Disease relevance of LIPF

• To ascertain if an inadequate selection of patients might explain part of this variability, two different groups of patients with interstitial pulmonary fibrosis, those with the "lone" form of the disease (LIPF) and those with associated collagen vascular disorders (AIPF), were studied separately [1].
• Recombinant HGL (r-HGL) was expressed in the baculovirus/insect cell system in the form of an active protein with a molecular mass of 45 kDa [2].
• These observations suggest a significant role for nonpancreatic lipolytic activity (lingual lipase and gastric lipase) in fat digestion in patients with pancreatic insufficiency secondary to chronic alcohol abuse [3].
• The aims of this study were to evaluate the amount of gastric lipase secreted by the stomach in normal adults and to elucidate a possible adaptative secretion of this enzyme in response to pancreatic insufficiency secondary to alcoholic chronic pancreatitis [4].
• On the other hand, high gastric lipase outputs were found in eight patients with duodenal ulcers and no evidence of pancreatic dysfunction (23,180 +/- 262 U/h) [4].

High impact information on LIPF

• The complete digestion of human milk triacylglycerol in vitro requires gastric lipase, pancreatic colipase-dependent lipase, and bile salt-stimulated lipase [5].
• Gastric lipase was unique in its ability to initiate hydrolysis of milk triacylglycerol [5].
• Activated bile salt-stimulated lipase could not on its own hydrolyze native milk fat globule triacylglycerol, whereas a limited hydrolysis by gastric lipase triggered hydrolysis by bile salt-stimulated lipase [5].
• Based on the in vivo data, lipolysis was also performed in vitro by mixing the meal either with gastric juice and subsequently with pancreatic juice and bile or with purified HGL and HPL [6].
• RESULTS: In vitro, the specific activities on the liquid meal TGs were 32 (gastric juice) and 34 (pure lipase) micromol x min(-1) x mg(-1) with HGL and 47 (pancreatic juice) and 43 (pure lipase) micromol x min(-1). mg(-1) with HPL [6].

Chemical compound and disease context of LIPF

• Gastric lipase in alcoholic pancreatitis. Comparison of secretive profiles following pentagastrin stimulation in normal adults and patients with pancreatic insufficiency [4].

Biological context of LIPF

• Epidermal growth factor and transforming growth factor alpha down-regulate human gastric lipase gene expression [7].
• In other words, gastric lipase might hydrolyze 1 acyl chain of 4, which need to be hydrolyzed for a complete intestinal absorption of monoglycerides and free fatty acids resulting from the degradation of two triglyceride molecules [8].
• In vitro experiments examined gastric lipolysis of differently sized phospholipid-triolein emulsions by human gastric juice or purified human gastric lipase, under close to physiological conditions [9].
• Mechanisms of inhibition of triacylglycerol hydrolysis by human gastric lipase [9].
• The positions of the HLAL intervening sequences are also absolutely conserved, except for the location of intron 1 [10].

Anatomical context of LIPF

• RESULTS: At enrollment, patients with LIPF and AIPF were of similar age, and had similar symptoms and derangement of lung function, but patients with LIPF presented with finger clubbing, more obvious radiographic abnormalities, and a greater percentage of eosinophils in bronchoalveolar lavage fluid [1].
• While no further activation occurred in the group of normal-hearing subjects, CI patients additionally recruited the right perirhinal/fusiform and mid-fusiform, the right temporo-occipito-parietal (TOP) junction and the left inferior prefrontal cortex (LIPF, Broca's area) [11].
• Gastric lipase remained active in the duodenum where it might still hydrolyze 7.5% of the triglyceride acyl chains [8].
• Comparison of the lipase activity levels in the gastric mucosa with lingual lipase activity levels in specimens of lingual serous glands indicates that in humans, gastric lipase is the main lipase active in the stomach [12].
• RESULTS: HGL was localized in the secretory granules of gastric chief cells as early as 13 weeks [7].

Associations of LIPF with chemical compounds

• CONCLUSIONS: Globally during the whole digestion period, gastric lipase might hydrolyze 17.5% of the triglyceride acyl chains [8].
• Chemical modification studies and site-directed mutagenesis experiments have provided evidence that human lysosomal acid lipase/cholesteryl ester hydrolase (HLAL), human gastric lipase (HGL), and rat lingual lipase (RLL) are serine esterases [13].
• To study the functional role of the HLAL and HGL cysteine residues, we replaced these amino acids with alanine by site-directed mutagenesis [13].
• The cysteine residues of recombinant human gastric lipase [14].
• Human gastric lipase (HGL) is a highly glycosylated protein, as glycan chains account for about 15% of the molecular mass of the native HGL [15].

Regulatory relationships of LIPF

• EGF and/or TGF-alpha down-regulated HGL mRNA levels and decreased enzymic activity [7].
• Gastric lipase was totally inhibited by 40 mg AR25/g tributyrin whereas pancreatic lipase inhibition was maximum (78.8 +/- 0.7%) with 80 mg AR25/g tributyrin [16].
• RESULTS: Gastric lipase secretion (the quantity as well as the lipolytic activity) was significantly stimulated by gastrin [17].

Other interactions of LIPF

• BACKGROUND & AIMS: It was recently reported that human gastric lipase (HGL) activity is modulated by epidermal growth factor (EGF) [7].
• RESULTS: On a weight basis, the ratio of pancreatic lipase to gastric lipase total secretory outputs was found to be around four after 3 hours of digestion [8].
• Hepatic LAL differed from fibroblast acid lipase at the N-terminus and revealed extensive similarities with human gastric lipase and rat lingual lipase, confirming a gene family of acid lipases [18].
• The aim of this study was to examine the effect of gastrin on the gastric lipase secretion in patients with pancreatic insufficiency [19].
• GLP-1 infused intravenously in amounts corresponding to the postprandial release significantly inhibited pentagastrin-stimulated gastric lipase secretion and lipolytic activity [20].

Analytical, diagnostic and therapeutic context of LIPF

• Gastric lipase activity was clearly distinguished from that of pancreatic lipase by using both a specific enzymatic assay and an enzyme-linked immunosorbent assay [8].
• Enzymic determinations, Western blotting, and Northern hybridization were used to analyze expression of HGL mRNA, protein, lipase activity, and the p42/p44(mapk) activation status [7].
• METHODS: Cellular localization of HGL was determined by immunohistochemistry using a polyclonal antibody [7].
• The lipolysis process was further investigated by scanning electron microscopy, and gastric lipase and free fatty acid movement during lipolysis were followed by fluorescence microscopy [9].
• Human lysosomal acid lipase/cholesteryl ester hydrolase and human gastric lipase: site-directed mutagenesis of Cys227 and Cys236 results in substrate-dependent reduction of enzymatic activity [13].

References