Systemic inflammation impairs respiratory chemoreflexes and plasticity

Denne studien beskriver hvordan systemisk betennelse påvirker pustefunksjonen og gjør at det blir vanskeligere å endre pustemønser, f.eks. å gjøre pusteøvelser, eller å tilpasse pusten til aktivitetsnivå. Spesielt den kjemiske og motoriske delen av pustefysiologien blir dårligere. Noe som viser seg i laver CO2 sensitivitet (kjemisk) og svakere pustemuskler (Motorisk).

Nevner spesielt at det er mikroglia celler i CNS som påvirkes av betennelse, og som kan oppretthodle betennelse siden de sender ut cytokiner, m.m. Astrosytter kan også bidra mye siden de aktiverer NFkB. Den gode nyheten her er at økt CO2 nedregulerer NFkB. TLR-4 (Toll-like receptor) aktiveres av patogener og problemer i cellene, og aktiverer NFkB, og nedreguleres av økt CO2.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3172820/

Abstract

Many lung and central nervous system disorders require robust and appropriate physiological responses to assure adequate breathing. Factors undermining the efficacy of ventilatory control will diminish the ability to compensate for pathology, threatening life itself. Although most of these same disorders are associated with systemic and/or neuroinflammation, and inflammation affects neural function, we are only beginning to understand interactions between inflammation and any aspect of ventilatory control (e.g. sensory receptors, rhythm generation, chemoreflexes, plasticity). Here we review available evidence, and present limited new data suggesting that systemic (or neural) inflammation impairs two key elements of ventilatory control: chemoreflexes and respiratory motor (vs. sensory) plasticity. Achieving an understanding of mechanisms whereby inflammation undermines ventilatory control is fundamental since inflammation may diminish the capacity for natural, compensatory responses during pathological states, and the ability to harness respiratory plasticity as a therapeutic strategy in the treatment of devastating breathing disorders, such as during cervical spinal injury or motor neuron disease.

Most lung and CNS disorders are associated with systemic and/or neural inflammation, including chronic lung diseases (Stockley, 2009), traumatic, ischemic and degenerative neural disorders (Teeling and Perry, 2009) and obstructive sleep apnea.

Systemic inflammation affects sensory receptors that modulate breathing, but can also trigger inflammatory responses in the central nervous system (CNS) through complex mechanisms. The primary CNS cells affected during systemic inflammation are microglia, the resident immune cells of the CNS, and astrocytes (Lehnardt, 2010).

Even when in their “resting state,” microglia are highly active, surveying their environment (Raivich, 2005,Parkhurst and Gan, 2010). When confronted with pathological conditions, such as neuronal injury/degeneration or bacterial/viral/fungal infection, they become “activated,” shifting from a stellate, ramified phenotype to an amoeboid shape (Kreutzberg, 1996). Activated microglia can be phagocytic, or they can release toxic and protective factors, including cytokines, prostaglandins, nitric oxide or neurotrophic factors (e.g. BDNF) (Kreutzberg, 1996Graeber, 2010). Despite the importance of microglia in immune function, they are diffuse in the CNS (~70-90% of CNS cells are glia; microglia are ~5-10% of those cells).

Astrocytes, on the other hand, contribute to the overall inflammatory response since they release cytokines, triggering nuclear factor-kappa B (NFκB) signaling elsewhere in the CNS. Further, they express many TLRs, including TLR-4, capable of eliciting an inflammatory response (Li and Stark, 2002Farina et al., 2007,Johann et al., 2008). Given their relative abundance, astrocytes may play a key role in CNS inflammatory responses.

TLR-4 receptors are cytokine family receptors that activate transcription factors, such as NFκB (Lu et al., 2008). NFκB regulates the expression of many inflammatory genes, including: IL-1β, -6 and -18, TNFα, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) (Ricciardolo et al., 2004Nam, 2006). Endogenous molecules known to activate TLR-4 receptors include (but are not limited to) heat shock proteins (specifically HSP60, Ohashi et al., 2000Lehnardt et al., 2008), fibrinogen, surfactant protein-A, fibronectin extra domain A, heparin sulfate, soluble hyaluronan, β-defensin 2 and HMGB1 (Chen et al., 2007).

The role of inflammation (and specifically microglia) in chronic pain has been studied extensively (reviewed in Woolf and Salter, 2000Trang et al., 2006Mika, 2008Abbadie et al., 2009Baumbauer et al., 2009). A remarkable story has emerged, demonstrating the interplay between neurons, microglia, inflammation and plasticity in this spinal sensory system. In short, inflammation induces both peripheral and central sensitization, leading to allodynia (hypersensitivity to otherwise non-painful stimuli) and hyperalgesia (exaggerated or prolonged responses to a noxious stimulus) (Mika, 2008).

An important aspect of ventilatory control susceptible to inflammatory modulation is the chemoreflex control of breathing. Chemoreflexes are critical for maintaining homeostasis of arterial blood gases viaclassical negative feedback (Mitchell et al., 2009), or acting as “teachers” that induce plasticity in the respiratory control system (Mitchell and Johnson, 2003). Major chemoreflexes include the hypoxic (Powell et al., 1998) and hypercapnic ventilatory responses (Nattie, 2001), arising predominantly from the peripheral arterial and central chemoreceptors (Lahiri and Forster, 2003).

To date, no studies have reported the impact of systemic inflammation on hypercapnic responses. However, increased CO2 suppresses NFκB activation, possibly suppressing inflammatory gene expression (Taylor and Cummins, 2011). In fact, hypercapnia has been used to treat ischemia/reperfusion injury to decrease inflammation and reduce lung tissue damage (Laffey et al., 2000O’Croinin et al., 2005Curley et al., 2010Li et al., 2010).

Further work concerning the influence of systemic inflammation on hypercapnic ventilatory responses is warranted, particularly since impaired CO2 chemoreflexes would allow greater hypercapnia and minimize the ongoing inflammation; in this sense, impaired hypercapnic ventilatory responses during inflammation may (in part) be adaptive.

Hypocapnia in patients with chronic neck pain: association with pain, muscle function, and psychologic states.

Nevner at hypokapni (lav CO2) er assosiert med smerte.

http://www.ncbi.nlm.nih.gov/pubmed/23958733

OBJECTIVE:

The aim of this study was to investigate whether patients with chronic neck pain have changes in their transcutaneous partial pressure of arterial carbon dioxide (PtcCO2) and whether other physical and psychologic parameters are associated.

DESIGN:

In this cross-sectional study, 45 patients with chronic idiopathic neck pain and 45 healthy sex-, age-, height-, and weight-matched controls were voluntarily recruited. The participants’ neck muscle strength, endurance of the deep neck flexors, neck range of movement, forward head posture, psychologic states (anxiety, depression, kinesiophobia, and catastrophizing), disability, and pain were assessed. PtcCO2 was assessed using transcutaneous blood gas monitoring.

RESULTS:

The patients with chronic neck pain presented significantly reduced PtcCO2 (P < 0.01). In the patients, PtcCO2 was significantly correlated with strength of the neck muscles, endurance of the deep neck flexors, kinesiophobia, catastrophizing, and pain intensity (P < 0.05). Pain intensity, endurance of the deep neck flexors, and kinesiophobia remained as significant predictors into the regression model of PtcCO2.

CONCLUSIONS:

Patients with chronic neck pain present with reduced PtcCO2, which can reach the limits of hypocapnia. This disturbance seems to be associated with physical and psychologic manifestations of neck pain. These findings can have a great impact on various clinical aspects, notably, patient assessment, rehabilitation, and drug prescription.

Differential blood flow responses to CO2 in human internal and external carotid and vertebral arteries

Denne viser hvordan CO2-responsen er litt forskjellige i forskjellige blodkar. Den er sterkere i blodkar inni hjernen enn i blodkar i kraniet, ansiktet og ryggraden. Blodkar i ryggraden har større respons enn blodkar i ansiktet, men mindre respons enn blodkar i hjernen.

http://jp.physoc.org/content/590/14/3277.long

Because of methodological limitations, almost all previous studies have evaluated the response of mean blood flow velocity (Vmean) in the middle cerebral artery (MCA) to changes in CO2 as a measure of CO2 reactivity across the whole brain (Aaslid et al. 1989Ainslie & Duffin, 2009Ainslie & Ogoh, 2009).

 

ICA, VA and BA CO2 reactivity was significantly higher during hypercapnia than during hypocapnia (ICA, P < 0.01; VA, P < 0.05; BA, P < 0.05), but ECA and MCA were not significantly different.

The major finding from the present study was that cerebral CO2 reactivity was significantly lower in the VA and its distal artery (BA) than in the ICA and its distal artery (MCA). These findings indicate that vertebro-basilar circulation has lower CO2 reactivity than internal carotid circulation. Our second major finding was that ECA blood flow was unresponsive to hypocapnia and hypercapnia, suggesting that CO2 reactivity of the external carotid circulation is markedly diminished compared to that of the cerebral circulation. These findings suggest that different CO2 reactivity may explain differences in CBF responses to physiological conditions (i.e. dynamic exercise and orthostatic stress) across areas in the brain and/or head.

Hypercapnic cerebral CO2 reactivity in global CBF was greater than the hypocapnic reactivity (Ide et al. 2003) (Table 3). The mechanisms underlying this greater reactivity to hypercapnia compared with hypocapnia may be related to a greater influence of vasodilator mediators on intracranial vascular tone compared with vasoconstrictive mediators (Toda & Okamura, 1998Ainslie & Duffin, 2009). In humans, Peebles et al.(2008) recently reported that, during hypercapnia, there is a large release of nitric oxide (NO) from the brain, whereas this response was absent during hypocapnia.

The difference in CO2 reactivity between vertebro-basilar territories (VA and BA) and the cerebral cortex (ICA and MCA) may be due to diverse characteristics of vasculature, e.g. regional microvascular density (Sato et al. 1984), basal vascular tone (Ackerman, 1973Haubrich et al. 2004Reinhard et al. 2008), autonomic innervation (Edvinsson et al. 1976Hamel et al. 1988) and regional heterogeneity in ion channels or production of NO (Iadecola & Zhang, 1994Gotoh et al. 2001).

Interestingly, the response of the ECA to changes in CO2 may be similar to other peripheral arteries. It has long been appreciated that the vasodilatory effect of hypercapnia is much more profound in cerebral than in peripheral vasculature, particularly leg (Lennox & Gibbs, 1932Ainslie et al. 2005) and brachial arteries (Miyazaki, 1973). These findings suggest that control of CO2 is particularly important in the cerebral circulation. The high resting metabolic requirements of the brain, compared with that of other vasculature, might be one reason why this circulatory arrangement is desirable (Ainslie et al. 2005). Specifically, high CO2 reactivity may be a way for the brain to match metabolism with flow (Ainslie et al. 2005).

Lower CO2reactivity in the vertebro-basilar system may be important for maintaining central respiratory function because Graphic in central chemoreceptors is regulated by Graphic and blood flow to maintain breathing stability.

In summary, our study shows that cerebral CO2 reactivity in the vertebro-basilar circulation is lower than that in the internal carotid circulation, while CO2 reactivity in the external carotid circulation is much lower compared with two other cerebral arteries. These findings indicate a difference in cerebral CO2 reactivity between different circulatory areas in the brain and head, which may explain different CBF responses to physiological stress. Lower CO2 reactivity in the vertebro-basilar system may be beneficial for preserving blood flow to the medulla oblongata to maintain vital systemic functions, while higher CO2 reactivity in the internal carotid system may imply a larger tolerance for varied blood flow in the cerebral cortex.

Morning attenuation in cerebrovascular CO2 reactivity in healthy humans is associated with a lowered cerebral oxygenation and an augmented ventilatory response to CO2

Denne beskriver hvordan blodkarenes respons på CO2 er dårligere om morgenen, og det er derfor det skjer flere slag og slikt om morgenen. Den nevner mange interessante prinsipper. Bl.a. at lavere vasomotor respons (på CO2) gir mindre oksygen til hjernen. Og at i opptil 20 sekunder etter en 20 sekunder holdning av pust (etter utpust) øker fortsatt oksygenmengden og blodgjennomstrømningen i hjernen. Nevner også at siden blodkarene i hjernen reagerer dårligere på CO2 om morgenen blir det lett at pusten over- eller underkompenserer, så pustemønsteret blir uregelmessig om morgenen. Spesielt om man har underliggende faremomenter som hjerte/karsykdommer.

http://jap.physiology.org/content/102/5/1891

 

Furthermore, our results suggest that morning cerebral tissue oxygenation might be reduced as a result of a decreased cerebrovascular responsiveness to CO2 or other factors, leading to a higher level of desaturation.

Our data indicate that the cerebrovascular reactivity to CO2 in healthy subjects is significantly reduced in the morning and is strongly associated with an augmented ventilatory response to CO2. It is likely that this reduction in MCAV CO2 reactivity, by reducing blood flow through medullary respiratory control centers, increases both the arterial-brain tissue PCO2 difference and the H+ concentration presented to the central chemoreceptor(s) (1144). In effect, it appears the brain tissue is more susceptible in the morning to changes in arterial PCO2, which could increase the likelihood of ventilatory overshoots and undershoots.

However, as was the case with the hypercapnic challenge, subjects holding their breath in the morning experienced a significantly blunted increase in MCAV compared with evening, likely a result of a reduced cerebrovascular responsiveness to CO2.

In conclusion, our results suggest that early morning reductions in cerebrovascular CO2 reactivity strongly influence the magnitude of the ventilatory response to CO2. This may have significant implications for breathing stability, increasing the chances of periodic breathing in the morning in patients with additional risk factors. The early morning reduction in cerebral oxygenation with hypercapnic challenge, mild hypoxemia, or during apnea may be a contributing factor in the high prevalence of early morning stroke. Whether differences in the responses of CBF, oxygenation, or V̇E to CO2challenge are associated with other risk factors for stroke, such as gender or age, remains to be elucidated.

CO2-beriket vann til fotbad

Å bade i CO2 beriket vann har vært brukt som medisin i alle år. Hellige og mirkauløse kilder har ofter vært vann med et høyt innhold av karbondioksid. Og det har blitt brukt i spa behandling i århundrer, spesielt i Bulgaria. Man finner Co2-rikt vann spesielt ved sovende og inaktive vulkaner.

CO2 er et veldig lite molekyl som diffunderer lett igjennom huden. I CO2-beriket vann kommer derfor CO2 inn i huden og inn til blodkarene i underhuden, hvor alle sansenerver ligger. Den økte CO2 en gjør at blodkarene rundt nervetrådene og i muskelvevet utvides (vasodilasjon) og at oksygene letter hopper av blodcellene slik at det kan bli brukt til energi i celler som vanligvis har lite tilgang på oksygen.

CO2 beriket vann kan vi lage selv på en svært enkel måte: blande Natron, Sitronsyre og vann. Begge disse stoffene fåes kjøpt på vanlig daglivarebutikk. Vannet begynner å bruse, og dette er CO2.

Studier nevner at man bør ha 900-1200 mg CO2 pr liter vann. Ved å måle pH kan vi regne med at vi har det når pH er nede på 5.

Vi kan se CO2 effekten på huden ved at det kommer tett-i-tett med ørsmå bobler. I f.eks. fotbad vil vi se at når vi tar foten opp fra vannet så er den rød, noe som er et tegn på økt blodsirkulasjon i huden.

For alle med nevropatier, diabetes, sår, nevromer, leggspenninger, restless leg syndrom, som lett blir sliten i bena av å gå, så vil dette være verdt et forsøk.

2-3 ganger i uka pleier å være den vanlige oppskriften. Noen studier har brukt det hver dag i mange uker. Spesielt når det gjelder diabetes sår.

Oppskrift: Bland 1 poseNatron med 2 poser Sitronsyre (blandingsforhold ca. 1:1) og hell innholdet i 5L vann. Det bruser veldig pga reaksjonen som lager CO2. Når du setter føttene nedi skal det komme mange små bobler som dekker huden. Etter 5-10 minutter vil huden som er under vann bli rød. Dette er et tegn på økt blodsirkulasjon.

5-15 minutter etter du er ferdig med fotbadet vil du sannsynligvis kjenne det prikker og strømmer ellers i kroppen også. Vanligvis kjennes det først og fremst i armer og bein, som er de stedene vi lettest kjenner økt blodsirkulasjon.

Her er noen studier som bekrefter effektene av CO2 beriket vann.

Beskriver det meste om balneotherapy, som det også heter. Inkludert kontraindikasjoner(hjerteproblemer og hypercapni som følge av lungeskade): http://www.centro-lavalle.com/edu/wp-content/uploads/2010/05/Carbon_Dioxide_Bath.pdf

Table 4. Major Indicators for CO2 Balneotherapy

1. Hypertension, especially borderline hypertension

2. Arteriolar occlusion, Stages I and II

3. Functional arteriolar blood flow disorders

4. Microcirculatory disorders

5. Functional disorders of the heart

Beskriver alt om hvordan det øker blodsirkulasjon og oksygenmetning: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3169585/?report=classic

Viser at det øker blodsirkulasjonen i huden og oksygenmetningen i muskelvev hos de som lett blir trøtte i beina: http://www.ncbi.nlm.nih.gov/pubmed/9112881/

Viser at det øker blodsirkulasjon og produksjonen av blodkar (angiogenese): http://circ.ahajournals.org/content/111/12/1523.long

Viser at det reparerer sår som ikke vil gro: http://iv.iiarjournals.org/content/24/2/223.long

Viser at det reparerer muskelskade: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3805014/

Viser at det reparerer muskelskade og atrofi (muskelsvikt) etter langtids post-operative sengeliggende: http://www.ncbi.nlm.nih.gov/pubmed/21371433

Viser at det reduserer hjertefrekvens gjennom å dempe sympaticus aktivering (ikke ved å øke parasymptaticus aktivering): http://jap.physiology.org/content/96/1/226

Viser at det øker mitokondrier og fjerner syster: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3499556/

Viser at det øker antioksidant status, reduserer frie radikaler og øker blodsirkulasjon i kapuillærene (mikrosirkulasjon): http://www.ncbi.nlm.nih.gov/pubmed/21248668

Viser at det hjelper til å reparere sår etter operasjon: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3595724/

Dr. Sircus sin forklaring av CO2 medisin som nevner mange måter å gjøre det på: http://drsircus.com/medicine/co2-medicine-bath-bombing-your-way-to-health

Denne artikkelen beskriver mye om historien til CO2-bad. http://ndnr.com/dermatology/cellulite-and-carbon-dioxide-bath/

Mange bilder av diabetes sår (OBS: ikke for sarte sjeler) som blir regenerert i løpet av få uker med 20-30 min fotbad. Disse bruker 900-1000ppm CO2 konsentrasjon. Jeg er usikker på om det er mulig med å blande Sitronsyre og Natron: http://www.iasj.net/iasj?func=fulltext&aId=48581

Denne artikkelen beskriver de fleste sider ved forskjellig bruk av CO2 behandling. God gjennomgang av hvordan blodsirkluasjonen påvirkes. http://www.scuolaeuropeamedicinaestetica.it/public/CARBOXYTHERAPY.pdf

Bench-to-bedside review: Permissive hypercapnia

Nevner veldig mye rundt hva hyperkapni kan brukes til i klinisk sammenheng, men spesielt interessant er kapittelet om hvordan det reduserer oksidativt stress, som forklarer godt og omfattende dette prinsippet.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1065087/

Effects on free radical generation and activity

Hypercapnic acidosis appears to attenuate free radical production and modulate free radical induced tissue damage. In common with most biological enzymes, the enzymes that produce these oxidizing agents function optimally at neutral physiological pH levels. Oxidant generation by both basal and stimulated neutrophils appears to be regulated by ambient carbon dioxide levels, with oxidant generation reduced by hypercapnia and increased by hypocapnia [54]. The production of superoxide by stimulated neutrophils in vitro is decreased at acidic pH [6567]. In the brain, hypercapnic acidosis attenuates glutathione depletion and lipid peroxidation, which are indices of oxidant stress [39]. In the lung, hypercapnic acidosis has been demonstrated to reduce free radical tissue injury following pulmonary ischaemia/ reperfusion [27]. Hypercapnic acidosis appears to attenuate the production of higher oxides of nitric oxide, such as nitrite and nitrate, following both ventilator-induced [26] and endotoxin-induced [29] ALI. Hypercapnic acidosis inhibits ALI mediated by xanthine oxidase, a complex enzyme system produced in increased amounts during periods of tissue injury, which is a potent source of free radicals [68] in the isolated lung [24]. In in vitro studies the enzymatic activity of xanthine oxidase was potently decreased by acidosis, particularly hypercapnic acidosis [24,25].

Concerns exist regarding the potential for hypercapnia to potentiate tissue nitration by peroxynitrite, a potent free radical. Peroxynitrite is produced in vivo largely by the reaction of nitric oxide with superoxide radical, and causes tissue damage by oxidizing a variety of biomolecules and by nitrating phenolic amino acid residues in proteins [6973]. The potential for hypercapnia to promote the formation of nitration products from peroxynitrite has been clearly demonstrated in recent in vitroexperiments [45,51]. However, the potential for hypercapnia to promote nitration of lung tissue in vivoappears to depend on the injury process. Hypercapnic acidosis decreased tissue nitration following pulmonary ischaemia/reperfusion-induced ALI [27], but it increased nitration following endotoxin-induced lung injury [29].