scholarly journals Remote ischemic preconditioning for prevention of high-altitude diseases: fact or fiction?

2015 ◽  
Vol 119 (10) ◽  
pp. 1143-1151 ◽  
Author(s):  
Marc Moritz Berger ◽  
Franziska Macholz ◽  
Heimo Mairbäurl ◽  
Peter Bärtsch
Keyword(s):  
High Altitude ◽  
Ischemic Preconditioning ◽  
Ischemia Reperfusion ◽  
Acute Mountain Sickness ◽  
Systolic Pressure ◽  
Hypoxia Tolerance ◽  
Remote Ischemic Preconditioning ◽  
High Altitude Cerebral Edema ◽  
Pulmonary Arterial ◽  
Altitude Tolerance

Preconditioning refers to exposure to brief episodes of potentially adverse stimuli and protects against injury during subsequent exposures. This was first described in the heart, where episodes of ischemia/reperfusion render the myocardium resistant to subsequent ischemic injury, which is likely caused by reactive oxygen species (ROS) and proinflammatory processes. Protection of the heart was also found when preconditioning was performed in an organ different from the target, which is called remote ischemic preconditioning (RIPC). The mechanisms causing protection seem to include stimulation of nitric oxide (NO) synthase, increase in antioxidant enzymes, and downregulation of proinflammatory cytokines. These pathways are also thought to play a role in high-altitude diseases: high-altitude pulmonary edema (HAPE) is associated with decreased bioavailability of NO and increased generation of ROS, whereas mechanisms causing acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) seem to involve cytotoxic effects by ROS and inflammation. Based on these apparent similarities between ischemic damage and AMS, HACE, and HAPE, it is reasonable to assume that RIPC might be protective and improve altitude tolerance. In studies addressing high-altitude/hypoxia tolerance, RIPC has been shown to decrease pulmonary arterial systolic pressure in normobaric hypoxia (13% O2) and at high altitude (4,342 m). Our own results indicate that RIPC transiently decreases the severity of AMS at 12% O2. Thus preliminary studies show some benefit, but clearly, further experiments to establish the efficacy and potential mechanism of RIPC are needed.

scholarly journals Remote ischemic preconditioning does not prevent acute mountain sickness after rapid ascent to 3,450 m

2017 ◽  
Vol 123 (5) ◽  
pp. 1228-1234 ◽  
Author(s):  
Marc M. Berger ◽  
Franziska Macholz ◽  
Lukas Lehmann ◽  
Daniel Dankl ◽  
Marcel Hochreiter ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
High Altitude ◽  
Ischemic Preconditioning ◽  
Acute Mountain Sickness ◽  
Remote Ischemic Preconditioning ◽  
Systolic Pulmonary Artery Pressure ◽  
Transthoracic Doppler Echocardiography ◽  
Rapid Ascent ◽  
Mountain Sickness ◽  
The Brain

Remote ischemic preconditioning (RIPC) has been shown to protect remote organs, such as the brain and the lung, from damage induced by subsequent hypoxia or ischemia. Acute mountain sickness (AMS) is a syndrome of nonspecific neurologic symptoms and in high-altitude pulmonary edema excessive hypoxic pulmonary vasoconstriction (HPV) plays a pivotal role. We hypothesized that RIPC protects the brain from AMS and attenuates the magnitude of HPV after rapid ascent to 3,450 m. Forty nonacclimatized volunteers were randomized into two groups. At low altitude (750 m) the RIPC group ( n = 20) underwent 4 × 5 min of lower-limb ischemia (induced by inflation of bilateral thigh cuffs to 200 mmHg) followed by 5 min of reperfusion. The control group ( n = 20) underwent a sham protocol (4 × 5 min of bilateral thigh cuff inflation to 20 mmHg). Thereafter, participants ascended to 3,450 m by train over 2 h and stayed there for 48 h. AMS was evaluated by the Lake Louise score (LLS) and the AMS-C score. Systolic pulmonary artery pressure (SPAP) was assessed by transthoracic Doppler echocardiography. RIPC had no effect on the overall incidence (RIPC: 35%, control: 35%, P = 1.0) and severity (RIPC vs. control: P = 0.496 for LLS; P = 0.320 for AMS-C score) of AMS. RIPC also had no significant effect on SPAP [maximum after 10 h at high altitude; RIPC: 33 (SD 8) mmHg; controls: 37 (SD 7) mmHg; P = 0.19]. This study indicates that RIPC, performed immediately before passive ascent to 3,450 m, does not attenuate AMS and the magnitude of high-altitude pulmonary hypertension. NEW & NOTEWORTHY Remote ischemic preconditioning (RIPC) has been reported to improve neurologic and pulmonary outcome following an acute ischemic or hypoxic insult, yet the effect of RIPC for protecting from high-altitude diseases remains to be determined. The present study shows that RIPC, performed immediately before passive ascent to 3,450 m, does not attenuate acute mountain sickness and the degree of high-altitude pulmonary hypertension. Therefore, RIPC cannot be recommended for prevention of high-altitude diseases.

Exploring the Role of Remote Ischemic Preconditioning In Long Term Cognitive Impairment after Global Ischemia-Reperfusion-Induced Vascular Dementia in Mice

2020 ◽  
Author(s):  
Amteshwar Singh Jaggi
Keyword(s):  
Cognitive Impairment ◽  
Cerebral Ischemia ◽  
Vascular Dementia ◽  
Ischemic Preconditioning ◽  
Ischemia Reperfusion ◽  
Remote Ischemic Preconditioning ◽  
Global Cerebral Ischemia ◽  
Cerebral Ischemic ◽  
The Brain

Aim: The aim of the present study is to explore the neuroprotective effects of remote ischemic preconditioning in long term cognitive impairment after global cerebral ischemia induced-vascular dementia in mice. Material and methods: The mice were subjected to global cerebral ischemia by occluding the bilateral common carotid arteries for 12 minutes followed by the 24 hours of the reperfusion. The remote ischemic preconditioning stimulus was delivered in the form of 4 cycles of ischemia/reperfusion for 5 minutes each. The cerebral ischemic injury induced-long term cognitive impairment-related learning and memory alterations was assessed using morris water maze, the motor performances of the animals were evaluated using rota-rod test and neurological severity score. The cerebral infract size of the brain were quantified using triphenyltetrazolium chloride staining. Results: Global cerebral ischemia causes long term memory impairment, decreases motor performances and increases the brain infract size in animals. The delivery of remote ischemic preconditioning stimulus significantly abolished the long-term cognitive impairment and ameliorates the motor performances as well as cerebral infract size in brain. Conclusion: The remote ischemic preconditioning mediates neuro protection against global cerebral ischemic injury induced long-term cognitive impairment.

scholarly journals Alternative Interventions to Prevent Oxidative Damage following Ischemia/Reperfusion

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Simón Quetzalcoatl Rodríguez-Lara ◽  
Ernesto German Cardona-Muñoz ◽  
Ernesto Javier Ramírez-Lizardo ◽  
Sylvia Elena Totsuka-Sutto ◽  
Araceli Castillo-Romero ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Oxidative Damage ◽  
Ischemic Preconditioning ◽  
Ischemia Reperfusion ◽  
Remote Ischemic Preconditioning ◽  
Therapeutic Approaches ◽  
Alternative Interventions ◽  
Stress States ◽  
The Relationship ◽  
Irreparable Damage

Ischemia/reperfusion (I/R) lesions are a phenomenon that occurs in multiple pathological states and results in a series of events that end in irreparable damage that severely affects the recovery and health of patients. The principal therapeutic approaches include preconditioning, postconditioning, and remote ischemic preconditioning, which when used separately do not have a great impact on patient mortality or prognosis. Oxidative stress is known to contribute to the damage caused by I/R; however, there are no pharmacological approaches to limit or prevent this. Here, we explain the relationship between I/R and the oxidative stress process and describe some pharmacological options that may target oxidative stress-states.

Hormonal changes in normal and polycythemic high-altitude natives

1995 ◽  
Vol 79 (3) ◽  
pp. 795-800 ◽  
Author(s):  
A. M. Antezana ◽  
J. P. Richalet ◽  
I. Noriega ◽  
M. Galarza ◽  
G. Antezana
Keyword(s):  
High Altitude ◽  
Systolic Pressure ◽  
Plasma Aldosterone ◽  
Control Group ◽  
Protective Mechanism ◽  
Hormonal Changes ◽  
Plasma Aldosterone Concentration ◽  
Pulmonary Arterial ◽  
Exercise Induced ◽  
Acute And Chronic Exposure

Acute and chronic exposure to high-altitude (HA) hypoxia inhibits the renin-angiotensin-aldosterone system and may modify the release of atrial natriuretic peptide (ANP) in sea-level (SL) natives. In HA natives, the release of these hormones could be influenced by changes in blood volume or pulmonary arterial pressure. Twenty-four men residing in La Paz, Bolivia, at 3,600 m were separated into two groups: one normocythemic (HAN; with hematocrit < 57%; n = 13) and the other polycythemic (HAP; with hematocrit > 57%; n = 11). A control group of 9 SL residents was studied in normoxia (SLN) as well as after 4 days spent at 4,350 m (SLH). The groups were tested for plasma active renin (PAR), plasma aldosterone concentration, ANP, and potassium and norepineprine concentrations at rest and after a maximal exercise. Pulmonary arterial systolic pressure was assessed by a Doppler technique. It was observed that PAR and plasma aldosterone concentration at rest and after exercise were lower in the SLH than in the SLN group. PAR and norepineprine concentration were higher among highlanders than in the SLN group. Renin response to exercise was normal among the HAN group and slightly decreased among the HAP group, and an exercise-induced increase in aldosterone was attenuated in both HA groups. Aldosterone response to renin was maintained among the SLH group but was attenuated in the HA groups, possibly owing to a protective mechanism against salt and water retention. Resting and exercise ANP was lower in the HA groups than in the SLN group.

Remote Ischemic Preconditioning Protects Against Endothelial Dysfunction in a Human Model of Systemic Inflammation: A Randomized Clinical Trial

2021 ◽  
Author(s):  
Marco Orlandi ◽  
Stefano Masi ◽  
Devina Bhowruth ◽  
Yago Leira ◽  
Georgios Georgiopoulos ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endothelial Dysfunction ◽  
Systemic Inflammation ◽  
Ischemic Preconditioning ◽  
Ischemia Reperfusion ◽  
Remote Ischemic Preconditioning ◽  
Human Model ◽  
Control Group ◽  
Flow Mediated Dilatation ◽  
And Oxidative Stress

Objective: Inflammation, oxidative stress, and endothelial dysfunction are known to contribute to ischemia-reperfusion injury. Remote ischemic preconditioning (RIPC) protects from endothelial dysfunction and the damage induced by ischemia-reperfusion. Using intensive periodontal treatment (IPT), an established human model of acute systemic inflammation, we investigated whether RIPC prevents endothelial dysfunction and modulates systemic levels of inflammation and oxidative stress. Approach and Results: Forty-nine participants with periodontitis were randomly allocated to receive either 3 cycles of ischemia-reperfusion on the upper limb (N=25, RIPC) or a sham procedure (N=24, control) before IPT. Endothelial function assessed by flow-mediated dilatation of the brachial artery, inflammatory cytokines, markers of vascular injury, and oxidative stress were evaluated at baseline, day 1, and day 7 after IPT. Twenty-four hours post-IPT, the RIPC group had lower levels of IL (interleukin)-10 and IL-12 compared with the control group ( P <0.05). RIPC attenuated the IPT-induced increase in IL-1β, E-selectin, sICAM-3 (soluble intercellular adhesion molecule 3), and s-thrombomodulin levels between the baseline and day 1 ( P for interaction <0.1). Conversely, oxidative stress was differentially increased at day1 in the RIPC group compared with the control group ( P for interaction <0.1). This was accompanied by a better flow-mediated dilatation (mean difference 1.75% [95% CI, 0.428–3.07], P =0.011). After 7 days from IPT, most of the inflammatory markers endothelial-dependent and -independent vasodilation were similar between groups. Conclusions: RIPC prevented acute endothelial dysfunction by modulation of inflammation and oxidation processes in patients with periodontitis following exposure to an acute inflammatory stimulus. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03072342.

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