Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation...
Transcript of Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation...
![Page 1: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/1.jpg)
Mitochondria , Sepsis and
Organ Dysfunction
John F FraserCritical Care Research Group, Brisbane, Australia
![Page 2: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/2.jpg)
First Time in Canada
![Page 3: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/3.jpg)
Intensive Care Unit Common ICU presentations:
• Sepsis Fluid resuscitation• Respiratory ARDS
• ARDS• Cardiovascular Heart Failure/Transplantation
• Ischaemia/ Infarct, arrhythmias• Neurologic ECMO
• Stroke/ trauma TAVI• Renal Acute kidney injury
• Renal failure• Post-operative Care
• Both inflammation and mitochondrial dysfunction play a significant roles in all common conditions, exacerbating pathophysiology and impeding treatment
Critical Care Research Group current focus
![Page 4: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/4.jpg)
Mitochondria• Powerhouse of the cell
• Roles in energy production, Ca2+ homeostasis, ROS elimination, cell death, thermoregulation
• Tissue injury rupture of cell membranes release of mitochondrial contents (mtDNA, DAMPs, ROS, cytochrome c etc) widespread tissue damage
Heart failureAgeingI-R injuryArrhythmiasNeurodegenerationSepsisARDSECMOTransplantationChronic kidney diseaseCancerMitochondrial diseases
![Page 5: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/5.jpg)
Mitochondria and Inflammation
Mitochondria damaged in response to sepsis
ROS from mitochondria may worsen tissue damage
May facilitate hibernation
![Page 6: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/6.jpg)
Mitochondria and Inflammation
• Mitochondrial dysfunction promotes inflammation
• Decreased ATP production
• Poor Ca2+ handling – apoptosis and necrosis
• Release of DAMP’s
• mtDNA• ATP• Succinate• mtROS
production
![Page 7: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/7.jpg)
Mitochondria and Inflammation
• Inflammation alters mitochondrial function
• IL-1β, TNF, IL-6 – known to induce
fragmentation – mitophagy
• ROS mediates inflammasome activation –
mtDNA release
Protti & Singer, Critical Care (2006)
![Page 8: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/8.jpg)
How are mitochondria affected during sepsis
Bioenergetic function and Oxygen-dependent oxidative phosphorylation
Biosynthetic functions
Immune functions
Oxidative stress
Cell death
![Page 9: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/9.jpg)
Fission and Fusion
Fission – damaged Mit isolated and removed to minimize negative effect on network
Fusion – Mildly damaged Mit brought into the network and assists function
Imbalance of these two can result in cell injury
![Page 10: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/10.jpg)
Self Cleaning Mechanism
• Auto/mitphagy – Debris isolated within phagosome and taken to lysosome for safe destruction
• Failure of this mechanism in rats worsens outcome
• Enhancing autophagy conversely improves organ function
![Page 11: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/11.jpg)
Biogenesis• Production of new mitochondria for ATP, calcium
homeostasis, maintenance of cellular redox state, cell signalling
• Septic pts with higher levels of PGC-1α ( co-activator) have higher survival , more ATP
• Pre Clinical- more biogenesis correlates with improved mito respiration
![Page 12: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/12.jpg)
Sepsis • Initiated by
PAMP’s and DAMP’s leading to “cytokine storm”
• Simultaneousimmunosuppression and hyperinflammation
• Persistent inflammation
OR
GA
N D
YSF
UN
CTI
ON
Ding R., et al, The Central Role of the Inflammatory Response in Understanding the Heterogeneity of Sepsis-3, Biomed Research International, 2018
![Page 13: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/13.jpg)
Sepsis- Pathophysiology
PRR Activation
Pro- & Anti-Inflammation
Immunosuppression
Nanez-Verona et al, 2016
Multiple Organ Failure
Tissue ischaemia
Mitochondrial Dysfunction
![Page 14: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/14.jpg)
Sepsis- Mitochondria
1. Impaired Perfusion
2. Generation of ROS
3. Hormonal Alterations
4. Mitochondrial Gene Alterations
Hypoxia → depletion of ATP
Excessive NO, CO, H2S → Inhibit
respiration & damage mito
proteins particularly Complex I
Decreased T3 “sick euthyroid” →
modulates mito respiration
Downregulated early in
inflammatory response
Singer M., Virulence, 2018
![Page 15: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/15.jpg)
ARDS Mitochondrial Dysfunction
↑NO
Disrupted
membrane
potential
APOPTOSIS
↑Caspase 3
↑ cytochrome c
↑Bax
expression
↑ROS ↓ATP
↑Intracellular
Ca2+
ARDS
![Page 16: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/16.jpg)
Emerging aspect in ARDS pathology:
Mitochondrial damage-associate molecular
patterns (mtDAMPs)ARDS
mtDAMPsmtDNA
formyl peptides
cardiolipin
Systemic Inflammatory
Response Syndrome↑Neutrophils
↑ Lung endothelial
permeability
↑ Mortality
ARDS
![Page 17: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/17.jpg)
Emerging aspect in ARDS pathology:
Mitochondrial damage-associated molecular
patterns (mtDAMPs)
Circulating cell-free mtDNA were ↑ in patients
• who died within 28 days of medical ICU admission
• in ICU patients with sepsis or ARDS
• in patients with severe trauma or sepsis in the emergency room
ARDS
![Page 18: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/18.jpg)
Renal Mitochondria
Kidneys require 10% of the body’s
total energy production
• Energy required to regulate
solute re-absorbance.
↑ renal energy demands = kidneys
rich in mitochondria
Healthy mitochondria are
essential for proper renal function
![Page 19: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/19.jpg)
Higher energy demands = renal
failure due to mitochondrial
conditions .
• Genetic conditions in infants
Reverse is also true, acute kidney
injuries associated with
mitochondrial dysfunction.
Kidney Injuries
![Page 20: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/20.jpg)
Kidney injuries
Kidney InjuryAKI
CKD
Kidney Tumours
Mitochondrial
Dysfunction↓ Electron Transport
Chain Function
↓ Metabolite Transport
↓ Cellular Energy
Production↓ Solute Re-absorbance
↑ Apoptosis
↑ ROS Production
Associated
Renal Failure
![Page 21: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/21.jpg)
Mitochondria have a crucial role in
neutrophil biology• Neutrophil function few mitochondria but dependent on them• If mitochondrial MP damaged, as occurs in sepsis, neutrophils chemotaxis almost stops
• Neutrophil releases its arsenal to vessel wall
![Page 22: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/22.jpg)
Other immune cells affected
• Macrophages – M1:M2 ratio
• Experimental ARDS diminished if Mit remain stable
• T Cells – Transition from Naïve to Memory is dependant on cellular metabolism
![Page 23: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/23.jpg)
Brown, D. A. et al. (2016) Mitochondrial function as a therapeutic target in heart failure
Nat. Rev. Cardiol. doi:10.1038/nrcardio.2016.203
Energy Demand vs. Supply
![Page 24: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/24.jpg)
Cardiac Issues in Sepsis
FEAST Maitland et al
![Page 25: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/25.jpg)
The Post Clinical Study - ‘FEAST in Sheep’
![Page 26: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/26.jpg)
Microcirculation26
HS
SS
SN
0
5
1 0
1 5
P e r fu s e d v e s s e l d e n s ity , P V D (m m /m 2 )
G ro u p s
mm
/m2
H S , H e a lth y s a lin e
S S , S e p s is s a lin e
S N , S e p s is n o re s u s
Fraser et al. (RESUS trial)
![Page 27: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/27.jpg)
27
Vasopressor dose (noradrenaline)
Less vasopressor needed, no saline group
4 hrs
Fraser et al. (RESUS trial)
![Page 28: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/28.jpg)
Brain death and HTx
Systemic Inflammatory Response
Brain Death
NeurohormonalDysfunction +
Haemodynamic Instability
Microvascular Damage
Heart Transplant Outcomes
Cardiac / VascularDamage
![Page 29: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/29.jpg)
Ovine model of BSD-HTx
Animals
Female sheep (45-55 kg)
• 6 x BSD-HTx• 4 x Sham-HTx
Ischaemic Times:
Cold ischaemia: 100 mins
Total ischaemia: 170 mins
Sampling (progressive)
• Blood (arterial and coronary sinus) and urine• Echocardiography• Microcirculation (SDF)• Tissue analyses (mitochondrial assessment)• Hearts collected at end 24 hrs BSD/SHAM
OR ≥ 6 hrs off CPB
![Page 30: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/30.jpg)
Assessing Mitochondrial Function
Sample Collection: 3 x Needle Biopsies
Pooled tissue homogenisation
Functional Assays:
1. Respiration utilising carbohydrates (CHO)
2. Respiration utilising fatty acids
Basal
Lateral
Apical
![Page 31: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/31.jpg)
Cardiac mitochondrial respiration in
BSD and HTx
HR SHAM BSD SHAM HTx BSD HTx
-0.1
0.0
0.1
0.2
0.3
Right Ventricular Leak RespirationFlux Control Ratio (max normalisation)
Leak F
lux C
on
tro
l R
ati
o *
• Post-HTx BD hearts:
• Significantly higher LEAK
for CHO substrates
Preliminary data courtesy of Matthew Wells
Elevated oxygen consumption
that does not contribute to
energy production
(ROS production)
![Page 32: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/32.jpg)
Cardiac mitochondrial respiration in
BSD and HTx
HR SHAM BSD SHAM HTx BSD HTx
-0.5
0.0
0.5
1.0
1.5
Right Ventricular ETS Coupling Efficiency
Co
up
lin
g E
ffic
ien
cy
*
LEAK + Poor ETS Capacity = Mitochondrial Dysfunction = impaired cardiac performance
• Post-Tx BD hearts:
Significantly lower ETS
efficiency for CHO
substrates
Preliminary data courtesy of Matthew Wells
![Page 33: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/33.jpg)
ASIC1a- opens MPT and Induces inflammation and Apoptosis
Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor of ASIC1a
Hi1a is highly stable in blood and cerebrospinal fluid
Hi1a known to protect the brain - 60% reduction in Stroke size given upto 6 hrs
Fraser island
funnel-web spider
We have now shown that it also protects cardiac tissue
Preliminary data courtesy of Matthew Wells
![Page 34: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/34.jpg)
Improved left ventricular developed pressure
Reactive hyperemia Decreased end-diastolic pressure
Hi1a protects whole organ viability after ischemia
reperfusion injury in Langendorff retrograde perfused
mouse hearts
Preliminary data courtesy of Meredith Redd
![Page 35: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/35.jpg)
ASIC1a inhibition prevents hiPSC death during ischemic/acidosis in vitro
Preliminary data courtesy of Dr Meredith Redd
![Page 36: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/36.jpg)
CACNA1
ASIC1a ?
ASIC1a inhibition prevents pH induced elevated
intracellular calcium
[schematic adapted
from Hu et. al.] 2
High-throughput
calcium imaging with
real time drug
addition and pH
stimulus
Preliminary data courtesy of Dr Meredith Redd
![Page 37: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/37.jpg)
Conclusions • Mit importance seems biphasic – cause and effect
• Adaptive vs Maladaptive
• Improved miotchondrial function generally associated with better outcomes
• Has general and organ specific effects
• Potential game changers may include cardiac Rx
![Page 38: Mitochondria , Sepsis and - criticalcarecanada.com · ASIC1a- opens MPT and Induces inflammation and Apoptosis Peptide Hi1a from funnel-web spider venom is the most potent known inhibitor](https://reader034.fdocuments.us/reader034/viewer/2022042320/5f09f1497e708231d4293f62/html5/thumbnails/38.jpg)
Thanks
Donald and Joan Wilson Foundation