No abstract

Honey is used as a therapy to aid wound healing. Previous data indicate that honey can stimulate cytokine production from human monocytes. The present study further examines this phenomenon in manuka honey. As inflammatory cytokine production in innate immune cells is classically mediated by pattern recognition receptors in response to microorganisms, bacterial contamination of honey and the effect of blocking TLR2 and -4 on stimulatory activity were assessed. No vegetative bacteria were isolated from honey; however, bacterial spores were cultured from one-third of samples, and low levels of LPS were detected. Blocking TLR4 but not TLR2 inhibited honey-stimulated cytokine production significantly. Cytokine production did not correlate with LPS levels in honey and was not inhibited by polymyxin B. Further, the activity was reduced significantly following heat treatment, indicating that component(s) other than LPS are responsible for the stimulatory activity of manuka honey. To identify the component responsible for inducing cytokine production, honey was separated by molecular weight using microcon centrifugal filtration and fractions assessed for stimulatory activity. The active fraction was analyzed by MALDI-TOF mass spectroscopy, which demonstrated the presence of a number of components of varying molecular weights. Additional fractionation using miniaturized, reverse-phase solid-phase extraction resulted in the isolation of a 5.8-kDa component, which stimulated production of TNF-alpha via TLR4. These findings reveal mechanisms and components involved in honey stimulation of cytokine induction and could potentially lead to the development of novel therapeutics to improve wound healing for patients with acute and chronic wounds.

Supplementary key words lipopolysaccharide • cytokines • infl a mmationAs a primary interface between the lung and pathogens, the epithelial cells lining the airways and the alveoli are

Abstract. Endotoxin was measured in over 1000 plasma samples from bone marrow transplant patients in a randomized trial of the IgM-enriched intravenous immunoglobulin (IVIG) Pentaglobin. Peak endotoxaemia was significantly reduced (P=O.O2) in patients receiving Pentaglobin and 70% of all pyrexias of unknown origin were associated with endotoxaemia. Gut mucosal damage, assessed by lactulose/mannitol ratios, was significantly associated (P= 0.02) with endotoxaemia. Specific IgM antibody to endotoxin core-glycolipid was significantly raised ( P < 0.01) in patients receiving the IVIG, and the IgM fraction of Pentaglobin was found to contain most of the antiendotoxin antibody activity of the IVIG. These results suggest a role for IgM-enriched WIG as a prophylactic agent for the reduction of endotoxaemia and its consequences in bone marrow transplant patients.

Sepsis, an overwhelming inflammatory response to infection, is a major cause of morbidity and mortality worldwide and has no specific therapy. Phospholipid metabolites, such as lysophospholipids, have been shown to regulate inflammatory responses in sepsis, although their mechanism of action is not well understood. The phospholipid-metabolizing enzymes, lysophospholipid acyltransferases, control membrane phospholipid composition, function, and the inflammatory responses of innate immune cells. Here, we show that lysophosphatidylcholine acyltransferase (LPCAT) regulates inflammatory responses to LPS and other microbial stimuli. Specific inhibition of LPCAT down-regulated inflammatory cytokine production in monocytes and epithelial cells by preventing translocation of TLR4 into membrane lipid raft domains. Our observations demonstrate a new regulatory mechanism that facilitates the innate immune responses to microbial molecular patterns and provide a basis for the anti-inflammatory activity observed in many phospholipid metabolites. This provides the possibility of the development of new classes of anti-inflammatory and antisepsis agents.