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Physiology internationalVol. 108. No 1. (March, 2021)



  • B. Székács ,
    S. Várbíró ,
    L. Debreczeni :

    DOI: 10.1556/2060.2021.00007

    Abstract: Purpose: We aimed to critically review the available information on the potential contribution of excessive kallikrein-kinin systems (KKSs) activation to severe respiratory inflammation in SARS-CoV-2 infection, and the likely consequence of ACE inhibition in seriously affected patients. Methods: The literature related to the above topic was reviewed including papers that analysed the connections, actions, interactions, consequences and occasionally suggestions for rational interventions. Results/Conclusion: Severe bronchoalveolar inflammation seems to be caused, at least in part, by upregulation of the KKS that increases plasma and/or local tissue concentrations of bradykinin (BK) in patients with COVID-19 infection. Besides KKS activation, suppression of ACE activity results in decreased bradykinin degradation, and these changes in concert can lead to excessive BK B1 and B2 receptor (BKB1R/BKB2R) activation. Aminopeptidase P (APP), and carboxypeptidase N also degrade bradykinin, but their protein expression and activity are unclear in COVID-19 infection. On the other hand, ACE2 expression is upregulated in patients with COVID-19 infection, so ACE2 activity is unlikely to be decreased despite blockade of part of ACE2 by the virus for entry into the cells. ACE2 cleaves lys-des-arginine9BK and arg-des-arginine9BK, the active metabolites of bradykinin, which stimulate the BKB1R receptor. Stimulation of BKB1R/BKB2R can exacerbate the pulmonary inflammatory response by causing vascular leakage and edema, vasodilation, smooth muscle spasm and stimulation of pain afferent nerves. Despite all uncertainties, it seems rational to treat comorbid COVID patients with serious respiratory distress syndrome with ARBs instead of high-dose ACE inhibitor (ACEi) that will further decrease bradykinin degradation and enhance BKB1R/BKB2R activation, but ACEi may not be contraindicated in patients with mild pulmonary symptoms.

    Keywords: COVID-19, cardiovascular, respiratory inflammation, RAS, ACE2, kallikrein-kinin system, bradykinin, ACE-inhibitor, angiotensin receptor blocker, old patient, hypertension

  • G. Xantus ,
    P. Allen ,
    P. Kanizsai :

    DOI: 10.1556/2060.2021.00011

    Abstract: In sepsis cytokine-mediated inflammation, clotting cascade activation and glycocalyx shedding impair both function and structure of the microcirculation, compromising adequate tissue oxygenation/perfusion. Such mismatch results in “dysoxia”, an imbalance in mitochondrial respiration. Microvessel injuries can be grouped into four types: cytotoxic oedema, micro-vessel heterogeneity, sluggish/absent flow, and focal anaemia. Recognition of such diversity in microcirculatory pathology, alongside with the implementation of novel biomarkers might reveal previously unobserved heterogeneity in adults diagnosed with sepsis. Early identification of distinct subtypes may help not only to better stratify disease severity but may also provide explanation to the often seen insufficient/absent response to resuscitative treatment. Experimental evidence suggests that impaired microcirculatory flow may correlate with organ dysfunction and mortality. Therefore, reliable/reproducible diagnostic tools, that provide real-time information about the dynamic state of the microcirculation, might be practice changers in managing the critically ill. The sublingual mucosa and the nailfolds provide easy access to microcirculation via hand-held, pointof- care devices. Accessing these windows, clinicians may recognise, understand and potentially correct the underlying tissue oxygenation/perfusion mismatch. This new clinical information might facilitate an individualised approach vs protocolised care aiming to administer the right balance of intravenous fluids/ vasopressors, time/dose auxiliary treatment modalities and, most importantly, might also guide determining the optimal duration of resuscitation to avoid/minimise harm and maximise benefits in sepsis management. However, before every-day clinical use of such point-of-care microcameras, validation studies are needed to establish not only feasibility but reliability and reproducibility as well.

Original papers - Animal experiment

  • F. Ahmadabadi ,
    M. Saghebjoo ,
    M. Hedayati ,
    R. Hoshyar ,
    C.-J. Huang :

    DOI: 10.1556/2060.2021.00009

    Abstract: This study was to investigate whether high-intensity interval training (HIIT) and saffron aqueous extract (SAE) would provide a synergistic effect to improve tumor volume reduction and also modulate pro- and anti-apoptotic protein expression in tumor tissue of 4T1 breast cancer-bearing mice. Female mice following induction of breast cancer through injection of 4T1 cell lines were randomly divided into four groups: (1) HIIT, (2) SAE, (3) HIIT+SAE, and (4) control. The tumor volume was significantly lower in the HIIT, SAE, and HIIT+SAE groups than in the controls. The protein level of caspase-3 in the HIIT and the SAE groups was higher than in the control and the HIIT+SAE groups. The Bax protein level in the SAE group was higher than in the control. The HIIT+SAE group showed a lower level of Bax than the HIIT and the SAE groups. The protein level of Bcl-2 was higher in the HIIT+SAE vs. both the HIIT and the SAE groups. Finally, the ratio of Bax/Bcl-2 was significantly higher in the HIIT and the SAE groups than in the HIIT+SAE and control groups. These findings indicate that a combination of HIIT and SAE interventions does not improve the apoptotic induction in tumor tissue, while both HIIT and SAE treatments may

    Keywords: exercise, high-intensity interval training, Crocus Sativus L. extract, caspase-3, Bax/Bcl-2, apoptosis, breast cancer

  • N. Almási ,
    Z. Murlasits ,
    A. Al-awar ,
    Á. Csonka ,
    S. Dvorácskó ,
    C. Tömböly ,
    S. Török ,
    D. Bester ,
    A. Pósa ,
    C. Varga ,
    K. Kupai :

    DOI: 10.1556/2060.2021.00012

    Abstract: Aging is a multifactorial process, which is considered as a decline over time. It is increasingly clear that there is a gender difference in aging and in the prevalence of age-related diseases as well. We aimed to examine the effects of the aging process in the colonic tissue of female Wistar rats aged 10 weeks (young) and 13 months (middle-aged) at an early stage, according to three main symptoms associated with aging: a decrease in the efficacy of the proteasome and muscle function and an increase in oxidative stress. The aging process was found to cause a significant decrease in ubiquitin C-terminal hydrolase ligase (UCHL-1) and a significant increase in 3-nitrotyrosine (3-NT), total glutathione (GSH), calcium (Ca²⁺), calcitonin gene-related peptide (CGRP) and superoxide dismutase (SOD) activity in middle-aged animals. In summary, it is suggested that the reduced activity of the proteasomal degradation system may be the result of the diminished expression of the UCHL-1 enzyme and the decreased levels of ubiquitin; furthermore, we found some key targets which may help to better understand the fundamental aging process.

    Keywords: aging, UCHL-1, proteasome, oxidative stress, calcium

  • J. Wang ,
    Q. Song :
    Inhibition of connexin 43 induces hearing loss in postnatal mice43-53en [986.78 kB - PDF]EPA-03963-00019-0050

    DOI: 10.1556/2060.2021.00008

    Abstract: Background: Connexin 43 (Cx43) is the most ubiquitously expressed member of the family of connexins, constituting gap junctions and mediating cell communication, still its role in hearing loss has been little studied. Methods: Immunohistochemistry was used to detect the expression pattern of Cx43. Spiral ganglia neurons (SGNs) and Corti co-culture were utilized to assay the re-innervation of hair cells by newborn SGNs. Gap19 was utilized to inhibit Cx43 hemichannels. Auditory brainstem responses (ABR) and endocochlear potential (E.P.) were measured to confirm the hearing loss. Results: The expression of Cx43 in P14 mice was higher than in P0 and P28 (adult) mice, the earlier time point coinciding with the early inner ear development. Additionally, the growth and synapse generation of fibers were inhibited after Gap 19 treatment of the co-cultures of the Corti and SGNs from newborn mice. Furthermore, the inhibition of Cx43 could increase the ABR threshold and decrease E.P. level in postnatal mice, whereas such an effect was not observed in adult mice. Conclusion: The function of Cx43 is critical during the early development of mouse cochlea but is dispensable in adult mice.

    Keywords: connexin 43, hearing-loss, cochlear, spiral ganglia neurons, hair cells

  • Y. Sato ,
    H. Mizuno ,
    N. Matsumoto ,
    Y. Ikegaya :

    DOI: 10.1556/2060.2021.00001

    Abstract: During behavioral states of immobility, sleep, and anesthesia, the hippocampus generates high-frequency oscillations called ripples. Ripples occur simultaneously with synchronous neuronal activity in the neocortex, known as slow waves, and contribute to memory consolidation. During these ripples, various neocortical regions exhibit modulations in spike rates and local field activity irrespective of whether they receive direct synaptic inputs from the hippocampus. However, little is known about the subthreshold dynamics of the membrane potentials of neocortical neurons during ripples. We patch-clamped layer 2/3 pyramidal cells in the posterior parietal cortex (PPC), a neocortical region that is involved in allocentric spatial representation of behavioral exploration and sequential series of relevant action potentials during ripples. We simultaneously monitored the membrane potentials of post hoc-identified PPC neurons and the local field potentials of the hippocampus in anesthetized mice. More than 50% of the recorded PPC neurons exhibited significant depolarizations and/or hyperpolarizations during ripples. Histological inspections of the recorded neurons revealed that the ripple-modulated PPC neurons were distributed in the PPC in a spatially non-biased fashion. These results suggest that hippocampal ripples are widely but selectively associated with the subthreshold dynamics of the membrane potentials of PPC neurons even though there is no monosynaptic connectivity between the hippocampus and the PPC.

    Keywords: hippocampus, membrane potential, whole-cell recording, posterior parietal cortex, ripple

Human studies

  • Á. Haris ,
    K. Polner ,
    J. Arányi ,
    H. Braunitzer ,
    I. Kaszás :

    DOI: 10.1556/2060.2021.00006

    Abstract: Background: Immunosuppressive therapy has improved the outcome of ANCA-associated vasculitis (AAV), but infectious morbidity and mortality remained high. Recognizing its risk factors seems crucial for prevention, aiming to increase survival of these patients. Methods: We investigated the incidence and types of infections and assessed predictive factors in 132 patients with severe systemic AAV. Results: Patients with lower than median incidence of total infections/patient-year during induction had lower baseline serum creatinine, dialysis requirement and Charlson comorbidity index (CCI), compared to those with higher than median incidence (P = 0.037; P = 0.024; P = 0.001; respectively). In subgroups with below and above than median number of severe infections/patient-year during induction, differences were found in baseline creatinine (P = 0.002) and dialysis requirement (P = 0.001); comparing the same cohorts during maintenance immunosuppression, baseline dialysis requirement, diabetes, CCI, and dose of cyclophosphamide (CYC) administered as induction therapy differed significantly (P = 0.019; P = 0.015; P = 0.001; P = 0.015, respectively). Severe infections were predicted by baseline serum creatinine (OR 1.002 [CI 1.001-1.003]) and pulmonary manifestation (OR 2.153 [CI 1.017-4.560]) during induction immunosuppression. In multivariable Cox regression model all-cause mortality was independently predicted by severe infection (HR 1.998 [CI 1.214-3.287]). Among the 168 positive cultures Gram-negative bacteria were responsible for blood stream infections in 33%, and respiratory tract infections in 72%. Conclusions: Advanced renal failure, pulmonary involvement and high degree of comorbidities increase the risk of infection in AAV. Those who suffer infection during induction immunosuppression have worse long-term survival. Our findings indicate the need for high vigilance for infections and close follow-up of comorbidities when treating AAV.

    Keywords: ANCA-associated vasculitis, comorbidity, immunosuppression, infections, mortality, survival

  • L. J. Reynolds ,
    O. A. Vsevolozhskaya ,
    B. B. Rice ,
    N. R. Chavan ,
    A. J. Dugan ,
    H. F. Maddox ,
    J. D. Preston ,
    L. B. DeHoff ,
    J. M. O'Brien ,
    K. J. Pearson :

    DOI: 10.1556/2060.2021.00003

    Abstract: Reducing the risk of developing chronic disease, such as obesity and type 2 diabetes, is an important component of successful aging. Offspring born to mothers who exercise during pregnancy have improved body composition and metabolic profiles. However, mechanisms to explain this phenomenon are lacking. Purpose: This study examined whether maternal step counts were correlated with neonatal gene expression markers related to glucose metabolism and adipogenesis. Methods: Physical activity levels were assessed in women with male neonates via Fitbit Flex® during the second and third trimester of pregnancy. The dartos and epidermal/dermal layers of the foreskin were collected following circumcision in full-term, singleton, neonates (n = 12 dartos and n = 14 dermal). Tissue was homogenized, RNA isolated, and a NanoString code set was run to quantify a panel of genes related to glucose metabolism and adipogenesis. Results: Twelve genes were correlated to steps per day with a P-value of <0.05. After adjusting for multiple comparisons, six genes remained significantly correlated to steps per day (False Discovery Rate-corrected P-value < 0.10). Notably, glucose transporter 1, adiponectin receptor 1, and CCAAT/enhancer-binding protein alpha and beta were positively correlated with steps per day, while peroxisome proliferatoractivated receptor alpha and peroxisome proliferator-activated receptor gamma coactivator 1- alpha were negatively correlated with steps per day. Conclusion: Maternal physical activity is associated with offspring gene expression markers of adipogenesis, insulin sensitivity and glucose uptake. Future studies should aim to mechanistically examine whether these markers are driving increased adiposity in offspring born to sedentary mothers.

    Keywords: exercise, developmental origins of health and disease, gestation, offspring, obesity

  • A. M. Kolonics-Farkas ,
    Z. Kovats ,
    A. Bohacs ,
    B. Odler ,
    K. Benke ,
    B. Agg ,
    Z. Szabolcs ,
    V. Müller :

    DOI: 10.1556/2060.2021.00002

    Abstract: Marfan syndrome is a genetic disorder of the connective tissue, including involvement of the lungs. Pulmonary function test was performed in 32 asymptomatic adult Marfan patients using European Community for Coal and Steel (ECCS) and Global Lung Function Initiative (GLI) reference values. Using GLI equations for reference, significantly lower lung function values were noted for forced vital capacity (FVC) (87.0 ± 16.6% vs. 97.1 ± 16.9%; P < 0.01) and forced expiratory volume in the first second (FEV1) (79.6 ± 18.9% vs. 88.0 ± 19.1%; P < 0.01) predicted compared to ECCS. Obstructive ventilatory pattern was present in 25% of the cases when calculating with GLI lower limit of normal (LLN), and it was significantly more common in men as compared to women (n = 6, 50% vs. n = 2, 10%; P = 0.03). GLI is more suitable to detect early ventilatory changes including airway obstruction in young patients with special anatomic features, and should be used as a standard way of evaluation in asymptomatic Marfan population.

    Keywords: Marfan syndrome, lung function, spirometry, reference values, Global Lung Function Initiative

  • G. Molnár ,
    V. A. Gyarmathy ,
    J. Takács ,
    S. Sándor ,
    B. Kiss ,
    J. Fazakas ,
    P. L. Kanizsai :

    DOI: 10.1556/2060.2021.00005

    Abstract: Objectives: Conditions that have similar initial presentations as sepsis may make early recognition of sepsis in an emergency room (ER) difficult. We investigated whether selected physiologic and metabolic parameters can be reliably used in the emergency department to differentiate sepsis from other disease states that mimic it, such as dehydration and stroke. Methods: Loess regression on retrospective follow-up chart data of patients with sepsis-like symptoms (N = 664) aged 18+ in a large ER in Hungary was used to visualize/identify cutoff points for sepsis risk. A multivariate logistic regression model based on standard triage data was constructed with its corresponding receiver operating characteristic (ROC) curve and compared with another model constructed based on current sepsis guidelines. Results: Age, bicarbonate, HR, lactate, pH, and body temperature had U, V, W, or reverse U-shaped associations with identifiable inflexion points, but the cutoff values we identified were slightly different from guideline cutoff values. In contrast to the guidelines, no inflexion points could be observed for the association of sepsis with SBP, DPB, MAP, and RR and therefore were treated as continuous variables. Compared to the guidelines-based model, the triage data-driven final model contained additional variables (age, pH, bicarbonate) and did not include lactate. The data-driven model identified about 85% of sepsis cases correctly, while the guidelines-based model identified only about 70% of sepsis cases correctly. Conclusion: Our findings contribute to the growing body of evidence for the necessity of finding improved tools to identify sepsis at early time points, such as in the ER.

    Keywords: sepsis, SIRS, SOFA, clinical patient data, guidelines

  • T. Laskow ,
    J. Langdon ,
    P. Abadir ,
    Q.-L. Xue ,
    J. Walston :

    DOI: 10.1556/2060.2021.00010

    Abstract: Background: Chronic inflammation (CI) is a common trait of aging associated with adverse outcomes including mortality. We hypothesized that recombinant human Lactoferrin (rhLf) would reduce chronic inflammation of aging. Methods: Thirty-six community dwelling older adults were randomly assigned to rhLf or placebo treatment in 1:1 ratio for 3 months. IL-6, sTNFR1, Comprehensive Metabolic Panel (CMP), and Complete Blood Count (CBC) were measured at baseline, 1 month, 3 months, and 6 months. Physical and cognitive measures were completed at same timepoints, including 4-m walking speed (m/s), grip strength (kg), 6-min walking distance (m), home activity measured by accelerometer, trail making test - Part A (s) and - Part B (s), and Digit symbol substitution test (number correctly coded). Primary outcomes were differences in IL-6 and sTNFR1 concentrations evaluated by generalized linear model with log-link and gamma family distribution, controlling for baseline cytokine concentrations. Results: rhLF was welltolerated. There were a significant number of abdominal complaints and increased drop-out rate in placebo group. Participants in rhLf arm had non-significant lower mean percent increase in IL6 at 3 months (rhLf mean IL-6 6% lower than control, P = 0.843), and sTNFaR1 (rhLf mean 2% lower than control, P = 0.36). No significant changes were observed for the cognitive or physical measures. Conclusion: Treatment with rhLf did not significantly alter serum IL6 or sTNFR1 concentrations of older adults. This study may have been underpowered to detect difference, but provided evidence that a larger sample-size could more definitively determine the effect of rhLF on age-associated CI.

    Keywords: lactoferrin, chronic inflammation, IL-6, sTNFR1


  • R. Afroundeh ,
    P. Hofmann ,
    S. Esmaeilzadeh ,
    M. Narimani ,
    A. J. Pesola :

    DOI: 10.1556/2060.2021.00004

    Abstract: We examined the agreement between heart rate deflection point (HRDP) variables with maximal lactate steady state (MLSS) in a sample of young males categorized to different body mass statuses using body mass index (BMI) cut-off points. One hundred and eighteen young males (19.9 ± 4.4 years) underwent a standard running incremental protocol with individualized speed increment between 0.3 and 1.0 km/h for HRDP determination. HRDP was determined using the modified Dmax method called S.Dmax. MLSS was determined using 2-5 series of constant-speed treadmill runs. Heart rate (HR) and blood lactate concentration (La) were measured in all tests. MLSS was defined as the maximal running speed yielding a La increase of less than 1 mmol/L during the last 20 min. Good agreement was observed between HRDP and MLSS for HR for all participants (±1.96; 95% CI = -11.5 to +9.2 b/min, ICC 5 0.88; P < 0.001). Good agreement was observed between HRDP and MLSS for speed for all participants (±1.96; 95% CI = -0.40 to +0.42 km/h, ICC 5 0.98; P < 0.001). The same findings were observed when participants were categorized in different body mass groups. In conclusion, HRDP can be used as a simple, non-invasive and time-efficient method to objectively determine submaximal aerobic performance in nonathletic young adult men with varying body mass status, according to the chosen standards for HRDP determination.

    Keywords: exercise intensity, heart rate deflection point, maximal lactate steady state, S.Dmax mode