Intestinal Alkaline Phosphatase Secretion in Oil-Fed Rats

Oil feeding is known to increase the secretion of intestinal alkaline phosphatase (IAP) into serum and this phenomenon is shown to be mediated by surfactant-like particles. These lipoprotein particles are secreted by enterocytes and are rich in phosphatidyl choline and IAP. The exact mechanisms underlying this phenomenon are not known. We studied the effect of feeding different oils varying in fatty acid composition, i.e., coconut oil, corn oil, and cod liver oil, on the secretion of IAP into serum. Also, the effect of actinomycin D treatment on this phenomenon was evaluated. Male albino rats were fed 2 ml of various oils. Alkaline phosphatase activity was measured in serum, luminal washings, and other intestinal fractions. Cod liver oil was found to maximally enhance the soluble and membrane-bound IAP as well as secretion of IAP into lumen and serum. Administration of actinomycin D significantly reduced the enzyme activity in serum and various intestinal fractions in both control and cod liver oil-fed rats. These results were further substantiated by 5-bromo-4-chloroindolyl phosphate staining of IAP in acrylamide gels and by western blotting. The effect of cod liver oil feeding was specific for IAP, as there was no change in the activity of another brush border enzyme, sucrase, under these conditions. These findings suggest that fatty acid composition of the oil determines the amount of IAP secretion and there is coordination between IAP synthesis and its secretion for transport into serum in response to oil feeding.     

Intestinal Alkaline Phosphatase Attenuates Alcohol-Induced Hepatosteatosis in Mice

Digestive Diseases and Sciences - Bacterially derived factors from the gut play a major role in the activation of inflammatory pathways in the liver and in the pathogenesis of alcoholic liver...     

Association of Serum Alkaline Phosphatase with Coronary Artery Calcification in Maintenance Hemodialysis Patients

Background and objectives: Recent in vitro studies have shown a link between alkaline phosphatase and vascular calcification in patients with chronic kidney disease (CKD). High serum levels of alkaline phosphatase are associated with increased death risk in epidemiologic studies of maintenance hemodialysis (MHD) patients. We hypothesized that coronary artery calcification is independently associated with increased serum alkaline phosphatase levels in MHD patients.Design, setting, participants, & measurements: We examined the association of coronary artery calcification score (CACS) and alkaline phosphatase in 137 randomly selected MHD patients for whom markers of malnutrition, inflammation, and bone and mineral disorders were also measured.Results: Serum alkaline phosphatase was the only measure with significant and robust association with CACS (P < 0.003), whereas either other biochemical markers had no association with CACS or their association was eliminated after controlling for case-mix variables. Serum alkaline phosphatase >120 IU/L was a robust predictor of higher CACS and was particularly associated with the likelihood of CACS >400 (multivariate odds ratio 5.0 95% confidence interval 1.6 to 16.3; P = 0.007). Serum alkaline phosphatase of approximately 85 IU/L seemed to be associated with the lowest likelihood of severe coronary artery calcification, but in the lowest tertile of alkaline phosphatase, the CACS predictability was not statistically significant.Conclusions: An association between serum alkaline phosphatase level and CACS exists in MHD patients. Given the high burden of vascular calcification in patients with CKD, examining potential therapeutic interventions to modulate the alkaline phosphatase pathway may be warranted.Vascular calcification is common in individuals with chronic kidney disease (CKD) and is a significant correlate of the high cardiovascular death risk (1–3). Both intimal and medial calcification are observed frequently in patients with CKD (4–7). Several mechanisms have been implicated for the high prevalence of vascular calcification in CKD, including the high burden of conventional cardiovascular risks such as diabetes, hypertension, and dyslipidemia; bone and mineral disorders such as calcium load and secondary hyperparathyroidism (SHPT); chronic inflammation such as high level of proinflammatory cytokines; and deficiency of anticalcemic factors such as fetuin (8,9). Lomashvili et al. (5) reported that vascular damage can induce expression of tissue-nonspecific alkaline phosphatase (AlkPhos), which per se hydrolyzes and inactivates inorganic pyrophosphates, a process that can enhance vascular calcification. We recently showed that higher serum AlkPhos levels in maintenance hemodialysis (MHD) patients were independently associated with increased all-cause and cardiovascular mortality in approximately 74,000 MHD patients, even after adjustment for surrogates of nutrition, inflammation, minerals, serum parathyroid hormone (PTH), and liver enzymes (10). Nevertheless, the pathophysiologic link between increased AlkPhos level and mortality in MHD patients is not clear. Given the recent in vitro findings about the link between AlkPhos and vascular calcification via the pyrophosphate pathway, we hypothesized that the increased cardiovascular and all-cause death risk observed in the setting of high serum AlkPhos level may be related to vascular calcification in MHD patients (6,11). To test this hypothesis, we examined the association of serum AlkPhos and coronary artery calcification in a cohort of MHD patients for whom other risk factors of cardiovascular disease including inflammatory markers were also examined.     

Combined Alkaline Phosphatase and Phosphorus Levels as a Predictor of Mortality in Maintenance Hemodialysis Patients

Hyperphosphatemia-induced vascular calcification and higher alkaline phosphatase (ALP) levels-related high-turnover bone diseases are linked to mortality among patients with chronic kidney disease (CKD). Nonetheless, no large epidemiological study in patients with CKD has been conducted to investigate the interaction and joint effect of hyperphosphatemia and higher ALP levels on mortality.We analyzed 11,912 maintenance hemodialysis patients from January 2005 to December 2010. Unadjusted and adjusted hazard ratios (aHRs) of death were calculated for different categories of serum phosphorus and ALP using the Cox regression model. The modification effect between serum phosphorus and ALP on mortality was determined using an interaction product term.Both hypophosphatemia (<3.0 mg/dL) and hyperphosphatemia (>7.0 mg/dL) were associated with incremental risks of death (aHR: 1.25 [95% confidence intervals (CIs): 1.09–1.44], and 1.15 [95% CI: 1.01–1.31], respectively) compared to the lowest hazard ratio (HR) group (5 mg/dL ≤ phosphorus < 6 mg/dL). ALP levels were linearly associated with incremental risks for death (aHR: 1.58 [95% CI: 1.41–1.76] for the category of ALP > 150 U/L). In the stratified analysis, patients with combined higher ALP (>150 U/L) and hyperphosphatemia (>7.0 mg/dL) had the greatest mortality risk (aHR: 2.25 [95% CI: 1.69–2.98] compared to the lowest HR group (ALP ≤ 60 U/L and 4 mg/dL ≤ phosphorus < 5 mg/dL). Although the effect of hyperphosphatemia on mortality seemed stronger in higher ALP levels, the interaction was not statistically significant (P = 0.22).The association between serum phosphorus levels and mortality was not limited to higher ALP levels. Regardless of serum ALP levels, we may control serum phosphorus levels merely toward the normal range. While considering the joint effect of ALP and hyperphosphatemia on mortality, the optimal phosphorus range should be stricter.     

A Novel Role of SLC26A3 in the Maintenance of Intestinal Epithelial Barrier Integrity

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Alkaline Phosphatase Activity in Immature Granulocytes

A positive reaction for alkaline phosphatase activity in granulocyte precursors (myelocytes, promyelocytes and even some blast cells) has been observed in three patients. Two of them had a blastic crisis of subacute or chronic myeloid leukaemia. In the third patient with a blastic crisis of a myeloproliferative syndrome, AP activity was unusually high in pseudo-Pelger forms of neutrophils from the myelocyte stage onwards. All other cytochemical reactions were normal and in accordance with the myeloid character of the blast cells. The nature of the cells involved and possible explanations of this unusual finding are discussed.     

The Role of Innate Immunity in the Host Defense Against Intestinal Bacterial Pathogens

Eradication of infectious disease is our global health challenge. After encountering intestinal infection with a bacterial pathogen, the host defense program is initiated by local antigen-presenting cells (APCs) that eliminate invading pathogens by phagocytosis and establish localized inflammation by secreting cytokines and chemokines. These pathogen-experienced APCs migrate to the mesenteric lymph nodes, where host immune responses are precisely orchestrated. Initiation and regulation of this defense program appear to be largely dependent on innate immunity which is antigen non-specific and provides a rapid defense against broader targets. On the other hand, many bacterial enteropathogens have evoked abilities to modify the host defense program to their advantage. Therefore, better understanding of the host-pathogen interactions is essential to establish effective eradication strategies for enteric infectious diseases. In this review, we will discuss the current understanding of innate immune regulation of the host defense mechanisms against intestinal infection by bacterial pathogens.     

Sodium Butyrate-Induced Liver-Type Alkaline Phosphatase Activity in a Small Intestinal Epithelial Cell Line, IEC6

Sodium butyrate is a well-recognizeddifferentiating agent inducing alkaline phosphataseactivity, one of the epithelial differentiation markers.When IEC6 cells, a nontransformed, small intestinalepithelial cell line, were cultured with butyrate, thissubstrate induced alkaline phosphate activity in a time-and dose-dependent fashion. However, the type ofisoenzyme involved was a liver-type, not anintestinal-type. Electron microscopy revealed that the inducedactivity was strictly localized in the cytosol and noton the plasma membrane. However, disaccharidaseactivities, another kind of differentiation marker, were also enhanced by sodium butyrate. In addition,the positive cells demonstrating the presence ofalkaline phosphatase activity were preferentiallyobserved in tubular structures. These data show thatbutyrate-induced alkaline phosphatase activity is closelyassociated with differentiation-like phenomena in IEC6cells, although the type of isoenzyme and cellularlocalization of the activity are different from thoseobserved in mucosa.     

利用碱性磷酸酶抗碱性磷酸酶法检测凝血酶受体

凝血酶受体被凝血酶激活时，凝血酶受体结合于细胞膜处氨基末端精氨酸41／丝氨酸42被裂解，释放出一个包含有41个氨基酸残基的多肽（TR1－41）。根据TR1－41的氨基酸序列，对其进行合成，并对小鼠进行免疫，筛选得到了4个产生抗TR1－41单克隆抗体的细胞株。利用抗TR1-41单克隆抗体建立了一种检测凝血酶受休的免疫酶组织化学方法-碱性磷酸酶抗碱性磷酸酶法，并成功地检测了心肌细胞凝血酶受体，该方法可以用于组织器官凝血酶受体的检测。     

Studies of Leukocyte Alkaline Phosphatase in Mongolism: A Possible Chromosome Marker

Leukocyte alkaline phosphatase was measured by a biochemical method ina group of 58 mongolian idiots. The mean activity found in the 41 childrenless than 10 years of age was equivalent to 89 mg. of phosphorus per 10¹⁰neutrophilic leukocytes per hour. This was compared to the value of 66 mg.of phosphorus per 10¹⁰ neutrophilic leukocytes per hour obtained in a groupof 41 control children in the same age group (after correction of the controlmean to the same mean age). The difference is significant at the 0.5 per centlevel of confidence.

This difference was interpreted as confirming (but not proving) the hypothesis that leukocyte alkaline phosphatase formation is controlled by a geneon chromosome number 21—the chromosome for which mongolian idiots aretrisomic. The hypothesis arose because of the known deficiency of this enzymein the leukocytes of patients with chronic granulocytic leukemia, and theknown partial deletion of chromosome 21 in this disease.

This finding should provide a stimulus to further investigations into thecontent of alkaline phosphatase in leukocytes, possible polymorphism of leukocyte alkaline phosphatases, linkages with other inherited traits, and relationships between leukocyte and other tissue phosphatases.

Submitted on December 10, 1962 Accepted on February 10, 1963     

Nitrogen Ligands at the Active Site of Alkaline Phosphatase

The two Zn(II) ions of native Escherichia coli alkaline phosphatase (EC 3.1.3.1) that are necessary for activity have been replaced by (63)Cu(II). Titration of apoenzyme with up to 2 eq of Cu(II) gives a homogeneous species with an electron spin resonance typical for Cu(II) in an axially symmetric environment, with A(z) = 496 MHz, g(z) = g = 2.27, and g(x) = g(y) = 2.05. At least seven nitrogen hyperfine lines, spaced 11 G apart, are clearly resolved on the M = +[unk] Cu(II) hyperfine peak in the parallel region. When more than 2 eq of Cu(II) are added, the electron spin resonance spectrum shows at least two types of Cu(II) binding sites; the additional site, or sites, are characterized by lower g and higher A(z) values. When Cu(II) is added to native Zn(II) alkaline phosphatase or to apoenzyme incubated with 2 eq of Zn(II), the electron spin resonance spectrum shows little or no trace of the species with higher g values and nitrogen splitting. These results indicate that the species with higher g represents copper bound at the site normally occupied by the 2 Zn (II) ions necessary for enzyme activity, and that the metal ion at this site has at least 3 equivalent nitrogen ligands, probably histidyl side chains.     

中性粒细胞碱性磷酸酶检验在大骨节病诊断中的初步探讨

本文报告了对青海省班玛大骨节病区儿童的中性粒细胞碱性磷酸酶(AKP)检验结果:(1)阳性率,西宁市与班玛非病区无显著性差异,而与轻、中、重病区有显著性差异;非病区与重病区有显著性差异。(2)活性积分,西宁市与非病区、轻病区无显著性差异,而与中、重病区有非常显著性差异;非病区与重病区有非常显著性差异。(3)不同性别的中性粒细胞AKP的阳性率与活性积分均无差异。(4)各病区有X线改变和无X线改变的阳性率和活性积分虽尢显著性差异。但都表现为X线改变组偏低,说明大骨节病区的儿童成骨过程较迟缓。     

Alkaline Phosphatase and Mortality in Patients on Peritoneal Dialysis

Background and objectives

Elevated total serum alkaline phosphatase levels have been associated with higher mortality in the general population, CKD patients, and hemodialysis patients. However, in peritoneal dialysis patients, this association has received little attention. The aim of this study was to evaluate the association between alkaline phosphatase and all-cause and cardiovascular mortality in peritoneal dialysis patients.

Design, setting, participants, & measurements

In this single center retrospective cohort study, 1021 incident peritoneal dialysis patients from January 1, 2006, to December 31, 2010 with baseline serum alkaline phosphatase values were enrolled. Collected baseline data included demographic characteristics and clinical and laboratory measurements. All patients were followed until December 31, 2012. The associations of total serum alkaline phosphatase levels with all-cause and cardiovascular mortality were assessed using multivariable-adjusted Cox models.

Results

Of 1021 patients, mean age was 47.5 (±15.5) years, 59.1% of patients were men, and 22.8% of patients were diabetic. The median serum alkaline phosphatase level was 64 U/L (interquartile range=52–82 U/L). During a median 31-month (interquartile range=19–45 months) follow-up period, 203 patients died, of which 109 deaths were caused by cardiovascular disease. After adjusting for demographics, comorbid conditions, liver function, and bone metabolism parameters, the highest alkaline phosphatase quartile was significantly associated with a hazard ratio for all-cause mortality of 1.70 (95% confidence interval, 1.06 to 2.74, P=0.03) and a hazard ratio for cardiovascular mortality of 1.94 (95% confidence interval, 1.02 to 3.72, P=0.04). Each 10 U/L higher baseline alkaline phosphatase level was associated with 4% (95% confidence interval, 1.00 to 1.08, P=0.04) and 7% (95% confidence interval, 1.02 to 1.11, P=0.003) higher risk of all-cause and cardiovascular mortality, respectively.

Conclusion

Higher total serum alkaline phosphatase levels at the commencement of peritoneal dialysis were independently associated with all-cause and cardiovascular mortality in peritoneal dialysis patients.     

Effect of Ethanol on Alkaline Phosphatase Activity in HeLa Cells

Incubation of HeLa cells with 10-80 mM ethanol, caused a dose-dependent decrease in alkaline phosphatase specific activity. With 80 mM ethanol, the decrease became apparent after 24-48 hr incubation. The same dose-dependent effect was observed with the nonmetabolizable alcohol t-butanol. The effect of ethanol was not due to toxicity as the cells continued to replicate for weeks in the presence of ethanol and was reversible. There were no differences in the Km values of alkaline phosphatase in crude extracts or solubilized enzyme prepared either from control or 80 mM ethanol-treated cells. Hydrocortisone and choline chloride, which by themselves increase alkaline phosphatase specific activity, altered the effect of ethanol on alkaline phosphatase. In the presence of either 1 microM hydrocortisone or 40 mM choline chloride, neither 10 nor 20 mM ethanol decreased alkaline phosphatase specific activity.     

Structural Comparison of Ectopic and Normal Placental Alkaline Phosphatase

An alkaline phosphatase immunochemically similar to placental alkaline phosphatase (EC 3.1.3.1) was purified from liver metastases of a giant-cell carcinoma of the lung. Some properties of its physical and chemical structure were determined and compared to those of purified placental alkaline phosphatase. The purified tumor phosphatase and the placental phosphatase were similar with regard to the following properties: (1) NH(2)-terminal sequence, (2) peptide map, (3) subunit molecular weight, and (4) isoelectric point. The physical properties and NH(2)-terminal sequence of alkaline phosphatase isoenzyme of liver differed from the placental and the tumor enzyme. The data from the present study strongly support the hypothesis that the tumor and the placental alkaline phosphatases are products of the same gene.     

The Volume of the Human Erythrocyte and Plasma Alkaline Phosphatase Activity

Changes in mean red cell count (RCC), mean cell volume (MCV) and plasma alkaline phosphatase activity (ALP) were observed in a group of 33 normal male university students at a 7-week interval. Linear regression analysis shows a negative linear relationship between changes in RCC and MCV (r = -0.77, P < 0.0005) while a positive correlation was found for changes both in ALP activity and in MCV (r = +0.37, P < 0.025). Multiple regression analysis indicates that 70% of the variation in MCV could be accounted for by changes in RCC and plasma ALP activity (r = +0.84, P < 0.0025).