Predictive value of molecular matching tools for the development of donor specific HLA-antibodies in patients undergoing lung transplantation.

Molecular matching is a new approach for virtual histocompatibility testing in organ transplantation. The aim of our study was to analyze whether the risk for de novo donor-specific HLA antibodies (dnDSA) after lung transplantation (LTX) can be predicted by molecular matching algorithms (MMA) and their combination. In this retrospective study we included 183 patients undergoing LTX at our center from 2012-2020. We monitored dnDSA development for 1 year. Eplet mismatches (epMM) using HLAMatchmaker were calculated and highly immunogenic eplets based on their ElliPro scores were identified. PIRCHE-II scores were calculated using PIRCHE-II algorithm (5- and 11-loci). We compared epMM and PIRCHE-II scores between patients with and without dnDSA using t-test and used ROC-curves to determine optimal cut-off values to categorize patients into four groups. We used logistic regression with AIC to compare the predictive value of PIRCHE-II, epMM, and their combination. In total 28.4% of patients developed dnDSA (n = 52), 12.5% class I dnDSA (n = 23), 24.6% class II dnDSA (n = 45), and 8.7% both class II and II dnDSA (n = 16). Mean epMMs (p-value = 0.005), mean highly immunogenic epMMs (p-value = 0.003), and PIRCHE-II (11-loci) (p = 0.01) were higher in patients with compared to without class II dnDSA. Patients with highly immunogenic epMMs above 30.5 and PIRCHE-II 11-loci above 560.0 were more likely to develop dnDSA (31.1% vs. 14.8%, p-value = 0.03). The logistic regression model including the grouping variable showed the best predictive value. MMA can support clinicians to identify patients at higher or lower risk for developing class II dnDSA and might be helpful tools for immunological risk assessment in LTX patients.

Influence of dental status on outcome after lung transplantation.

INTRODUCTION: Poor oral hygiene can cause infections and inflammatory diseases. Data on its impact on outcome after lung transplantation (LuTX) is scarce. Most transplant centers have individual standards regarding dental care as there is no clinical guideline. This study's objective was to assess LuTX-listed patient's dental status and determine its effect on postoperative outcome. METHODS: Two hundred patients having undergone LuTX from 2014 to 2019 were selected. Collected data comprised LuTX-indication, periodontal status, and number of carious teeth/fillings. A preoperative panoramic dental X-ray and a dentist's consultative clarification were mandatory. RESULTS: 63.5% had carious dental status, differing significantly regarding TX-indication (p < 0.001; ILD: 41.7% vs. CF: 3.1% of all patients with carious teeth). Mean age at the time of LuTX differed significantly within these groups. Neither preoperative carious dental status nor periodontitis or bone loss deteriorated post-LuTX survival significantly. No evidence was found that either resulted in a greater number of deaths related to an infectious etiology. CONCLUSION: This study shows that carious dental status, periodontitis, and bone loss do not affect post-TX survival. However, literature indicates that they can cause systemic/pulmonary infections that deteriorate post-LuTX survival. Regarding the absence of standardized guidelines regarding dental care and LuTX, we strongly recommend emphasizing research in this field.

Defect Coverage after Forequarter Amputation-A Systematic Review Assessing Different Surgical Approaches.

Autologous fillet flaps are a common reconstructive option for large defects after forequarter amputation (FQA) due to advanced local malignancy or trauma. The inclusion of osseous structures into these has several advantages. This article therefore systematically reviews reconstructive options after FQA, using osteomusculocutaneous fillet flaps, with emphasis on personalized surgical technique and outcome. Additionally, we report on a case with an alternative surgical technique, which included targeted muscle reinnervation (TMR) of the flap. Our literature search was conducted in the PubMed and Cochrane databases. Studies that were identified were thoroughly scrutinized with regard to relevance, resulting in the inclusion of four studies (10 cases). FQA was predominantly a consequence of local malignancy. For vascular supply, the brachial artery was predominantly anastomosed to the subclavian artery and the brachial or cephalic vein to the subclavian or external jugular vein. Furthermore, we report on a case of a large osteosarcoma of the humerus. Extended FQA required the use of the forearm for defect coverage and shoulder contour reconstruction. Moreover, we performed TMR. Follow-up showed a satisfactory result and no phantom limb pain. In case of the need for free flap reconstruction after FQA, this review demonstrates the safety and advantage of osteomusculocutaneous fillet flaps. If the inclusion of the elbow joint into the flap is not possible, we recommend the use of the forearm, as described. Additionally, we advocate for the additional implementation of TMR, as it can be performed quickly and is likely to reduce phantom limb and neuroma pain.

The Role of Thoracic Surgery in Small Cell Lung Cancer - A Large Longitudinal Analysis (2002-2015) Based on Real-World Data.

BACKGROUND: Most SCLC patients are diagnosed with extensive disease (ED) and the prognosis in this cohort remains poor. However, some patients are diagnosed with limited (LD) or very limited (VLD, T1-2, N0-1, M0) disease and previous data suggest that surgical resection might improve outcomes in these patients. Most of the existing evidence comes from small case series. For this reason, we investigated clinical features and surgical outcomes in a large cohort of resected SCLC patients. PATIENTS AND METHODS: We used a large pseudomized dataset (n = 32432) provided by the Munich Cancer Registry to analyze all documented SCLC patients (n = 5043) between 2002 and 2015. We correlated patients' characteristics as well as surgery modalities with survival data and describe trends in the role of surgery in SCLC over the time. RESULTS: We analyzed 5043 SCLC patients. A total of 161 (3.2%) received either oncological (lobectomy, bilobectomy and pneumonectomy) or limited resection (segmentectomy and wedge resection). We found a significant trend suggesting that resections in SCLC patients become less common in all stages of disease, accompanied by an increased proportion of oncological resections. This suggests a more accurate preoperative staging. In VLD resection was significantly associated with longer survival compared to nonsurgical management (log-rank P = .013). Survival was better with oncological resection compared to atypical resection. Administration of adjuvant chemotherapy was associated with better outcome in all resected patients (P = .01). CONCLUSION: VLD SCLC patients benefit from oncological resection. We recommend invasive staging in these patients to ensure VLD. Furthermore, adjuvant chemotherapy should be offered to all resected patients.

COVID-19 in Recent Lung Transplant Recipients: Clinical Outcomes and Management Strategies.

BACKGROUND: COVID-19 causes a wide range of symptoms, with particularly high risk of severe respiratory failure and death in patients with predisposing risk factors such as advanced age or obesity. Recipients of solid organ transplants, and in particular lung transplantation, are more susceptible to viral infection owing to immune suppressive medication. As little is known about the SARS-CoV-2 infection in these patients, this study was undertaken to describe outcomes and potential management strategies in early COVID-19 infection early after lung transplantation. METHODS: We describe the incidence and outcome of COVID-19 in a cohort of recent lung transplant recipients in Munich. Six of 186 patients who underwent lung transplantation in the period between March 2019 and March 2021 developed COVID-19 within the first year after transplantation. We documented the clinical course and laboratory changes for all patients showing differences in the severity of the infection with COVID-19 and their outcomes. RESULTS: Three of 6 SARS-CoV-2 infections were hospital-acquired and the patients were still in inpatient treatment after lung transplantation. All patients suffered from symptoms. One patient did not receive antiviral therapy. Remdesivir was prescribed in 4 patients and the remaining patient received remdesivir, bamlanivimab and convalescent plasma. CONCLUSIONS: COVID-19 does not appear to cause milder disease in lung transplant recipients compared with the general population. Immunosuppression is potentially responsible for the delayed formation of antibodies and their premature loss. Several comorbidities and a general poor preoperative condition showed an extended hospital stay.

Over-the-scope clip (OTSC®) closure of a recto-acetabular fistula.

A 25-year-old male Syrian refugee presented in our hospital with recurrent hip infections after having undergone hip arthroplasty abroad following destruction of his right hip joint by shell splinters in the Syrian civil war. The patient underwent hip arthroplasty revision with implantation of a cement spacer. CT-scan with rectal contrast media filling revealed a recto-acetabular fistula. Consecutively, the patient underwent ileostomy formation. The fistula was then successfully closed by endoscopic over-the-scope clipping (OTSC®). Fistulas between intestines and joints rarely develop and in the few cases published mostly extensive abdominal rescue surgery has been performed. Here, we present a case of a traumatic recto-acetabular fistula that was successfully closed by OTSC. This innovative method could represent a safe and suitable option to effectively close fistulas between joints and intestines thereby avoiding extensive rescue surgery with bowel resection or permanent ostomy.

Dehydroepiandrosterone modulates T-cell response after major abdominal surgery.

BACKGROUND: The immune balance controlled by T-helper (Th)1 and Th2 cells is critical in protecting the host from pathogenic invasion, and its imbalance may increase susceptibility to infection in patients undergoing major surgery. The differentiation of naive T cells to Th1 and Th2 cells is largely driven by cytokines. In addition, steroid hormones have been shown to affect Th1/Th2 balance, particularly in autoimmune diseases. The regulation of Th1/Th2 balance in patients undergoing surgery and its potential clinical relevance remain unclear. MATERIALS AND METHODS: Blood samples were obtained from patients both before and 2 h after major abdominal surgery. Peripheral blood mononuclear cells were isolated and cultured in wells coated with either anti-CD3 (direct T-cell stimulation) or phytohemagglutinin (PHA) (indirect T-cell stimulation), with or without 10(-5) M dehydroepiandrosterone (DHEA). The release of interleukin (IL)-2, interferon gamma, and IL-10 was measured by an enzyme-linked immunosorbent assay, and the expression of CD4, CD8, and CD69 was determined by flow cytometry. RESULTS: DHEA decreased the release of IL-2 and IL-10 in directly (anti-CD3) and indirectly (PHA)-stimulated T cells from postoperative samples, whereas the release of interferon gamma in PHA-stimulated T cells was not affected. The distribution of CD4/CD8 was not significantly different after surgery or DHEA. DHEA was associated with a decrease in the expression of the activation marker CD69 on CD4(+) T cells, whereas the activation of CD8(+) T cells remained unchanged. CONCLUSIONS: These results demonstrate that DHEA plays a critical role in controlling Th1/Th2 balance in the immediate postoperative period. Attenuation of both the Th1 and Th2 responses has been suggested to have immunoprotective effects. The role of DHEA in the regulation of Th1/Th2 balance in patients undergoing major abdominal surgery may, therefore, also be of significant clinical relevance and warrants further investigation.

Short-term prognosis of critically ill surgical patients: the impact of duration of invasive organ support therapies.

PURPOSE: We wanted to identify the importance of the duration of invasive ventilation and of renal replacement therapy for short-term prognosis of surgical patients treated in an intensive care unit (ICU). METHODS: We analyzed adult patients (n = 1462) who had an ICU length of stay of more than 4 days and who were followed up until the end of the short-term phase after ICU admission. Duration of different invasive therapies was evaluated by constructing specific vectors that tested effects of time-dependent variables on outcome after a lag time of 7 days. MEASUREMENTS AND MAIN RESULTS: Eight hundred eight patients (56.6%) were still alive at the end of the short-term phase. During the short-term phase, 85.3% of the 1462 patients required invasive ventilation, and 16.1%, a continuous renal replacement therapy. Besides the underlying disease and disease severity at ICU admission, the need for invasive ventilation or renal replacement therapy was associated with poorer outcome. Duration of invasive ventilation shortened survival if treatment lasted for more than 11 days (nonlinear association). In contrast, duration of renal replacement therapy was unimportant for short-term prognosis. CONCLUSION: Prolonged duration of invasive ventilation but not of renal replacement therapy is inversely related to short-term survival.

Long-term survival after surgical critical illness: the impact of prolonged preceding organ support therapy.

OBJECTIVE: To identify the prognostic importance of preceding invasive ventilation, renal replacement therapy, and catecholamine therapy for long-term survivors after surgical critical illness. SUMMARY BACKGROUND DATA: Nothing is known about the effect of preceding intensive care unit (ICU)-related therapies on long-term outcome. METHODS: We performed a retrospective analysis of prospectively collected data of an ICU patient cohort linked to a local database. Adult patients (n = 1462) admitted to a 12-bed ICU between 1993 and 2005, who had an ICU length of stay of more than 4 days, were followed up until the end of the second year after ICU admission. Hazard function was explored by Weibull modeling and likelihood ratio tests. Cox-type structured hazard regression models were used to analyze linear, nonlinear, or time-varying associations of therapeutic variables with 2-year survival time of a patient subgroup, which had survived the period of high hazard. RESULTS: Hazard rate declined exponentially up to day 195 after ICU admission, and became constant thereafter. A total of 808 patients reached this stable stage of their disease forming the study population. Of these patients, 648 (80.2%) were still alive at the end of the second year after ICU admission. Underlying diseases were major determinants for long-term outcome. Long-term mortality was significantly associated with the acute extent of physiological derangement during ICU stay (maximum Apache II score), but was independent from the duration of preceding invasive organ support. CONCLUSION: In surgical patients with a prolonged ICU length of stay, an exorbitant mortality exists for about half a year after ICU admission. Later on, life expectancy of surviving patients is largely determined by the underlying disease and, to a minor degree, by the acute extent of homeostatic disturbance during ICU stay. The duration of preceding invasive therapies does not limit long-term survival.

Activated partial thromboplastin time waveform analysis as specific sepsis marker in cardiopulmonary bypass surgery.

Throughout the last years, several new diagnostic biomarkers have been introduced into clinical routine to identify a systemic inflammatory response syndrome (SIRS) or a septic state and to discriminate between these two entities. According to studies in selected patients, measurement of these biomarkers may be advantageous under certain clinical conditions. On an individual basis, however, these sepsis markers usually lack an adequate negative or positive predictive power. Therefore, physicians in charge still have to rely on a combination of personal experience and results from clinical or laboratory tests when deciding on a patient's therapy. For surgical patients, a key problem consists of the time delay which is associated with the diagnosis of serious postoperative infections and which may negatively affect outcome. It is in this context where the activated partial thromboplastin time waveform analysis may represent a promising new method to discriminate between SIRS and sepsis, thereby shortening the time to therapy. Nevertheless, studies involving large patient populations will be necessary to prove the efficacy of this new diagnostic concept either as a single tool or in combination with the measurement of other biomarkers.

The potential role of T-cells and their interaction with antigen-presenting cells in mediating immunosuppression following trauma-hemorrhage.

OBJECTIVE: Trauma-hemorrhage results in depressed immune responses of antigen-presenting cells (APCs) and T-cells. Recent studies suggest a key role of depressed T-cell derived interferon (IFN)-g in this complex immune cell interaction. The aim of this study was to elucidate further the underlying mechanisms responsible for dysfunctional T-cells and their interaction with APCs following trauma-hemorrhage. DESIGN: Adult C3H/HeN male mice were subjected to trauma-hemorrhage (3-cm midline laparotomy) followed by hemorrhage (blood pressure of 35 +/- 5 mmHg for 90 min and resuscitation) or sham operation. At 24 h thereafter, spleens were harvested and T-cells (by Microbeads) and APCs (via adherence) were Isolated. Co-cultures of T-cells and APCs were established for 48 h and stimulated with concanavalin A and lipopolysaccharide. T-Cell specific cytokines known to affect APC function (i.e. interleukin(IL)-2, IL-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF)) were measured in culture supernatants by Multiplex assay. The expression of MHC class II as well as co-stimulatory surface molecules on T-cells and APCs was determined by flow cytometry. RESULTS: The release of IL-4 and GM-CSF by T-cells was suppressed following trauma-hemorrhage, irrespective of whether sham or trauma-hemorrhage APCs were present. Antigen-presenting cells from animals subjected to trauma-hemorrhage did not affect T-cell derived cytokine release by sham T-cells. In contrast, T-cells from trauma-hemorrhage animals depressed MHC class II expression of CD11c(+) cells, irrespective of whether APCs underwent sham or trauma-hemorrhage procedure. Surprisingly, co-stimulatory molecules on APCs (CD80, CD86) were not affected by trauma-hemorrhage. CONCLUSIONS: These results suggest that beside IFN-g other T-cell derived cytokines contribute to immunosuppression following trauma-hemorrhage causing diminished MHC II expression on APCs. Thus, T-cells appear to play an important role in this interaction at the time-point examined. Therapeutic approaches should aim at maintenance of T-cell function and their interaction with APCs to prevent extended immunosuppression following trauma-hemorrhage.

Accuracy of procalcitonin for outcome prediction in unselected postoperative critically ill patients.

The importance of postoperative procalcitonin (PCT) measurements for outcome prediction is currently controversial. Conflicting results have been obtained for patients after polytrauma, sepsis, peritonitis, or cardiac surgery and may result from incomplete adjustment for important confounders or from nonlinear PCT effects. We retrospectively analyzed the association of PCT concentration with postoperative mortality, morbidity, and length of stay in an unselected series of 220 consecutive patients who required postoperative intensive care unit therapy or surveillance. Biochemical markers were measured on the first day after intensive care unit admission. Results were adjusted for various confounding variables (Acute Physiology and Chronic Health Evaluation II score, underlying disease), and test accuracy was evaluated by receiver operating characteristic statistics. We found a significant nonlinear, logarithmic association between PCT concentration and outcome. After adjustment for relevant covariates, PCT was an independent determinant of mortality, combined mortality/morbidity, and postoperative hospital length of stay in survivors. At mortality analysis, the predictive power of PCT was superior to that of Acute Physiology and Chronic Health Evaluation II score and of IL-6 (optimal cutoff point, 1.44 ng/mL; sensitivity, 80.8%; specificity, 80.4%). The use of PCT was comparable to that of other prognostic markers when combined mortality/morbidity were examined. Our results suggest that PCT may deserve further testing as a prognostic tool in unselected, critically ill, surgical patients.

Prognostic factors in critically ill patients suffering from secondary peritonitis: a retrospective, observational, survival time analysis.

BACKGROUND: Acute mortality of unselected critically ill patients has improved during the last 15 years. Whether these benefits also affect survival of critically ill patients with secondary peritonitis is unclear as is the relevance of specific prognostic factors, such as source control. METHODS: We performed a retrospective analysis of data collected prospectively from March 1993 to February 2005. A cohort of 319 consecutive postoperative patients with secondary peritonitis requiring intensive care was evaluated. End points for outcome analysis were derived from daily changes of hazard rate. RESULTS: Four-month survival rate after intensive care unit (ICU) admission was 31.7%. For patients who have survived for more than 4 months, the 1-year survival was 82.7%. After adjustment for relevant covariates, a high disease severity at ICU admission and during ICU stay, specific comorbidities (extended malignancies, liver cirrhosis) and sources of infection (distal esophagus, stomach), and an inadequate initial antibiotic therapy were associated with worse 4-month prognosis. Inability to obtain source control was the most important determinant of mortality, and treatment after 2002 was combined with improved prognosis. CONCLUSIONS: Four-month prognosis of critically ill, surgical patients with secondary peritonitis is poor and mostly determined by the ability to obtain source control. Outcome has improved since 2002, and after successful surgical and intensive care therapy long-term survival seems to be good.

Bench-to-bedside review: latest results in hemorrhagic shock.

Hemorrhagic shock is a leading cause of death in trauma patients worldwide. Bleeding control, maintenance of tissue oxygenation with fluid resuscitation, coagulation support, and maintenance of normothermia remain mainstays of therapy for patients with hemorrhagic shock. Although now widely practised as standard in the USA and Europe, shock resuscitation strategies involving blood replacement and fluid volume loading to regain tissue perfusion and oxygenation vary between trauma centers; the primary cause of this is the scarcity of published evidence and lack of randomized controlled clinical trials. Despite enormous efforts to improve outcomes after severe hemorrhage, novel strategies based on experimental data have not resulted in profound changes in treatment philosophy. Recent clinical and experimental studies indicated the important influences of sex and genetics on pathophysiological mechanisms after hemorrhage. Those findings might provide one explanation why several promising experimental approaches have failed in the clinical arena. In this respect, more clinically relevant animal models should be used to investigate pathophysiology and novel treatment approaches. This review points out new therapeutic strategies, namely immunomodulation, cardiovascular maintenance, small volume resuscitation, and so on, that have been introduced in clinics or are in the process of being transferred from bench to bedside. Control of hemorrhage in the earliest phases of care, recognition and monitoring of individual risk factors, and therapeutic modulation of the inflammatory immune response will probably constitute the next generation of therapy in hemorrhagic shock. Further randomized controlled multicenter clinical trials are needed that utilize standardized criteria for enrolling patients, but existing ethical requirements must be maintained.

Secular trends in mortality associated with new therapeutic strategies in surgical critical illness.

BACKGROUND: Since 1999 randomized controlled trials have shown that new therapeutic strategies, such as strict glycemic control, increased use of noninvasive ventilation and of lung-protective ventilation, and early goal-oriented shock therapy, may reduce mortality in selected groups of critically ill patients. Whether these benefits can be translated to a surgical clinical setting is unclear. We wanted to evaluate longitudinally the successive routine implementation of new therapeutic measures and its effect on postsurgical patients admitted to the intensive care unit. METHODS: We performed a retrospective analysis on data collected prospectively from March 1, 1993 through February 28, 2005. RESULTS: A cohort of 1,802 consecutive cases requiring intensive care therapy for more than 4 days was analyzed. A significant decrease in mortality was observed in the last years of the study. With adjustment for relevant covariates, treatment after the implementation of new therapeutic strategies was identified as an independent factor linked with a reduced risk of death (odds ratio [OR] .518; 95% confidence interval [CI] .337-.796), whereas older age (OR 1.030; 95% CI 1.015-1.045), a high severity score on admission (OR 1.155; 95% CI 1.113-1.198) or during intensive care unit stay (OR 1.187; 95% CI 1.145-1.231), a high number of failing organs (OR 1.918; 95% CI 1.635-2.250), and peritonitis (OR 3.277; 95% CI 2.046-5.246) were independently associated with death. CONCLUSIONS: Implementing of a variety of new therapeutic measures into routine care of critically ill surgical patients was associated with improved survival after 2001.

Acute and long-term survival in chronically critically ill surgical patients: a retrospective observational study.

INTRODUCTION: Various cohort studies have shown that acute (short-term) mortality rates in unselected critically ill patients may have improved during the past 15 years. Whether these benefits also affect acute and long-term prognosis in chronically critically ill patients is unclear, as are determinants relevant to prognosis. METHODS: We conducted a retrospective analysis of data collected from March 1993 to February 2005. A cohort of 390 consecutive surgical patients requiring intensive care therapy for more than 28 days was analyzed. RESULTS: The intensive care unit (ICU) survival rate was 53.6%. Survival rates at one, three and five years were 61.8%, 44.7% and 37.0% among ICU survivors. After adjustment for relevant covariates, acute and long-term survival rates did not differ significantly between 1993 to 1999 and 1999 to 2005 intervals. Acute prognosis was determined by disease severity during ICU stay and by primary diagnosis. However, only the latter was independently associated with long-term prognosis. Advanced age was an independent prognostic determinant of poor short-term and long-term survival. CONCLUSION: Acute and long-term prognosis in chronically critically ill surgical patients has remained unchanged throughout the past 12 years. After successful surgical intervention and intensive care, long-term outcome is reasonably good and is mainly determined by age and underlying disease.

Impact of sex and age on bone marrow immune responses in a murine model of trauma-hemorrhage.

Although studies have demonstrated that trauma markedly alters the bone marrow immune responses, sex and age are crucial determinants under such conditions and have not been extensively examined. To study this, 21- to 27-day-old (premature), 6- to 8-wk-old (mature), and 20- to 24-mo-old (aged) male and female (proestrus) C3H/HeN mice were sham operated or subjected to trauma (i.e., midline laparotomy) and hemorrhagic shock (30 +/- 5 mmHg for 90 min) followed by fluid resuscitation. Twenty-four hours after resuscitation, bone marrow cells were harvested. Trauma-hemorrhage induced an increased number of the early pluripotent stem cell-associated bone marrow cell subsets (Sca1(+)CD34(-)CD117(+/-)lin(+/-)) in young mice. The CD117(+) proportion of these cell subsets increased in mature proestrus females, but not in males. Aged males displayed significant lower numbers of Sca1(+)CD34(-)CD117(+/-)lin(+/-) cells compared with young male mice. Trauma-hemorrhage also increased development of granulocyte/macrophage progenitor cells (CD11b(+)Gr-1(+)). Proliferative responses to granulocyte macrophage colony-stimulating factor were maintained in mature and aged proestrus females, but decreased in young mice and mature males. Augmented differentiation into monocyte/macrophage lineage in mature and aged proestrus females was observed and associated with the maintained release of TNF-alpha and IL-6. Conversely, increased IL-10 and PGE(2) production was observed in the male trauma-hemorrhage groups. Thus, sex- and age-specific effects in bone marrow differentiation and immune responses after trauma-hemorrhage occur, which are likely to contribute to the sex- and age-related differences in the systemic immune responses under such conditions.

Influence of gender and age on T-cell responses in a murine model of trauma-hemorrhage: differences between circulating and tissue-fixed cells.

Clinical studies indicate that peripheral blood lymphocyte functions are depressed following trauma; however, it is unclear whether tissue-fixed lymphocyte functions are also altered under those conditions. Moreover, the impact of gender and age on peripheral T-cell responses following trauma-hemorrhage (TH) are unknown. To study this, immature (approximately 3 wk of age), mature (approximately 7 wk of age), and aged (approximately 23 mo of age) male and proestrus female C3H/HeN mice were sham operated or subjected to trauma (i.e., midline laparotomy) and hemorrhagic shock (30+/-5 mmHg for 90 min). Twenty-four hours after resuscitation, blood and splenocytes were harvested and T-cell functions assessed. In immature animals, TH induced an enhanced immune response in the splenic compartment and a suppressed response in the peripheral blood mononuclear cells (PBMC) that was independent of gender. Differential responses were observed in cells from mature mice. Splenic responses were enhanced following TH, independent of gender, whereas PBMC displayed gender dimorphism with suppressed proliferation and T-cell helper 1 responses in males but not in females. A similar pattern was observed in cells from aged mice. Splenic T cells from male mice displayed a suppressed CD4-to-CD8 ratio after TH, whereas no such change was observed in cells from proestrus females. In contrast, only PBMC from mature males displayed a suppressed CD4-to-CD8 ratio after TH. Thus gender differences exist in PBMC responses after TH that do not necessarily correlate with changes in the tissue-fixed compartment. Age is also an important factor in the immune responses after TH. In view of this, both gender and age should be taken into consideration in evaluating the immune status and in treatment of TH shock.

The role of interleukin-10 in the regulation of the systemic inflammatory response following trauma-hemorrhage.

Pro-inflammatory cytokine release after shock is central in the development of subsequent multiple organ dysfunction syndrome. Some studies suggest that interleukin-10 (IL-10) is an immunosuppressive mediator after injury or sepsis, while others suggest that IL-10 is an important regulator of the pro-inflammatory response. We hypothesized that in a model of trauma and hemorrhagic shock (TH), IL-10 regulates pro-inflammatory cytokine activity via an autocrine effect on cytokine mRNA transcription in Kupffer cells early after TH. To study this, male C3H/HeN mice were sham-operated or subjected to TH. Plasma levels of TNF-alpha, IL-6 and PGE(2) were elevated following TH. A sharp peak in IL-10 levels was observed at 2 h after the insult. Kupffer cell (KC) depletion prior to TH reduced plasma IL-6, IL-10 and TNF-alpha levels, whereas treatment with anti-IL-10 after TH increased IL-6 and TNF-alpha levels. Kupffer cell mRNA expression for IL-6, IL-10 and TNF-alpha was elevated in the TH group and further increased by anti-IL-10 treatment. These findings indicate that KC-dependent IL-10 regulates the early systemic inflammatory response after TH. Thus, while IL-10 is an important mediator of immunosuppression following traumatic injury, it also is beneficial with regard to its ability to counter-regulate the early inflammatory response under such conditions.

Androgen-mediated modulation of macrophage function after trauma-hemorrhage: central role of 5alpha-dihydrotestosterone.

Androgens have been implicated as the causative factor for the postinjury immune dysfunction in males; however, it remains unknown whether androgens directly affect macrophages. To study this, male mice were sham operated or subjected to trauma (i.e., midline laparotomy) and hemorrhagic shock (mean arterial pressure, 30 +/- 5 mmHg for 90 min and then resuscitated). The mice received the 5alpha-reductase inhibitor 4-hydroxyandrostenedione (4-OHA) before resuscitation. Plasma TNF-alpha, IL-6, and IL-10 levels were elevated after trauma-hemorrhage and normalized by 4-OHA. TNF-alpha and IL-6 production by splenic macrophages was decreased after injury, whereas Kupffer cell production of these mediators was enhanced. 4-OHA normalized cytokine production. Androgens suppressed cytokine production by splenic macrophages from hemorrhaged mice, whereas it enhanced TNF-alpha and IL-6 production by Kupffer cells. The addition of 4-OHA in vitro normalized cytokine production by cells treated with testosterone, but it had no effect on dihydrotestosterone-treated cells. These results indicate that androgens directly affect macrophage function in males after trauma and hemorrhagic shock and that the intracellular conversion of testosterone to dihydrotestosterone is of particular importance in mediating the androgen-induced effects.