Metabolic Depletion of Atp by Fructose Inversely Controls Cd95- and Tumor Necrosis Factor Receptor 1–Mediated Hepatic Apoptosis

Hepatocyte apoptosis is crucial in several forms of liver disease. Here, we examined in different models of murine liver injury whether and how metabolically induced alterations of hepatocyte ATP levels control receptor-mediated apoptosis. ATP was depleted either in primary hepatocytes or in vivo by various phosphate-trapping carbohydrates such as fructose. After the activation of the tumor necrosis factor (TNF) receptor or CD95, the extent of hepatocyte apoptosis and liver damage was quantified. TNF-induced cell death was completely blocked in ATP-depleted hepatocyte cultures, whereas apoptosis mediated by CD95 was enhanced. Similarly, acute TNF-induced liver injury in mice was entirely inhibited by ATP depletion with ketohexoses, whereas CD95-mediated hepatotoxicity was enhanced. ATP depletion prevented mitochondrial cytochrome c release, loss of mitochondrial membrane potential, activation of type II caspases, DNA fragmentation, and cell lysis after exposure to TNF. The extent of apoptosis inhibition correlated with the severity of ATP depletion, and TNF-induced apoptosis was restored when ATP was repleted by increasing the extracellular phosphate concentration. Our study demonstrates that TNF-induced hepatic apoptosis can be selectively and reversibly blocked upstream of mitochondrial dysfunction by ketohexose-mediated ATP depletion

The standardized herbal combination BNO 2103 contained in Canephron® N alleviates inflammatory pain in experimental cystitis and prostatitis

Background: Urinary tract infections are among the most common types of infections and give rise to inflammation with pain as one of the main symptoms. The herbal medicinal product Canephrod (R) N contains BNO 2103, a defined mixture of pulverized rosemary leaves, centaury herb, and lovage root, and has been used in the treatment of urinary tract infections for more than 25 years.Purpose: To test the hypothesis that BNO 2103 reduces pain in cystitis and prostatitis by virtue of anti-inflammatory properties, and to reveal potential mechanisms underlying the anti-inflammatory features.Study design: BNO 2103 was studied for anti-inflammatory and analgesic properties in three animal models in vivo, and the mode of action underlying the anti-inflammatory features was investigated in human leukocytes and cell-free assays in vitro.Methods: To assess the anti-inflammatory and analgesic efficacy of BNO 2103 we employed cyclophosphamide-induced cystitis and carrageenan-induced prostatitis in rats, and zymosan-induced peritonitis in mice. Human neutrophils and monocytes as well as isolated human 5-lipoxygenase and microsomal prostaglandin E-2 synthase-1-containing microsomes were utilized to assess inhibition of leukotriene and/or prostaglandin E-2 production by HPLC and/or ELISA.Results: When given orally, BNO 2103 reduced inflammation and hyperalgesia in experimental cystitis in rats, while individual components of BNO 2103 also reduced hyperalgesia. Furthermore, BNO 2103 reduced hyperalgesia in rats with carrageenan-induced prostatitis. Cell-based and cell-free studies implicate inhibition of prostaglandin E-2 and leukotriene B-4 biosynthesis as potential mechanisms underlying the analgesic and anti-inflammatory effects.Conclusion: Our data support the hypothesis that BNO 2103 reduces pain by virtue of its anti-inflammatory properties, possibly related to suppression of prostaglandin E-2 and leukotriene B-4 formation, and suggest that this combination has the potential to treat clinical symptoms such as inflammatory pain. Thus BNO 2103 may represent an alternative to reduce the use of antibiotics in urinary tract infections

Cytokine-Mediated Hepatic Apoptosis

Thirty years ago liver pathology defined apoptosis as a novel mode of cell death. Recently, experimental models of liver injury have been made available for examining the signaling molecules and receptors of apoptotic mechanisms as well as their pathological relevance. Experimental evidence suggests the involvement of apoptosis not only in various inflammatory liver disorders, but also in conditions of poisoning with xenobiotic hepatotoxins. The presence of several differentially regulated apoptosismediating receptors and their ligands on hepatocytes may explain the liver's susceptibility to autoimmune reactions, toxins, and viruses causing chronic liver disease, as well as the differential sensitivity of this system in various metabolic and pathologic conditions. Tumor necrosis factor (TNF) and its receptors (TNF-R), as well as CD95L and its receptor (CD95), are well-known cytokine/cytokine receptor systems relevant to hepatic disease and to apoptosis. Neutralization of endogenously released TNF prevents hepatocyte apoptosis associated with inflammatory liver damage. Direct injection of TNF in sensitized mice results in large scale hepatocyte apoptosis which is exclusively and selectively mediated by the 55-kDa TNF-R. Fulminant apoptotic liver damage is also triggered upon stimulation of CD95. Possible triggering cells include hepatocytes that express CD95L under pathological conditions. Despite the lack of interaction between TNF-R and CD95 on the receptor level, their signal transduction inside the cell seems to involve common proteolytic steps since inhibition of proteases of the caspase family blocks hepatocyte death, liver damage, or lethality in mice signaled by either receptor

ICE-protease inhibitors block murine liver injury and apoptosis caused by CD95 or by TNF-alpha

The two apoptosis receptors of mammalian cells, i.e. the 55 kDa TNF receptor (TNF-R1) and CD95 (Fas/APO1) are activated independently of each other, however, their signaling involves a variety of ICE-related proteases. We used a cell-permeable inhibitor of ICE-like protease activity to examine in vivo whether post-receptor signaling of TNF and CD95 are fully independent processes. Mice pretreated with the inhibitor, Z-VAD-fluoromethylketone (FMK) were dose-dependently protected from liver injury caused by CD95 activation as determined by plasma alanine aminotransferase and also from hepatocyte apoptosis assessed by DNA fragmentation (ID50=0.1 mg/kg). A dose of 10 mg/kg protected mice also from liver injury induced by TNF-α. Similar results were found when apoptosis was initiated via TNF-α or via CD95 in primary murine hepatocytes (IC50=1.5 nM) or in various human cell lines. In addition to prevention, an arrest of cell death by Z-VAD-FMK was demonstrated in vivo and in vitro after stimulation of apoptosis receptors. These findings show in vitro and in vivo in mammals that CD95 and the TNF-α receptor share a distal proteolytic apoptosis signal