Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Vitamin K in CKD Bone Disorders

Vitamin K is principally known because it is involved in blood coagulation. Furthermore, epidemiological studies showed that its deficit was associated with increased fragility fractures, vascular calcification and mortality. There are two main types of vitamin K vitamers: Phylloquinone (or PK) and Menaquinones (MKn). Vitamin K acts both as coenzyme of y-glutamyl carboxylase (GGCX) transforming undercarboxylated in carboxylated vitamin K-dependent proteins (e.g., Osteocalcin and Matrix Gla Protein) and as a ligand of the nuclear steroid and xenobiotic receptor (SXR) (in murine species Pregnane X Receptor: PXR), expressed in osteoblasts. It has been highlighted that the uremic state is a condition of greater vitamin K deficiency than the general population with resulting higher prevalence of bone fractures, vascular calcifications and mortality. The purpose of this literature review is to evaluate the protective role of Vitamin K in bone health in CKD patients.

Jugular Vein-Mammary Artery Fistula after Catheterism for Hemodialysis: Case Report

The demographic characteristics of hemodialysis (HD) patients increase the need for the tunneled cuffed permanent catheter (TCC) as a definitive vascular access (VA) for HD. The internal jugular vein is increasingly being used as a route for TCC or temporary catheter placement and can be associated with serious complications. Among them other authors have described arteriovenous fistula (AVF) creation between the common carotid artery and the right jugular vein. We describe a case of an AVF between the right internal jugular vein and the right internal mammary artery. The fistula was detected during the TCC placement in a patient who underwent several jugular and subclavian catheterisms for HD in her clinical history.

Hemoperfusion with a New Anion Exchange Resin Corrects the Metabolic Alkalosis in Pyloric Stenosis: An Experimental Demonstration

An experimental model of hypertrophic pyloric stenosis was made by suture of the pyloric wall and gastrostomy in 10 rabbits under general anesthesia. Blood sampling indicated severe alkalosis and hypochloremia 3h 30 min after surgery. To correct the derangement, we tested an ion exchange resin (Dowex SAR), coated with a methacrylic hydrogel. A cartridge containing 18 g of this resin was inserted in an extracorporeal circuit. This chloride charged resin achieved uptake of HCO−3 ions, and elution of CI− ions. The electrolytic balance was fully restored after 10 min of treatment.

Effect of Different Dialysis Membranes on Platelet Function. A Tool for Biocompatibility Evaluation

Intradialytic coagulative and platelet activation, one of the main consequences of blood-membrane contact, was studied in a group of 5 RDT patients with a comparative evaluation of 3 different dialytic membranes: Cuprophan (CU), Polysulfone (PS) and Cellulose Triacetate (CT). Each patient underwent 5 consecutive dialysis sessions with the above mentioned membranes. Intradialytic platelet activation was studied through a morpho-functional evaluation between the mean platelet volume (MPV) and Serotonin (S), ß-Thromboglobulin (ß-TG) and Platelet Factor 4 (PF4) serum levels. These determinations were made before HD (time 0) and after 30', 120’ and 240'. We also checked the intradialytic status of thrombogenesis and fibrinolysis determining aPTT, thrombin time, fibrinogen, antithrombin III (AT III), α-2 antiplasmin and plasminogen, at the same time intervals. All membranes tested (CU, PS, CT) caused appreciable intradialytic platelet activation, above all after 15’ and at the end of dialysis sessions, more marked for CU than PS or CT. In particular MPV showed a decrease throughout the session (-5% at 30’ and -9% at 240') while S, ßTG and PF4 peripheral blood levels showed a significant increase at the same intervals with CU membrane. Lastly coagulative and fibrinolytic parameters showed no significant differences among any of the membranes tested.

Clinical Application of Sodium Profiling in the Treatment of Intradialytic Hypotension

Background

Intradialytic hypotension is mainly induced by the removal of extracellular sodium during dialysis, which impairs intravascular fluid refilling and reduces blood volume. To counter this complication we tested a new kind of profiled hemodialysis (PHD) consisting of the intradialytic modulation of dialysate sodium concentration according to individual profiles set up using a new mathematical model for intradialytic solutes and water kinetics. The clinical aim of this PHD is to stabilize blood pressure maintaining higher blood volume values than standard dialysis treatments. We clinically validated PHD in comparison with constant dialysate sodium dialysis (CHD).

Methods

Twenty hypotensive dialysis patients underwent one PHD and one CHD session maintaining the same dialysis length, sodium mass removal and body weight decrease. A new mathematical model was used to define both the dialysate sodium profiles for PHD and the constant dialysate sodium for CHD. Percent blood volume variation (Crit-line), mean blood pressure, heart rate, cardiac output (Doppler-echocardiography) were monitored intradialitically.

Results

Cardiovascular stability improved on PHD as compared with CHD sessions; blood volume and cardiac output during PHD showed a lower decrease than on CHD, the differences statistically significant (from 30' and 60' respectively). Mean blood pressure was, at all time intervals, more stable on PHD than on CHD and was accompanied, on PHD, by a lower heart rate increase (differences statistically significant).

Conclusions

This study shows that PHD performed using dialysate sodium profiles elaborated by our mathematical model obtains, in hypotensive patients, a higher hemodynamic intradialytic stability than CHD, probably due to a higher stabilization of blood volume.

Is β2-Microglobulin-Related Amyloidosis of Hemodialysis Patients a Multifactorial Disease? a New Pathogenetic Approach

Purpose

β2-microglobulin amyloidosis (Aβ2M) is one of the main long-term complications of dialysis treatment. The incidence and the onset of Aβ2M has been related to membrane composition and/or dialysis technique, with non-homogeneous results. This study was carried out to detect: i) the incidence of bone cysts and CTS from Aβ2M; ii) the difference in Aβ2M onset between cellulosic and synthetic membranes; iii) other risk factors besides the membrane.

Methods

480 HD patients were selected between 1986 to 2005 and grouped according to the 4 types of membranes used (cellulose, synthetically modified cellulose, synthetic low-flux, synthetic high-flux). The patients were analyzed before and after 1995, when the reverse osmosis treatment for dialysis water was started at our center, and the incidence of Aβ2M was compared between the two periods. Routine plain radiography, computer tomography (CT) and nuclear magnetic resonance imaging (MRI) as well as electromyography were used to investigate the clinical symptoms.

Results

Bone cysts occurred in 29.2% of patients before 1995 vs. 12.2% after 1995 (p<0.0001). CTS occurred in 24% of patients before 1995 vs. 7.1% after 1995 (p<0.0001). Bone cysts and CTS occurred in older patients, who began dialysis at a late age, with high CRP, low albumin, low residual GFR, and low Hb. Cox regression analysis showed that the risk factor for bone cysts was high CRP (RR 1.3, p<0.01), while albumin (RR 0.14, p<0.0001) and residual GFR (RR 0.81, p<0.0001) were revealed to be protective factors. Cox analysis for CTS confirmed CRP as a risk factor (RR 1.2, p<0.01), and albumin (RR 0.59, p<0.0001) and residual GFR (RR 0.75, p<0.0001) as protective factors. The comparison obtained between membranes did not suggest any protective effect on Aβ2M.

Conclusions

The findings that the inflammatory status as well as low albumin and the residual GFR of the uremic patient are predictive of Aβ2M lesions suggests that Aβ2M has a multifactorial origin rather than being solely a membrane- or technique-related side effect.

The cardiovascular burden of end-stage renal disease patients

Patients with end-stage renal disease are 10 to 20 times more at risk of cardiovascular death than the general population. Traditional cardiovascular risk factors are not able to explain the increase in the onset of cardiovascular diseases in dialysis patients. Some of the most important non traditional risk factors in uremic patients are: the inflammatory state of the patients, cytokines and growth factors, hyperhomocysteinemia, the presence of alterations of the calcium phosphorous product which can already be in progress when the glomerular filtration rate decreases to less than 60 mL/min. Clinically, these alterations cause vascular calcifications, calcifications of the heart valves and calcific uremic arteriolopathy or calciphylaxis. The pathogenesis of vascular calcification is complex and cannot be assigned to a simple, passive process: in fact, it includes factors which promote or inhibit calcification. In turn, these pathologic conditions have been found to be highly predictive of general and cardiovascular death. Given the serious clinical consequences that vascular calcifications can cause, it is necessary to carry out an early mapping of the traditional and non traditional risk factors of uremic patients as it seems that therapeutic interventions aimed at reducing or inverting the calcification process can improve the outcome of patients, above all when they are started quickly.

[Factors determining cardiovascular disease progression after kidney transplant]

Cardiovascular disease is the leading cause of mortality and morbidity in renal transplant recipients as well as the leading cause of death with a functioning graft. The high cardiovascular risk is attributable to the prolonged exposure to multiple traditional and nontraditional risk factors in the pretransplant and posttransplant period. Particular attention must be paid to cardiovascular screening of candidates for kidney transplantation. After a transplant, treatment and prevention strategies should be focused on the modifiable risk factors including smoking, dietary habits, physical activity, weight control, hypertension, and dyslipidemia. Further studies on these factors are needed to better define the pharmacological approaches (hypotensive or hypolipemic drugs) and therapeutic targets. In view of the role of immunosuppressive therapy in the onset or worsening of several risk factors, it is important to tailor the treatment approach and dosage to the cardiovascular risk profile of the individual patient.

Metabolic Syndrome After Kidney Transplantation

BACKGROUND

Metabolic syndrome (MS) includes some risk factors for development of diabetes and cardiovascular disease, obesity (BMI > 30), high triglycerides, low HDL cholesterol, hypertension and impaired glucose tolerance. Following the definition of the Adult Treatment Panel III criteria, a diagnosis of MS was established when 3 or more factors were present. In renal transplant patients MS has been reported to negatively influence both patient and graft survivals. The present study sought to verify the effect of MS among our cases.

METHODS

298 cadaveric renal transplant recipients operated between January 1, 1996 and December 31, 2001 with absence of diabetes before transplantation, stable renal function 1 year posttransplantation and at least 4 years follow up were retrospectively evaluated from the end of the first post-operative year.

RESULTS

50 patients out of 298 (16,7%) had MS at the beginning of the study, including 37 of them with 3 and 13 with 4 risk factors. Only one patient with MS died of cardiovascular disease. Graft failure was observed in 23.5% MS patients versus 9,7% patients without the Syndrome (p:n.s.) Only Creatinine and the incidence of Cardiovascular Diseases at 4 years were statistically higher in MS patients (P < .001).

CONCLUSIONS

These results suggested that MS is a risk factor for increasing CVD morbidity and decreased graft function, but early treatment of risk factors as soon as they become apparent can limit the adverse effects on patient and graft survival.

Anticoagulation therapy for the prevention of hemodialysis tunneled cuffed catheters (TCC) thrombosis

BACKGROUND

Chronic oral anticoagulation is currently used to avoid thrombosis and the malfunction of tunneled cuffed catheters (TCCs) for hemodialysis (HD). The aim of the study was to assess the efficacy of early warfarin administration, after TCC placement, in comparison to its administration after the first thrombosis or malfunction event of the TCC.

PATIENTS AND METHODS

One hundred and forty-four chronic dialysis patients, who underwent TCC placement between June 2001 and June 2005, were randomized into two groups: 81 patients, group A, started oral anticoagulation 12 hr after the TCC placement (target international normalized ratio (INR) 1.8-2.5), in association with ticlopidine 250 mg/die; 63 patients, group B, started warfarin after the first thrombosis/malfunction episode (target INR 1.8-2.5) in association with ticlopidine 250 mg/die. The efficacy of oral anticoagulation therapy in preventing TCC thrombotic complications was evaluated in a 12-month follow-up period, after TCC placement, in terms of: a) the number of patients with thrombotic-malfunction events; b) the number of thrombotic-malfunction events with urokinase infusion (events/patient/year); c) intradialytic blood flow rate (BFR, ml/min); d) negative blood pressure (BP) from the arterial line of the TCC (AP, mmHg); e) positive BP, in the extracorporeal circuit from the venous line (VP, mmHg); and f) bleeding complications.

RESULTS

Ten patients (12%) in group A showed TCC thrombosis/malfunction vs. 33 patients (52%) in group B (p < 0.01). In group A, 0.16 events of thrombosis/malfunction per patient/year vs. 1.65 in group B (p < 0.001) were ob-served. BFR was respectively 305 +/- 34 vs. 246 +/- 42 ml/min (p < 0.001). AP was -124 +/- 13 in group A vs. -174 +/- 21 mmHg in group B (p < 0.05). VP was 112 +/- 28 in group A vs. 168 +/- 41 mmHg in group B (p < 0.05). No patient showed any bleeding events.

CONCLUSIONS

Early warfarin therapy allows a significant reduction in TCC thrombotic complications and an improvement in both arterial and venous fluxes in comparison with the same therapy administered after the first TCC thrombotic/malfunction event. This therapy did not induce any bleeding complications in the patients included in the study.

[Protonic pump inhibitors in kidney transplant patients: efficacy and safety]

Kidney transplant patients show a significantly elevated incidence of gastrointestinal disorders. Protonic pump inhibitors (PPI) are considered to be the correct therapy in the treatment of peptic ulcers, as they have proven to be safe and efficient. The metabolization of the PPIs mainly occurs on a hepatic level; therefore, there is no need to change the therapy accordingly, as there is with the inhibitors of the histamine receptors (anti-H2). The PPIs currently available are omeprazole, pantoprazole, lansoprazole, esomeprazole, rabeprazole which present different pharmacokinetic characteristics and different metabolic routes which are responsible both for differences in terms of efficacy between the different molecules, and for the possible side-effects they may have. All the PPIs, apart from rabeprazole, are metabolized through an oxidization and sulphurization processes which involves the enzymatic system of the P450 cytochrome. The rabeprazole metabolism is different from the other molecules of the same category in that it only moderately involves the CYP450 (CYP3A4 and CYP2C19) from the moment its metabolization begins through nonenzymatic routes and 80% is involved in a thioether non enzymatic reduction mechanism. Consequently, rabeprazole represents: a) a potentially low pharmacological interaction with immunosuppressive drugs; b) a pharmacokinetic aspect much less subject to interindividual differences between one patient and another, due to genetically determined polymorphisms of the CYP2C19 and of the CYP3A4. Moreover, rabeprazole may be administered safely in standard doses with no need to change the dosage of the other pharmaceutical drugs taken simultaneously in nephropathic patients, patients undergoing dialysis and transplanted patients.

Jugular vein-mammary artery fistula after catheterism for hemodialysis: case report

The demographic characteristics of hemodialysis (HD) patients increase the need for the tunneled cuffed permanent catheter (TCC) as a definitive vascular access (VA) for HD. The internal jugular vein is increasingly being used as a route for TCC or temporary catheter placement and can be associated with serious complications. Among them other authors have described arteriovenous fistula (AVF) creation between the common carotid artery and the right jugular vein. We describe a case of an AVF between the right internal jugular vein and the right internal mammary artery. The fistula was detected during the TCC placement in a patient who underwent several jugular and subclavian catheterisms for HD in her clinical history.

Molecular adsorbent recirculating system (MARS) application in liver failure: clinical and hemodepurative results in 22 patients

PURPOSE

Acute liver failure (ALF) and acute on chronic liver failure (ACLF) still show a poor prognosis. MARS was used in 22 patients with ALF or ACLF to prolong patient survival for liver function recovery or as a bridge to transplantation.

DESIGN

Evaluation of depurative efficiency, biocompatibility, hemodynamics, encephalopathy (HE) and clinical outcome.

PROCEDURES

During 71 five-hour sessions we evaluated (0', 60', 120', 180', 240', 300'): bilirubin, ammonia, cholic acid (CCA), chenodeoxycholic acid (CCDCA), leukocytes, platelets, hemoglobin and mean arterial pressure (MAP). Serum creatinine, electrolytes, cardiac output, cardiac index (bioimpedence) and HE (West Haven Criteria score) were evaluated at 0' and 300'. STATISTICAL METHODS AND OUTCOME MEASURES: Student's t-test for pre- vs. end-session values was used. For bilirubin and ammonia the correlation test was made between pre- and end-session values and between pre-session values and removal rates (RRS).

MAIN FINDINGS

Survival was 90.9% at 7 days, 40.9% at 30 days. Pre- vs. end-session: bilirubin from 37.2 +/- 12.5 mg/dL to 24.9 +/- 8.9 mg/dL (p < 0.01), ammonia from 88.0 +/- 60.4 micromol/L to 43.6 +/- 32.9 micromol/L (p < 0.01), CCA from 42.8 +/- 21.0 micromol/L 18.2 +/- 9.8 micromol/L (p < 0.01), CCDCA from 26.3 +/- 6.3 micromol/L to 15.7+/-7.6 micromol/L (p<0.01). The correlation test between pre-session values of bilirubin and ammonia vs. RR S was respectively 0.32 (p = 0.01) and 0.30 (p = 0.04). Leukocytes, platelets and hemoglobin remained stable. MAP increased from 82.0 +/- 12.0 mmHg to 87.0 +/- 13.0 mmHg (p < 0.05), West Haven Criteria score decreased from 2.7 +/- 0.7 to 0.7 +/- 0.7 (p < 0.001).

CONCLUSION

MARS treatment led in all patients to an improvement of clinical, hemodynamic and neurological conditions, with significant reduction in the hepatic toxins blood level. Treatment biocompatibility and tolerance were satisfactory.

Artificial kidney: status of the art and new perspectives

Extracorporeal dialysis was first performed in 1943 and has become a routine for End Stage Renal Patients from the early sixties. In the last 30 years researchers have focused on biocompatibility of artificial materials and optimisation of removal of uremic toxins by the membrane as in the long term treatment many complications like amylodosis heart and bone lesions, accelerated amyloidosis and immune system failure can occur. From this point of view high flux dialytic membranes are currently considered more biocompatible therefore being able to prevent such diseases.

Inflammatory response of a new synthetic dialyzer membrane. A randomised cross-over comparison between polysulfone and helixone

Hemodialysis patients suffer from chronic inflammation due to intradialytic contact of blood with artificial materials. The FX 60 dialyzer which belongs to the new FX-class series of dialyzers is composed of the new membrane Helixone. This membrane is derived from the original Fresenius Polysulfone membrane. The FX-class design is based on modified geometry of fibres and housing and has resulted in a new dialyzer with improved efficiency, safety and ease of handling compared to the F series (F 60S) dialyzer. The aim of the study was to investigate whether the biocompatibility pattern in terms of inflammatory parameters of the new type of polysulfone dialyzer has changed compared to the standard. A clinical in vivo study was conducted to compare the intradialytic inflammatory response of the two dialyzers, FX 60 and F 60S. Eight chronic dialysis patients were selected for the study: mean age 65.5 +/- 15.5 years, mean time on dialysis 100 +/- 95 months. The randomized cross-over study involved a treatment period of 2 weeks (total 6 sessions), one week with each dialyzer, starting with one or the other according to the randomization scheme. Blood samples were taken at 0 (T0), 15, 60, and 240 minutes to evaluate white blood cell (WBC) count, complement factor C5a, leukocyte elastase, soluble intercellular adhesion molecule 1 (sICAM-1), platelet count, C-reactive protein (CRP). At 15 min, WBC count showed a comparably, low decrease for both dialyzers: -7.6% for FX 60 versus -6.6% for F 60S, p=not significant (ns). At the same time the C5a concentration decreased from 15.0 +/- 7.5 ng/ml to 13.5 +/- 6.7 ng/ml (p=ns) for FX 60, and from 15.1 +/- 12.5 ng/ml to 14.9 +/- 25.0 ng/ml for F 60S (p=ns). The elastase concentration progressively increased over time with no statistical difference between the two dialyzers. The levels of sICAM-1, CRP, and platelet count were similar at each time point for both dialyzers, varying around the baseline values (p=ns). No significant difference emerged in terms of inflammatory response between the two dialyzers, hemo demonstrating that the biocompatibility of the F-series was maintained in the FX-class series of dialyzers and is independent of design factors.

Platelet activation and PDGF-AB release during dialysis

During hemodialysis the blood-membrane contact causes a release of platelet granule content, which contains Platelet Derived Growth Factor (PDGF-AB). In view of its possible role in accelerated atherosclerotic processes, we evaluated the intra- and post-dialytic changes in PDGF-AB serum levels during hemodialysis sessions performed with Hemophan and Polysulfone membranes. PDGF-AB, PF4, betaTG and MPV levels were determined in the peripheral blood in 30 patients each of whom underwent 6 dialysis sessions: 3 with Hemophan (HE) membrane and 3 with Polysulfone (PS) membrane, interpolated by a wash out session with PS membrane. Blood samples were taken at times 0', 30', 120', 180', 240' during dialysis sessions and at 1, 4 and 20 hours after the end of the session. Statistical analysis was done using the ANOVA one way test and Student's t test PDGF-AB serum levels initially increased and, except for a sharp fall at 120', remained constantly high during HD with both membranes tested, not returning to basal values until 20 hours after the end of the session. PF4, betaTG and MPV all showed a similar trend to PDGF. No statistically significant difference was found between the two membranes tested. PDGF-AB, a powerful growth factor in cells of mesenchymal origin, is released during dialysis mainly as a result of the blood-membrane contact. This we found regardless of the type of dialyzer we tested, and, above all, proved to return very slowly to basal values. We speculate that the release of PDGF-AB could play a part like other atherosclerosis risk-factors in the appearance and worsening of atherosclerotic lesions in hemodialysis patients.

Inducible expression of the alpha2-macroglobulin signaling receptor in response to antigenic stimulation: a study of second messenger generation

Thioglycollate (TG)-elicited murine, peritoneal macrophages express two receptors for activated forms of the proteinase inhibitor alpha2-macroglobulin (alpha2M*)--namely, the low density lipoprotein receptor-related protein (LRP) and the alpha2M signaling receptor (alpha2MSR). We now report that resident peritoneal macrophages express only 400+/-50 alpha2MSR receptors/cell compared to 5000+/-500 receptor/TG-elicited macrophage. By contrast, LRP expression is only 2-2.5-fold greater on elicited cells. The low level of alpha2MSR expression by resident cells is insufficient to trigger signal transduction in contrast to TG-elicited cells which when exposed to alpha2M* demonstrate a rapid rise in inositol 1,4,5-trisphosphate and a concomitant increase in cytosolic free Ca2+. We then studied a variety of preparations injected subcutaneously for their ability to upregulate alpha2MSR. Macroaggregated bovine serum albumin (macroBSA) injection upregulated alpha2MSR and triggered signaling responses by splenic macrophages. Nonaggregated BSA injection alone or in the presence of alum, by contrast, did not alter alpha2MSR expression. Recombivax (hepatitis B antigen adsorbed to alum) injection also upregulated alpha2MSR on splenic macrophages while the alum carrier had no effect. We conclude that macrophage alpha2M* receptors are inducible and their expression may be regulated, in part, by potential antigens.

Intra- and post-dialytic platelet activation and PDGF-AB release: cellulose diacetate vs polysulfone membranes

BACKGROUND

During haemodialysis the blood-membrane contact causes a release of platelet granule content, which contains platelet-derived growth factor AB (PDGF-AB). In view of the potential role of this in altering biocompatibility during haemodialysis, we evaluated the intra- and post-dialytic changes in PDGF-AB serum levels during haemodialysis sessions performed with cellulose diacetate (CDA) and polysulfone (PS) membranes respectively.

METHODS

PDGF-AB, platelet factor 4 (PF4), beta thromboglobulin (betaTG), and mean platelet volume (MPV) levels were determined in 30 patients, each of whom underwent six dialysis sessions: three with a CDA and three with a PS membrane. Blood samples were taken at times 0, 15, 30, 120, 180, and 240 min during dialysis and at 1, 4, and 20 h after the end of the session. Statistical analysis was performed using a one-way ANOVA and Student's t test.

RESULTS

PDGF-AB at 15 min was increased to +41+/-9% with CDA vs +20+/-5% with PS (P<0.001) from the T0 values, and at 120 min it was +19+/-8% with CDA vs -25+/-9% with PS (P<0.001) from T0 levels. At 240 min it was +95+/-14% with CDA vs +49+/-15% with PS (P<0.001) from the T0 values, returning to basal only 20 h after the end of the session. betaTG at 15 min was +60+/-8% for CDA vs +24+/-7.5% for PS (P<0.001) from the T0 values. PF4 showed a similar trend to betaTG. MPV at 30 min from the start of dialysis was 7.4+/-0.3 fl with CDA and 8+/-0.3 fl with PS (P<0.001), and at 240 min MPV was 7.9+/-0.3 fl with CDA and 8.4+/-0.3 fl with PS (P<0.001).

CONCLUSIONS

Platelet activation and platelet release reactions are lower with PS than with CDA membranes. PDGF-AB, released during and after dialysis, represents a clear biocompatibility marker. Its slow return to basal values and its action on vascular cells make it a potential risk factor for atherosclerosis in uraemic patients.

Evaluation of intradialytic solute and fluid kinetics. Setting Up a predictive mathematical model

A mathematical model of solute kinetics for the improvement of hemodialysis treatment is presented. It includes a two-compartment description of the main solutes and a three-compartment model of body fluids (plasma, interstitial and intracellular). The main model parameters can be individually assigned a priori, on the basis of body weight and plasma concentration values measured before beginning the session. Model predictions are compared with clinical data obtained in vivo during 11 different hemodialysis sessions performed on 6 patients with a profiled sodium concentration in the dialysate and a profiled ultrafiltration rate. In all cases, the agreement between the time pattern of model solute concentrations in plasma and the in vivo data proves fairly good as to urea, sodium, chloride, potassium and bicarbonate kinetics. Only in two sessions was blood volume directly measured in the patient, and in both cases the agreement with model predictions was good. In conclusion, the model allows a priori computation of the amount of sodium removed during hemodialysis, and makes it possible to predict the plasma volume changes and plasma osmolarity changes induced by a given sodium concentration profile in the dialysate and by a given ultrafiltration profile. Hence, it can be used to improve clinical tolerance to the dialysis session taking the characteristics of individual patients into account, in order to minimize intradialytic hypotension.

PDGF-AB release during and after haemodialysis procedure

BACKGROUND

During haemodialysis blood membrane contact causes the release of the content of platelet alpha-granules, which contain platelet-derived growth factor (PDGF). In view of its possible role in accelerated atherosclerotic processes, we evaluated the intra- and post-dialytic changes in PDGF-AB serum levels during haemodialysis sessions performed using a cellulosic membrane.

METHODS

Using the ELISA method, PDGF-AB, platelet factor-4 (PF4) and beta-thromboglobulin (beta-TG) levels were determined in peripheral blood, as well as in arterial and venous haemodialyser lines, in 10 patients each of whom underwent five consecutive dialysis sessions with a CU membrane. Blood samples were taken at 0, 15, 30, 60, 120, 180 and 240 min during dialysis and at 1, 4 and 20 h after the end of the session. In the same group of patients the levels of the same molecules were also determined after a heparin bolus injection of 4500 IU, blood samples were taken at 0, 15 and 30 min after injection of the bolus.

RESULTS

PDGF-AB serum levels increased, remained consistently high during the haemodialysis session (in particular +134+/-20% after 30 min, P<0.001, and +140+/-5% after 240 min, P<0.001) and returned to basal values only after 20 h following the end of the session. PF4 and beta-TG showed a similar trend to PDGF. The heparin bolus injection caused only a small increase (+15+/-5% at 30 min) in PDGF-AB serum levels.

CONCLUSIONS

PDGF-AB is released during dialysis mainly as consequence of the blood-membrane contact and it returns only slowly to basal values.

Effect of different dialysis membranes on platelet function. A tool for biocompatibility evaluation

Intradialytic coagulative and platelet activation, one of the main consequences of blood-membrane contact, was studied in a group of 5 RDT patients with a comparative evaluation of 3 different dialytic membranes: Cuprophan (CU), Polysulfone (PS) and Cellulose Triacetate (CT). Each patient underwent 5 consecutive dialysis sessions with the above mentioned membranes. Intradialytic platelet activation was studied through a morpho-functional evaluation between the mean platelet volume (MPV) and Serotonin (S), beta-Thromboglobulin (beta-TG) and Platelet Factor 4 (PF4) serum levels. These determinations were made before HD (time 0) and after 30', 120', and 240'. We also checked the intradialytic status of thrombogenesis and fibrinolysis determining aPTT, thrombin time, fibrinogen, antithrombin III (AT III), alpha-2 antiplasmin and plasminogen, at the same time intervals. All membranes tested (CU, PS, CT) caused appreciable intradialytic platelet activation, above all after 15' and at the end of dialysis sessions, more marked for CU than PS or CT. In particular MPV showed a decrease throughout the session (-5% at 30' and -9% at 240') while S, beta TG and PF4 peripheral blood levels showed a significant increase at the same intervals with CU membrane. Lastly coagulative and fibrinolytic parameters showed no significant differences among any of the membranes tested.

Strategies in renal failure and the impact of lipids

The main points to note in terms of strategies in renal failure and the impact of lipids are: 1) Timing and typing of dyslipidemia; 2) Occurrence of dyslipidemia in the course of strategies (conservative, dialysis and transplantation); 3) How the strategies can handle the impact of lipids. Analysis of point 1 confirms what a complex profile uremic dyslipidemia presents, involving the type, class, composition and enzyme systems involved in lipid metabolism. In conservative and dialysis, type IV (triglycerides) predominates; in transplantation, type II (cholesterol). Examination of point 2 shows the non obligatory relationship between dyslipidemia and the various strategies of treatment. Lipid abnormalities, type IV or II, occur in 50-60% of patients. Uremic factors for dyslipidemia include: 1) enhanced hepatic stimulation or altered removal in conservative strategies; 2) the same causes plus "specific" promotors in dialysis (dialysis fluid, plasticizer leaching; bioincompatibility, etc.); 3) steroid therapy and other "accessories" in transplantation. A genetic predisposition is very likely present in all patients. Point 3, finally, analyzes the various "supplements" that each strategy requires to cope with the lipid impact. Generic rules (ranging from doing nothing, to diet, drugs, etc.) are of value in all strategies when dyslipidemia occurs. More specific rules include: a) Conservative strategies: appropriate dietetic optimization and modulation (protein-lipid-carbohydrate ratio in terms of calories); b) Dialysis: timing treatment and improving biocompatibility; c) Transplantation: reducing steroids as much as possible.

Strategies in Renal Failure and the Impact of Lipids

The main points to note in terms of strategies in renal failure and the impact of lipids are: 1) Timing and typing of dyslipidemia; 2) Occurrence of dyslipidemia in the course of strategies (conservative, dialysis and transplantation); 3) How the strategies can handle the impact of lipids. Analysis of point 1 confirms what a complex profile uremic dyslipidemia presents, involving the type, class, composition and enzyme systems involved in lipid metabolism. In conservative and dialysis, type IV (triglycerides) predominates; in transplantation, type II (cholesterol). Examination of point 2 shows the non obligatory relationship between dyslipidemia and the various strategies of treatment. Lipid abnormalities, type IV or II, occur in 50-60% of patients. Uremic factors for dyslipidemia include: 1) enhanced hepatic stimulation or altered removal in conservative strategies; 2) the same causes plus “specific” promotors in dialysis (dialysis fluid, plasticizer leaching; bioincompat-ibility, etc.); 3) steroid therapy and other “accessories” in transplantation. A genetic predisposition is very likely present in all patients. Point 3, finally, analyzes the various “supplements” that each strategy requires to cope with the lipid impact. Generic rules (ranging from doing nothing, to diet, drugs, etc.) are of value in all strategies when dyslipidemia occurs. More specific rules include: a) Conservative strategies: appropriate dietetic optimization and modulation (protein-lipid-carbohydrate ratio in terms of calories); b) Dialysis: timing treatment and improving biocompatibility; c) Transplantation: reducing steroids as much as possible.

Hemoperfusion in chronic uremia

Hemoperfusion is a blood purification technique involving direct contact between blood and adsorbent substances (sorbents). There are three basic kinds of sorbent: activated charcoal, immunoadsorbents, resins. Following our previous experience on charcoal hemoperfusion, a new coated anionic exchange resin for blood purification specifically designed to remove phosphates was experimentally employed in animals. 3 pigs, in which uremia had been surgically induced, underwent 6 extracorporeal hemoperfusion sessions (2 per pig) with a cartridge containing 100 gr of resin. The phosphate clearance proved satisfactory, values being 120 ml/min after 10' and around 80 ml/min after 2 hours. The biocompatibility of the resin and of the coating membrane was satisfactory. The negligible variation in pH and plasma bicarbonate during all sessions confirmed the low absorption by the tested resin of other blood anions competing with phosphate.

Hemoperfusion with a new anion exchange resin corrects the metabolic alkalosis in pyloric stenosis: an experimental demonstration

An experimental model of hypertrophic pyloric stenosis was made by suture of the pyloric wall and gastrostomy in 10 rabbits under general anesthesia. Blood sampling indicated severe alkalosis and hypochloremia 3h 30 min after surgery. To correct the derangement, we tested an ion exchange resin (Dowex SAR), coated with a methacrylic hydrogel. A cartridge containing 18 g of this resin was inserted in an extracorporeal circuit. This chloride charged resin achieved uptake of HCO3- ions, and elution of Cl- ions. The electrolytic balance was fully restored after 10 min of treatment.

Value of panel reactive antibodies (PRA) as a guide to the treatment of hyperimmunized patients in renal transplantation

Patient presensitization represents a considerable problem in candidacy for renal transplantation. While it is well known that hyperimmunized patients--panel reactive antibody (PRA) higher than 60%--create difficulties in donor matching and have a worse outcome than non-hyperimmunized patients, less information is available on patients with an intermediate degree of sensitization (30-60%). In order to evaluate how graft outcome relates to such degrees of sensitization, 241 consecutive transplanted patients were divided into two groups on the basis of their previous year's PRA peak: group A, PRA 0-29%; group B, PRA 30-60%. Group A showed a significantly better survival both in the first year (90% vs 79%, P < 0.05) and in the third year (82% vs 64%, P < 0.01). However, detailed analysis of group B demonstrated that some parameters may significantly influence graft outcome: (1) better compatibility on locus DR; (2) a primary kidney transplant; (3) a dialysis duration of less than 6 months; and (4) the prophylactic use of antilymphocyte globulin (ALG).

Application of flow cytometry in clinical renal transplantation

Flow cytometry (FC) may be considered as a fundamental technique in studying cell biology and pathology. It combines the quantitative character of biochemical methods with the multiparametric capacities of microscope analysis in a high-precision process for rapid analysis of individual cell characteristics. Three original FC techniques routinely applied in the field of renal transplantation are reported in the present study. They concern the donor-recipient cross-match test, the morphological analysis of urinary sediment and the modulation of the density of various membrane antigens on the lymphocyte surface. A common factor underlies all these methods: they aim to provide the physician with a reliable diagnostic tool in clinical renal transplantation.

Phosphate removal by resin hemoperfusion efficacy and biocompatibility of a new exchange resin

A new coated anionic exchange resin for blood purification specifically designed to remove phosphates was experimentally employed in animals. 3 pigs, in which uremia had been surgically induced, underwent 6 extracorporeal hemoperfusion sessions (2 per pig) with a cartridge containing 100 gr of resin. The phosphate clearance proved satisfactory, values being 120 ml/min after 10' and around 80 ml/min after 2 hours. The biocompatibility of the resin and of the coating membrane was satisfactory. The negligible variation in pH and plasma bicarbonate during all sessions confirmed the low absorption by the tested resin of other blood anions competing with phosphate.

Phase I study of pharmacological and immunological effects of human lymphoblastoid interferon given to patients with cancer

An extensive Phase I evaluation of human lymphoblastoid interferon has been completed which, in addition to describing its clinical and pharmacological effects, emphasized a broad-scale evaluation of the immune response as a function of interferon dosage. Dose-limiting toxicity was generally due to constitutional symptoms which are remarkably similar to those produced by influenza, although transient peripheral and central neurotoxicity (including deterioration in cognitive and behavioral functions) is observed at higher doses. It is difficult to establish "clean" dose-response effects except for fever and bone marrow suppression, neither of which is a major dose limitation. Enhancement of the immune system was limited to natural killer cells which had a complex dose-response relationship, whereby low interferon concentrations were less stimulatory (than were high doses) following a single dose but gave more sustained stimulation over a 5-week course of 3 times per week i.m. administration. The effects on various measures of monocyte function and of nonspecific immunity (hypersensitivity, immunoglobulins, complement) were negative. We suspect that in practice it may be difficult to exploit the narrow dosage window of immunostimulation, but it is important to note that the nontoxic lower doses were more stimulatory than were the very high doses which are being used in numerous clinical trials.

Inhibitors of monocyte responses to chemotaxins are present in human cancerous effusions and react with monoclonal antibodies to the P15(E) structural protein of retroviruses

Individuals with cancer have previously been shown to have abnormal chemotactic responsiveness. Surgical removal of the tumor often resulted in normalization of monocyte function, which suggests that human neoplasms might inhibit monocyte chemotaxis by release of soluble mediators. We therefore examined the effects of cancerous effusions on monocyte polarization, i.e., the rapid change in monocyte morphology from round to a triangular "motile" configuration in response to chemoattractants. All 17 malignant effusions, representing 15 tumor types, inhibited monocyte polarization induced by the chemoattractant N-formyl-methionyl-leucyl-phenylalanine by 45-89% (mean 55.9 +/- 12.7%, P less than 0.01) in blinded assays. None of 17 benign effusions signigicantly inhibited polarization (0-15%, mean 6.2 +/- 4.2%). Dilutions of cancerous effusions as low as 1:200 produced inhibition that was time, temperature, and dose dependent . Monocyte polarization induced by activated serum or by chemotactic lymphokine was also blocked by cancerous effusions. The inhibitory activity affected the monocyte directly, and did not destroy the chemoattractant or block the polarization of granulocytes to chemotactic factors. High pressure liquid chromatography of five cancerous fluids revealed three peaks of inhibitory activity: greater than or equal to 200,000, 46,000 +/- 13,000, and 21,000 +/- 3,000 daltons. Fractionation of noncancerous effusions revealed only small amounts of the highest molecular weight inhibitory activity. The inhibitory activity in cancerous effusion was heat stable (56 degrees C, 30 min), trypsin sensitive, and could be absorbed by three different monoclonal antibodies reactive to P15(E), a structural component of type C retroviruses. In contrast, six monoclonal antibodies with other specificities had no effect on the inhibitors of polarization. This study demonstrates that human cancerous effusions contain novel proteins that are potent inhibitors of monocyte function and that are recognized by antibodies reactive to the P15(E) component of retroviruses. By producing such factors, tumor cells may subvert monocyte-mediated surveillance.