Ketan Sheth

The liver as an immune organ

Systemic inflammation contributes to significant morbidity in the ICU. With its ability to generate antiinflammatory acute-phase proteins, cytokines via Kupffer cells, and recently acknowledged resident lymphocytes, the liver provides a central regulatory role in inflammation. The liver has constant exposure to foreign material as a result of gut translocation and first-pass metabolism from the bloodstream. Consequently, the balance between hepatic activation and tolerance becomes an important factor in the host response to inflammation. Interventions and therapies that can assess and modulate these hepatic functions can improve outcomes for ICU patients.

Effect of Neoadjuvant Chemoradiation on Operative Mortality and Morbidity for Pancreaticoduodenectomy

BackgroundNeoadjuvant chemoradiotherapy (neo-CRT) is being used with increasing frequency for periampullary tumors, but how it alters the complication rate of pancreaticoduodenectomy (PD) is unclear.MethodsA retrospective analysis was conducted of 79 patients with periampullary malignancies who received 5-fluorouracil–based neo-CRT followed by PD.ResultsThere was no difference in mortality between PD after neo-CRT (3.8%) and conventional PD for either malignant (4.5%) or benign (2.2%) disease. Focusing only on patients with malignancy, the neo-CRT group had a significantly lower pancreatic leak rate than the conventional group (10% vs. 43%; P < .001). Intra-abdominal abscesses were less common in the neo-CRT group (8.8% vs. 21%; P = .019), and there was one (1.2%) amylase-rich abscess in neo-CRT group, compared with eight (12%) in the conventional group. In addition, two patients in the conventional group died of leak-associated sepsis, compared with none in the neo-CRT group. Multivariate analysis revealed that neoadjuvant chemoradiation (odds ratio, .15) was the most significant factor associated with a reduced risk of pancreatic leak.ConclusionsNeo-CRT does not increase the mortality or morbidity of PD. In contrast, neo-CRT was associated with a marked reduction in the incidence of pancreatic leak, as well as leak-associated morbidity and mortality.

Inhibited neutrophil apoptosis: proteasome dependent NF-kappaB translocation is required for TRAF-1 synthesis.

Neutrophil (PMN) apoptosis regulates local and systemic inflammation during sepsis. Tumor necrosis factor receptor-associated factors (TRAFs) have been implicated as mediators of apoptosis; however, the signaling pathways for their production in stimulated PMN are unclear. We hypothesize that NF-kappaB translocation is necessary for the induction of TRAF-1 in PMNs with prolonged survival. Neutrophils were isolated from the blood of healthy volunteers by Ficoll gradient centrifugation and red blood cell sedimentation. Neutrophil NF-kappaB was inhibited with a proteasome inhibitor, PSI-I. Cells were treated with PSI-I (30 microM) or vehicle (DMSO 0.2%) for 50 min then incubated over an 18-h time course with LPS (10 to 1000 ng/mL), tumor necrosis factor alpha (TNFalpha) (2 to 20 ng/mL) or control media. In vitro apoptosis was quantified by propidium iodide FACS analysis. Total cellular TRAF-1 was detected by Western blot analysis of cell lysates. Steady state TRAF-1 mRNA was detected by RPA. NF-kappaB activity was determined by Western blot analysis for nuclear p65. Means and standard errors were calculated; data were analyzed by ANOVA. Lipopolysaccharide (LPS) and TNFalpha increased PMN nuclear p65 and steady state TRAF-1 mRNA. Apoptosis was inhibited by TNFalpha and LPS at 12 and 18 h (P < 0.01). Incubation of cells in the NF-kappaB inhibitor PSI-I blocked LPS and TNFalpha-induced inhibition of apoptosis (P < 0.05) and the induction of both nuclear p65 and TRAF-1 mRNA. These data demonstrate that inhibition of PMN apoptosis and TRAF-1 induction by LPS and TNFalpha is NF-kappaB dependent.

Management of hepatic metastases from colorectal cancer.

The majority of hepatic metastases in the United States occur in patients with a primary colorectal malignancy. Advances in technology combined with increasing surgeon experience have broadened the treatment options available for hepatic metastases from colorectal cancer. Surgical resection is the most effective therapy for metastatic colorectal cancer isolated to the liver. The aim of this article is to discuss the role of locally aggressive treatment options including resection, ablation, and regional chemotherapy in the management of patients with metastases from colorectal cancer.

Activated neutrophils induce nitric oxide production in Kupffer cells.

Neutrophils (PMN) are proposed to contribute to hepatic dysfunction during sepsis. Transmigrating PMN have been demonstrated to adhere to and injure parenchymal cells (hepatocytes); however, the effect of sepsis-activated PMN on hepatic macrophages or Kupffer cells (KC) is poorly characterized. We hypothesize that PMN influence KC inflammatory mediator production, including nitric oxide. Rodent KC were co-cultured with PMN obtained from controls (Norm-PMN) or endotoxemic rats [lipopolysaccharide (LPS)-PMN] for 18 h. After an 18-h incubation, supernatants and cell lysates of the KC were analyzed for nitric oxide (NO) production. Co-cultures with LPS-PMN/KC demonstrated significantly increased production of nitrite and up-regulation of inducible nitric oxide synthase (iNOS) protein compared to KC alone or Norm-PMN/KC co-cultures. Immunohistochemistry revealed preferential iNOS protein staining in the cytoplasm of KC cultured with LPS-PMN compared to controls. Nitrite production in co-cultures of KC and LPS-PMN where cell contact was inhibited by a cell impermeable but diffusable membrane was significantly reduced. These data provide evidence that KC can be stimulated directly by activated PMN for production of NO. Further, they suggest another mechanism by which PMN modulate hepatic function during sepsis.

Down-regulated circulating PMN function after injury despite enhanced p38 MAPK activity.

BACKGROUND Neutrophils (PMN) are initially primed by injury. However, remaining PMN found in the circulation postinjury demonstrate a down-regulated phenotype with inhibited apoptosis, CXCR2 expression, and endotoxin (LPS) responsiveness that may contribute to infectious complications and organ dysfunction. The p38 mitogen activated protein kinase (MAPK) signal transduction pathway has been implicated in regulating each of these PMN functions. We, therefore, hypothesize that p38 signaling is similarly down-regulated in postinjury circulating PMN. MATERIALS AND METHODS PMN were isolated from trauma patients (ISS > 20, postinjury day 3) and concurrently from healthy volunteers (control). PMN were cultured with LPS (100 ng/mL) and p38 activity assessed by Western blotting of cell lysates using a dual phosphospecific antibody for phosphorylated, active p38. In separate experiments, PMN from healthy volunteers were cultured in plasma from either healthy or injured subjects +/- LPS and p38 activity assessed by a cell-free in vitro kinase assay using the transcription factor, ATF-2, as a substrate. Apoptosis and IL-1beta secretion of the cultured PMN from each experimental condition were also quantified. RESULTS Circulating PMN from trauma patients have an upregulated LPS signaled p38 MAPK response (threefold) compared to PMN from healthy volunteers (p < 0.05). Furthermore, circulating factors present in trauma plasma can transfer this response to normal PMN. There was no significant alteration in apoptosis following LPS treatment between control and trauma patients PMN (control: 62 +/- 3% vs. trauma: 55 +/- 5%), but there was decreased secretion of IL-1beta (control: 100 +/- 28 pg/mL vs. trauma: 12 +/- 5 pg/mL, p < 0.05). CONCLUSION We conclude that injury down-regulates selective PMN function despite enhanced p38 activity. These results suggest a shift in the role of PMN p38 signal transduction following injury with additional critical regulation of LPS responses downstream to p38 MAPK activity.