Prof. Dr. Eng. Jörg VienkenBioSciences, Fresenius Medical Care

Bad Homburg

Requested Profiles For Dialysis Membranes Today

Dialyser,Filter, Artificial Kidney

Anticoagulation Bloodpump

Principles of Hemodialysis

Routine chronic therapy : 3 treatments / weekDuration : ca 4 hrs / treatmentLongest therapy in 2008 : 40 years in JapanGuestimate annual cost : ca 50.000,- € / patient

Membrane polymers

Performance and Biocompatibility

Conditions for Dialyser Choices

Summary

Requested Profiles For Dialysis Membranes Today

Dialysis Patients To Date

Re: S Moeller, FMC Re: S Moeller, FMC AnnualAnnual SurveySurvey 20112011** S. ** S. NakaiNakai et al., et al., TherTher ApherApher & & DialDial, 14:505, 14:505-- 540 (2010)540 (2010)

1970 1975 1980 1985 1990 19950

150

300

450

600

Year

Patie

nt n

umbe

rsx

1,00

0Hemodialysis patients: Annual growth rate 6%World population: Annual growth rate 1.1%

750

900

2000

1.050

´05

World 2010*:World 2010*:HD: 1,815,000HD: 1,815,000PD: 213,000PD: 213,000

Japan 2008**HD: 274,121PD: 9,300

Japan 70,793 HD-Pts >10 years therapy10,017 HD-Pts >25 years therapy

´10

1.300Annual need for dialysers in 2011: 220,000,000 filters

“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

“Dialysis is useless and dangerous.”Franz Volhard, famous Internist and Professorat Halle (1918) and Frankfurt (1927),both in Germany.

8022

Franz Volhard

Negative Standards by Opinion Leaders

2355Bad Homburg, August 1999

Therapy Changes to Come (I)?Incident Age Distribution of Dialysis Patients

Germany 1996 - 2002

4022 QuaSi-Niere 2002

05

1015

20253035

0-19 20-29 30-39 40-49 50-59 60-69 70-79 > 80Years

Perc

ent

% 1996 2002

8978

Therapy Changes to Come (II)?Hemodialysis in the USA

Re: C Hsu, J Am Soc Nephrol, 21:1607-1611 (2010)

Mean serum creatininat onset of dialysis therapy

Prevalence by age group

Consequences for technical requirementsin dialysis therapy?

Japan 2008

o Mean age of patients: 65,3 yearso Mean age of dialysis beginner: 67,2 yearso 43,3 % 43,3 % diabeticsdiabetics

o Mean duration of HD therapy: 3.92 hrs

o Average blood flow : 197ml/mino Average dialysate flow: 487 ml/mino 50.7 % with polysulfone membraneso Membrane surface area : 1.63 m²

Therapy Changes to Come (III)?Hemodialysis in Japan

Year 2010

Annual production of capillary membranesfor dialysis worldwide:

ca. 420.000.000 Kmca. 420.000.000 Km

ca 3x distancebetween the Earth and the Sun, or…, ca 10.000 x around equator.

2990

Take Home Message

o Dialysis, the most successful therapy in keepingpatients alivee.g., the longest dialysis therapy in Japan:40 years, 8 months in 2008.

o Dialysis with exponential increase in patient numbersin the years to come: > 6% / annually

Need for more filters, tubings and therapies.

o Significant increase of diabetic dialysis patients, Need for adapted therapies essential.

Membrane polymers

Performance and Biocompatibility

Conditions for Dialyser Choices

Summary

Requested Profiles For Dialysis Membranes Today

Membrane - Polymers in Dialysis

4611

End ofproduction in 2006

End ofproduction in 2006

Cellulose-tri-acetate

(Cuprophan)

Compositemembranes

Composite membranes

Development of Dialyser Sales- World 2000 - 2006 -

Re: J Paal, FMC 20084865

0

20

40

60

80

100

120

140

160

180

2000 2001 2002 2003 2004 2005 2006Year

Dia

lyse

rsso

ld[M

io]

0

20

40

60

80

100

120

140

160

180

Synthetic* high flux membranes

Synthetic low flux membranes

Cellulose** high flux membranes

Cellulose low flux membranes

ca 50%

* Synthetic membrane polymers: Polysulfone, Polyacrylonitrile, PMMA, Polyamide** Cellulosic membranes: Cuprophan, Hemophan, Cellulose Acetates

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 ofsynthetic membranes by nephrologists:- versatility- biocompatibility- adsorptive features

o The majority of cellulosic membranes have disappearedfrom the dialysis market ( exception CTA) after havingdominated it in the past decades. Reason: alleged lack of biocompatibility.

Membrane polymers

Performance and Biocompatibility

Conditions for Dialyser Choices

Summary

Requested Profiles For Dialysis Membranes Today

Determinant for the

physical (Performance, adsorption)chemical (Biocompatibility)biological-medical (Adverse events, safety)

properties of membranes in medicalapplication

Polymer Polymer selectionselection of of membranesmembranes

200 µm

Capillary-MembraneFresenius Polysulfone®

Inner diameter

Filtration,Backfiltration

200 µm

Current dialysis treatmentmainly based

on the removal of water and matter!

Pore Sizes of Dialysis Membranes

Cellulosic Membranes Synthetic Membranes

1,3 nm low flux polysulfone3,1 nm highflux polysulfone3,3 nm Helixone (polysulfone)

1738-1

2795-2

Bloodproteins and Their Dimensions

4,5 x 2,5 x 2,0 nm

- charge

+ charge

without charge

14 x 4 nm

ß-2 Microglobulin Albumin

Re: T ChouardNature, 471:151-153 (2011)

p53 Tumor Suppressor Protein

Protein Permeability of Dialysis MembranesAnalyses of Ultrafiltrate

Re: H. Mann, 2007Interneph Institute, Aachen

PSu F6: < 0,050 g / L

Cuprophan: < 0,050 g / L

PSu – F60: 0,069 g / L

Cellulose Acetate: 1,5 g / L

Increasing molecular weight8149

SDS-Gel UrineUltrafiltratefrom membrane

Proteins found in ultrafiltrate

ProteomicsAdding to the complexity of uremic toxins?

EM Weissinger et al.,Nephrol Dial Transplant, 19:3068-77 (2004)

1394 Polypeptides in high flux vs

1046 Polypetides in low flux ultrafiltrate samplesfrom uraemic plasma.

Measured polypeptides in filtrate

73

307263

182137

87

311 2

105

401

344

247

147 142

6917 7

050

100150200250300350400450

0.8 - 1 kD

1 - 1,5 kD

1,5 - 2 kD

2 - 2,5 kD 2,5 - 3 3 - 4

4 - 5

5 - 6 kD> 6 kD

polypeptide mass class

tota

l num

ber

F10F70

Highflux F70

Lowflux F10

Is there evidence to support that kidney failurecan be attributed to a single substance?

The Dilemma in Blood PurificationWhich substances to target ?

“Tell us which substances should be removed !... 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!”

Industry:Industry:

“We need better membranes and sophisticated therapies!”Nephrologists:Nephrologists:

1300 “toxins” are to be found in thefiltrate / urine.

Proteomics Proteomics people:people:

~ 100 uremic retention solutes(“Uremic Toxins”) involved.EUToxEUTox Group:Group:

Expert Recommendation:Maximise Middle Molecule Removal

How? Use of highflux synthetic membranesApplication of convection: Hemodiafiltration

HDFCaution! “Opening-up” membrane structure (larger pores) indefinitely

would also lead to loss of ‘useful’ proteins (HD = size-exclusion based)

Increasing the mean pore size alone is insufficient!

Nephrol Dial Transplant, 17(Suppl. 7):16-31 (2002)

SC = Sieving Coefficient; QF = Filtrate flow; TMP = Transmembrane pressure0844-2

High-Flux:Solvent drag Convective Clearance

f(∆p)

f(TMP)

Type of membrane:

Low-Flux

High-Flux

Convective clearance = SC x QF

Sieving Through Size-Exclusion with Membranesfrom Polysulfone

00,10,20,30,40,50,60,70,80,9

1

1.000 10.000 100.000 1.000.000

Mol.-Weightß2-m Albumin IgG Fibrinogen IgM

Siev

ieng

coef

ficie

nt

PSuPSu F6F6Low Low fluxflux

DialysisDialysisZone of

Impermeability

Zone ofPermeability

4631-1

AlbuFlowPSu –

Polysulfone

PSu F60SPSu F60SHigh High FluxFlux

Fx60Fx60

PSuPSuAlbuFlowAlbuFlow

TherapyTherapy of of LiverLiver FailureFailure

0845-1

Pressure Drop In DialysersFavours Increased Convection

Bloodin Bloodout QB

ΔL

Δp = ΔL

N · r r 4 · π

r

pin pout

•

Hagen-Poiseuille´s Law· (8η·QB)

η • QB

Dialyserr = Radius of capillary membranesL = Dialyser lengthN = Number of capillary membranes

BloodQB = Blood flowη = Blood viscosity

J Vienken & C RoncoContrib Nephrol, 133: 105-118 (2001)

Reduced Internal Fiber Diameter and HigherClearance of Large Molecules

PSu PSu

PSu – Dialysers: A : 0.5 m²

3850

2034-1

Ultrafiltration:Ultrafiltration: LowLow-- and and HighfluxHighflux PSuPSu--DialysersDialysers

FMC, St. Wendel

Ultrafiltration Ultrafiltration profilesprofilesIn vitro, human blood,Hct. 32 %, TP 6 %, QB = 300 ml/min

UF - UltrafiltrationUltrafiltrationTMP - TransmembraneTransmembrane pressurepressure

0

TMP mmHg

0

2000

4000

6000

0 100 200 300 400 500

F 8 HPS

F 7 HPSF 7 HPSF 6 HPS

F 5 HPS

F 4 HPS

UF

ml/h

UF = 3000 ml/h

Lowflux Membranes6000

4000

2000

100 200 300 400 500

HF 80 (S) HF 80 (S)

F 70 (S) F 70 (S)

F 60 (S) F 60 (S) 9000

12000HdF100S HdF100S Highflux Membranes

Filtration ProfilesLow vs. High-Flux Dialysers

In vitro, Human boodt,Hct.32 %, TP 6 %,QB = 300 ml/min

Ultr

afilt

ratio

n ra

te [m

l/h]

TMP [mmHg]

High-Flux

Low-FluxPotential Gain in Kkonvective

Filtrate flow (QF) & Membrane permeability

0

2.000

4.000

6.000

8.000

10.000

12.000

0 100 200 300 400 500

F4HPS F5HPS F6HPS F7HPS F8HPS F60 F70 HF80 HDF100S

7922

0140

OnLine HDF: the Principle

Reverseosmosis

EndotoxinFilter I

EndotoxinFilter II

Dialysis fluid

Concentrates

Substitution fluid

0573-1

The dialysis membrane is nota „One-Way-Street“!

PSu Fibers:High Intrinsic Adsorptive Features for Endotoxins

Artificial Organs, 32(9):701–710 (2008)

Blood

Dialysate

8100

Endotoxinstudies

Re.: M Henry et al., Utah UniversityArtif Organs, 32:701-710 (2008)

0

2040

6080

100

120140

160

0 10 20 30 40 50 60 70µm

Inte

nsity

PSu

Polysulfone capillaries with intrinsic adsorption capacity for ETs.

BC

DC

C Weber et al., Artif Organs, 24: 323-328 (2000)

0

Standarddialysate

Post1. Filter

post2. Filter

Bacterial concentrationCFU/ml

EU SEU Standardtandard for for ultrapure ultrapure dialysatedialysate..<0.1 <0.1 CFU/mlCFU/ml

0.001

0.1

10:0001:000

100:000

0.01

10100

1

Reduction of Bacterial Contaminantsthrough Ultrafilters

EU Standard for ultrapure EU Standard for ultrapure dialysatedialysate: : <0.03 <0.03 IU/mlIU/ml

0.01

0.001Standarddialysate

post1. Filter

Endotoxin - levelsIU/ml

1

0.1

10

post2. Filter

Water Quality Requirementsfor Hemodialysis and onLine HDF

Water Concentrates Dialysis fluid OnLineOnLine HDFHDF(Ultrapure) Substitution sol.

Germ count < 100 < 100 < 0,1 < 10-6

CFU/ml

Endotoxin level < 0.25 <0.5 < 0.03 < 0.01IU/ml below detection

level

Ph. Eur 2005 EN 13867 (2002) AAMI 2004 ISO Standard 11663Ph. Eur 2005 2009

Determinant for the

physical (Performance, adsorption)chemical (Biocompatibility)biological-medical (Adverse events, safety)

properties of membranes in medicalapplication

Polymer Polymer selectionselection of of membranesmembranes

0321

Biostability

.......the ability of a substance toremain unchanged in a given

biological environment!

CCBConsensus Conference on Biocompatibility

Königswinter, Germany, March 1993Nephrol Dial Transplant, 9(Suppl 2): 1-186 (1994)

0244-3

Dialyser Sterilisation ProceduresEuropean Community 1986 - 2006

1986 1990

ETOγ

SteamUnknown

- Irradiation

87.7%

12.3%

70.6%

15% 6%8.4%

25%58%17%

2006

0250

ETO and Anaphylactoid Reactions

ETO (ETO-HSA) bound to Albumin acts as Hapten.

IgE-Antibodies against ETO-HSAprovoke allergic reactions in hypersensitive patients.

Handlos 1986

Time days

ETO

pp

m

0 10 20 30 40 50 60 70

1

35

10

3050

100200

PSPC ABS POM PSu SAN

LD-PE

PP

EVAPUR SilikoneSoft PVC

Hard PVC

HD-PE

PA

Ethylene-OxideDesorptionskinetics of Polymers

0255

0245

Membrane Polymers and Sterilisation

Gamma-rays

ETO Steam

Cell. AcetatePANPMMA

PolyamideEVAL

Glass-transitiontemp. > 45°CGlass-transitiontemp. > 80°CETO - Reservoir, Tmax: 70°C

Partial: HydrolysisGlass-transitiontemp. > 66°C

+ + -(+?) + -

+ - (-)

+ + -+ + -

PolysulfoneCellulosePVC (hard)

+++

Membrane-Polymer

Problems

PVC (soft) Max temperature: 110°C+ + -

PUR ETO - Reservoir+ - +

+++

+++

1053

Ageing of membrane polymers

adverse clinical reactions by extractablesThe case of Cellulose Acetate

October 1996 Severe loss of hearing and visualtroubles in patients of a dialysiscenter in Alabama/USA

Mai 1997 Three patients diedReasons: Use of dialysers withcellulose acetate membranes, manufactured in 1985

Observation:Observation: Neurological reactions within 24h after the end of dialysis therapyNo reuse

Nephrol News Isues, May 1997; pp 8-13

Hutter et alJAMA, 283:2128-2134 (2000)

Dialyser-Extractables and Adverse Clinical EventsChanges in Molweight during ageing of CA*-dialysers

2640

* Celluloseacetate

Adverse Clinical Events Through Extractablesfrom Cellulose Acetate (CA) Dialysers

Z. Averbukh et alArtif Organs, 25:437-440 (2001)

Symptoms Affected Patients Duration ofOccurence after 24 h No % Symptoms

Conjunctivitis 22/22 100 3 - 7 daysOstealgia / Myalgia 21/22 95 1 - 21 daysTinnitus 12/22 55 up to 6 monthsHeadache 4/22 18 3 - 7 daysAngiodemias 1/22 4 -Breastache 1/22 4 -

Dialyser: CA 210, Single useNaCl-Rinse + Heparin/NaCl-Rinse

3810

Determinant for the

physical (Performance, adsorption)chemical (Biocompatibility)biological-medical (Adverse events, safety)

properties of membranes in medicalapplication

Polymer Polymer selectionselection of of membranesmembranes

Contribution of Physical and Biochemical FactorsBiocompatibility of Membrane Capillaries

Commercial Dialysers

Blood Coagulation cannot be avoided, if.........

Blood stagnant.

Blood in contact with air & oxygen interfaces.

Blood in contact with thrombogenicsurfaces (collagen, biomaterials).

Membrane Biocompatibility

200 μm

Capillary LumenDeterminant for blood flow and optimized flow behaviour

Consequence: Quality requirements for capillary membranes:

Need for homogenous bloodflow paths

2980

Nor

m. P

late

letD

ensi

ty

Blood Flow

Aneurysm

Stenosis Contraction/expansion

Control

Impact on normalized platelet density

AC B

D

2758

Area of interest

Area of interest

Area of interest

A

A

B

BC

C

D

123

3

12

3 2 1I

II

III

Schoephoerster et al,Arterioscler Thromb,13:1806-13 (1993)

Flow Streamlines into Expansion, Contractionand after an Aneurysm

Flow

•

2885-1

Modified celluloseHemophan®LSM

U. ThomanekRostock

G. MishkinSem Dial, 14:170-173 (2001)

Domain – Structures of modern Membranes

Polyamide

Polysulfone / Polyethersulfone

0012-1

Complement - Activation„Alternative Pathway“

Membrane surface

C6,C7,C8,C9,C5Terminal complementcomplex(TCC)

C3b C3b C3b

H I

SpontaneousC3(H2O)

-Bb

C5a

C5

C5b

C3a

Bb-

C3

C3C3--ConvertaseConvertase

C3b-Binding through nucleophilic Substitutents

0925-1

C5b-9 Complement ActivationLevels during Hemodialysis

N Hoenich et al.,Biomaterials, 18:1299-1303 (1997)

0

1000

2000

3000

0 30 60 90 120 150 180

Time min

C5b

-9

ng/m

l

Unmodified Cellulose

Cellulose Acetate

Low flux Polysulfone

Benzyl-Cellulose

Maximum between15-60 min

0222

Blood Pressure Regulation-- after Contact-phase activation -

Endotoxins,neg. charged

surfacesPrekallikrein

Kallikrein

HMW KininogenFactor XIIa

Phospholipids

Blood pressure regulation

ProstaglandinsPgE2, Pgl2

(Angiotensin converting enzyme, ACE from lungs and tissue)

ACE

ACE-InhibitorsStopX

Bradykinin

0225

Bradykinin Generation in Plasma through negatively - charged surfaces

Cuprophan®GFE 18

Hemophan®GFS Plus 16

AN69Biospal 3000S

PolysulfoneF60

0

100

200

300

400

Bra

dyki

nin

fmol

/ml

arterialvenous

5 min post onset of dialysisMean + SEMn = 10

18.7 5.1 29.2 17.2

61.2 91.5 39.7

327.6

Verresen et al,Kidney Int; 45: 1497-1503 (1994)

Normal values

w/o charge + charge w/o charge- charge

1244Krieter et al,

Kidney Int, 53: 1026-35 (1998)

ACE-Inhibitors & Anaphylactoid ReactionsSheepmodel and PAN-Blended Membranes

Membrane: AN69 AN69: PAN – Methallysulfonate- Blend

0

40

80

120

160

0

40

80

120

160

0 5 10 15 20 25 30 35 40 45 50 55 60

0

40

80

120

160

* *

*

*

* * * * * *

*

* * * * * *Syst

olic

Blo

odpr

essu

rem

m/h

gPu

lse

bea

ts/m

in

time min

Systolic Blood pressure PulseAN69 (0) = no ACE-Inhibitors

AN69 (20) = 20 mg/day Enalapril

AN69 (30) = 30 mg/day Enalapril

Systolic Bloodpressure

Systolic Bloodpressure

Pulse

Pulse

A Désormeaux et al.,Biomaterials, 29:1139-1146 (2008)

Bradykinin Generation by PAN Membranes

7763

PAN-ST(surface treated)

ACE-Inhibitor Arelix September 2003

3815

Warning: Avoid contact of blood with negatively charged

surfaces

Take Home Message

o Geometry of capillary membranes determinesperformance and biocomaptibility features.

o The membrane is not a one-way street and must beprotective against endotoxin passage (through adsorptivefeatures, e.g., based on polysulfone membranes)

o Extractables through degradation or after blood leachingimportant for chronic therapies.

o Simultaneously administered medicainl drugs mayinterfere with polymer structures.

o Ethylene oxide as sterilizing agent for membranes and dialysers increasingly replaced by steam sterilization,due to its allergic potential in conjunction with albumin.

Membrane polymers

Performance and Biocompatibility

Conditions for Dialyser Choices

Summary

Requested Profiles For Dialysis Membranes Today

4423

MoireStructure

Moiré-Structures and Capillary membranes- Improved Clearance -

3-D Microwave StructureAnalogy with human hair

Waved hair separate, even if wet

Hair stuck together once wet, and arranged in parallel

Membrane Bundle - Modificationfor Improved Flow Profiles

J Vienken & C RoncoContrib Nephrol, 133: 105-118 (2001)3856

A B C

A

B

CC

168 164 158 150 140 168 164 158 150 140

2,4m² in housing 8QB=200ml/minQD=500ml/min

2,4m² in housing 8QB=200ml/minQD=500ml/min

Local Urea - Clearance Profile

Conventional Dialyser New FX-Class

Homogeneous Dialysateflow through optimizedFiberbundle - Geometry:

Improved Diffusive Clearance

Lower Need of Dialysis Fluids- Through Moiré-Structured Capillary Membranes -

3337

Reduction

Membrane polymers

Performance and Biocompatibility

Conditions for Dialyser Choices

Summary

Requested Profiles For Dialysis Membranes Today

Membranes in Dialysis

1980 201020001990

Properties in need

Properties in need

Product-PropertiesProduct-

Properties

System System SolutionsSolutions

2254

2020?

New Generations of Dialysis Machines- Concept of ”Physiological Dialysis“ -

Dialysis machine

Dialysis FluidSensors

BloodSensors

PatientSensors

SensorsSensors

HydraulicsHydraulics

BTM, BVM BPMOCM®

Filter

MonitorMonitor

Na+

K+ K+K+

Na+ Na+Na+

Na+ Na+

K+K+ K+

K+

Leak Gate Pump Carrier ReceptorCa2+

Glucose

Protein Functions of Biological Membranes

0169-1

Ca2+

Glucose

Thicknesses Biological Membranes 10 nmto be compared: Dialysis Membranes 1.000 - 10.000 nm