Leucine Aminopeptidase Levels Research Articles

Longitudinal Follow-Up of Serum and Urine Biomarkers Indicative of COVID-19-Associated Acute Kidney Injury: Diagnostic and Prognostic Impacts.

In patients hospitalized for severe COVID-19, the incidence of acute kidney injury (AKI) is approximately 40%. To predict and understand the implications of this complication, various blood and urine biomarkers have been proposed, including neutrophil gelatinase-associated lipocalin (NGAL), chemokine (C-C motif) ligand 14 (CCL14), cystatin C, leucine aminopeptidase (LAP), and soluble urokinase plasminogen activator (suPAR). This study, conducted between mid-January and early May 2021, aimed to assess the diagnostic and prognostic capabilities of these biomarkers in a cohort of COVID-19 patients monitored during the initial two weeks of hospitalization. Among the 116 patients included in this study, 48 developed AKI within the first three days of hospitalization (41%), with 29 requiring intensive care unit (ICU) admission, and the overall mortality rate was 18%. AKI patients exhibited a statistically significant increase in urinary LAP levels, indicating acute tubular injury as a potential mechanism underlying COVID-19-related renal damage. Conversely, urinary NGAL and CCL-14 excretion rates did not differ significantly between the AKI and non-AKI groups. Importantly, elevated plasma suPAR and cystatin C levels upon admission persisted throughout the first week of hospitalization and were associated with unfavorable outcomes, such as prolonged ICU stays and increased mortality, irrespective of AKI development. In conclusion, this study underscores the early predictive value of urinary LAP levels in identifying acute tubular injury in COVID-19-induced AKI. Moreover, elevated plasma suPAR and cystatin C levels serve as valuable prognostic markers, offering insights into the short-term morbidity and mortality risks among COVID-19 patients, regardless of AKI occurrence. These findings shed light on the complex interplay between COVID-19, renal injury, and biomarkers with diagnostic and prognostic potential.

Recent Progress of Activity-Based Fluorescent Probes for Imaging Leucine Aminopeptidase.

Leucine aminopeptidase (LAP) is an important protease that can specifically hydrolyze Leucine residues. LAP occurs in microorganisms, plants, animals, and humans and is involved in a variety of physiological processes in the human body. In the physiological system, abnormal levels of LAP are associated with a variety of diseases and pathological processes, such as cancer and drug-induced liver injury; thus, LAP was chosen as the early biochemical marker for many physiological processes, including cancer. Considering the importance of LAP in physiological and pathological processes, it is critical that high-efficiency and dependable technology be developed to monitor LAP levels. Herein, we summarize the organic small molecule fluorescence/chemiluminescence probes used for LAP detection in recent years, which can image LAP in cancer, drug-induced liver injury (DILI), and bacteria. It can also reveal the role of LAP in tumors and differentiate the serum of cirrhotic, drug-induced liver injury and normal models.

Variations in the activity of proteolytic and lipidic enzymes of wild and cultured individuals of the prawn Macrobrachium tenellum Smith, 1871 (Decapoda: Caridea: Palaemonidae) fed with different diets

Abstract The freshwater longarm river prawn (Macrobrachium tenellumSmith, 1871) is common in the coastal lagoons and freshwater bodies of the Mexican Pacific region. Its potential for aquaculture has been investigated recently, including evaluating its nutritional needs by investigating the digestive enzymatic activity of wild and culture individuals. We collected wild prawns from three different habitats and fed two laboratory-prepared diets and a commercial food for two months. The levels of lipase, trypsin, and leucine aminopeptidase were measured at the time of sampling and after one and two months of culture. Survival and growth were also recorded. It was observed that food consumption during culture causes a significant increase in growth and survival as well as a tendency towards an increase in the digestive enzymatic activity with time. The habitat of origin can also influence performance in digestion from the start.

Effects of Phytoremediation on Microbial Biomass, Composition, and Function in a Sulphide-Rich Tailing From a Metal-Contaminated Region

Mining activities lead to serious land deterioration and large scale mine waste generation. Reclamation has been carried out on several technogenic materials to encourage the development of soils. To date no detailed studies have been conducted to assess if soil developed in reclaimed tailings can be suitable for microbial community sustainability and associated plant population. This study investigated if 1) soil metal contamination affects microbial biomass and composition in sulphide tailings and 2) phytoremediation of tailing increases microbial abundance, diversity, and function. Microbial biomass was assessed using Phospholipid fatty acid analysis (PLFA). Soil bacterial and fungal microbiota was determined by high throughput sequencing of 16S rRNA gene for bacteria and internal transcribed spacer region for fungi using the Illumina platform. Total copper, nickel, iron, and titium were higher in unreclaimed sites compared to vegetated areas but the total microbial biomass was significantly higher in reclaimed sites compared to reference areas. More importantly, the levels of microbial biomass were not impacted by metals since the bioavailable Cu, Ni, and Ti were low in all the sites. Site-specific bacterial and fungal genera were identified. Proteobacteria was the most dominant bacterial phylum while Ascomicota was the predominant fungal phylum. Interestinlgy, Acidiferrobacter, an acidophilic, thermotolerant and facultatively anaerobic was the most predominant genus in unreclaimed site that is characterized by extreme acidity (pH = 2.8). Analysis of microbial diversity revealed higher Chao 1, # of OTUs, Shannon index, and species richness in bacterial and fungal populations from reclaimed sites compared to controls. The levels of β-glucosidase (BG), cellobiohydrolase (CBH), β-N-acetylglucosaminidase (NAGase), aryl sulfatase (AS), acid phosphatase (AP), alkaline phosphatase (AlP), glycine aminopeptidase (GAP), and leucine aminopeptidase (LAP) activities were significantly higher in vegetated sites compared to reference areas. Strong positive correlation coefficients were observed between soil organic matter and total microbial biomass (r = 0.99). These two factors were positively correlated with enzymatic activities and bacterial population diversity. Overall, newly developed soils can sustain diverse microbial communities and associated vegetations.

A leucine aminopeptidase activatable photosensitizer for cancer cell selective photodynamic therapy action

Activity based photosensitizers (PS) continue to attract great attention as they enable selective photodynamic therapy action on cancer cells while sparing normal cells even under light irradiation. Sensitivity to specific enzymes that are differentially overexpressed in cancer cells is crucial in the design of activatable PSs. In this direction, we report here, for the first time, a leucine aminopeptidase (LAP) activatable PDT agent (HCL), which is a red-shifted, water soluble and photostable brominated hemicyanine derivative. HCL was activated by endogenous LAP enzyme selectively in A549 (lung) and HCT116 (colon) cancer cells containing high LAP levels and induced effective photocytotoxicity with negligible dark toxicity. Furthermore, the fluorescence of the parent bromo-hemicyanine core was restored upon LAP-based activation in cancer cells. On the other side, no remarkable phototoxicity or fluorescence turn-on was detected in healthy L929 cells. Thus, HCL serves as an effective and tumour associated LAP-sensitive phototheranostic agent. We believe different cancer-associated analytes can be utilized in combination with near-IR absorbing scaffolds in the scope of activatable PDT designs to enrich the tumour-selective PS arsenal.

In vivo imaging via a red-emitting fluorescent probe to diagnosing liver cancer or drug-induced liver disease

Leucine aminopeptidase (LAP) as an important proteolytic enzyme, has been mainly found in hepatobiliary cells, and overexpressed in hepatoma cells. Herein, a new highly selective red-emitting fluorescent probe (DCDHF-Ala) for LAP has been synthesized based on 2-dicyanomethyldiene-3-cyano-2, 5-dihydrofuran (DCDHF) as fluorophore, and alanine (Ala) as the detection group. More importantly, it's the first time to use Ala as a reactive group for LAP. DCDHF-Ala has a low detection limit (0.20 U/L), excellent water solubility and cell membrane permeability. In addition, the probe has been successfully applied to fluorescent imaging in cells and zebrafish. It's especially worth mentioning that, DCDHF-Ala has a high biosafety and enables a real-time detection of LAP levels in mice model. What's the most important is that DCDHF-Ala may be an effective tool to qualitatively monitor the upregulation of LAP induced by liver injury and liver cancer.

Effect of fish paste products, fish balls 'tsumire', intake in Sprague-Dawley rats.

The fish paste product, fish balls 'tsumire', is a traditional type of Japanese food made from minced fish as well as imitation crab, kamaboko and hanpen. Although tsumire is known as a high-protein and low-fat food, there is a lack of scientific evidence on its health benefits. Hence, we aimed to investigate the effects of tsumire intake on organ weight and biomarker levels in Sprague-Dawley rats for 84 d as a preliminary study. Six-week-old male Sprague-Dawley rats were divided into two groups: group I, fed normal diets, and group II, fed normal diets with 5 % dried tsumire. Throughout the administration period, we monitored their body weight and food intake; at the end of this period, we measured their organ weight and analysed their blood biochemistry. No significant differences were observed with respect to body weight, food intake, organ weight and many biochemical parameters between the two groups. It was found that inorganic phosphorus and glucose levels were higher in group II rats than in group I rats. On the other hand, sodium, calcium, amylase and cholinesterase levels were significantly lower in group II than in group I. Interestingly, we found that the levels of aspartate aminotransferase, alanine transaminase, lactate dehydrogenase and leucine aminopeptidase in group II were significantly lower than in group I, and that other liver function parameters of group II tended to be lower than in group I. In conclusion, we consider that the Japanese traditional food, 'tsumire,' may be effective as a functional food for human health management worldwide.

Purification of Leucine aminopeptidase and its correlation with biochemical parameters in sera of subclinical hypothyroidism and hypothyroidism

The aim of this study purification of Leucine aminopeptidase (LAP) from hypothyroidism patients sera and its relation to thyroid hormones, lipid peroxidation levels of subclinical hypothyroidism and hypothyroidism patients, blood samples were collected from (50) healthy subject and (100) patients, consisted of fifty with hypothyroidism and fifty with subclinical hypothyroidism.. The purification is done by addition of ammonium sulfate, dialysis, anion- exchange chromatography and size-exclusion chromatography. FT3, FT4, TSH, LAP, peroxynitrite, malondialdehyde were determined. Results showed the precipitate and concentrated protein appeared five peaks in ion exchange column, LAP activity located in the first and second protein peak, also, results showed single peak for both first and second peaks after eluted in gel filtration chromatography following steps by using SDS-polyacrylamide gel electrophoresis. From current study, it is concluded hypothyroidism (LAP) have two isoenzymes, also, concluded a highly significant increase in LAP, MDA and peroxynitrite levels in the subclinical hypothyroidism and hypothyroidism patients when compared to the healthy subject, and their correlation with FT3, FT4, TSH in the patient group, when compared by the control group that indicate these parameters could be play an effect role in these diseases.

Sex differences in the excretion levels of traditional and novel urinary biomarkers of nephrotoxicity in rats.

Urinary biomarkers have been used widely in preclinical toxicity studies to detect dysfunctions and injuries of the kidney caused by drugs under development. While they have been well studied for evaluating nephrotoxicity, knowledge of sex differences in excretion levels of urinary biomarkers remains inadequate. We conducted experiments focused on effects of endogenous sex hormones on urinary biomarkers using intact and castrated male and female rats. Comparisons of the urinary biomarker excretion levels between intact male and female rats at 5, 7, 9 and 12 weeks of age revealed higher excretion levels of leucine aminopeptidase (LAP), γ-glutamyl transpeptidase (γGTP), total protein, liver-type fatty acid-binding protein (L-FABP), cystatin C (Cys-C) and β2-microglobulin (β2-MG), and lower excretion level of kidney injury molecule 1 (Kim-1), in male rats as compared to female rats. Orchidectomized male rats showed lower urinary excretion levels of alkaline phosphatase (ALP), LAP, γGTP, N-acetyl-β-D-glucosaminidase (NAG), glucose, total protein, L-FABP, Cys-C, β2-MG and neutrophil gelatinase-associated lipocalin (NGAL), and higher urinary excretion levels of clusterin (CLU) and Kim-1, than sham-operated male rats. On the other hand, no significant differences in the urinary biomarker excretion levels excluding ALP were observed between ovariectomized and sham-operated female rats. In the present study, we demonstrated the existence of sex differences in excretion levels of urinary biomarkers that are universally used in preclinical toxicity studies, and also that these differences, especially in relation to the urinary excretions of ALP, LAP, γGTP, total protein, L-FABP, Cys-C, and β2-MG, may closely relate to the endogenous testosterone.

Endothelial Injury and Oxidative Stress in Patients with Schistosomal Hepatic Fibrosis: Relation to Renal Dysfunction and Hemodynamics

Background Schistosomiasis mansoni is associated with immune-mediated glomerulopathy; however, the mechanism of renal involvement is not well established. Endothelial injury plays an important role in the pathogenesis of chronic renal diseases and may be related to oxidative stress. The present work was designed to study markers of endothelial injury and oxidative stress in patients with schistosomal hepatic fibrosis (SHF) in relation to renal dysfunction and hemodynamics.Methods Forty-five patients with SHF (15 without albuminuria, 15 with mild/moderate albuminuria, and 15 with severe albuminuria) and 15 healthy subjects were included in the study. Endothelial injury was assessed by plasma von Willibrand factor (vWF) activity and serum angiotensin converting enzyme (ACE) levels. Serum malondialdehyde (MDA) levels and 24-hour urinary levels of leucine aminopeptidase (LAP) were measured as markers for oxidative stress and tubular damage respectively. Renal hemodynamics were assessed using Duplex-Doppler ultrasonography by calculating the diastolic/systolic renal flow velocity ratio (d/s), intrarenal resistive index (RI), and hilar renal blood flow (RBF).ResultsPatients with SHF showed significant increases in plasma vWF activity, serum levels of ACE and MDA, urinary LAP levels and RI and significant decreases in d/s and RBF compared with healthy subjects (P < 0.05). The increase in plasma vWF activity and the changes in renal hemodynamics were positively correlated but were not related to the severity of glomerular injury (P > 0.05). Serum MDA and urinary LAP levels were significantly higher in patients with albuminuria than in patients without albuminuria while serum ACE level was significantly higher in patients with severe albuminuria than in other patients (P < 0.05). There was a significant positive correlation between serum MDA levels and severity of liver disease in patients with SHF (P < 0.05).Conclusion Endothelial injury, possibly due to oxidative stress, may play an important role in the pathogenesis of renal dysfunction and increased renovascular impedence in SHF and in the initiation of schistosomal nephropathy in this disease.Disclosures All authors: No reported disclosures.

BML-111 Attenuates Renal Ischemia/Reperfusion Injury Via Peroxisome Proliferator-Activated Receptor-α-Regulated Heme Oxygenase-1.

We examine whether BML-111, a lipoxin receptor agonist, inhibits renal ischemia/reperfusion (I/R) injury, and whether peroxisome proliferator-activated receptor-α (PPARα) or heme oxygenase-1 (HO-1) is involved in protective effects of BML-111 on kidney against I/R injury. Rats subjected to renal I/R injury were treated with or without BML-111. Renal histological and immunohistochemical studies were performed. Expressions of phosphorylated p38 mitogen-activated protein kinase (pp38 MAPK), phosphorylated PPARα (pPPARα), and HO-1 were assessed in NRK-52E cells exposed to BML-111. The binding activity of PPARα to peroxisome proliferator-responsive element (PPRE) on HO-1 promoter in the cells was determined. BML-111 treatment resulted in a marked reduction in the severity of histological features of renal I/R injury, and attenuated the rise in renal myeloperoxidase and malondialdehyde, blood urea nitrogen and creatinine, urinary N-acetyl-β-glucosaminidase, and leucine aminopeptidase levels caused by I/R injury. BML-111 stimulated the renal expressions of pPPARα and HO-1, and cellular messenger RNA (mRNA) and protein expressions of pPPARα and HO-1 which were both blocked by GW6471, a selective PPARα antagonist, and ZnPP-IX, a specific inhibitor of HO-1 pretreatment. The pp38 MAPK inhibitor SB203580 blocked the BML-111-induced expressions of pp38 MAPK, pPPARα, and HO-1 in NRK-52E cells. The binding activity of PPARα to PPRE in nuclear extracts of NRK-52E cells was enhanced by treatment of the cells with BML-111, and was suppressed by GW6471 and SB203580. BML-111 protects the kidney against I/R injury via activation of p38 MAPK/PPARα/HO-1 pathway.

Effects of pre-incubation laser irradiation on hatchability and small intestine enzymes activity in post-hatched broiler chickens

The aim of this study was to investigate effects of short-term laser application on hatchability, died embryo in eggs and effects on post-hatch enzyme activity in different sections of small intestine (1, 10, 30, 50, 70 and 90%) in broiler chickens at 21 and 42 days of age. Two experiments were carried out. In the first experiment, 900 fertilised eggs (Ross 308) were randomly divided into three experimental groups (three replications and 100 eggs per group), which were irradiated with laser (HeliumNeon) at 0, 6 and 10 mW power respectively for 90 s; 12 h prior to incubation. The eggs were randomly incubated at industrial hatcheries. At hatch day, rates of unfertilised eggs, hatched, unhatched, dead unhatched embryos were determined in different phase of incubation (1–6 and 7–18 days). In the second experiment, 234 one-day-old chickens where allocated into three experimental groups based on irradiation laser levels (three replications and 26 birds per group). At post hatch days 21 and 42, six birds were randomly selected from each group, slaughtered and various sections of small intestine (1, 10, 30, 50, 70 and 90%) were sampled to evaluate alkaline phosphates (ALP), leucine aminopeptidase (LAP) and sucrase activities. According to the results, laser irradiation had no significant difference on egg hatchability, unfertilised eggs, unhatched died and died embryos (P>0.05). A significant difference was observed in small intestine LAP and ALP levels at days 21 and 42 (P<0.05). These results suggested that laser irradiation altered small intestine enzyme activity in broilers.

English

INTRODUCTION: Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver. Hepatic metastasis occurs in 40-50% of adult patients with extrahepatic primary malignancies. The levels of enzymes alkaline phosphatase (ALP), gamma glutamyl transpeptidase (GGT) and leucine aminopeptidase (LAP) are deranged in pathological conditions. AIM: To study and compare the serum enzymes Alkaline phosphatase (ALP), Gamma-glutamyl transpeptidase (GGT) and Leucine aminopeptidase (LAP) in cases of hepatobiliary carcinoma. METHODOLOGY: 30 patients diagnosed with heptobiliary carcinoma were enrolled for the study and 50 healthy individuals of matched age and sex served as controls. Serum Leucine Aminopeptidase (LAP), Alkaline Phosphatase (ALP) and Gamma-glutamyl Transpeptidase (GGT) were determined and compared in study and control groups. RESULTS: The mean levels of serum ALP, GGT and LAP in the study group were 786.3±465.05 IU/L, 193.3±116.73 IU/L and 96.86±34.74 IU/L respectively. These values were significantly higher than in the control groups. Serum LAP showed abnormal levels in maximum number of cases (93.3%) followed by serum GGT in 83.3% and serum ALP in 76.6% cases. ALP, GGT and LAP levels were significantly higher in icteric and nonicteric groups as compared to control group. CONCLUSIONS: Serum ALP, GGT and LAP were significantly elevated in the patients with hepatobiliary carcinoma and the elevations were significantly higher in icteric as compared to nonicteric groups. Serum LAP is a better indicator of hepatobiliary carcinoma.

PTU-037 Endothelial injury and oxidative stress in patients with schistosomal hepatic fibrosis: relation to renal dysfunction and haemodynamics

IntroductionEndothelial injury plays an important role in the pathogenesis of chronic renal diseases and may be related to oxidative stress. The present work was designed to study markers of endothelial...

A New Glucose-6-phosphate Dehydrogenase Deficiency Variant, G6PD Mizushima, Showing Increases in Serum Ferritin and Cytosol Leucine Aminopeptidase Levels

We made a diagnosis of glucose-6-phosphate dehydrogenase (G6PD) deficiency with a new mutation of 848A→G (exon 8) in a 16-year-old male patient presenting with severe hemolysis. He was administered a diclofenac sodium suppository (50 mg) at the time of first visit to our hospital because of pyrexia. In the acute phase, pyrexia, severe general fatigue, lumbar back pain, hemoglobinuria, and jaundice developed. Laboratory blood examinations showed hemolysis, and remarkable increases in serum ferritin and cytosol leucine aminopeptidase levels. Serum interleukin-6 and interferon-γ levels were also increased. No liver injury was found. He had neonatal jaundice persisting over 3 weeks. He did not have a history of chronic hemolysis or hyperbilirubinemia. Increases in serum ferritin or cytosol leucine aminopeptidase levels in G6PD-deficient patients were not reported earlier. In this case, it is presumed that infection and administration of anti-inflammatory agents induce the hemolytic episode and that hypercytokinemia deteriorates the disease condition.

Effect of Maternal Diabetes on Postnatal Development of Brush Border Enzymes and Transport Functions in Rat Intestine

The effect of alloxan-induced maternal diabetes has been studied on the postnatal development of brush border enzymes in rat intestine. Diabetes was induced by injecting alloxan in rat mothers on day 3 of gestation. There was no change in gestational period (22 days) in control and diabetic groups; however, the litter size was reduced (P < 0.001) in diabetic mothers compared with controls. Body weight of pups born to diabetic mothers was significantly low up to 45 days of postnatal age compared with controls. Analysis of brush border enzymes revealed elevated levels of lactase (76%), sucrase (46%), maltase (25%), trehalase (38%), alkaline phosphatase (57%), and leucine aminopeptidase (56%) up to 21 days of postnatal age in diabetic group compared with controls. However, in 30- to 45-day-old animals, the enzyme levels were either reduced in diabetic group or there was no change compared with controls. Western blot analysis corroborated the enzyme analysis data in purified brush borders. Also, 45 days after birth, the intestinal uptake of D-glucose and glycine was significantly high (30%-61%) in pups from diabetic dams compared with controls. These findings indicate that alloxan-induced maternal diabetes influences the postnatal development of intestine and the expression of various brush border enzymes and transport functions in rat intestine. This could affect the growth and development of the offspring during the postnatal period.

The Hepatocellular Hypoxia Criteria:2’Nitroimidazole Effect on Hepatocyte Carbohydrate Metabolizing Enzymes

AbstractAim: to understand the 2’-nitroimidazole induced hypoxia and liver cell interaction, we proposed a “Hapatocellular Hypoxia Criteria”. Hypothesis: The nitroimidazole induced metabolic energy loss and oxygen depletion (hypoxia) in liver cell mitochondria causes the phagocytosis. Based on it, ten control subjects with 2’-nitroimidazole therapy were studied for their carbohydrate metabolizing enzymes in serum and hepatocellular enzymes in liver biopsy tissues. Materials and Methods: Proven ten control subjects were studied for hypoxia by enzyme assays. The 2’nitroimidazole treated paired ten subjects were studied for hypoxia using enzyme assays and hepatocellular cytomorphology by electron microscopy. Results and Discussion: Out of ten subjects on 2’-nitroimidazole, nine showed elevated carbohydrate metabolizing and lysosomal enzyme levels in serum. The enzymes glucokinase (in 80% samples), aldolase (in 80% samples), phosphofructokinase (in 80% samples), malate dehydrogenase (in 75% samples), isocitrate dehydrogenase (ICDH) (in 60% patients) were elevated while succinate dehydrogenase and lactate dehydrogenase (LDH) levels remained unaltered. Lysosomal enzymes β-glucuronidase, alkaline phosphatase, acid phosphatase, showed enhanced levels in the serum samples. In control ten liver biopsies, the hepatocytes and Kupffer cell preparations showed altered enzyme levels. Hepatocytes showed lowered glucokinase (in 80%), LDH (in 80%), and higher content of aldolase (in 80%), pyruvate kinase (in 100%), malate dehydrogenase (in 80%), ICDH (in 80%), citrate dehydrogenase (in 70%), phosphogluconate dehydrogenase (in 80%). Kupffer cells showed higher enzyme levels of β-glucuroronidase (in 80%), leucine aminopeptidase (in 70%), acid phosphatase (in 80%) and aryl sulphatase (in 88%). In these 10 biopsy samples from subjects on 2’-nitronidazole clinical trial, the electron microscopy cytomorphology observations showed swollen bizarre mitochondria, proliferative endoplasmic reticulum, and anisonucleosis after 2’-Nitroimidazole effect in liver cell damage. Conclusion: The proposed “Hepatocellular Hypoxia Criteria” served to define origin of liver hypoxia and showed altered hepatic enzyme activities with active phagocytosis and cytotoxicity in subjects after 2’-nitroimidazole treatment. The study suggests the enzyme based evaluation of nitroimidazole induced hypoxia monitoring and treatment of hepatic tumors and infected liver.

Comparison of the T lymphocyte-dependent induction of angiotensin-converting enzyme and leucine aminopeptidase in cultured human monocytes

The T lymphocyte-mediated induction of angiotensin-converting enzyme (ACE) in cultured autologous peripheral blood monocytes has been proposed as a model system for the investigation of the in vivo induction of ACE in the monocyte-derived granuloma epithelioid cells of some granulomatous diseases such as sarcoidosis. The studies described here were designed to evaluate the specificity of the model system by comparing the parameters for induction of ACE with those for the induction of another monocyte metallo-ecto-peptidase, leucine aminopeptidase (LAP). The concentration of LAP in freshly isolated monocytes was 0.09 mU/10(6) monocytes (s.e.m. 0.04) and increased to a maximal value of 0.19 mU/10(6) monocytes (s.e.m. 0.32) after 3 days when monocytes were cultured alone. ACE was not detectable in freshly isolated monocytes. However, after 6 days of culture, monocytes contained 0.22 mU ACE/10(6) monocytes (s.e.m. 0.04). Comparison of the levels of ACE and LAP induced during culture of monocytes alone indicated that the induction of these two enzymes were correlated. The induction of both enzymes was further enhanced by the presence of T lymphocytes in a dose-dependent manner. At 4 x 10(6) T lymphocytes per culture, ACE levels increased to 1.81 mU/10(6) monocytes (s.e.m. 0.24) and LAP levels to 1.03 mU/10(6) monocytes (s.e.m. 0.35). The enhancement of ACE activity required autologous lymphocytes, while heterologous T lymphocytes were equally effective in inducing LAP. Comparison of the levels of ACE and LAP induced during coculture of autologous T lymphocytes and monocytes from 21 independent donors, demonstrated no correlation between the induction of ACE and LAP. These data indicate that, although T lymphocytes also enhance the induction of LAP, the underlying mechanism must differ from that of ACE induction.

Dietary Insulin Affects Leucine Aminopeptidase, Growth Hormone, Insulin-Like Growth Factor I and Insulin Receptors in the Intestinal Mucosa of Neonatal Pigs

Background: Recent studies suggest that milk-borne insulin may regulate the development of the gastrointestinal tract in neonatal mammals. Objectives: To explore the mechanism by which milk-borne insulin affects gastrointestinal tract development, we examined the effect of dietary insulin on the expression levels of leucine aminopeptidase (LAP) and insulin-like growth factor I (IGF-I), as well as its effect on growth hormone (GH), IGF-I and insulin receptors in the small intestinal mucosa of neonatal pigs. Methods: Five piglets were anesthetized and sampled within 2–4 h after birth. They were not allowed to suckle and were used as newborn controls (group N). Ten other piglets from 5 litters were randomly divided into group M (n = 5), which was fed cow’s milk, and group MI (n = 5), which was fed cow’s milk and insulin (2.5 mg/l). Piglets in groups M and MI were artificially fed for 3 days and then sampled. Total RNA in their intestinal mucosa was extracted with Tripure reagents (Roche, USA). Reverse transcription PCR (RT-PCR) was used to semi-quantify mRNA levels of target genes and 18S rRNA was used in an RT-PCR system as an internal control. PCR products were loaded onto a 9% nondenaturing polyacrylamide gel. The gel was stained by silver staining agents. Digital photos were taken and the strength of the band areas was quantified using software. Results: The results showed that the DNA contents and LAP activity in the small intestines of the piglets in group MI were higher (p < 0.05) than in the piglets in group N. Compared with group M, piglets in group MI exhibited significantly increased expression levels of both insulin and GH receptor in the ileum, and LAP in the jejunum (p < 0.05); IGF-I receptor expression levels in both the jejunum and ileum were significantly decreased (p < 0.01 and p < 0.05, respectively), while IGF-I expression was unchanged (p > 0.05). Conclusion: Collectively, dietary insulin increased mRNA levels of insulin and GH receptor, which could help explain the effect of dietary insulin on receptor-mediated postnatal development of the small intestine. Dietary insulin suppressed IGF-I receptor expression, which may be the result of negative feedback caused when insulin binds to IGF-I receptors.

Alterations in the biochemical markers of renal function after sevoflurane anaesthesia

This study has been carried out to see whether renal function is acutely altered in patients undergoing sevoflurane anaesthesia. For this purpose, the urinary levels of markers of renal tubular function, namely leucine amino peptidase (LAP), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and beta-2 microglobulin (beta-2M), and urinary albumin as a predictor of renal glomerular function were measured before and after sevoflurane anaesthesia. This study was comprised of 20 patients (11 males and nine females) aged 18-55, who underwent various elective surgical procedures under general anaesthesia. Urine samples of all patients were collected before and 1, 2 and 8 h after the anaesthesia. The levels of LAP, GGT, beta-2M, and albumin were then expressed as factored by urinary creatinine. In all patients, the anaesthesia was maintained with sevoflurane (2% end-tidal) at a high flow-rate (6 L/min). Urinary beta-2M and LAP levels after anaesthesia were unchanged (P > 0.05). While urinary GGT and ALP levels were found elevated in the first hour, LDH levels were higher in the second hour (P < 0.05). They returned to normal levels in the later periods after the anaesthesia. Urinary albumin excretion (UAE) was significantly elevated in the second hour after the anaesthesia (P < 0.001). Although UAE was decreased in the eighth hour after the anaesthesia, it still remained higher than the pre-anaesthesia level (P < 0.001). These results suggest that a 2% end-tidal concentration of sevoflurane at a high flow-rate (6 L/min) acutely alters renal glomerular function but does not have a significant acute effect on biochemical markers of renal tubular damage.