) or on AN69 membranes (N = 5), hemofiltration (N = 4) and CAPD (N = 3). Plasma activity was fitted to a three compartment model. In controls almost 100% of the radioactivity was recovered in urine within 96 hours and there was no extrarenal catabolism. In patients the fractional catabolic rate ranged from 0.0008 to 0.0022 min-1 versus 0.026 to 0.047 min-1 in controls. The synthetic rate was within the range of values from controls in 10 patients but higher in the seven others. It was correlated with plasma beta 2m concentration. Kinetic data indicate a retention of intact beta 2m. The original model was therefore modified with an additional compartment representing beta 2m captation. The amount of capted beta 2m was more elevated in hemodialyzed patients than in patients treated by hemofiltration or CAPD, in whom it could reach 5 mg/kg/day. Hemofiltration or CAPD may eliminate about 30 to 100% of beta 2m produced and therefore contribute to the low captation amount of these patients, as compared with that of patients treated by hemodialysis.

Musculoskeletal complications after renal transplantation: pathogenesis and treatment

Renal transplantation is associated with several abnormalities of function and structure of the musculoskeletal system. Some of these skeletal problems result from incomplete resolution of abnormalities of bone and mineral metabolism present at the time of transplantation. In this regard, persistent hyperparathyroidism, diabetes mellitus type 1, and accumulation of beta 2-microglobulin may lead to residual skeletal effects despite excellent function of the allograft. Persistent hyperparathyroidism may accelerate bone loss and increase the risk for osteonecrosis, as well as cause hypercalcemia and hypophosphatemia; some patients with severe hyperparathyroidism require parathyroid surgery. Osteonecrosis is the most debilitating skeletal complication after transplantation and frequently requires surgical therapy. Although osteomalacia associated with aluminum overload generally resolves after transplantation, bone complications due to dialysis amyloidosis and diabetes mellitus type 1 often fail to improve. Alternatively, skeletal abnormalities can be acquired after transplantation. Most of the new derangements of bone and mineral metabolism are due to the immunosuppressive medications. Toxic effects of glucocorticoids on bone contribute to the pathogenesis of osteonecrosis, increase the risk for fractures by decreasing cancellous bone mass and synthesis of bone matrix, and dampen the linear growth response in pediatric recipients. Whether cyclosporine independently causes appreciable toxic effects on bone metabolism is not yet clear, but use of this drug increases the prevalence of gout and dental problems. Osteonecrosis, osteopenia, and short stature remain important skeletal complications in recipients of renal allografts. Therapeutic efforts should be directed toward alleviating pretransplant bone disease and attenuating bone loss after transplantation.