Haemodialysis

Podocyte Death in Diabetic Kidney Disease: Potential Molecular Mechanisms and Therapeutic Targets

Cell deaths maintain the normal function of tissues and organs. In pathological conditions, the abnormal activation or disruption of cell death often leads to pathophysiological effects. Diabetic kidney disease (DKD), a significant microvascular complication of diabetes, is linked to high mortality and morbidity rates, imposing a substantial burden on global healthcare systems and economies. Loss and detachment of podocytes are key pathological changes in the progression of DKD. This review explores the potential mechanisms of apoptosis, necrosis, autophagy, pyroptosis, ferroptosis, cuproptosis, and podoptosis in podocytes, focusing on how different cell death modes contribute to the progression of DKD. It recognizes the limitations of current research and presents the latest basic and clinical research studies targeting podocyte death pathways in DKD. Lastly, it focuses on the future of targeting podocyte cell death to treat DKD, with the intention of inspiring further research and the development of therapeutic strategies.

Application of nanotechnology in the treatment of glomerulonephritis: current status and future perspectives

Glomerulonephritis (GN) is the most common cause of end-stage renal failure worldwide; in most cases, it cannot be cured and can only delay the progression of the disease. At present, the main treatment methods include symptomatic therapy, immunosuppressive therapy, and renal replacement therapy. However, effective treatment of GN is hindered by issues such as steroid resistance, serious side effects, low bioavailability, and lack of precise targeting. With the widespread application of nanoparticles in medical treatment, novel methods have emerged for the treatment of kidney diseases. Targeted transportation of drugs, nucleic acids, and other substances to kidney tissues and even kidney cells through nanodrug delivery systems can reduce the systemic effects and adverse reactions of drugs and improve treatment effectiveness. The high specificity of nanoparticles enables them to bind to ion channels and block or enhance channel gating, thus improving inflammation. This review briefly introduces the characteristics of GN, describes the treatment status of GN, systematically summarizes the research achievements of nanoparticles in the treatment of primary GN, diabetic nephropathy and lupus nephritis, analyzes recent therapeutic developments, and outlines promising research directions, such as gas signaling molecule nanodrug delivery systems and ultrasmall nanoparticles. The current application of nanoparticles in GN is summarized to provide a reference for better treatment of GN in the future.

Optimization of FDM 3D printing process parameters to produce haemodialysis curcumin-loaded vascular grafts

3D printing has provided a new prospective in the manufacturing of personalized medical implants, including fistulas for haemodialysis (HD). In the current study, an optimized fused modelling deposition (FDM) 3D printing method has been validated, for the first time, to obtain cylindrical shaped fistulas. Printing parameters were evaluated for the manufacturing of fistulas using blank and 0.25% curcumin-loaded filaments that were produced by hot melt extrusion (HME). Four different fistula types have been designed and characterized using a variety of physicochemical characterization methods. Each design was printed three times to demonstrate printing process accuracy considering outer and inner diameter, wall thickness, width, and length. A thermoplastic polyurethane (TPU) biocompatible elastomer was chosen, showing good mechanical properties with a high elastic modulus and maximum elongation, as well as stability at high temperatures with less than 0.8% of degradation at the range between 25 and 250 °C. Curcumin release profile has been evaluated in a saline buffer, obtaining a low release (12%) and demonstrating drug could continue release for a longer period, and for as long as grafts should remain in patient body. Possibility to produce drug-loaded grafts using one-step method as well as 3D printing process and TPU filaments containing curcumin printability has been demonstrated.

Effects of Descurainia sophia on Oxidative Stress Markers and Thirst Alleviation in Hemodialysis Patients: A Randomized Double-Blinded Placebo-Controlled Cross-Over Clinical Trial

Background

Patients undergoing hemodialysis (HD) are regularly exposed to oxidative stress and inflammation and may suffer from thirst distress with no definitive treatment to address these complications. Descurainia sophia (DS) has been used to alleviate thirst in traditional Persian medicine. This study aimed to assess the effectiveness of DS on oxidation factors and thirst score in HD patients.

Methods

This study was conducted on fifty-three HD patients referred to Tehran Shahid Modarres hospital. The patients were randomly divided into two groups: Group 1 received DS for six weeks, then underwent four weeks of washout period followed by six weeks of placebo treatment, while group 2 received placebo initially followed by treatment with DS. Biochemistry, malondialdehyde (MDA), and total antioxidant capacity (TAC) were measured in four phases: at the beginning, before washout, after washout, and at the end of the study. The patient's body weight was recorded at the start of each session to assess interdialytic weight gain. Thirst scores also were measured using a visual analog scale.

Results

A total of 53 patients, including 23 (43.4%) male and 30 (56.6%) female subjects, were included in the study. The results showed a reduction in thirst score (p=0.001), cholesterol levels (p=0.046), triglycerides (0.003), and MDA (p < 0.001) following the four-week administration of DS treatment in HD patients. The mean levels of TAC were increased (p < 0.001), and calcium, as well as Na+, remained unchanged (p > 0.05). Also, a significant decrease in the patient's weight was observed (p value <0.001). This effect persisted after shifting to a placebo. However, the two groups had no significant difference (p value = 0.539).

Conclusion

DS powder-mixed syrup may benefit HD patients by facilitating free radical scavenging and alleviating thirst distress with minimal adverse effects. The seeds could therefore be utilized as a complementary therapy for hemodialysis patients.

Differential Inductive Sensing System for Truly Contactless Measuring of Liquids' Electromagnetic Properties in Tubing

Certain applications require a contactless measurement to eliminate the risk of sensor-induced sample contamination. Examples can be found in chemical process control, biotechnology or medical technology. For instance, in critically ill patients requiring renal replacement therapy, continuous in-line monitoring of blood conductivity as a measure for sodium should be considered. A differential inductive sensing system based on a differential transformer using a specific flow chamber has already proven suitable for this application. However, since the blood in renal replacement therapy is carried in plastic tubing, a direct measurement through the tubing offers a contactless method. Therefore, in this work we present a differential transformer for measuring directly through electrically non-conductive tubing by winding the tube around the ferrite core of the transformer. Here, the dependence of the winding type and the number of turns of the tubing on the sensitivity has been analyzed by using a mathematical model, simulations and experimental validation. A maximum sensitivity of 364.9 mV/mol/L is measured for radial winding around the core. A longitudinal winding turns out to be less effective with 92.8 mV/mol/L. However, the findings prove the ability to use the differential transformer as a truly contactless sensing system.

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.

Using two-holed needles for both arterial and venous accesses to the arteriovenous fistula to improve flow during hemodialysis

This prospective study compared methods using both arterial and venous needles with back eyes with those using only arterial needle with back eye for arteriovenous fistula cannulation. Sixty-one patients receiving hemodialysis (HD) via an arteriovenous fistula were evaluated. All patients underwent arteriovenous fistula puncture using only arterial needle with back eye in first 3 months and both arterial and venous needles with back eyes in following 3 months. Arterial and venous pressures, blood flow velocities, total blood volume cleared, and Kt/V values were compared. Mean blood flow velocity, arterial pressure, Kt/V, and cleared total blood volume values were higher and venous pressure was lower in patients who underwent cannulation using both needles with back eyes than in those with only the arterial needle with back eye. For arteriovenous fistula cannulation, using both arterial and venous needles with back eyes provides adequate HD more successfully.

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.

Neurological sequel of chronic kidney disease: From diminished Acetylcholinesterase activity to mitochondrial dysfunctions, oxidative stress and inflammation in mice brain

With increasing prevalence, chronic kidney disease (CKD) has become a global health problem. Due to the retention of uremic toxins, electrolytes and water, and the resultant metabolic disturbances, CKD affects several organs, including the nervous system. Thus, CKD patients suffer from several neurological complications, including dementia, cognitive impairment, motor abnormalities, depression, and mood and sleep disturbances. However, the mechanisms underlying the neurological complications are least elucidated. We have recently reported a highly reproducible mice model of CKD induced by high adenine diet, which exhibited psychomotor behavioral abnormalities and blood-brain barrier disruption. In the present study, using the mice model, we have investigated psycho-motor and cognitive behaviour, and the neurochemical and histopathological alterations in brain relevant to the observed behavioural abnormalities. The results demonstrate global loss of Acetylcholinesterase activity, and decrease in neuronal arborisation and dendritic spine density in discrete brain regions, of the CKD mice. Oxidative stress, inflammation, and mitochondrial dysfunctions were found in specific brain regions of the mice, which have been regarded as the underlying causes of the observed neurochemical and histopathological alterations. Thus, the present study is of immense importance, and has therapeutic implications in the management of CKD-associated neurological complications.

Evaluation of changes in salivary composition in renal failure patients before and after hemodialysis

Background

Saliva plays a major role in preserving the integrity of oral tissues. The oral health of renal failure patients could be negatively affected by the underlying pathology, the dialysis treatment, or an altered salivary composition. Major systemic changes occur during hemodialysis (HD), which could affect the flow rate and biochemical composition of saliva. Therefore, the aim of this study was to evaluate the effects of HD on the salivary flow rate, pH and biochemical composition before and after completion of a dialysis session.

Material and Methods

Thirty Renal failure patients undergoing hemodialysis were selected based on the inclusion and exclusion criteria set forth for the study. Unstimulated whole saliva (UWS) was collected by the spitting method, immediately before and after a dialysis session. Salivary flow rate, pH, concentration of urea, creatinine, sodium, chloride, potassium and calcium were measured.

Results

Hemodialysis had an acute stimulating effect on the salivary flow rate. The mean pH of UWS showed no significant changes before and after dialysis. The concentrations of urea, creatinine, chloride and potassium in whole saliva changed markedly before and after a hemodialysis session; whereas no significant difference was seen in the concentration of sodium and calcium.

Conclusions

This study shows that HD has significant acute effects on both salivary secretion and biochemical composition in saliva. We conclude that the observed changes in salivary concentrations and flow rate are mainly due to an increased watery secretion from the salivary glands and also saliva can be used as a tool for monitoring hemodialysis.

Key words:Saliva, Hemodialysis, Flow rate, pH, biochemical constituents.

A highly reproducible mice model of chronic kidney disease: Evidences of behavioural abnormalities and blood-brain barrier disruption

AIMS

In the present study, a novel mice model of chronic kidney disease (CKD) was developed, and psycho-motor behavioural abnormalities, blood-brain barrier (BBB) integrity and brain histology were studied.

MAIN METHODS

Swiss albino female mice were given high adenine diet (0.3% w/w mixed with feed) for 4weeks. Serum urea and creatinine levels and renal histological studies were performed to validate the model. Psycho-motor behavioural abnormalities and neurological severity were studied. BBB integrity was assessed using Evans blue extravasation method. Nissl staining was performed to see possible morphological aberrations in brain.

KEY FINDINGS

There was a significant increase in serum urea and creatinine levels in mice given high adenine diet, and the mice had abnormal kidney morphology. Deposition of adenine and 2,8-dihydroxyadenine crystals, and increased collagen deposits in the renal tissues were found, which validate induction of CKD in the mice. Motor behavioural abnormalities, depression-like and anxiolytic behaviour and increase in neurological severity were prevalent in mice with CKD. Evans Blue dye extravasation was found to occur in the brain, which signifies disruption of BBB. However, Nissl staining did not reveal any morphological aberration in brain tissue.

SIGNIFICANCE

The present study puts forward a highly reproducible mice model of CKD validated with serum parameters and renal histopathological changes. The mice showed psycho-motor behavioural abnormalities and BBB disruption. It is a convenient model to study the disease pathology, and understanding the associated disorders, and their therapeutic interventions.

Advance care planning for haemodialysis patients

BACKGROUND

End-stage kidney disease (ESKD) is a chronic, debilitative and progressive illness that may need interventions such as dialysis, transplantation, dietary and fluid restrictions. Most patients with ESKD will require renal replacement therapy, such as kidney transplantation or maintenance dialysis. Advance care planning traditionally encompass instructions via living wills, and concern patient preferences about interventions such as cardiopulmonary resuscitation and feeding tubes, or circumstances around assigning surrogate decision makers. Most people undergoing haemodialysis are not aware of advance care planning and few patients formalise their wishes as advance directives and of those who do, many do not discuss their decisions with a physician. Advance care planning involves planning for future healthcare decisions and preferences of the patient in advance while comprehension is intact. It is an essential part of good palliative care that likely improves the lives and deaths of haemodialysis patients.

OBJECTIVES

The objective of this review was to determine whether advance care planning in haemodialysis patients, compared with no or less structured forms of advance care planning, can result in fewer hospital admissions or less use of treatments with life-prolonging or curative intent, and if patient's wishes were followed at end-of-life.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register to 27 June 2016 through contact with the Information Specialist using search terms relevant to this review. We also searched the Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Social Work Abstracts (OvidSP).

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs (RCTs in which allocation to treatment was obtained by alternation, use of alternate medical records, date of birth or other predictable methods) looking at advance care planning versus no form of advance care planning in haemodialysis patients was considered for inclusion without language restriction.

DATA COLLECTION AND ANALYSIS

Data extraction was carried out independently by two authors using standard data extraction forms. Studies reported in non-English language journals were translated before assessment. Where more than one publication of one study exists, reports were grouped together and the publication with the most complete data was used in the analyses. Where relevant outcomes are only published in earlier versions these data were used. Any discrepancies between published versions were highlighted. Non-randomised controlled studies were excluded.

MAIN RESULTS

We included two studies (three reports) that involved 337 participants which investigated advance care planning for people with ESKD. Neither of the included studies reported outcomes relevant to this review. Study quality was assessed as suboptimal.

AUTHORS' CONCLUSIONS

We found sparse data that were assessed at suboptimal quality and therefore we were unable to formulate conclusions about whether advance care planning can influence numbers of hospital admissions and treatment required by people with ESKD, or if patients' advance care directives were followed at end-of-life. Further well designed and adequately powered RCTs are needed to better inform patient and clinical decision-making about advance care planning and advance directives among people with ESKD who are undergoing dialysis.

Sodium gradient, xerostomia, thirst and inter-dialytic excessive weight gain: a possible relationship with hyposalivation in patients on maintenance hemodialysis

Purpose

The aim of the study was to assess whether hyposalivation is linked with increased thirst sensation and weight gain in hemodialysis (HD) patients and whether there is any connection between hyposalivation and sodium balance.

Methods

One hundred and eleven participants (64 males and 47 females) receiving maintenance hemodialysis, mean age 59.1 ± 13.6 years old, were involved in the study. All participants completed a survey evaluating thirst intensity (DTI) and xerostomia inventory (XI). In addition, pre-dialysis sodium concentration and inter-dialytic weight gain (IWG) were assessed. The division into no-hyposalivation and hyposalivation groups was based on an unstimulated whole saliva (UWS) flow rate.

Results

Hyposalivation, UWS below 0.1 mL/min, was reported in 28.8 % of HD patients. In these participants, IWG was higher than in patients with UWS > 0.1 mL/min (3.65 ± 1.78 vs 3.0 ± 1.4; p = 0.042), as well as the pre-dialysis sodium gradient (3.22 ± 2.1 vs 1.6 ± 2.8; p = 0.031). The mean XI and DTI scores did not differ between study groups. In the hyposalivation group, pre-dialysis sodium serum gradient negatively correlated with saliva outflow (ρ = −0.61, p = 0.019) and positively with IWG (ρ = 0.49, p = 0.022). IWG correlated with XI (ρ = 0.622, p = 0.016) in hyposalivation group and with DTI in no-hyposalivation group (ρ = 0.386, p = 0.033).

Conclusions

Hyposalivation significantly correlates with IWG; however, its influence on thirst and self-reported mouth dryness seems to be weaker than expected. Additionally, hyposalivation was found to be associated with an elevated pre-dialysis sodium gradient.

[A prediction model development on quality of life in kidney transplant recipients]

PURPOSE

The purpose of this study was to identify factors influencing quality of life in kidney transplant recipients and to understand the concrete pathway of influence and the power of each variable, so that integrated prediction model to promote the quality of life of kidney transplant recipients could be developed.

METHODS

The sample was composed of 218 patients in follow-up care after a kidney transplant in one of 4 university hospitals in the Honam area. A structured questionnaire was used and the collected data were analyzed for fitness, using the LISREL program.

RESULTS

This model was concise and extensive in predicting the quality of life of kidney transplant recipients.

CONCLUSION

The research verified the factors influencing quality of life for kidney transplant recipients and it verified that direct factors such as perception of health state, compliance, self-efficacy, stress and indirect factors such as self-efficacy and social support can be important factors to predict the quality of life for recipients. Moreover, those variables represent 87% of variance in explaining quality of life in a prediction model so that the variables can be utilized to predict quality of life for kidney transplant recipients.

Neurological complications of chronic kidney disease

Chronic kidney disease (CKD) is a critical and rapidly growing global health problem. Neurological complications occur in almost all patients with severe CKD, potentially affecting all levels of the nervous system, from the CNS through to the PNS. Cognitive impairment, manifesting typically as a vascular dementia, develops in a considerable proportion of patients on dialysis, and improves with renal transplantation. Patients on dialysis are generally weaker, less active and have reduced exercise capacity compared with healthy individuals. Peripheral neuropathy manifests in almost all such patients, leading to weakness and disability. Better dialysis strategies and dietary modification could improve outcomes of transplantation if implemented before surgery. For patients with autonomic neuropathy, specific treatments, including sildenafil for impotence and midodrine for intradialytic hypotension, are effective and well tolerated. Exercise training programs and carnitine supplementation might be beneficial for neuromuscular complications, and restless legs syndrome in CKD responds to dopaminergic agonists and levodopa treatment. The present Review dissects the pathophysiology of neurological complications related to CKD and highlights the spectrum of therapies currently available.

Interdialytic weight gain and ultrafiltration rate in hemodialysis: lessons about fluid adherence from a national registry of clinical practice

Excessive interdialytic weight gain (IWG) and ultrafiltration rates (UFR) above 10 mL/h/kg body weight imply higher morbidity and mortality. This study aimed to estimate the prevalence of high fluid consumers, describe UFR patterns, and describe patient characteristics associated with IWG and UFR. The Swedish Dialysis DataBase and The Swedish Renal Registry of Active Treatment of Uremia were used as data sources. Data were analyzed from patients aged >/=18 on regular treatment with hemodialysis (HD) and registered during 2002 to 2006. Interdialytic weight gain and dialytic UFR were examined in annual cohorts and the records were based on 9693 HD sessions in 4498 patients. Differences in proportions were analyzed with the chi-square test and differences in means were tested using the ANOVA or the t test. About 30% of the patients had IWG that exceed 3.5% of dry body weight and 5% had IWG >/=5.7%. The volume removed during HD was >10 mL/h/kg for 15% to 23% of the patients, and this rate increased during the first dialytic year. Patient characteristics associated with fluid overload were younger age, lower body mass index, longer dialytic vintage, and high blood pressure. By studying IWG and dialytic UFR as quality indicators, it is shown that there is a potential for continuing improvement in the care of patients in HD settings, i.e., to enhanced adherence to fluid restriction or alternatively to extend the frequency of dialysis for all patients, e.g., by providing daily treatment.

Effect of lanthanum carbonate and calcium acetate in the treatment of hyperphosphatemia in patients of chronic kidney disease

OBJECTIVES

The tolerability and efficacy of lanthanum carbonate has not been studied in the Indian population. This study was, therefore, undertaken to compare the efficacy and tolerability of lanthanum carbonate with calcium acetate in patients with stage 4 chronic kidney disease.

DESIGN

A randomized open label two group cross-over study.

MATERIALS AND METHODS

Following Institutional Ethics Committee approval and valid consent, patients with stage 4 chronic kidney disease were randomized to receive either lanthanum carbonate 500mg thrice daily or calcium acetate 667 mg thrice daily for 4 weeks. After a 4-week washout period, the patients were crossed over for another 4 weeks. Serum phosphorous, serum calcium, serum alkaline phosphatase, and serum creatinine were estimated at fixed intervals.

RESULTS

Twenty-six patients were enrolled in the study. The mean serum phosphorous concentrations showed a declining trend with lanthanum carbonate (from pre-drug levels of 7.88 +/- 1.52 mg/dL-7.14 +/- 1.51 mg/dL) and calcium acetate (from pre-drug levels of 7.54 +/- 1.39 mg/dL-6.51 +/- 1.38 mg/dL). A statistically significant difference was seen when comparing the change in serum calcium produced by these drugs (P < 0.05). Serum calcium levels increased with calcium acetate (from pre-drug levels of 7.01 +/- 1.07-7.46 +/- 0.74 mg dL), while it decreased with lanthanum carbonate (from pre-drug levels 7.43 +/- 0.77-7.14 +/- 0.72 mg/dL). The incidence of adverse effects was greater with lanthanum carbonate.

CONCLUSION

Lanthanum carbonate and calcium acetate are equally effective phosphate binders with trends obvious in the first 4 weeks of therapy. The decrease in serum calcium levels with lanthanum carbonate when compared to the increase in serum calcium levels due to calcium acetate is statistically significant. The drawback of lanthanum carbonate is its high cost and relatively higher incidence of adverse events during treatment.

Fluid Intake Appraisal Inventory: development and psychometric evaluation of a situation-specific measure for haemodialysis patients' self-efficacy to low fluid intake

OBJECTIVE

Self-efficacy is an important determinant of health behaviour and reflects a person's belief about their capability to complete a given task. The relationship between self-efficacy and fluid adherence has been investigated, although limited attention has been given to measurement issues. The purpose of this study was to develop a measure of situation-specific self-efficacy for constructive fluid intake behaviour in haemodialysis patients, the Fluid Intake Appraisal Inventory (FIAI).

METHODS

Items were generated from an analysis of empirical studies available in the literature and exposed to an interpretability critique before haemodialysis patients confirmed sufficiency of each item. In a multi-centre study, data from 144 haemodialysis patients were collected regarding general self-efficacy, situation-specific self-efficacy, and estimated fluid consumption. Internal consistency, criterion-related validity, and structural validity were tested.

RESULTS

The FIAI was found to have high internal consistency (Cronbach alpha 0.96) and the theoretical assumptions for criterion-related validity and known-group validity were supported. Structural validity was not confirmed, however, because the theoretically hypothesized four-factor model was not the prime structure.

CONCLUSION

The FIAI was revealed to have satisfactory psychometric properties. The scale may be used in research or in clinical settings to study the mediating effects of self-efficacy or to modify haemodialysis patients' fluid-intake behaviour. Although this first validity study is promising, further validation focusing on reliability and cultural validity is needed.

Uremic neuropathy: clinical features and new pathophysiological insights

Neuropathy is a common complication of end-stage kidney disease (ESKD), typically presenting as a distal symmetrical process with greater lower-limb than upper-limb involvement. The condition is of insidious onset, progressing over months. and has been estimated to be present in 60%-100% of patients on dialysis. Neuropathy generally only develops at glomerular filtration rates of less than 12 ml/min. The most frequent clinical features reflect large-fiber involvement, with paresthesias, reduction in deep tendon reflexes, impaired vibration sense, muscle wasting, and weakness. Nerve conduction studies demonstrate findings consistent with a generalized neuropathy of the axonal type. Patients may also develop autonomic features, with postural hypotension, impaired sweating, diarrhea, constipation, or impotence. The development of uremic neuropathy has been related previously to the retention of neurotoxic molecules in the middle molecular range, although this hypothesis lacked formal proof. Studies utilizing novel axonal excitability techniques have recently shed further light on the pathophysiology of this condition. Nerves of uremic patients have been shown to exist in a chronically depolarized state prior to dialysis, with subsequent improvement and normalization of resting membrane potential after dialysis. The degree of depolarization correlates with serum K(+), suggesting that chronic hyperkalemic depolarization plays an important role in the development of nerve dysfunction in ESKD. These recent findings suggest that maintenance of serum K(+) within normal limits between periods of dialysis, rather than simple avoidance of hyperkalemia, is likely to reduce the incidence and severity of uremic neuropathy.

Renal disease: the anesthesiologist's perspective

The kidney is a remarkable organ whose functions include maintaining fluid and electrolyte balance, excreting metabolic waste products, and controlling vascular tone. Blood flow within the kidney is very heterogeneous, which places the metabolically active medulla at high risk for ischemic injury. A number of mediators play a role in the modulation of renal blood flow, including angiotensin II, dopamine, vasopressin, prostaglandins, atrial natriuretic peptide, endothelin, and nitric oxide. Early markers of renal injury elicit strong interest, although currently there is no reliable marker available. Surgery causes the release of catecholamines, renin, angiotensin, and AVP that lead to a redistribution of renal blood flow and a decrease in GFR. Additionally, general anesthesia often results in some degree of hypotension and depressed cardiac output, which further reduces renal perfusion and potentially jeopardizes renal function. A careful anesthetic plan is imperative in the patient with renal insufficiency or failure because acute renal failure in the perioperative period is associated with a high morbidity and mortality. Factors including advanced age, diabetes, underlying renal insufficiency, and heart failure place a patient at high risk for developing acute renal failure. It is imperative to maintain euvolemia, normotension, and cardiac output, and to avoid nephrotoxic agents to optimize renal blood flow and renal perfusion as the best prevention of renal dysfunction. Further studies are needed to establish if any therapies exist to prevent or treat renal dysfunction effectively.

The cost-effectiveness of lanthanum carbonate in the treatment of hyperphosphatemia in patients with end-stage renal disease

OBJECTIVE

To assess the cost-effectiveness of lanthanum carbonate (LC) as a second-line therapy for hyperphosphatemia in end-stage renal disease (ESRD) patients not achieving target phosphorus levels.

METHODS

A cohort of ESRD patients not adequately maintained on calcium carbonate (CC) and three subgroups of patients with baseline phosphorus levels of 5.6 to 6.5 mg/dl, 6.6 to 7.8 mg/dl, and more than 7.9 mg/dl were modeled. The following policy options were considered: continued CC (Policy 1); LC trial-if successful continue LC, if unsuccessful switch to CC (Policy 2). The survival benefit of using second-line LC to improve phosphorus control has been extrapolated from the relationship between hyperphosphatemia and mortality. Lifetime UK National Health Service drug and monitoring costs, expected survival, and quality-adjusted life-years (QALYs) were examined (discounting at 3.5% per annum).

RESULTS

Policy 2 had a cost-effectiveness ratio (cost/QALY) of pound25,033 relative to Policy 1. The results show it is particularly cost-effective to treat patients with phosphorus levels above 6.6 mg/dl. The outcomes did not vary significantly during the one-way sensitivity analysis carried out on important model parameters and assumptions except when the utility value for ESRD was decreased by more than 30%.

CONCLUSIONS

Applying a cost-effectiveness threshold of pound30,000 per QALY, the model shows it is cost-effective to follow current treatment guidelines and treat all patients who are not adequately maintained on CC (serum phosphorus above 5.6 mg/dl) with second-line LC. This is particularly the case for patients with serum phosphorus above 6.6 mg/dl. Our estimates are probably conservative as the possible compliance difference in favor of LC and the reduced number of hypercalcemic events with LC relative to CC was not considered.

Hemodiafiltration During Cardiac Surgery in Patients on Chronic Hemodialysis

BACKGROUND

We have developed a hemodiafiltration (HDF) protocol used during cardiac surgery to preserve fluid and electrolyte balance and prevent postoperative bleeding in patients on chronic hemodialysis. This retrospective study examined the operative results associated with our new protocol.

METHODS

The study included 33 consecutive patients on long-term hemodialysis who underwent cardiac surgery at our hospital between January 2001 and April 2005, including off-pump coronary artery bypass grafting (CABG) in 19 patients. Vascular access was achieved via a 12-French double-lumen catheter inserted into the left femoral vein under general anesthesia, and HDF begun when the operation was started. After completion of cardiopulmonary bypass or, in patients who underwent off-pump CABG, after the distal anastomoses were completed, HDF was continued until target hematocrit between 30% and 35%, central venous pressure between 3 and 5 mmHg, and serum potassium concentration between 3.0 and 3.5 mEq/L were reached. The chest was closed after confirmation of hemostasis.

RESULTS

There was no in-hospital death. Three patients were extubated in the operating room. There were no postoperative wound infection, mediastinitis, respiratory tract infection, or hemorrhage. The patients were discharged at a mean of 15.6 days after operation.

CONCLUSIONS

These results suggest that intraoperative HDF lowers postoperative morbidity and mortality in chronic dialysis patients. Other advantages include early extubation and ambulation, and a shortened hospitalization.

Emerging strategies for lowering serum phosphorous in patients with end-stage renal disease

Hyperphosphataemia is a major problem in patients with chronic kidney disease as it has been associated with increased morbidity and mortality. Over the last four decades, different modalities have been applied to treat hyperphosphataemia with varying degrees of success. Unfortunately, treatment strategies have led to unforeseen complications. These have prompted the development of new classes of medications with potentially better efficacy and few short-term and long-term side effects. This article reviews the causes, mechanism and management of hyperphosphataemia.

Noninvasive continuous monitoring of digital pulse waves during hemodialysis

Intermittent hemodynamic instability during hemodialysis treatment is a frequent complication in patients with end-stage renal failure. A noninvasive method for continuous hemodynamic monitoring is needed. We used noninvasive digital photoplethysmography and an algorithm for continuous, investigator-independent, automatic analysis of digital volume pulse in 10 healthy subjects and in 20 patients with end-stage renal failure during the hemodialysis session. The reflective index was defined representing the diastolic component of the digital pulse wave. The properties of the reflective index were studied in healthy control subjects (n=10). An increased reflective index was due to increased peripheral pulse wave reflection (e.g., vasoconstriction). During a hemodialysis session, the reflective index increased significantly from 36+/-3 arbitrary units to 41+/-3 arbitrary units (n=20; p<0.05) measured using digital photoplethysmography. This increase appeared in 15 of the 20 patients with end-stage renal failure. Our data establish digital photoplethysmography as a noninvasive, reliable, and sensitive method for continuous monitoring during the hemodialysis session.

Altered motor nerve excitability in end-stage kidney disease

Although multiple toxins have been implicated in the development of uraemic neuropathy, no causative agent has been identified. In the present study, the excitability properties of lower limb motor nerves in patients with end-stage kidney disease treated with haemodialysis were measured before, during and after a standard 5 h haemodialysis session, in an attempt to explore the pathophysiology of uraemic neuropathy. Compound muscle action potentials were recorded from tibialis anterior and extensor digitorum brevis, following stimulation of the common peroneal nerve in 14 patients. Measures of excitability were assessed in relation to changes in serum levels of potential neurotoxins, including potassium, calcium, urea, uric acid, parathyroid hormone and beta-2-microglobulin. Before dialysis, measures of nerve excitability were significantly abnormal in the patient group for axons innervating tibialis anterior and extensor digitorum brevis, consistent with axonal depolarization: refractoriness was increased and superexcitability and depolarizing threshold electrotonus were reduced. Pre-dialysis excitability abnormalities were strongly correlated with serum K+. Correlation was also noted between the severity of symptoms and excitability abnormalities. Haemodialysis normalized the majority of nerve excitability parameters. In conclusion, lower limb motor axons in uraemic patients are depolarized before dialysis. The correlation between serum K+ and excitability measures indicates that hyperkalaemia is primarily responsible for uraemic depolarization, and a likely contributing factor to the development of neuropathy.

Collecting unit cost data in multicentre studies. Creating comparable methods

International comparisons of health care systems and services have created increased interest in the comparability of cost results. This study compared top-down and bottom-up approaches to collecting unit cost data across centres in the context of examining the cost-effectiveness of dialysis therapy across Europe. The study tested whether health care technologies in different countries can be costed using consistent and transparent methods to increase the comparability of results. There was more agreement across the approaches for peritoneal dialysis than for than haemodialysis, with differences, respectively of Euro 91-1,687 vs. 333-7,314 per patient per year. Haemodialysis results showed greatest differences where dialysis units were integrated as part of larger hospitals. Deciding which approach to adopt depends largely on the technology. However, bottom-up costing should be considered for technologies with a large component of staff input or overheads, significant sharing of staff or facilities between technologies or patient groups and health care costing systems which do not routinely allocate costs to the intervention level. In these circumstances this costing approach could increase consistency and transparency and hence comparability of cost results.

Interdialytic weight gain in patients on hemodialysis is associated with dry mouth and thirst

BACKGROUND

Patients receiving hemodialysis (HD) have to maintain a fluid-restricted diet. Severe thirst can induce noncompliance to this diet, resulting in an increase of interdialytic weight gain (IWG = weight predialysis - postdialysis) associated with poor patient outcomes. Because oral dryness may contribute to experienced thirst, we investigated the possible relation between thirst, salivary flow rate, xerostomia, and IWG.

METHODS

Unstimulated (UWS) and stimulated (CH-SWS) whole saliva were collected from 94 HD patients (64 men, 54.8 +/- 15.5 years; 30 women, 59.5 +/- 18.7 years). Secretion rates of saliva were determined gravimetrically. Xerostomia was assessed with a validated Xerostomia Inventory (XI), and thirst with a newly developed Dialysis Thirst Inventory (DTI).

RESULTS

Before dialysis, 36.2% of the patients had hyposalivation (UWS < or =0.15 mL/min). The XI scores had a positive relation with IWG (r=.250, P < 0.001). Gender and age differences were observed for thirst, salivary flow rates, and xerostomia. The prevalence and severity of thirst and xerostomia were greater in younger subjects. Patients with urine output did not differ from those without urine output with respect to thirst, xerostomia, and IWG. Correlations were found between thirst (DTI) and both IWG and xerostomia (XI) (r=.329, P < 0.001, respectively; r=.740, P < 0.001). Other correlations were observed between xerostomia and both the salivary flow rate and total number of medications (r=-.252, P < 0.05, respectively; r=.235, P <.05).

CONCLUSION

In HD patients, xerostomia (XI) and thirst (DTI) are associated with a higher IWG. Our data provide evidence that, in HD patients, xerostomia is related to both salivary flow rate and thirst (DTI).

Prospective study of hepatitis C virus infection in hemodialysis patients by monthly analysis of HCV RNA and antibodies

The aims of this study were to (i) evaluate the prevalence and the incidence of hepatitis C virus (HCV) infection in hemodialysis patients in two different centers in São Paulo (Brazil), (ii) determine the time required to detect HCV infection among these patients by serology or PCR, (iii) establish the importance of alanine aminotransferase determination as a marker of HCV infection, and (iv) identify the HCV genotypes in this population. Serum samples were collected monthly for 1 year from 281 patients admitted to hospital for hemodialysis. Out of 281 patients, 41 patients (14.6%) were HCV positive; six patients seroconverted during this study (incidence = 3.1/1000 person-month). In 1.8% (5/281) of cases, RNA was detected before the appearance of antibodies (up to 5 months), and in 1.1% (3/281) of cases, RNA was the unique marker of HCV infection. The genotypes found were 1a, 1b, 3a, and 4a. The presence of genotype 4a is noteworthy, since it is a rare genotype in Brazil. These data pointed out the high prevalence and incidence of HCV infection at hemodialysis centers in Brazil and showed that routine PCR is fundamental for improving the detection of HCV carriers among patients undergoing hemodialysis.

Capillary electrophoresis coupled to mass spectrometry to establish polypeptide patterns in dialysis fluids

Combination of capillary electrophoresis with mass spectrometry (CE-MS) allows generation of polypeptide patterns of body fluids. In a single CE-MS (45 min) run more than 600 polypeptides were analyzed in hemodialysis fluids obtained with different membranes (high-flux/low-flux). Larger polypeptides (M(r) > 10 000) were almost exclusively present in high-flux dialysates only, while in low-flux dialysates additional small polypeptides were detected. Comparison to the normal urine pattern yielded a surprisingly low consensus: a number of polypeptides present in urine were missing. We established a fast and sensitive technique, easily applicable to the monitoring of different modalities of dialyzers.

The antioxidant acetylcysteine reduces cardiovascular events in patients with end-stage renal failure: a randomized, controlled trial

BACKGROUND

Patients with end-stage renal failure have increased oxidative stress and show elevated cardiovascular mortality. Whether increased cardiovascular events can be prevented by the administration of antioxidants is unknown.

METHODS AND RESULTS

We evaluated the effects of acetylcysteine, a thiol-containing antioxidant, on cardiovascular events in patients undergoing hemodialysis. A prospective, randomized, placebo-controlled trial was conducted between October 1, 1999, and September 30, 2001, in 134 patients (76 male and 58 female) with a mean age of 62+/-16 years (mean+/-SD) who had been undergoing maintenance hemodialysis for a minimum of 3 months 3 times weekly in an ambulatory center. Median (range) follow-up was 14.5 (1 to 24) months. Patients were randomly assigned either to receive acetylcysteine (600 mg BID) or placebo. The primary end point was a composite variable consisting of cardiac events including fatal and nonfatal myocardial infarction, cardiovascular disease death, need for coronary angioplasty or coronary bypass surgery, ischemic stroke, peripheral vascular disease with amputation, or need for angioplasty. Secondary end points included each of the component outcomes, total mortality, and cardiovascular mortality. A total of 18 (28%) of the 64 hemodialysis patients assigned to acetylcysteine group and 33 (47%) of the 70 hemodialysis patients assigned to control group had a primary end point (relative risk, 0.60 [95% CI, 0.38 to 0.95], P=0.03). No significant differences in secondary end points or total mortality were detected.

CONCLUSIONS

In hemodialysis patients, treatment with acetylcysteine (600 mg BID) reduces composite cardiovascular end points.

How to adjust for comorbidity in survival studies in ESRD patients: a comparison of different indices

BACKGROUND

Many patients with end-stage renal disease (ESRD) have additional comorbid conditions. Differences in the presence and severity of these comorbid conditions can bias comparisons between treatment groups. Adjustment for prognostic factors can statistically counterbalance these differences. For this purpose, appropriate weighting of comorbid conditions is necessary. We evaluated three existing methods to score comorbidity in patients with ESRD and compared their ability to predict survival: the Khan, Davies, and Charlson indices. In addition, these three indices were compared with a new index that explicitly incorporates the severity grading of a number of comorbid diseases.

METHODS

In a large Dutch prospective multicenter study (Netherlands Co-operative Study on the Adequacy of Dialysis-2), new patients with ESRD were included. Comorbidity was assessed at the start of dialysis therapy. Patient data were randomly allocated to a modeling or testing set. The new index was developed in the modeling set. All indices were evaluated in the testing set.

RESULTS

We obtained data for 1,205 patients. Of the three existing indices, the Charlson index had the best discriminating features, with a concordance c statistic of 0.71. The addition of severity grading of several comorbid conditions did not improve discrimination. After combining the comorbidity indices with age, all c statistics improved. These final values ranged from 0.72 to 0.75.

CONCLUSION

We conclude that the Khan, Davies, and Charlson scores are appropriate for expressing the prognostic impact of comorbidity on mortality risk in patients with ESRD provided sufficient adjustment for age is performed. Adding the severity grading of several comorbid conditions will not lead to improved prognostic power.

Alphabeta and gammadelta T cell subsets in chronic renal failure in children on dialysis treatment

BACKGROUND

Impaired immunity, particularly cell-mediated, is one of the features of chronic renal failure. This also concerns impaired T cell dependent responsiveness.

METHODS

The expression of T cell surface antigens (CD3, CD25, TCRalphabeta, TCRgammadelta) was evaluated on peripheral blood (PB) mononuclear cells using two-color flow cytometry in 10 children on continuous ambulatory peritoneal dialysis (CAPD) and in 13 children on maintenance hemodialysis (HD) with polysulfone and cuprophane dialysers.

RESULTS

In HD children absolute numbers of leukocytes, lymphocytes, CD3+, alphabeta, gammadelta T cells and a percentage of gammadelta T cells were decreased versus healthy children. Also, we observed a relative increase of CD3+, CD3+/CD25+ and alphabeta T cells after sessions with cuprophane membranes, and an increase of CD3+/CD25+, alphabeta T cell percentages after sessions with the polysulfone membranes. Additionally we found a decrease of both relative and absolute numbers of gammadelta T cells after HD with polysulfone. In CAPD children we found declined absolute numbers of total lymphocytes, CD3+ and alphabeta T cells and higher relative values of CD3+ and alphabeta T cells versus controls.

CONCLUSIONS

The T cell depletion in chronic renal failure (CRF) patients primarily results from uremic-related toxicities, rather than from CAPD or HD-related incompatibilities. We showed a significant decrease of gammadelta T cells in CRF patients on HD, that may be partly responsible for impaired T-dependent responsiveness in that group. The intradialytic changes of gammadelta Tcells may result from a different degree of biocompatibility during the application of various dialysis membranes.

Ramipril prolongs life and is cost effective in chronic proteinuric nephropathies

BACKGROUND

Our objectives were to predict the long-term cost and efficacy of the angiotensin-converting enzyme, ramipril, in patients with nondiabetic chronic nephropathies.

METHODS

The time to end-stage renal disease (ESRD) was predicted by two different models based on the rate of glomerular filtration rate decline (DeltaGFR) and incidence of ESRD (events) measured during the Ramipril Efficacy in Nephropathy Trial in 117 and 166 patients, respectively, randomized to comparable blood pressure control with ramipril or conventional therapy. Direct medical costs of conservative and renal replacement therapy were estimated by a payer perspective, and cases more and less favorable to ramipril were computed by a sensitivity analysis. The study took place at the Clinical Research Center for Rare Diseases, "Aldo & Cele Daccò," Bergamo, Italy. Patients included those with chronic, nondiabetic nephropathies and persistent urinary protein excretion rate >/=3 g/24 h. Time to ESRD, survival, and direct costs of conservative and renal replacement therapy are discussed.

RESULTS

Both in the DeltaGFR-based or events-based models, ramipril delayed progression to ESRD and prolonged patient survival by 1.5 to 2.2 and 1.2 to 1.4 years, respectively, and saved $16,605 to $23,894 lifetime and $2, 422 to $4203 yearly direct costs per patient. Even in the less favorable hypotheses, ramipril allowed lifetime and yearly cost savings that exceeded 10 to 11 and 20 to 40 times, respectively, the additional costs related to prolonged survival.

CONCLUSIONS

In our study population, ramipril prolongs life while saving money because of its beneficial effect on the course of nondiabetic chronic nephropathies.

[Conservative treatment of renal ptosis]

BACKGROUND

Nephroptosis or floating kidney is an acquired, caudal displacement of one or both kidneys, with differing stages and etiology. It has been almost completely ignored over the past few years. The general tendency to regard nephroptosis as a urological pathology has prompted researchers to look for resolutive surgical treatment. The existence of over 150 surgical techniques is a clear demonstration of the high failure rate with the result that surgeons are unwilling to tackle this pathology, often leaving the patient alone with his problems. The numerous nephrological complications caused by nephroptosis have prompted us to look for alternative therapies to propose to nephrologists for the consecutive treatment of the floating kidney, enabling the patient to live with his pathology.

METHODS

A longitudinal study was performed for 60 months in 102 patients with mono or bilateral nephroptosis. Hematuria, urinary cylindroids, asthenia, pain and the daily intake of antispastic lenitives were analysed at 6, 12, 24 and 60 months. Throughout this period all patients were treated with a water cure (31/day) and nocturnal decubitus in Trendelenburg's position (the foot of the bed is raised by 10 cm). Patients with primary or secondary kidney pathology, UTI and nephrolithiasis were excluded from the study.

RESULTS

All the parameters showed a marked and steady improvement. At one year, over half the patients treated had improved, and at two years over two thirds only complained of marginal symptoms.

CONCLUSIONS

Quali-quantitative and temporal values are reported in the light of which we can affirm that conservative treatment enables the patient to lead an almost normal life, as well as returning to work, with a reduced risk of complications.

Peritoneal dialysis

Peritoneal dialysis has now become an established form of renal replacement therapy; nearly half the patients on dialysis in the UK are treated in this way. Survival of patients is now equal to that with haemodialysis. However, long-term peritoneal dialysis (>8 years) is limited to a small percentage of patients because of dropout to haemodialysis for inherent complications of peritoneal dialysis--peritonitis, peritoneal access, inadequate dialysis, and patient-related factors. However, improvements in the understanding of the pathophysiological processes involving the peritoneal membrane have paved the way for advances in the delivery of adequate dialysis, more biocompatible dialysis fluids, and automated peritoneal dialysis. Other technical advances have led to a reduction in peritonitis. Peritoneal dialysis is an important dialysis modality and should be used as an integral part of RRT programmes.