Lung compartmentalization of inflammatory cells in sepsis

Evaluation of HLA-DR expression in monocytes and CD64 in neutrophils as A predictor of SEPSIS/sirs in the infectious-inflammatory process

Sepsis is a highly fatal disease that affects millions of people worldwide every year. Currently, the diagnosis of sepsis is made by identifying at least two symptoms of systemic inflammatory response syndrome (SIRS), along with confirming the presence of microorganisms using a blood culture examination. Some biomarkers are already used to aid in the diagnosis, such as increased levels of C-reactive protein (CRP), leukocytes, immature granulocytes (IG), and bands. In addition, studies have shown a relationship between the expression of certain antigen receptors in the body's defense cells and its infectious state. CD64 is a receptor expressed in monocytes, and, in cases of infection, its expression is strongly observed in neutrophils. On the other hand, the class II MHC (major histocompatibility complex) marker, HLA-DR (human leukocyte antigen-DR), decreases its expression in monocytes in response to infection. This cohort study was conducted with 77 adult patients from a university hospital, divided into two groups: Non-Sepsis/SIRS and Sepsis/SIRS. The selected samples were analyzed by flow cytometry, identifying the expression of CD64 and HLA-DR according to their MFI, and calculating the sepsis index (SI) for each patient. All three parameters exhibited significant differences in expression between the two groups. When compared to the laboratory tests already in use, the utilization of HLA-DR, CD64, and the new index has shown greater sensitivity and specificity in identifying sepsis. This study contributes to knowledge about the relationship between the expression of antigens on defense cells and sepsis. The use of these biomarkers can help to improve the diagnosis and treatment of sepsis, which may contribute to the reduction of mortality related to the disease.

Altered Lung Heat Shock Protein-70 Expression and Severity of Sepsis-Induced Acute Lung Injury in a Chronic Kidney Disease Rat Model

Enhanced heat shock protein-70 (HSP-70) expression in the lungs is associated with attenuated acute lung injury (ALI) in a sepsis model. Chronic kidney disease (CKD) significantly contributes to the poor prognosis of patients with sepsis. This study examined the relationship between sepsis-induced ALI severity and altered lung HSP-70 expression in CKD. Experimental rats underwent a sham operation (control group) or 5/6 nephrectomy (CKD group). Sepsis was induced with cecal ligation and puncture (CLP). Laboratory tests and lung harvest were performed in the control group (without CLP and after 3, 12, 24, and 72 h of CLP) and in the CKD group (without CLP and after 72 h of CLP). ALI was the most severe after 12 h of sepsis. The mean lung injury score at 72 h after sepsis was significantly higher in the CKD group than in the control group (4.38 versus 3.30, p < 0.01). Nonetheless, enhanced lung HSP-70 expression was not observed in the CKD group. This study shows that altered lung HSP-70 expression is associated with the worsening of sepsis-induced ALI in patients with CKD. Enhancing lung HSP-70 is a novel treatment target for patients with CKD and sepsis-induced ALI.

Influence of photobiomodulation therapy on the treatment of pulmonary inflammatory conditions and its impact on COVID-19

We are currently facing a pandemic that continuously causes high death rates and has negative economic and psychosocial impacts. Therefore, this period requires a quick search for viable procedures that can allow us to use safe and non-invasive clinical tools as prophylactic or even adjuvant methods in the treatment of COVID-19. Some evidence shows that photobiomodulation therapy (PBMT) can attenuate the inflammatory response and reduce respiratory disorders similar to acute lung injury (ALI), complications associated with infections, such as the one caused by the new Coronavirus (SARS-CoV-2). Hence, the aim of the present study was to evaluate the influence of PBMT (infrared low-level laser therapy) on the treatment of ALI, one of the main critical complications of COVID-19 infection, in an experimental model in rats. Twenty-four male Wistar rats were randomly allocated to three experimental groups (n = 8): control group (CG), controlled ALI (ALI), and acute lung injury and PBM (ALIP). For treatment, a laser equipment was used (808 nm; 30 mw; 1.68 J) applied at three sites (anterior region of the trachea and in the ventral regions of the thorax, bilaterally) in the period of 1 and 24 h after induction of ALI. For treatment evaluation, descriptive histopathological analysis, lung injury score, analysis of the number of inflammatory cells, and expression of interleukin 1 β (IL-1β) were performed. In the results, it was possible to observe that the treatment with PBMT reduced inflammatory infiltrates, thickening of the alveolar septum, and lung injury score when compared to the ALI group. In addition, PBMT showed lower immunoexpression of IL-1β. Therefore, based on the results observed in the present study, it can be concluded that treatment with PBMT (infrared low-level laser therapy) was able to induce an adequate tissue response capable of modulating the signs of inflammatory process in ALI, one of the main complications of COVID-19.

The influence of splenic tissue on the survival and TCD4 and TCD8 lymphocyte rates in rats subjected to fecal peritonitis induction

PURPOSE

Comparing survival rates of rats subjected to spleen procedures after fecal peritonitis induction. Assessing changes in TCD4 and CD8 lymphocyte rates before and after the procedures. Correlating animal survival with CD4 and CD8 lymphocytes.

METHODS

Thirty male Wistar rats were distributed into 3 groups of ten: spleen manipulation (SM); total splenectomy (TS); subtotal splenectomy with preservation of the inferior pole (IP). Rats were subjected to surgical procedure depending on the group. Seven days after surgery they underwent induction of peritonitis and survival time was recorded. All animals were subjected to two blood collections: before surgery and 70 days after it for TCD4/TCD8 lymphocyte counting.

RESULTS

Mean survival time was longer in the IP and SM groups and shorter in the TS group; there was significant difference between them. The comparison of the median number of CD4 did not present changes, whereas the comparison of the median number of CD8 decreased in the SM and IP groups. The correlation between the median number of TCD4 and TCD8 lymphocytes and the animals' survival was not significant.

CONCLUSION

The maintenance of splenic tissue contributed to increase the survival of rats and there was a change in the number of TCD8 lymphocytes.

The Early Expression of HLA-DR and CD64 Myeloid Markers Is Specifically Compartmentalized in the Blood and Lungs of Patients with Septic Shock

Identification of reliable biomarkers is key to guide targeted therapies in septic patients. Expression monitoring of monocyte HLA-DR and neutrophil CD64 could fulfill the above need. However, it is unknown whether their expression on circulating cells reflects the status of tissue resident cells. We compared expressions of HLA-DR and CD64 markers in the circulation and airways of septic shock patients and evaluated their outcome prognostic value. The expression of CD64 on neutrophils and HLA-DR on monocytes was analyzed in the peripheral blood and mini-bronchoalveolar lavage fluid cells by flow cytometry. Twenty-seven patients with septic shock were enrolled into the study. The fluorescence intensity of HLA-DR on circulating monocytes was 3.5-fold lower than on the pulmonary monocytes (p = 0.01). The expression of CD64 on circulating and airway neutrophils was similar (p = 0.47). Only the expression of CD64 on circulating neutrophils was higher in nonsurvivors versus survivors (2.8-fold; p = 0.031). Pulmonary monocytes display a higher level of HLA-DR activation compared to peripheral blood monocytes but the expression of neutrophil CD64 is similar on lung and circulating cells. Death in septic patients was effectively predicted by neutrophil CD64 but not monocytic HLA-DR. Prognostic value of cellular activation markers in septic shock appears to strongly depend on their level of compartmentalization.

Transcompartmental inflammatory responses in humans: IV versus endobronchial administration of endotoxin*

OBJECTIVES

Transcompartmental signaling during early inflammation may lead to propagation of disease to other organs. The time course and the mechanisms involved are still poorly understood. We aimed at comparing acute transcompartmental inflammatory responses in humans following lipopolysaccharide-induced pulmonary and systemic inflammation.

DESIGN

Randomized, double-blind, placebo-controlled, crossover study.

SETTING ICU SUBJECTS

Healthy male volunteers.

INTERVENTIONS

Fifteen volunteers (mean age, 23; SD, 2 yr) received Escherichia coli endotoxin (lipopolysaccharide, 4 ng/kg) IV or endobronchially on two different study days. Groups were evaluated by bronchoalveolar lavage at baseline (0 hr) and 2, 4, 6, 8, or 24 hours postchallenge. Cardiorespiratory variables were continuously recorded throughout the study day, and plasma and bronchoalveolar lavage fluid markers of inflammation were measured.

MEASUREMENTS AND MAIN RESULTS

IV endotoxin elicited a systemic inflammatory response with a time-dependent increase and peak in tumor necrosis factor-α, interleukin-6, and leukocyte counts (all p < 0.001). Furthermore, a delayed (6-8 hr) increase in bronchoalveolar lavage fluid interleukin-6 concentration (p < 0.001) and alveolar leukocyte count (p = 0.03) and a minor increase in bronchoalveolar lavage fluid tumor necrosis factor-α were observed (p = 0.06). Endobronchial endotoxin was followed by progressive alveolar neutrocytosis and increased bronchoalveolar lavage fluid tumor necrosis factor-α, interleukin-6, and albumin (all p < 0.001); a systemic inflammatory response was observed after 2-4 hours, with no change in plasma tumor necrosis factor-α.

CONCLUSIONS

Acute lung or systemic inflammation in humans is followed by a transcompartmental proinflammatory response, the degree and differential kinetics of which suggests that the propagation of inflammation may depend on the primary site of injury.

Cecal ligation and puncture-induced murine sepsis does not cause lung injury

OBJECTIVE

The cause of death in murine models of sepsis remains unclear. The primary purpose of this study was to determine if significant lung injury develops in mice predicted to die after cecal ligation and puncture-induced sepsis compared with those predicted to live.

DESIGN

Prospective, laboratory controlled experiments.

SETTING

University research laboratory.

SUBJECTS

Adult, female, outbred Institute of Cancer Research mice.

INTERVENTIONS

Mice underwent cecal ligation and puncture to induce sepsis. Two groups of mice were euthanized at 24 and 48 hrs postcecal ligation and puncture and samples were collected. These mice were further stratified into groups predicted to die (Die-P) and predicted to live (Live-P) based on plasma interleukin-6 levels obtained 24 hrs postcecal ligation and puncture. Multiple measures of lung inflammation and lung injury were quantified in these two groups. Results from a group of mice receiving intratracheal normal saline without surgical intervention were also included as a negative control. As a positive control, bacterial pneumonia was induced with Pseudomonas aeruginosa to cause definitive lung injury. Separate mice were followed for survival until Day 28 postcecal ligation and puncture. These mice were used to verify the interleukin-6 cutoffs for survival prediction.

MEASUREMENTS AND MAIN RESULTS

After sepsis, both the Die-P and Live-P mice had significantly suppressed measures of respiratory physiology but maintained normal levels of arterial oxygen saturation. Bronchoalveolar lavage levels of pro- and anti-inflammatory cytokines were not elevated in the Die-P mice compared with the Live-P. In addition, there was no increase in the recruitment of neutrophils to the lung, pulmonary vascular permeability, or histological evidence of damage. In contrast, all of these pulmonary injury and inflammatory parameters were increased in mice with Pseudomonas pneumonia.

CONCLUSIONS

These data demonstrate that mice predicted to die during sepsis have no significant lung injury. In murine intra-abdominal sepsis, pulmonary injury cannot be considered the etiology of death in the acute phase.

Acute Lung Injury:Apoptosis and Signaling Mechanisms

Acute lung injury (ALI) has been documented clinically following several pathological states such as trauma, septic shock and pneumonia. The histopathological characteristics, paired with the production of a number of cellular pro-inflammatory mediators, play a crucial role in the progression of ALI. During ALI, polymorphonuclear neutrophil (PMN)-mediated apoptosis is delayed by macrophages, possibly via effects on the Fas/FasL mediated pathway, leading to the accumulation of these cells at the site of injury and inflammation. The transcriptional regulation of NFκB, CREB, and AP-1 also regulates the pathogenesis of ALI. During sepsis and septic shock, we found evidence of infiltrating leukocytes in the alveolar spaces along with an increased number of TUNEL-positive cells in the lung sections. We also observed an increased expression of TRADD and Bax/Bcl2 ratio at 7 days post-sepsis. In contrast, the NFκB/IκB ratio increased at 1 day post-sepsis. Together, these data provide evidence illustrating the induction of apoptosis in lung tissues subsequent to the onset of polymicrobial sepsis. The results support the concept that the upregulation of apoptosis following lung inflammation plays a crucial role in the development of acute lung injury and related disorders such as ARDS.

Gasometria arterial e inflamação pulmonar de ratos com diferentes tempos de sepse abdominal

RACIONAL: Sepse é a principal causa de morbi-mortalidade nas vítimas de trauma e em pacientes cirúrgico e apesar de toda tecnologia e terapêutica disponível não há diminuição nestas estatísticas. OBJETIVOS: Avaliar as repercussões ácido-básicas e o grau de injúria pulmonar decorrentes de sepse abdominal em ratos após seis e 24 horas de peritonite fecal através da ligadura e punção do ceco. MÉTODOS: Foram utilizados 40 ratos Wistar, machos, adultos. A amostra foi dividida aleatoriamente em quatro grupos: grupo A (sham/6 h - n=5) submetidos à laparotomia mediana infra-umbilical sem nenhuma outra intervenção; grupo B (sham/24h - n=5) submetidos à laparotomia mediana infra-umbilical sem nenhuma outra intervenção; grupo C (LPC/6 h - n=15) submetidos à ligadura e punção do ceco e grupo D (LPC/24h - n=15) submetidos à ligadura e punção do ceco. Após seis ou 24 horas, conforme o grupo em estudo, os animais foram novamente anestesiados e submetidos as seguintes análises: observação clínica de sinais de sepse, laparotomia através do mesmo acesso anterior e realização de cultura do líquido peritoneal e punção cardíaca para obtenção de amostra sangüínea suficiente para gasometria arterial, hematócrito e leucometria. Procedeu-se eutanásia e os pulmões retirados para análise de edema pulmonar e o infiltrado inflamatório. RESULTADOS: Ocorreram quatro óbitos no grupo D. Verificou-se, em todos os grupos, a presença de acidose mista. Comparando os grupos experimento 6h versus controle 6h foram encontradas duas variáveis significativas - HCO3 (p=0,0015) e BE (p=0,0015) -, demonstrando acidose metabólica mais grave no grupo experimento. Nos grupos controle também se confirmou acidose mista, devido às alterações das variáveis HCO3 (p=0,0079), PO2 (p=0,0079) e SO2 (p=0,0079). A correlação entre o grau de comprometimento pulmonar e o estado metabólico confirma a existência de resposta inflamatória sistêmica evidenciada por aumento de neutrófilos e hemorragia alveolar difusa nos pulmões do rato séptico. CONCLUSÃO: O modelo de LPC foi método eficaz para indução de sepse. A laparotomia e a manipulação de alças intestinais são fatores desencadeantes de acidose mista em ratos, comprovado pelos resultados da gasometria, que demonstrou ser método confiável na detecção de alterações no metabolismo ácido-básico dos ratos estudados.

Up-regulation of functional CXCR4 expression on human lymphocytes in sepsis

OBJECTIVE

Lymphocyte dysfunction has been documented in sepsis, and evidence suggests that lymphocyte infiltration contributes to tissue injury. The purpose of this study was to examine chemokine receptor expression and function in lymphocytes from septic patients and healthy donors.

DESIGN

Observational study of septic patients and laboratory investigation of normal controls.

SETTING

Tertiary care intensive care unit.

PATIENTS AND SUBJECTS

Nine critically ill patients fulfilling criteria for the systemic inflammatory response syndrome and with a Sepsis Score of >/=3 were included in this study. Lymphocytes were also obtained from healthy volunteers.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The total number of circulating leukocytes in septic patients was markedly increased; however, lymphocyte counts were decreased. Chemokine receptor expression on lymphocytes was examined by flow cytometry. CXCR4 expression on lymphocytes from septic patients was increased whereas CCR5 was decreased and CCR7 was unchanged. Lipopolysaccharide stimulation of normal lymphocytes increased CXCR4 expression but decreased CCR5 and did not change CCR7 expression. This lipopolysaccharide-stimulated CXCR4 expression required 20 hrs of stimulation and was accompanied by increased messenger RNA. Lymphocytes from septic patients or after lipopolysaccharide treatment demonstrated enhanced actin polymerization and migration in response to CXCL12. Taken together, sepsis and lipopolysaccharide up-regulated CXCR4 expression and enhanced lymphocyte activation and migration in response to CXCL12.

CONCLUSIONS

Blocking CXCR4 and CXCL12 function may provide a novel therapeutic method for controlling systemic inflammation and tissue injury in sepsis.

MACROPHAGE MIGRATION INHIBITORY FACTOR WITHIN THE ALVEOLAR SPACES INDUCES CHANGES IN THE HEART DURING LATE EXPERIMENTAL SEPSIS

Respiratory dysfunction during sepsis is common. However, although lung function can often be adequately supported, death frequently results from cardiovascular collapse. Despite intense investigation, the mechanism underlying the myocardial dysfunction of sepsis remains unclear. Macrophage migration inhibitory factor (MIF), an important cytokine released in sepsis and the acute respiratory distress syndrome, is a known cardiac depressant. We hypothesized that MIF released from the lung results in myocardial dysfunction during sepsis. In murine models of polymicrobial sepsis, we demonstrate a significant increase in the lungs of total and lavagable MIF between 20 and 30 h post induction of sepsis. At 30 h post sepsis, the lungs released MIF into the pulmonary circulation, increasing the plasma concentration by up to 51% in a single pass. Exogenous MIF, instilled into the lungs, increased alveolar keratinocyte-derived chemokine (KC), Macrophage inflammatory protein-2 (MIP2), and tumor necrosis factor alpha (TNFalpha) at 3 h, and plasma KC and MIP2 at 6 h postinstillation. This was associated with an increase in p38 mitogen-activated protein kinase and c-Jun N-terminal kinase phosphorylation. Because changes in mitogen-activated protein kinase activation can lead to myocardial depression, these data suggest that MIF released from the lungs may be responsible, at least in part, for the cardiac dysfunction seen in the late stages of sepsis.

Alpha-chemokine receptor blockade reduces high mobility group box 1 protein-induced lung inflammation and injury and improves survival in sepsis

High mobility group box 1 (HMGB1) protein, a late mediator of lethality in sepsis, can induce acute inflammatory lung injury. Here, we identify the critical role of alpha-chemokine receptors in the HMGB1-induced inflammatory injury and show that alpha-chemokine receptor inhibition increases survival in sepsis, in a clinically relevant time frame. Intratracheal instillation of recombinant HMGB1 induces a neutrophilic leukocytosis, preceded by alveolar accumulation of the alpha-chemokine macrophage inflammatory protein-2 and accompanied by injury and increased inflammatory potential within the air spaces. To investigate the role of alpha-chemokine receptors in the injury, we instilled recombinant HMGB1 (0.5 microg) directly into the lungs and administered a subcutaneous alpha-chemokine receptor inhibitor, Antileukinate (200 microg). alpha-Chemokine receptor blockade reduced HMGB1-induced inflammatory injury (neutrophils: 2.9 +/- 3.2 vs. 8.1 +/- 2.4 x 10(4) cells; total protein: 120 +/- 48 vs. 311 +/- 129 microg/ml; reactive nitrogen species: 2.3 +/- 0.3 vs. 3.5 +/- 1.3 microM; and macrophage migration inhibitory factor: 6.4 +/- 4.2 vs. 37.4 +/- 15.9 ng/ml) within the bronchoalveolar lavage fluid, indicating that HMGB1-induced inflammation and injury are alpha-chemokine mediated. Because HMGB1 can mediate late septic lethality, we administered Antileukinate to septic mice and observed increased survival (from 58% in controls to 89%) even when the inhibitor treatment was initiated 24 h after the induction of sepsis. These data demonstrate that alpha-chemokine receptor inhibition can reduce HMGB1-induced lung injury and lethality in established sepsis and may provide a novel treatment in this devastating disease.

Protective effect of β-glucan on lung injury after cecal ligation and puncture in rats

OBJECTIVE

Understanding the biological mediators involved in the complex inflammatory response of sepsis and acute lung injury offers the possibility of future investigations targeting treatment based on these mediators. This study investigated whether macrophage activator beta-glucan has a protective effect on acute lung injury in an experimental model of sepsis.

DESIGN AND SETTING

Experimental study in an experimental research center.

MATERIALS

30 rats randomized into three groups (sham, sepsis, and beta-glucan).

INTERVENTIONS

Cecal ligation and puncture were performed in the beta-glucan and sepsis groups. The beta-glucan group was given a single intraperitoneal dose of beta-glucan (4 mg/kg) following cecal ligation.

MEASUREMENTS AND RESULTS

Rats treated with beta-glucan had fewer circulating neutrophils, more blood monocytes, and higher serum interleukin 6 levels than septic animals. The percentages of neutrophils and lymphocytes from the bronchoalveolar lavage fluid and the myeloperoxidase activity measured in the lung tissue were lower in the beta-glucan group than in the sepsis group. Less alveolar hemorrhage and neutrophil infiltration were observed in lungs from animals in the beta-glucan group in the septic groups.

CONCLUSIONS

In this rat model of intra-abdominal sepsis beta-glucan treatment partially protected against secondary lung injury, decreased lung hemorrhages, and lung neutrophilia. These results suggest that beta-glucan protects against sepsis-associated lung damage.

Physiopathological studies in septic rats and the use of fructose 1,6-bisphosphate as cellular protection

OBJECTIVE

The aim of this research project was to test the ability of fructose 1,6-bisphosphate (FBP), which has anti-inflammatory effects and maintains cellular energy levels, to inhibit the septic process in an experimental model in rats.

DESIGN

Prospective, controlled animal trial.

SETTING

Research laboratory.

SUBJECTS

Fed male Wistar rats.

INTERVENTIONS

Three experimental groups were formed for the test: control group, untreated septic group, and septic group treated with FBP (500 mg/kg).

MEASUREMENTS AND MAIN RESULTS

In the control group, there were no deaths; in the untreated septic group, the mortality rate was 100% within 15 hrs; in the septic group treated with FBP, the mortality rate reached 20% within 15 hrs. The blood cell tests revealed that concentrations of hematocrit, leukocytes, monocytes, and immature cells increased significantly in the untreated septic group compared with both the FBP-treated septic group and the control group. The histologic lesions verified in the heart, lungs, liver, and kidneys of septic animals were smaller and even absent in those treated with FBP.

CONCLUSION

FBP reduced the mortality rate provoked by experimental sepsis and ameliorated hematologic and histologic alterations.