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Requested Profiles for Dialysis Membranes Today Requested Profiles For Dialysis Membranes Today Prof. Dr. Eng. Jörg Vienken BioSciences, Fresenius Medical Care Bad Homburg Principles of Hemodialysis Anticoagulation Blood pump Dialyser, Filter, Artificial Kidney Routine chronic therapy : 3 treatments / week Duration : ca 4 hrs / treatment Longest therapy in 2008 : 40 years in Japan Guestimate annual cost : ca 50.000,- € / patient Requested Profiles For Dialysis Membranes Today Membrane polymers Performance and Biocompatibility Conditions for Dialyser Choices Summary Dialysis Patients To Date Hemodialysis patients: Annual growth rate 6% 1.300 World population: Annual growth rate 1.1% Annual need for dialysers in 2011: 220,000,000 filters 1.050 900 750 World 2010*: 600 HD: 1,815,000 PD: 213,000 450 Japan 2008** 300 HD: 274,121 PD: 9,300 Patient numbers x 1,000 150 Japan 70,793 HD-Pts >10 years therapy 10,017 HD-Pts >25 years therapy 0 1970 1975 1980 1985 1990 1995 2000 ´05 ´10 Year Re: S Moeller, FMC Annual Survey 2011 ** S. Nakai et al., Ther Apher & Dial, 14:505- 540 (2010) Negative Standards by Opinion Leaders “Dialysis is useless and dangerous.” Franz Volhard, famous Internist and Professor at Halle (1918) and Frankfurt (1927), both in Germany. Franz Volhard “From the initial idea to the actual realization of the dialysis method, it was a very long way. I would have to say, it was the way of the Cross…” Georg Haas(1928) at Giessen, Germany 8022 Bad Homburg, August 1999 2355 Therapy Changes to Come (I)? Incident Age Distribution of Dialysis Patients Germany 1996 - 2002 35 30 25 1996 2002 20 15 Percent10 % 5 0 0-19 20-29 30-39 40-49 50-59 60-69 70-79 > 80 Years 4022 QuaSi-Niere 2002 Therapy Changes to Come (II)? Hemodialysis in the USA Mean serum creatinin Prevalence by age group at onset of dialysis therapy Æ Consequences for technical requirements in dialysis therapy? Re: C Hsu, 8978 J Am Soc Nephrol, 21:1607-1611 (2010) Therapy Changes to Come (III)? Hemodialysis in Japan Japan 2008 o Mean age of patients: 65,3 years o Mean age of dialysis beginner: 67,2 years o 43,3 % diabetics o Mean duration of HD therapy: 3.92 hrs o Average blood flow : 197ml/min o Average dialysate flow: 487 ml/min o 50.7 % with polysulfone membranes o Membrane surface area : 1.63 m² Year 2010 Annual production of capillary membranes for dialysis worldwide: ca.ca. 420.000.000420.000.000 KmKm ca 3x distance between the Earth and the Sun, or…, ca 10.000 x around equator. 2990 Take Home Message o Dialysis, the most successful therapy in keeping patients alive e.g., the longest dialysis therapy in Japan: 40 years, 8 months in 2008. o Dialysis with exponential increase in patient numbers in the years to come: > 6% / annually Æ Need for more filters, tubings and therapies. o Significant increase of diabetic dialysis patients, Æ Need for adapted therapies essential. Requested Profiles For Dialysis Membranes Today Membrane polymers Performance and Biocompatibility Conditions for Dialyser Choices Summary Membrane - Polymers in Dialysis End of (Cuprophan) production in 2006 Cellulose-tri-acetate End of production in 2006 Composite membranes Composite membranes 4611 Development of Dialyser Sales - World 2000 - 2006 - 180 * Synthetic membrane polymers: Polysulfone, Polyacrylonitrile, PMMA, Polyamide 180 ** Cellulosic membranes: Cuprophan, Hemophan, Cellulose Acetates 160 160 140 140 120 120 Synthetic* high flux membranes ca 50% 100 100 80 80 Synthetic low flux membranes 60 60 Dialysers sold [Mio] 40 Cellulose** high flux membranes 40 20 20 Cellulose low flux membranes 0 0 2000 2001 2002 2003 2004 2005 2006 Year 4865 Re: J Paal, FMC 2008 Take Home Message o Synthetic membranes – PSu (> 50%), PMMA, PA, PAN, and respective blends, etc - dominate the dialysis market in the world today. o Reasons for market success and acceptance of synthetic membranes by nephrologists: - versatility - biocompatibility - adsorptive features o The majority of cellulosic membranes have disappeared from the dialysis market ( exception CTA) after having dominated it in the past decades. Reason: alleged lack of biocompatibility. Requested Profiles For Dialysis Membranes Today Membrane polymers Performance and Biocompatibility Conditions for Dialyser Choices Summary PolymerPolymer selectionselection ofof membranesmembranes Determinant for the physical (Performance, adsorption) chemical (Biocompatibility) biological-medical (Adverse events, safety) properties of membranes in medical application Current dialysis treatment mainly based on the removal of water and matter! Capillary- Membrane Fresenius Polysulfone® Filtration, Backfiltration 200 µm 200 µm Inner diameter Pore Sizes of Dialysis Membranes 1,3 nm low flux polysulfone 3,1 nm highflux polysulfone 3,3 nm Helixone (polysulfone) Cellulosic Membranes Synthetic Membranes 1738-1 Bloodproteins and Their Dimensions ß-2 Microglobulin Albumin -charge + charge without charge 4,5 x 2,5 x 2,0 nm 14 x 4 nm 2795-2 p53 Tumor Suppressor Protein Re: T Chouard Nature, 471:151-153 (2011) Protein Permeability of Dialysis Membranes Analyses of Ultrafiltrate Proteins found in ultrafiltrate SDS-Gel Urine PSu F6: < 0,050 g / L Ultrafiltrate from membrane Cuprophan: < 0,050 g / L PSu – F60: 0,069 g / L Cellulose Acetate: 1,5 g / L Increasing molecular weight Re: H. Mann, 2007 8149 Interneph Institute, Aachen Adding to the complexity of uremic toxins? 450 Proteomics 400 350 Measured polypeptides in filtrate 300 250 200 401 total150 number 307 100 50 344 73 105 263 0 0.8 - 1 kD 247 Highflux F70 182 1 - 1,5 kD 137 1,5 - 2 kD 147 Lowflux F10 1394 142 2 - 2,5 kD 87 polypeptide mass class 2,5 - 3 1046 Polypeptides in high flux 3 - 4 31 69 4 - 5 1 Polypetides in low flux 17 ultrafiltrate samples F10 vs 5 - 6 kD 2 from uraemic plasma. 7 F70 > 6 kD Nephrol Dial Tran splant,EM 19:3068-77 Weissinger (2004) et al., The Dilemma in Blood Purification Which substances to target ? EUTox Group: ~ 100 uremic retention solutes EUTox Group: (“Uremic Toxins”) involved. ProteomicsProteomics ¾1300 “toxins” are to be found in the filtrate / urine. people:people: Nephrologists: “We need better membranes and sophisticated Nephrologists: therapies!” Industry: “Tell us which substances should be removed ! Industry: ... and to what extent? Data on concentrations of uremic toxins in human serum vary when analysed in different publications up to a factor of 3!” Is there evidence to support that kidney failure can be attributed to a single substance? Expert Recommendation: Maximise Middle Molecule Removal Nephrol Dial Transplant, 17(Suppl. 7):16-31 (2002) How? Æ Use of highflux synthetic membranes Æ Application of convection: Hemodiafiltration HDF Caution! “Opening-up” membrane structure (larger pores) indefinitely would also lead to loss of ‘useful’ proteins (HD = size- exclusion based) Æ Increasing the mean pore size alone is insufficient! High-Flux: Solvent drag Æ Convective Clearance Convective clearance = SC x QF Type of f(∆p) membrane: Low-Flux f(TMP) High-Flux SC = Sieving Coefficient; QF = Filtrate flow; TMP = Transmembrane pressure 0844-2 Sieving Through Size-Exclusion with Membranes from Polysulfone Dialysis Therapy of Liver Failure 1 Zone of 0,9 Impermeability 0,8 0,7 0,6 0,5 PSu F6 PSu F60S PSu 0,4 Low flux High Flux AlbuFlow 0,3 Fx60 0,2 Zone of Sievieng coefficient 0,1 Permeability 0 1.000 10.000 100.000 1.000.000 ß2-m Albumin IgG Fibrinogen IgM AlbuFlow PSu – Mol.-Weight Polysulfone 4631-1 Pressure Drop In Dialysers Favours Increased Convection r ΔL Bloodin • Bloodout QB η • QB pin pout ΔL Δp = ·(8η· Hagen-Poiseuille´s Law N · r 4 · π QB) Dialyser Blood r = Radius of capillary membranes QB = Blood flow L = Dialyser length η = Blood viscosity N = Number of capillary membranes 0845-1 Reduced Internal Fiber Diameter and Higher Clearance of Large Molecules PSu PSu PSu – Dialysers: A : 0.5 m² J Vienken & C Ronco Contrib Nephrol, 133: 105-118 (2001) 3850 Ultrafiltration:Ultrafiltration: LowLow-- andand HighfluxHighflux PSuPSu--DialysersDialysers 12000 Highflux Membranes HdF100S Ultrafiltration profiles In vitro, HF 80 (S) human blood, Hct. 32 %, TP 6 %, QB = 300 ml/min F 70 (S) UF - Ultrafiltration 9000 TMP - Transmembrane pressure F 60 (S) 6000 6000 Lowflux Membranes F 8 HPS F 7 HPS 4000 F 6 HPS 4000 UF = 3000 ml/h UF ml/h F 5 HPS 2000 F 4 HPS 2000 0 0 0 100 200 300 400 500 100 200 300 400 500 TMP mmHg 2034-1 FMC, St. Wendel Filtration Profiles Low vs. High-Flux Dialysers Filtrate flow (QF) & Membrane permeability 12.000 In vitro, Human boodt, Hct.32 %, TP 6 %, QB = 300 ml/min 10.000 High-Flux 8.000 6.000 Potential 4.000 Gain in Low-Flux Kkonvective 2.000 Ultrafiltration rate [ml/h] 0 0 100 200 300 400 500 TMP [mmHg] F4HPS F5HPS F6HPS F7HPS F8HPS F60 F70 HF80 HDF100S 7922 OnLine HDF: the Principle Reverse Endotoxin Endotoxin osmosis Filter I Filter II Substitution fluid Concentrates Dialysis fluid 0140 The dialysis membrane is not a „One-Way-Street“! 0573-1 PSu Fibers: High Intrinsic Adsorptive Features for Endotoxins Dialysate Blood Artificial Organs, 32(9):701–710 (2008) 8100 DC Endotoxinstudies BC 160 140 120 100 80 60 Intensity 40 20 0 0 10203040506070 PSu µm Polysulfone capillaries with intrinsic adsorption capacity for ETs. Re.: M Henry et al., Utah University Artif Organs, 32:701-710 (2008) Reduction of Bacterial Contaminants through Ultrafilters Bacterial concentration Endotoxin - levels CFU/ml IU/ml 100:000 10 10:000 1:000 1 100 10 0.1 1 0.1 0.0 0 0.01 1 0.001 0.001 Standard Post post Standard post post dialysate 1. Filter 2. Filter dialysate 1. Filter 2. Filter EU Standard for ultrapure dialysate. EU Standard for ultrapure dialysate: <0.1 CFU/ml <0.03 IU/ml C Weber et al., Artif Organs, 24: 323-328 (2000) Water Quality Requirements for Hemodialysis and onLine HDF Water Concentrates Dialysis fluid OnLine HDF (Ultrapure) Substitution sol.
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