Nuclear factor κB (NF-κB) is a ubiquitous inducible transcription factor responsible for mediating the expression of a large number of genes involved in inflammation, embryonic development, tissue injury, and repair.1 2 NF-κB is a complex of dimeric subunits that belong to the NF-κB/Rel family: NF-κB1 (p50 and its precursor p105), NF-κB2 (p52 and its precursor p100), p65 (RelA), RelB and c-Rel.2 3 Normally, NF-κB is inactive and resides in the cytoplasm, where it is sequestered by inhibitors of κB (IκB), of which the most important are IκBα and IκBβ.2 When cells are stimulated by cytokines, lipopolysaccharide (LPS), or reactive oxygen species (ROS), IκBs are rapidly phosphorylated at specific serine residues by IκB kinase (IKK), and subsequently polyubiquinated and then degraded by the 26S proteasome.4 IKK consists of three subunits: the catalytic IKKα and IKKβ, and the regulatory IKKγ (or NF-κB essential modulator, NEMO). IKK activity depends on its state of phosphorylation and serves as a point of convergence for NF-κB regulators [mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase kinase kinase 1 (MEKK1), NF-κB-inducing kinase (NIK), and protein kinase B (Akt)]. When IκB degrades, nuclear translocation signals (NLS) of NF-κB are unmasked, and the transcription factor is able to translocate into the nucleus. NF-κB then binds to its cognate DNA sequence and induces the transcription of its target genes (fig. 1). In certain cases, NF-κB activation can occur independently of IκB phosphorylation or degradation.

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Figure 1 Schematic diagram depicting NF-κB activation in pancreatic acinar cells in response to cerulein and inflammatory cytokines. Upon stimulation of cells, IκB kinase rapidly phosphorylates IκBα and IκBβ which leads to their degradation and release of active NF-κB. This allows NF-κB to translocate to the nucleus and bind to its cognate DNA and increase the transcription of several important pro-inflammatory genes.

This review investigates the pancreatic and extrapancreatic NF-κB activation in acute pancreatitis with an overview of recent advances since the reviews by Algül et al,5 Kim et al,6 Schmid and Adler,7 and Weber and Adler.8

NF-κB ACTIVATION IN MODELS OF EXPERIMENTAL ACUTE PANCREATITIS

Acute pancreatits is an inflammatory disease of the pancreas which ranges from mild to severe. In recent years, intense efforts have been devoted to elucidate the signalling pathways involved in regulating this disease so that novel therapeutic targets may be identified. A number of different animal models of pancreatitis have identified factors such as cholecystokinin (CCK), proinflammatory cytokines, and ROS, all of which activate pancreatic NF-κB. Table 1 provides a summary of acute pancreatitis models in which pancreatic NF-κB activation was detected.

Cholecystokinin-induced pancreatitis

Cholecystokinin (CCK) is a gastrointestinal hormone which plays a major role in normal pancreatic secretion. However, when administered at supramaximal concentrations, it inhibits pancreatic secretion and instigates a cascade of events which lead to acinar cell injury and acute pancreatitis. There is a substantial body of evidence which suggests that supramaximal doses of CCK or cerulein, its synthetic analogue, activate pancreatic NF-κB in mice and rats early in the onset of acute pancreatitis, which in turn leads to the increased expression of inflammatory mediators.9^–15 NF-κB activation occurs in a biphasic manner. The first phase of activation (due to IκBα degradation) was reported 30 min after CCK administration and then returned to near basal levels after 90 min.9 The second phase of activation (due to IκBβ degradation) occurred after 3 h and lasted for up to 6 h.9 Supershift analysis revealed that p50, p65, and p52, but not c-Rel, NF-κB complexes were induced by CCK.9 13 Consequently, NF-κB activation was found to alter the mRNA and protein levels of numerous inflammatory mediators including TNF-α in both acinar and inflammatory cells.16

Studies have shown that ethanol-feeding (a major risk factor in the development of pancreatitis) sensitises rats to CCK-induced pancreatitis.17 18 A low dose (3000 pmol/kg/h) of CCK alone was unable to induce acute pancreatitis in control-fed rats.17 18 In contrast, when the same dose of CCK was administered to rats that had received a 2- or 6-week ethanol diet, they developed acute pancreatitis. In the combined ethanol–CCK pancreatitis model, ethanol-potentiated, CCK-induced activation of pancreatic NF-κB and mRNA expression levels of TNF-α, IL-6, monocyte chemotactic protein-1, macrophage inflammatory protein-2, and inducible nitric oxide synthase (iNOS), whereas ethanol alone decreased NF-κB activation (and cytokine–chemokine expression).17^–21

Taurocholate-induced acute pancreatitis

The injection of sodium taurocholate into the bilopancreatic duct of rats causes severe acute necrotising pancreatitis and increases NF-κB DNA-binding activity.22 26 Nuclear translocation of the NF-κB p65 subunit was associated with upregulated P-selectin, ICAM-1 and adhesion molecules, in acinar and endothelial cells 1 h after taurocholate administration.27 This led to a large increase of adherent and transmigrated polymorphonuclear neutrophils. Once activated, neutrophils help increase ROS production which in turn leads to further pancreatic NF-κB activation.28 For example, phorbol myristate acetate-primed neutrophils have been shown to increase NF-κB DNA binding (p50/p50, p50/p65) as well as cytokine (IL-1β, IL-6, TNF-α) synthesis in pancreatic acinar cells.28 These increases were significantly inhibited when treated with small-molecule antioxidants.28 29

Bile–pancreatic duct ligation-induced pancreatitis

The ligation of rats’ bile–pancreatic duct leads to the increased expression and activation of protein kinases (p38 MAPK, Akt) and NF-κB, all of which were associated with elevated TNF-α levels when compared with the sham-operated control group.30^–33 NF-κB activation was detectable within 1 h and greatly increased by 24 h. Supershift assays demonstrated that the p65 subunit of NF-κB was activated in this pancreatitis model.

l-Arginine-induced acute pancreatitis

Large doses of intraperitoneally injected l-arginine (Arg) to rats and mice induces acute necrotising pancreatitis.34 35 Only one study has investigated NF-κB activation in Arg-induced pancreatitis in rats, where Arg administration was found to increase pancreatic NF-κB activation in a dose- and time-dependent manner.36 This was also associated with elevated TNF-α and IL-1β levels. NF-κB activation occurred at a later stage (12 h after Arg injection) as compared with other pancreatitis models. This delay may be attributed to the much slower progression of pancreatits.

Active RelA/p65-induced pancreatitis

Studies reported by Chen et al37 used adenoviral-mediated transfer of the active RelA/p65 NF-κB subunit via intraductal retrograde injection to eludicate pancreatic NF-κB activation. In this model, NF-κB activation was significantly elevated as compared with rats administered the control AdGFP virus. NF-κB activation led to a massive increase in the pancreatic activity of the neutrophil marker myeloperoxidase within 16 h, and remained elevated for 48 h. The neutrophils infiltrated the pancreas and lungs and resulted in widespread tissue damage. The level of NF-κB activation and the severity of inflammation were reduced when IκBα was co-administered with the RelA/p65.

The above studies, which have employed the use of numerous different models to induce pancreatitis, demonstrate an early and significant increase in pancreatic NF-κB activation. This coincides with an increase in pro-inflammatory cytokine as well as adhesion molecule expression and the influx of inflammatory cells into the pancreas, which encourage the further progression of pancreatitis.

THE EFFECTS OF INHIBITING NF-κB ACTIVATION IN EXPERIMENTAL MODELS OF ACUTE PANCREATITIS

There is an emerging body of evidence which suggests that NF-κB plays an important role in the early stages of acute pancreatitis, and that inhibiting this transcription factor (table 1) reduces its severity.

Studies have shown NF-κB activation to be localised in areas of oxidative stress, and it is now generally accepted that antioxidants are efficient inhibitors of NF-κB activation. N-acetylcysteine (NAC) (a thiol-based antioxidant) has been widely used to inhibit NF-κB activation and to decrease inflammatory cytokine production in CCK-induced, taurocholate-induced or bile-duct ligation-induced pancreatitis.19 25 33 38 In addition, lipid peroxidation inhibitors such as raxofelast also decreased NF-κB activation and reduced the severity of cerulein-induced pancreatitis.39 Another antioxidant, pyrrolidine dithiocarbamate (PDTC), has been shown to inhibit NF-κB activity in numerous animal models of pancreatitis.22 36 38 40 41 PDTC treatment reduced serum amylase and lipase activities as well as the expression of inflammatory cytokines and chemokines in the pancreas and lungs, thereby providing further evidence that NF-κB activation is crucial in the early development and continued progression of pancreatitis.

Anti-inflammatory agents have also proven effective inhibitors of pancreatic NF-κB activation. The peroxisome proliferator-activated receptor γ (PPARγ) is a member of the superfamily of ligand-dependent nuclear receptors, and possesses anti-inflammatory properties. Pre-treatment with the PPARγ ligand 15d-PGJ₂ significantly inhibited pancreatic IκB degradation and NF-κB DNA-binding activity, it also attenuated cerulein-induced acute pancreatitis in mice.42 This resulted in concomitant decrease in the levels of pro-inflammatory mediators [cyclooxygenase-2 (COX-2), ICAM-1, IL-6]. Further support for the role of anti-inflammatory agents in acute necrotising pancreatits was demonstrated using ethyl pyruvate, which significantly decreased NF-κB activation and the expression of pro-inflammatory cytokines (TNF-α, IL-6).43 Furthermore, ethyl pyruvate had a protective effect against local and systemic organ injury, as evidenced by reduced pancreatic, liver and lung injury, gut mucosal permeability, and improved long-term survival.

COX-2 is an inducible enzyme which has been shown to play a central role in the progression of inflammatory diseases. The specific inhibition of COX-2 by SC-58125 decreased the severity of pancreatitis.44 It did not, however, diminish the elevated serum and pancreatic levels of IL-1β and IL-6. Song et al12 found that COX-2 inhibition (via the use of pharmacological inhibitors and knockout mice) also decreased pancreatitic severity and pancreatitis-associated lung injury in mice. Both studies found that COX-2 inhibition did not prevent the early activation of NF-κB (30 min), but that it did inhibit the late phase of its activation (6 h).

The increased activity of various proteases has been reported in both human and experimental pancreatitis, and protease inhibitors have been shown to decrease the severity of pancreatitis via inhibition of NF-κB. Guamerin-derived synthetic peptide (a pancreatic and leukocyte elastase inhibitor), for example, significantly blocked local hallmarks of cerulein-induced pancreatitis, including neutrophil infiltration and NF-κB activation.45 Similarly, pre-treatment with a calpain I (thiol protease, which has been shown to facilitate IκBα degradation) inhibitor markedly reduced the degree of murine cerulein-induced pancreatic and lung injury.46 This was accompanied by a reduction in NF-κB activation as well as ICAM-1 expression levels and leukocyte infiltration.47 In addition, pre-treating rats with the cell-penetrable MG-132 tripeptide, a proteasome inhibitor that also inhibits other proteases (including calpains and cathepsins), significantly reduced CCK-induced NF-κB activation and was associated with reduced pancreatitic severity.48 All of the above studies provide strong evidence for the important role of NF-κB in the initiation and progression of acute pancreatitis. However, some degree of caution must be exercised when largely unspecific pharmacological inhibitors (anti-oxidants, anti-inflammatory agents) are used which have a number of limitations, including cell-type specificity, inhibition of other signalling molecules, and potential toxicity.

To address the concerns outlined above, several recent studies have used more specific compounds or knockout mice to evaluate the role of NF-κB in pancreatitis. Letoha et al49 50 described the effects of a novel cell-permeable NF-κB inhibitor. The NLS of the NF-κB p50 subunit was conjugated to the cell-penetrating penetratin peptide. That inhibitor peptide (PN50) blocked the activation of NF-κB and had a protective effect in CCK-induced acute pancreatitis.49 More importantly, PN50 effectively decreased the severity of the disease even if it was administered after the injection of CCK (although it did not inhibit NF-κB DNA-binding activity). In another study, mice were pre-treated with a novel hexapeptide that selectively inhibits NF-κB activation by blocking the interaction of NEMO with IKK; here, too, pancreatic and lung inflammation were decreased in cerulein-induced pancreatitis.51 Altavilla et al52 investigated cerulein-pancreatitis in NF-κB/p105 knockout mice. These mice had significantly decreased pancreatic NF-κB DNA-binding activity, TNF-α expression, leukocyte accumulation and oxidative stress as compared with their wild-type controls. Furthermore, laboratory and histological measurements determined that knockout animals had less severe pancreatitis. Aleksic et al53 observed pancreatic leukocyte infiltration and aggravated cerulein-induced pancreatitis in mice which expressed a constitutively active IKKβ subunit. Furthermore, Baumann et al54 described another transgenic mouse model that allows for the conditional activation and suppression of acinar cell-specific IKKβ/NF-κB signalling. In Baumann’s study, dominant-negative IKK2 expression led to a significant improvement in cerulein-induced pancreatitis. More importantly, the activation of constitutively active IKKβ by itself resulted in massive tissue damage that closely resembled cerulein-induced pancreatitis. The authors suggest that NF-κB activation within the acinar cell is critical in the development of pancreatitis via the transcriptional regulation of pro-inflammatory genes, which in turn is sufficient for the development of the disease.

Although most researchers agree that blocking NF-κB activation is beneficial in acute experimental pancreatitis, the opposite effect was seen in one of the earliest studies investigating cerulein-induced pancreatitis in rats.13 Steinle et al13 demonstrated that PDTC and NAC perpetuate acute pancreatitis. The authors reasoned that NF-κB may be involved in preventing apoptosis, and that inhibiting NF-κB could therefore result in increased apoptosis and necrosis. Notably, a recent study reported by Algül et al55 describes the use of a transgenic mouse model with a pancreas-specific deletion of the Rel A gene encoding the Rel homology domain, which is important for NF-κB DNA binding and RelA/p65 dimerisation. Surprisingly, the truncation of NF-κB resulted in a severe necrotising pancreatitis that was associated with lung inflammation and liver damage. This unexpected finding was at least in part attributed to the lack of pancreatitis-associated protein-1 (PAP-1) induction, which is vital for acinar cell protection during pancreatitis.

IS THERE A LINK BETWEEN PANCREATIC NF-κB AND TRYPSINOGEN ACTIVATION?

A possible link between NF-κB and trypsinogen activation in acute pancreatitis has been a matter of dispute. It is well known that supramaximal doses of cerulein induce the parallel activation of both pancreatic NF-κB and trypsinogen. Tando et al56 suggested that CCK-induced trypsinogen activation in rat pancreatic acinar cells may contribute to induction of NF-κB via IKK activation. Others have demonstrated that, although acinar NF-κB and trypsinogen activation occur with similar time dependence, they are independent events.10 57 NF-κB activation can occur independently of trypsinogen activation induced by LPS in vivo and by phorbol ester in pancreatic acini in vitro. Protease inhibitors PDTC and NAC attenuated both trypsin activity and NF-κB activation in cerulein-stimulated acini.10 57 However, the chymotrypsin inhibitor N-tosylphenylalanine chlormethyl ketone decreased NF-κB activation without affecting trypsin activity. Furthermore, secretagogue stimulation of pancreatic acini led to increased NF-κB activation without a concomitant increase in intra-acinar trypsinogen activation. The administration of CCK to CHO-CCK_A cells, which do not express trypsinogen, resulted in increased NF-κB activation, suggesting trypsin is not needed to activate the transcription factor.57 Furthermore, the adenovirus-mediated transfer of active p65 subunits to stimulate NF-κB, or of IκBα to inhibit NF-κB, did not affect either basal or CCK-mediated trypsinogen activation.37 57 These results suggest that the two processes can occur independently.

INTRACELLULAR SIGNALLING PATHWAYS LEADING TO NF-κB ACTIVATION

Only a few reports have described the signalling pathways leading to NF-κB activation in pancreatic acini. Recent studies have shown that NF-κB activation by CCK is mediated by an increase in intracellular Ca²⁺ levels and by protein kinase C (PKC) activation.57^–60 Hietaranta et al61 showed that water immersion stress (which is known to increase heat shock protein 60) prevents cerulein-induced NF-κB activation in vivo and in vitro. In contrast, TNF-α-induced NF-κB activation was not affected. Furthermore, the chelation of intracellular Ca²⁺ by BAPTA in pancreatic acini prevented cerulein-induced but not TNF-α-induced NF-κB activation.61 The resting [Ca²⁺]_i in acini prepared from water-immersed animals was lower when compared to their controls, and both the peak and sustained increases in [Ca²⁺]_i noted after cerulein administration were attenuated. These results support another study, which described the involvement of Ca²⁺ in pancreatitis by using the Ca²⁺ ATP-ase inhibitor thapsigargin.60 The intracellular Ca²⁺ chelator TMB-8 and the Ca²⁺/calmodulin-dependent protein phosphatase inhibitor cyclosporine A prevented the IκBα degradation and NF-κB activation induced by cerulein. It thus appears that there exists both Ca²⁺-dependent and independent mechanisms responsible for regulating NF-κB activation.

In addition, there have been several reports identifying the role of PKC in regulating CCK-induced pancreatic NF-κB activity. Treating acini with the PKC inhibitor bisindolylmaleimide prevented CCK-induced NF-κB activation. Furthermore, both CCK and TNF-α activated the novel isoforms PKC-δ and PKC-∊ as well as the atypical isoform PKC-ξ, but not the conventional isoform PKC-α.58 60 Pharmacological or antisense inhibition of the novel PKC isoforms resulted in the prevention of CCK or TNF-α induced NF-κB activation.58 60 Activating PKC isoforms and NF-κB with CCK involved both the phosphatidylinositol-specific phospholipase C (PLC) and phosphatidylcholine-specific PLC.

To date, two studies have investigated the role of phosphatidylinositide 3-kinase (PI3K) in intrapancreatic trypsinogen and NF-κB activation by secretagogue stimulation.62 63 The administration of the PI3K inhibitor wortmannin significantly decreased trypsinogen activation but not that of NF-κB in cerulein-induced and sodium taurocholate-induced pancreatitis in mice and rats.62 Cerulein-induced trypsinogen activation in rat pancreatic acinar cells was also blocked by pre-treatment with the PI3K inhibitors wortmannin and LY294002. Gukovsky et al62 also found that PI3K inhibition prevented the CCK-induced activation of trypsinogen. However, they also reported that PI3K inhibition significantly decreased CCK-induced NF-κB activation at 15–60 min in rat and mouse pancreatic acini. Moreover, pancreatic acini from mice deficient in the PI3Kγ catalytic subunit p110γ also had reduced trypsinogen and NF-κB activation, which could be further inhibited by LY294002. The differences between the two studies could possibly be attributed to the way in which PI3K was inhibited. Singh et al63 assessed the role of PI3K inhibition on NF-κB activity after in vivo administration of wortmannin. In contrast, Gukovsky et al62 assessed PI3K inhibition in isolated pancreatic acini from wild-type and PI3Kγ-deficient mice at different time points. Thus, it appears that calcium, PKC, and PI3K signalling pathways play an important role in regulating NF-κB activity in acute pancreatitis (fig. 2). Therefore, targeting these signalling pathways may help reduce the severity of acute pancreatitis.

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Figure 2 Pathways of NF-κB activation in pancreatic acinar cells in response to cerulein and TNF-α. Cerulein-induced NF-κB activation is mediated via a Ca²⁺-dependent pathway which involves both the PKC and PI3K signalling molecules. TNF-α induced NF-κB activation is mediated by a Ca²⁺-independent pathway which involves PKC.

EXTRAPANCREATIC NF-κB ACTIVATION

Numerous studies have demonstrated that NF-κB is also activated outside of the pancreas (table 2) during acute pancreatitis, which is not surprising given the fact that the inflammatory disease also affects extrapancreatic tissues.

NF-κB activation in the liver and lungs

A study reported by Gray et al64 showed significantly increased NF-κB activation using bioluminescence in both the liver and lungs of transgenic mice (expressing luciferase controlled by an NF-κB-dependent promoter) fed a choline-deficient diet supplemented with ethionine (CDE) to induce acute necrotising pancreatitis. However, in a later investigation, the same group could only show a 2-fold hepatic, but no pulmonary NF-κB, activation in wild-type mice subjected to CDE.65 Similarly, Peng et al found that CDE-pancreatitis induces nuclear translocation of the RelA/p65 subunits in the liver.66 In addition, hepatic NF-κB activation was observed in rats with taurocholate-induced pancreatitis.67

PAP, which is over-expressed during acute pancreatitis induced lung inflammation and exacerbated the severity of sodium taurocholate-induced acute pancreatitis when injected into the vena cava of rats.69 A significant increase in plasma TNF-α levels as well as over-expression of its mRNA in hepatocytes was observed with concomitant activation of NF-κB. Lung inflammation induced by PAP was prevented by the injection of anti-TNF-α antibodies. In contrast to these findings, a study reported by Vasseur et al showed that treating isolated alveolar macrophages or AR42J cells with PAP-I almost completely prevented TNF-α-induced NF-κB activation and inflammatory cytokine expression.70 Algül et al also demonstrated that PAP-I plays a role in preventing acinar cell death, and that NF-κB is responsible for mediating its expression.55

Fujita et al investigated the role of pancreatitis-associated ascitic fluid (PAAF) on cerulein-induced pancreatitis.71 Intraperitoneally injected PAAF decreased the survival rates of rats, despite a similar picture of pancreatic histological damage and laboratory values (haematocrit, serum amylase, oedema index, pancreatic myeloperoxidase activity) as compared with controls. However, destroyed blood vessels, alveolar septal thickening, interstitial hypertrophy, and infiltration of numerous inflammatory cells were noted in the lungs of PAAF-treated rats. Furthermore, NF-κB activation was observed in the infiltrating mononuclear cells and increased levels of TNF-α and IL-1β were also detected in the lungs of PAAF-injected animals. PDTC and NAC ameliorated the histological findings in the lung and improved survival rates. PAAF administration also significantly increased NF-κB activation as well as TNF-α production in rat pancreatic acinar cells.72

Endothelial NF-κB activation

Endothelial activation is thought to be involved in the pathogenesis of acute pancreatitis. Masamune et al examined the effect of rat PAAF on the expression of adhesion molecules in human umbilical vein endothelial cells (HUVEC).73 74 Endothelial NF-κB (p50/p65), ICAM-1 and VCAM-1 levels were dose-dependently increased in HUVEC. Furthermore, enhanced ICAM-1 expression was also noted in the pancreas and lungs of pancreatitic animals.

Monocyte–macrophage NF-κB activation

Peritoneal and alveolar macrophages collected from rats with cerulein- or taurocholate-induced acute pancreatitis exhibited increased NF-κB activation (3–24 h after disease induction).75^–78 Treatment with antioxidants PDTC or resveratrol dose-dependently inhibited NF-κB activation in rat peritoneal macrophages.76 77 Macrophages isolated from rats with acute necrotising pancreatitis had higher levels of NF-κB activation as well as TNF-α, IL-6, and iNOS expression.76 78 In addition, the supernatant of taurocholate-pancreatitis ascites was able to induce iNOS production in the peritoneal macrophages of normal rats in vitro.76 Taken together, the above results provide strong evidence that soluble mediators are produced and released during pancreatic inflammation and then circulate into the bloodstream to activate NF-κB in macrophages and endothelial cells in distant organs, thereby perpetuating multi-organ inflammation.

Only a few reports have investigated NF-κB activation in human acute pancreatitis. Satoh et al examined NF-κB activation in peripherial blood mononuclear cells (PBMCs) of 45 patients with acute pancreatitis at admission and 14 days after the onset of the disease.79 At admission, PBMCs from patients with acute pancreatitis showed significantly higher levels of NF-κB activities and p50/p65 heterodimers when compared to the control subjects. Similarly, O’Reilly et al detected significantly increased NF-κB activation in PBMCs of acute pancreatitic patients within 24 h of symptom onset.80 No significant differences were detected between patients with severe and mild pancreatitis.79 80 LPS treatment of PBMCs from control subjects and patients with mild pancreatitis further activated NF-κB.79 However, this response was significantly reduced in patients with severe pancreatitis. Patients who had persistently high NF-κB DNA-binding activity, a reduced response of NF-κB to LPS, and a low p50/p65 ratio after LPS stimulation at 14 days were more likely to develop serious systemic complications.

CONCLUSION

In the past few years, the role of NF-κB activation in the pathogenesis of acute pancreatitis has been under intense scrutiny. Although the cytoprotective effect of blocking NF-κB activation in animal models prior to induction of acute pancreatitis is more or less proven, further studies are required to test whether or not inhibiting NF-κB activation after the onset of the disease (which closely resembles the clinical situation) is beneficial. Also, signalling proteins and pathways which are involved with regulating NF-kB activation must be further identified, so that these molecules can be assessed for their therapeutic potential. Neither can we forget that the transcription factor also regulates anti-inflammatory genes, so that future studies which are designed to inhibit NF-κB activation must consider targeting strategies to the organ of interest. Finally, we are far behind in the field of human investigations; determining genetic polymorphisms in the genes involved in inflammation, for example, would shed light on the pathogenesis of pancreatitis. Hopefully, the continued discovery and application of more selective NF-κB inhibitors and the use of transgenic mice will help us to better understand the exact role of NF-κB in inflammatory diseases like pancreatitis.