Redistribution of lymphocytes following E. coli sepsis

Cell therapy attenuates endothelial dysfunction in hypertensive rats with heart failure and preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is defined by increased left ventricular (LV) stiffness, impaired vascular compliance, and fibrosis. Although systemic inflammation, driven by comorbidities, has been proposed to play a key role, the precise pathogenesis remains elusive. To test the hypothesis that inflammation drives endothelial dysfunction in HFpEF, we used cardiosphere-derived cells (CDCs), which reduce inflammation and fibrosis, improving function, structure, and survival in HFpEF rats. Dahl salt-sensitive rats fed a high-salt diet developed HFpEF, as manifested by diastolic dysfunction, systemic inflammation, and accelerated mortality. Rats were randomly allocated to receive intracoronary infusion of CDCs or vehicle. Two weeks later, inflammation, oxidative stress, and endothelial function were analyzed. Single-cell RNA sequencing of heart tissue was used to assay transcriptomic changes. CDCs improved endothelial-dependent vasodilation while reducing oxidative stress and restoring endothelial nitric oxide synthase (eNOS) expression. RNA sequencing revealed CDC-induced attenuation of pathways underlying endothelial cell leukocyte binding and innate immunity. Exposure of endothelial cells to CDC-secreted extracellular vesicles in vitro reduced VCAM-1 protein expression and attenuated monocyte adhesion and transmigration. Cell therapy with CDCs corrects diastolic dysfunction, reduces oxidative stress, and restores vascular reactivity. These findings lend credence to the hypothesis that inflammatory changes of the vascular endothelium are important, if not central, to HFpEF pathogenesis.NEW & NOTEWORTHY We tested the concept that inflammation of endothelial cells is a major pathogenic factor in HFpEF. CDCs are heart-derived cell products with verified anti-inflammatory therapeutic properties. Infusion of CDCs reduced oxidative stress, restored eNOS abundance, lowered monocyte levels, and rescued the expression of multiple disease-associated genes, thereby restoring vascular reactivity. The salutary effects of CDCs support the hypothesis that inflammation of endothelial cells is a proximate driver of HFpEF.

Protective Effects of Methane-Rich Saline on Rats with Lipopolysaccharide-Induced Acute Lung Injury

Objective. The aim of this research is to evaluate the protective effects of methane-rich saline (MS) on lipopolysaccharide- (LPS-) induced acute lung injury (ALI) and investigate its potential antioxidative, anti-inflammatory, and antiapoptotic activities. Methods. LPS-induced (20 mg/kg) ALI rats were injected with MS (2 ml/kg and 20 ml/kg) before the initiation of LPS induction. Survival rate was determined until 96 h after LPS was induced. Lung injury was assayed by oxygenation index, lung permeability index (LPI), wet-to-dry weight (W/D), and histology. The cells in the bronchoalveolar lavage fluid (BALF) were counted. Oxidative stress was examined by the level of malondialdehyde (MDA) and superoxide dismutase (SOD). Inflammatory factors including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in BALF were determined by ELISA. Lung tissue apoptosis was detected by TUNEL staining and western blotting of caspase-3. Results. It was found that methane significantly prolonged the rat survival, decreased the lung W/D ratio and the content of the inflammatory factors, and reduced the amount of caspase-3 and apoptotic index. In addition, MS increased the level of SOD and decreased the level of MDA significantly. Conclusions. MS protects the LPS-challenged ALI via antioxidative, anti-inflammatory, and antiapoptotic effect, which may prove to be a novel therapy for the clinical management of ALI.

Lipopolysaccharide is required for the lethal effects of enterotoxin B after D-galactosamine sensitization

We tested the D-galactosamine sensitization model with staphylococcal enterotoxin B (SEB). LPS was required for the lethal effects of SEB in D-galactosamine sensitized mice. Only two (2/62) among the C3HeB/FeJ (H-2k), Balb/c (H-2d) and C57BL/6J (H-2b) mice died in response to SEB in the absence of LPS whereas injection of SEB and minimally lethal concentrations of LPS became highly toxic. Similar to LPS, the lethal effect of SEB was dependent on the mouse strain used. Mouse strains more sensitive to the effects of LPS (Balb/c and C57BL/6J) were also more sensitive to the effects of SEB in comparison to C3H mice when equivalent doses of LPS and SEB were used. Among Balb/c and C3HeB/FeJ but not C57BL/6J mice, SEB (20 μg) potentiated the lethal effects of LPS at low doses (0.1 μg LPS), but had an apparent protective effect at high doses (1 μg LPS). Lastly, there was an inverse correlation between pathogenesis and serum IL-2 concentrations and splenic T cell activation in C3H mice. However, macrophage mobilization did correlate with lethality. Therefore, some questions remain about the mechanisms involved in the D-galactosamine/SEB pathogenesis model. We conclude that when sensitizing mice with D-galactosamine and assessing the lethal effects of SEB, endotoxin contamination must be assessed.

Clinical significance of changes in peripheral lymphocyte count after surgery in early cervical cancer

OBJECTIVE

Immune competence is an important prognostic factor in cancer patients. Surgical management of cancer can cause a variety of immunological disturbances, the clinical consequences of which are still unclear.

MATERIALS AND METHODS

Patients with clinically staged cervical carcinoma (IB to IIA) who were treated at Samsung Medical Center, Seoul, Korea from 1994 to 2007 were retrospectively enrolled. We compared peri-operative peripheral lymphocyte counts, tumor-infiltrating lymphocyte scores, and survival in patients with early cervical cancer treated by abdominal type III radical hysterectomy.

RESULTS

The sample included 756 patients. The median follow-up was 58 months with a range of 3-181 months. There was a positive correlation between pre-operative peripheral lymphocyte counts and tumor infiltrating lymphocyte score. Pre-operative peripheral lymphocyte counts decreased significantly after surgery. In multivariate analyses for recurrence, higher pre-operative peripheral lymphocyte counts and recovery of lymphocyte counts (more than 100/μL from the pre-operative level) on post-operative day 3 were independent positive prognostic factors and LN metastasis was negatively associated with post-operative recovery of peripheral lymphocyte counts.

CONCLUSION

Peripheral lymphocyte counts after cervical cancer surgery are important prognostic factors, and management aimed at minimizing immune disturbances after surgery should be assessed, especially in patients with LN metastasis.

Perioperative reductions in circulating lymphocyte levels predict wound complications after excisional breast cancer surgery

OBJECTIVE

Postoperative wound complications after excisional surgery for primary breast cancer can result in patients requiring additional treatments and delay adjuvant therapy and are associated with worse prognoses.We investigated factors that might predispose patients to wound complications.

BACKGROUND

A number of patient characteristics have been associated with wound complications, but there is currently no quantitative measure of the risk of their occurrence. Our hypothesis was that wound complications are related, in part, to the immune status of patients.

METHODS

We recruited patients undergoing surgery for primary breast cancer and determined their circulating levels of various immune cells shortly before and after surgery as a measure of immune status.

RESULTS

One hundred seventeen patients were recruited; 16 (13.7%) developed wound complications. The following patient and tumor characteristics were associated with higher wound complication rates: diabetes (P = 0.02); larger tumors (T2/3 vs T1; P = 0.02); metastatic axillary nodes (P = 0.006). With respect to immune status, no significant differences in preoperative levels of circulating immune cells were detected between patients who developed wound complications and those who did not. However, patients who developed complications showed greater reductions in lymphocyte levels 4 hours postoperatively than those who did not (P <0.001). Multivariate analyses demonstrated that falls in lymphocyte levels of greater than 20% or 50% 4 hours postoperatively acted as a significant and independent predictor of wound complications (P < 0.005 and P < 0.0001,respectively).

CONCLUSIONS

Perioperative changes in lymphocyte levels could provide a practical predictive marker for wound complications on which selective antibiotic prophylaxis could be based.

Surgery induced immunosuppression

Surgery and anaesthesia result in a variety of metabolic and endocrine responses, which result in a generalised state of immunosuppression in the immediate post-operative period. Surgery induced immunosuppression has been implicated in the development of post-operative septic complications and tumour metastasis formation. In addition the effectiveness of many treatments in the adjuvant setting is dependent on a functioning immune system. By understanding the mechanisms contributing to surgery-induced immunosuppression, surgeons may undertake strategies to minimise its effect and reduce potential short-term and long-term consequences to patients.

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.

Premedication with clonidine does not attenuate suppression of certain lymphocyte subsets after surgery

Sixty-four patients undergoing elective major surgery were randomly assigned into a double-blinded, placebo-controlled, clinical trial to test the hypothesis that premedication with clonidine would attenuate postoperative reductions in circulating lymphocytes. The treatment group (n = 28) received a clonidine skin patch (0.3 mg/d) and a 0.6-mg oral loading dose 60-90 min before surgery. The control group (n = 36) received placebo patches and pills. Absolute blood levels of the following lymphocyte subsets were measured before induction of a standardized general anesthetic (baseline) and the morning after surgery: CD2, CD3, CD4, CD8, CD20, CD56, and the CD4:CD8 ratio. Significant decreases in lymphocyte subsets CD2, CD3, and CD4 were found in both groups; CD56 was significantly decreased only in the placebo group. However, the extent of lymphocyte depletion from baseline to Postoperative Day 1 between the clonidine and placebo groups was not different. Plasma concentrations of epinephrine, norepinephrine, and cortisol were measured from blood samples drawn at 8:00 AM on Postoperative Day 1. Plasma norepinephrine levels were significantly lower among patients who received clonidine. However, no significant differences were found in plasma epinephrine or cortisol levels between the clonidine and placebo groups. With a clinical dose, clonidine did not prevent postoperative lymphocyte depletion. alpha2-Agonists may not suppress adrenocortical stress responses sufficiently to prevent postoperative immune suppression.

IMPLICATIONS

Lymphocyte (white blood cell) counts often decrease after major surgery. We hypothesized that clonidine would reduce hormonal stress and blunt reductions in lymphocytes after major surgery. In a randomized trial, we found no differences from placebo in cortisol levels or lymphocyte changes. Lymphocyte levels did not predict infectious complications.

A synthetic lipopolysaccharide-binding peptide based on the neutrophil-derived protein CAP37 prevents endotoxin-induced responses in conscious rats

The lipid A component of lipopolysaccharide (LPS) derived from Escherichia coli has been implicated as a significant mediator in the development of circulatory and metabolic dysfunction and lethality associated with sepsis. A synthetic peptide corresponding to amino acid residues 20 through 44 of the neutrophil-derived 37-kDa cationic antimicrobial protein (CAP37 P(20-44)) possesses lipid A binding characteristics which may be useful in attenuating in vivo responses induced during circumstances of endotoxemia, including sepsis. The E. coli LPS to be used in the in vivo study was shown to be attenuated by CAP37 P(20-44) in a dose-dependent manner in the in vitro reaction with Limulus amoebocyte lysate. Intravenous infusion of CAP37 P(20-44) (1.5 or 3.0 mg/kg of body weight) with E. coli LPS (250 microg/kg over 30 min) into conscious, unrestrained rats prevented LPS-induced hyperdynamic and hypodynamic circulatory shock, hyperlactacidemia, and leukopenia in a dose-related fashion. CAP37 P(20-44) (0.2, 1.0, and 5.0 mg/kg) administered intravenously to conscious, actinomycin D-sensitized rats following a lethal dose of LPS neutralized LPS toxicity, resulting in dose-dependent 7-day survival rates of 30, 50, and 80%, respectively. CAP37 P(20-44) (5.0 mg/kg) significantly inhibited the endotoxin-induced increase in circulating tumor necrosis factor alpha in sensitized rats. These data demonstrate that CAP37 P(20-44) has the capacity to abolish in vivo biological responses to LPS that are relevant to human sepsis and to significantly neutralize the toxicity of circulating E. coli LPS.

Interleukin-6 is required for a protective immune response to systemic Escherichia coli infection

Interleukin-6 (IL-6) is a multipotential cytokine detected in the serum of patients or experimental animals undergoing bacterial sepsis. To date, the role of IL-6 in gram-negative sepsis models has been controversial. We have used IL-6-deficient mice to investigate the role of IL-6 during virulent Escherichia coli infection and in lipopolysaccharide (LPS)-induced mortality. In this report we describe an increased susceptibility of IL-6-deficient mice to E. coli infection in terms of mortality and accumulation of viable bacteria in tissues, indicating a protective role for IL-6 during the immune response against E. coli. In contrast, mortality rates of IL-6-deficient mice and control animals undergoing LPS-induced shock did not differ, indicating that IL-6 was inconsequential for survival in this model. Furthermore, we have shown that neutrophils were crucial for resistance to E. coli in normal mice. IL-6-deficient mice were unable to efficiently induce neutrophilia in the bloodstream immediately following challenge with E. coli, in contrast to a characteristic neutrophilia induced in control animals. Prophylactic treatment of the mutant animals with recombinant IL-6 protein reverted both the deficit of neutrophilia and the accumulation of bacteria in tissues. These data clarify the role of IL-6 as protective in virulent E. coli infection and suggest that the protective effect may be at least partially mediated through neutrophils.

Changes in the peripheral blood T-Cell receptor V beta repertoire in vivo and in vitro during shigellosis

A sequential activation of T cells in peripheral blood during shigello sis has been observer (D. Islam, P.K. Bradham, A. A. Lindberg, and B. Christensson, Infect. Immun 63:2941-2949, 1995). To further investigate the cellular response during the course of Shigella infection, changes in the T-cell receptor (TCR) repertoire in the subsets in blood in patients during shigellosis was that Shigella antigens may modulate the function of T cells carrying TCRs capable of recognizing Shigella-specific epitopes or superantigens. Such a selective preference for T cells expressing certain TCR Vbeta types could lead to the expansion or deletion of these T cells. In the present study of 27 adult male Bangladeshi patients with dysentery (14 cases caused by Shigella Dysenteriae 1 and 13 cases caused by Shigella flexneri), the changes in the TCR Vbeta repertoire of peripheral blood CD4+ and CD8+ T-cell subsets have been analyzed with a panel of nine anti-Vbeta monoclonal antibodies by flow cytometry. Twenty healthy males from Bangladesh and 20 healthy males from Sweden served as controls. Compared with the Bangladeshi controls, the patients had an increased frequency of CD4+T cells expression Vbeta2, Vbeta3, and Vbeta17, with a maximum at day 7 after the onset of disease. The frequency of CD4+T cells expressing Vbeta5.1 was increased only in patients with S. flexneri infection. Peripheral blood T cells from Shigella-infected patients also responded to in vitro stimulation in a TCR Vbeta-specific manner. Stimulation with heat-killed S. dysenteriae 1 and Shiga toxin enhanced the frequency of cells expressing Vbeta2, Vbeta3, Vbeta5.1, Vbeta13.6, and Vbeta17, especially in samples obtained at day 7. The enhanced frequency of cells expressing Vbeta2, Vbeta3, Vbeta5.1, and Vbeta17 found both in in vivo and in vitro could suggest that in shigellosis antigens or superantigens are presented to the immune system and preferentially activate certain TCR Vbeta types in T-cell subsets. The kinetics of the change in the TCR Vbeta repertoire in blood during shigellosis may indicate that following local activation, the antigen activated T cells can be retrieved in the blood and restimulated in vitro. If confirmed by parallel analysis of T cells in the gut and blood by TCR sequence analysis, the possibility suggested by our findings would facilitate further analysis of the role of cell-mediated immune responses in the pathogenesis of and protection against Shigella infection.