Dr Matteo Brivio
Dipartimento Emergenza Urgenza
HPG23 Bergamo
Razionale clinico per l’ utilizzo dell’
adsorbimento selettivo delle endotossine e
delle citochine nel paziente critico
Highlights
Pathophysiology and characteristics of inflammatory mediators
Reason for their removal from bloodstream
Adsorbers characteristics and clinical application
Literature analysis
Conclusions
 PAMPS (pathogen-associated
molecular patterns): bind on TLRs
and CLRs receptors on antigen
presenting cells
 DAMPS (damage-associated
molecular patterns):
inflammation perpetuation by
acting on the same patternrecognition receptors triggered
by pathogens.
Which
targets?
autoamplificatory loops after activation of
monocytes/macrophages
IL6 TNFa
IFNy
IL1 TNFa
Sepsis
inflammatory
response
Cytokine storm: pro and
antiinflammatory mediators
overespression: leads to a derangement
in immune system regulation
Hours?
Days?
• T0: LPS
• 1,5h: TNF peak
• 3h: IL1, IL6 e IL8 peaks
Time dipendent intervention
How to bring order to
chaos?
‘Peak concentration hypothesis’
1. Bloodstream: aspecific cut of cytokines peaks (pro and
antinflammatory)
2. Mediators redistribution: tissues > bloodstream
Mediators removal
Ronco C- et al. Artif Organs 2003; 27: 792-801.
“Mediator delivery hypothesis”
20-40 times linfatic flux increase
from basal values
Cytokines and inflammatory
mediators drag from interstitial
linfatic tissues towards
bloodstream
Mediators removal
Ronco C- et al. Artif Organs 2003; 27: 792-801.
“Threshold immunomodulation
hypothesis”
• Targeting a threshold concentration
below which there is a block of
immunitary system disregulation and
inflammatory mediators production
• Rebound at the withdrawal of
hemoperfusion (importance of
etiological therapy)
Honoré et al. Contrib Nephrol 2007; 156: 387-95
Citokines
molecular weight
•
•
•
•
•
•
•
IL1 a 18 KDa
IL 1 b 17,3 KDa
IL2 15,5 KDa
IL6 21 kDa
IL8 8,4 KDa
IL 10 18,6 (37,2) KDa
TNF a 17 (52,2)KDa
Size matters?
LPS size
O-antigen:
 high degree of structural variability
 tends to form aggregates of varying sizes
 reported "molecular mass" range up to 1000
KDa
 Negative charge
Atan R et al.Blood Purif 2012;33:88-100,; Morgera S,Bellomo R et al.Crit Care Med. 2006;34:2099-04; Glycobiology Analysis Manual, 2nd Edition
3-5 nm
Cytokines size
High cut-off membranes
• Cutoff 60 KDa
• Surface 1,1 m2
• 10 nm median diameter> ok cytokines, no
LPS
• Removal limited by:
1. Sieving coefficient
2. Solute ultrafiltration/diffusion flux
Morgera S,Bellomo R et al.Crit Care Med. 2006;34:2099-04; Ronco Bellomo Crit. Care Nephrology 3° ed.
Sorbent cartridges
Natural or syntetic porous polimers
Selective or non selective
Very large surface/volume ratio 300-1200 m2/g
Biocompatibility: surface coating (polisulfone)
Harmful substancecs release into blood stream (cytotoxity induction)
Activation of immune system (complement cascade)
1.1
2
m
60.000
V
S
2
m
• Beads, granules,flakes, fibers, spheres,
cylindric pellets (50 μm to 1.2 cm)
• Contained in cartridges provided ports for
plasma/blood inflow and outflow
• Screens to avoid dissemination of particles
into the circulation.
• A. External (interphase) mass transfer of solute
from the bulk fluid by convection through a film to
the outer surface of the sorbent.
• B. Internal (intraphase) mass transfer of the
solute from the outer surface of the sphere to the
inner surface of the porous structure.
• C. Diffusion along the porous surface and
adsorption
Ronco Bellomo Crit. Care Nephrology 3° ed.
Ricci 2022 Intensive Care Med (2022) 48:1397–1408
How does adsorbption take place?
A. Van der Waals forces: interaction between electrons of one
molecule and the nucleus of another molecule; weak and reversible.
B. Ionic bonds: electrostatic attraction between positively charged
and negatively charged ions.
C. Hydrophobic bonds: strong binding forces generated by the
hydrophobic affinity of the sorbent and the solute molecules
Resin pore size: 500 Da- 60 KDa
Average beads diameter: 0,8 mm (0,6-1,8 mm)
Huge surface: 50.000 m2 (HA330); 60.000 m2 (HA380)
HP/ HP+ CRRT/ HP+ ECMO/ HP+ CRRT+ ECMO/ HP+ CPB
Heparin/citrate
Blood flow 100-700 ml/min
Treatment time 2-12h
Jafron HA
380
LPS adsorbtion
 Polietylene porous matrix (100
µm pores diameter) coated with
cationic peptide
Selective LPS endotoxin bind
(negative charge)
HP +/- CRRT, +/- ECMO
(150-200 ml/min)
Heparin or citrate
Adsorptive capacity 8 ug
2 hours sessions
Ecmo+ adsorber
Small RCTs
 Lower ICU mortality
 Lower hospital stay
 Lower VP dose
 Lower cytokines levels
A prospective randomized, parallel controlled
analysis
Control group: n= 21; STM
HP group: n=25; STM+ HP once/day, 3 days
Results
 Significant cytokines Removal
 Improve respiratory dysfunction
 Reduce vasopressors needs
 Reduce ICU stay and 28-day mortality
Huang, Zhao, et al. Therapeutic apheresis and dialysis 17.4 (2013): 454-461.
Primary endpoint: feasibility
Secondary endpoint: LPS levels, cytokines levels, inflammatoty response
Max 12h after recruitment, 6hx 2 days
 15 pts, 7 treatment, 8 sham;
 Safe, no differences in adverse events
 No differences in citokynes levels, severity scores or variables
24 healty pigs:
 12 cytosorb
 12 sham
17 ATBs, antifungals, antiviral drugs levels
tested
Effects on clearance significant in 5/17
drugs:
 Moderate:
fluconazole (282%) and linezolid (115%),
 Mild:
liposomal amphotericin B (75%),
posaconazole (32%)
teicoplanin (31%)
 Negligible: others
Once positive results concerning surrogate markers, a
phase 3 trial exploring clinical outcomes can be
considered
 Some patients may benefit from adsorption
 Need to identify such individuals using adequate
biomarkers or phenotype identification techniques.
 For the moment should be considered experimental and
in the context of a specific research protocol.
Research recommendations:
 Hemoperfusion
indications
 Defining adequate and
safe dosage (how many
sessions, how often
change cartridges )
Lack of consensus:
1. Indications
2. Clinical practice
guidelines
No magic bullets
 Exploring the move from
intermittent to continuous
treatments
 Setting up a
hemoperfusion registry
(similar to ECMO
registries)
Good reasons for cytokines and LPS removal in septic
patients
Increased safeness and biocompatibility
Lack of evidences from literature
Conclusions
Futher RCTs are needed to investigate real and effective role
of hemoadsorbtion:
1. Hemoperfusion indications, dosage and timing
2. Define different primary endpoints rather than mortality
Thank you for
your
attention!