Progression and Regression of Abdominal Aortic Aneurysms in Mice.

OBJECTIVE: Abdominal aortic aneurysm (AAA) is a significant medical problem with a high mortality rate. Nevertheless, the underlying mechanism for the progression and regression of AAA is unknown. METHODS: Experimental model of AAA was first created by porcine pancreatic elastase incubation around the infrarenal aorta of C57BL/6 mice. Then, AAA progression and regression were evaluated based on the diameter and volume of AAA. The aortas were harvested for hematoxylin-eosin staining (HE), orcein staining, sirius red staining, immunofluorescence analysis and perls' prussian blue staining at the indicated time point. Finally, ß-aminopropionitrile monofumarate (BAPN) was used to explore the underlying mechanism of the regression of AAA. RESULTS: When we extended the observation period to 100 days, we not only observed an increase in the AAA diameter and volume in the early stage, but also a decrease in the late stage. Consistent with AAA diameter and volume, the aortic thickness showed the same tendency based on HE staining. The elastin and collagen content first degraded and then regenerated, which corresponds to the early deterioration and late regression of AAA. Then, endogenous up-regulation of lysyl oxidase (LOX) was detected, accompanying the regression of AAA, as detected by an immunofluorescent assay. BAPN and LOX inhibitor considerably inhibited the regression of AAA, paralleling the degradation of elastin lamella and collagen. CONCLUSION: Taken together, we tentatively conclude that endogenous re-generation of LOX played an influential role in the regression of AAA. Therefore, regulatory factors on the generation of LOX exhibit promising therapeutic potential against AAA.

A validated mouse model capable of recapitulating the protective effects of female sex hormones on ascending aortic aneurysms and dissections (AADs).

Fewer females develop AADs (ascending aortic aneurysms and dissections) and the reasons for this protection remain poorly understood. The present study seeks to develop a mouse model that may be utilized to address this sexual dimorphism. Adult normolipidemic mice were challenged with BAPN (ß-aminopropionitrile), AngII (angiotensin II), or BAPN + AngII. An initial protocol optimization found that 0.2% BAPN in drinking water plus AngII-infusion at 1,000 ng kg-1  min-1 produced favorable rates of AAD rupture (~50%) and dilation (~40%) in 28 days. Using these dosages, further experiments revealed that BAPN is toxic to naïve mature aortas and it acted synergistically with AngII to promote aortic tears and dissections. BAPN + AngII provoked early infiltration of myeloid cells and subsequent recruitment of lymphoid cells to the aortic wall. AADs established with BAPN + AngII, but not AngII alone, continued to expand after the cessation of AngII-infusion. This indefinite growth precipitated a 61% increase in the AAD diameter in 56 days. More importantly, with the optimized protocol, significant differences in AAD dilation (p = .012) and medial degeneration (p = .036) were detected between male and female mice. Treatment of ovariectomized mice with estradiol protected AAD formation (p = .014). In summary, this study developed a powerful mouse AAD model that can be used to study the sexual dimorphism in AAD formation.

Female Mice Exhibit Abdominal Aortic Aneurysm Protection in an Established Rupture Model.

BACKGROUND: Male gender is a well-established risk factor for abdominal aortic aneurysm (AAA), whereas estrogen is hypothesized to play a protective role. Although rupture rates are higher in women, these reasons remain unknown. In the present study, we sought to determine if female mice are protected from AAA rupture. MATERIALS AND METHODS: Apolipoprotein E-deficient male and female mice (aged 7 wk; n = 25 per group) were infused with angiotensin II (AngII; 2000 ng/kg/min) plus ß-aminopropionitrile (BAPN) in the drinking water for 28 d to test the effects of gender on AAA rupture. Separately, a second group of male apolipoprotein E-deficient mice underwent AngII infusion + BAPN while being fed high-fat phytoestrogen free or a high-fat phytoestrogen diet to assess effects of phytoestrogens on rupture. In a third group, female mice either underwent oophorectomy or sham operation 4 wk before infusion of AngII and BAPN to further test the effects of female hormones on AA rupture. Surviving mice abdominal aorta were collected for histology, cytokine array, and gelatin zymography on postoperative day 28. RESULTS: Female mice had decreased AAA rupture rates (16% versus 46%; P = 0.029). Female mice expressed fewer elastin breaks (P = 0.0079) and decreased smooth muscle cell degradation (P = 0.0057). Multiple cytokines were also decreased in the female group. Gelatin zymography demonstrated significantly decreased pro-matrix metalloproteinase 2 in female mice (P = 0.001). Male mice fed a high dose phytoestrogen diet failed to decrease AAA rupture. Female mice undergoing oophorectomy did not have accelerated aortic rupture. CONCLUSIONS: These data are the first to attempt to tease out hormonal effects on AAA rupture and the possible role of gender in rupture.

Nitrosonifedipine, a Photodegradation Product of Nifedipine, Suppresses Pharmacologically Induced Aortic Aneurysm Formation.

BACKGROUND/AIMS: We have reported that nitrosonifedipine (NO-NIF), a photodegradation product of nifedipine, has strong antioxidant and endothelial protective effects, and can suppress several cardiovascular diseases in animal models. The objective of the present study was to investigate the effects of NO-NIF on aortic aneurysm formation. METHODS: The mice were infused with ß-aminopropionitrile for 2 weeks and angiotensin II for 6 weeks to induce aortic aneurysm formation. The oxidative stress was measured by dihydroethidium staining and nitrotyrosine staining. The expressions of inflammation-related genes were assessed by quantitative real-time PCR and immunohistochemical staining. To clarify the mechanisms of how NO-NIF suppresses vascular cell adhesion molecule (VCAM)-1, endothelial cells were used in in vitro system. RESULTS: NO-NIF suppressed pharmacologically induced the aortic aneurysm formation and aortic expansion without blood pressure changes. NO-NIF suppressed elastin degradation and matrix metalloproteinase-2 mRNA expression. NO-NIF suppressed the reactive oxygen species-cyclophilin A positive feedback loop. Upregulated mRNA expressions of inflammation-related genes and endothelial VCAM-1 were suppressed by NO-NIF co-treatment in aortae. CONCLUSION: NO-NIF has the potential to be a new, nifedipine-derived therapeutic drug for suppressing aortic aneurysm formation by directly improving aortic structure with its strong ability to reduce oxidative stress and inflammation.

Acute lysyl oxidase inhibition alters microvascular function in normotensive but not hypertensive men and women.

The lysyl oxidase (LOX) family of enzymes regulates collagen cross-linking. LOX is upregulated in hypertension, increasing vascular stiffness. In vivo human research is sparse, as long-term LOX inhibition in animals causes vascular instability. Our aim was to evaluate the effects of LOX inhibition on cutaneous microvascular function to determine whether LOX function was upregulated in hypertensive humans. Four intradermal microdialysis fibers were placed in the forearm of 10 young [age: 24 ± 1 yr, mean arterial pressure (MAP): 87 ± 2 mmHg], 10 normotensive (age: 50 ± 2 yr, MAP: 84 ± 1 mmHg), and 10 hypertensive (age: 53 ± 2 yr, MAP: 112 ± 2 mmHg) subjects. Two sites were perfused with 10 mM ß-aminopropionitrile (BAPN) to inhibit LOX. The remaining two sites were perfused with lactated Ringer solution (control). A norepinephrine dose response (10-12-10-2 M) was performed to examine receptor-mediated vasoconstrictor function. A sodium nitroprusside dose response (10-8-10-1.3 M) was performed to examine vascular smooth muscle vasodilator function. Red blood cell flux was measured via laser-Doppler flowmetry and normalized to cutaneous vascular conductance (flux/MAP). LogEC50 values were calculated to determine changes in vasosensitivity. Skin tissue samples were analyzed for both extracellular matrix-bound and soluble LOX. LOX inhibition augmented vasoconstrictor sensitivity in young (control: -6.0 and BAPN: -7.1, P = 0.03) and normotensive (control: -4.8 and BAPN: -7.0, P = 0.01) but not hypertensive (control: -6.0 and BAPN: -6.1, P = 0.79) men and women. Relative to young subjects, extracellular matrix-bound LOX expression was higher in hypertensive subjects (young: 100 ± 8 and hypertensive: 162 ± 8, P = 0.002). These results suggest that upregulated LOX may contribute to the vascular stiffness and microvascular dysfunction characteristic in hypertension. NEW & NOTEWORTHY Matrix-bound lysyl oxidase (LOX) and LOX-like 2 expression are upregulated in the microvasculature of hypertensive men and women. Microvascular responsiveness to exogenous stimuli is altered with localized LOX inhibition in healthy men and women but not hypertensive adults. The LOX family differentially affects microvascular function in hypertensive and normotensive men and women.

Suppression of Phosphatidylinositol 3-Kinase/Akt Signaling Attenuates Hypoxia-Induced Pulmonary Hypertension Through the Downregulation of Lysyl Oxidase.

Lysyl oxidase (LOX) is a copper-dependent enzyme that catalyzes covalent cross-linking of collagen. In response to hypoxia, phosphatidylinositol 3-kinase (PI3K) pathway is activated and contributes to pulmonary arterial hypertension (PAH). However, potential role of LOX in hypoxia-induced PAH is poorly understood. In this study, we explored the mechanism responsible for the development of hypoxia-induced PAH. Potent inhibitors of PI3K/Akt and LOX, wortmannin and ß-aminopropionitrile (ß-APN), were administrated in rat model of hypoxia-induced PAH. The cross-linking of collagen was assessed by the determination of hydroxyproline. LOX, LOXL-1, LOXL-2, LOXL-3, LOXL-4, Akt, and phospho-Akt expression was detected by real-time polymerase chain reaction and western blot analysis. We observed that collagen cross-linking and LOX activity were elevated in hypoxia-exposed rat lung tissue, but these effects were reversed by ß-APN and wortmannin. In addition, exposure to hypoxia enhanced mRNA and protein expression and activity of LOX and LOXL-1 in a PI3K/Akt-dependent manner and induced the development of PAH. After the administration of wortmannin, the upregulation of LOX and cross-linking of collagen were significantly reversed in hypoxia-exposed rat pulmonary artery tissue. Taken together, the present study demonstrated that the upregulation of LOX expression and collagen cross-linking is PI3K/Akt dependent in rat with hypoxia-induced PAH. Suppression of PI3K/Akt pathway may alleviate hypoxia-induced PAH through the downregulation of LOX.

The lysyl oxidase inhibitor (ß-aminopropionitrile) reduces leptin profibrotic effects and ameliorates cardiovascular remodeling in diet-induced obesity in rats.

Lysyl oxidase (LOX) is an extracellular matrix (ECM)-modifying enzyme that has been involved in cardiovascular remodeling. We explore the impact of LOX inhibition in ECM alterations induced by obesity in the cardiovascular system. LOX is overexpressed in the heart and aorta from rats fed a high-fat diet (HFD). ß-Aminopropionitrile (BAPN), an inhibitor of LOX activity, significantly attenuated the increase in body weight and cardiac hypertrophy observed in HFD rats. No significant differences were found in cardiac function or blood pressure among any group. However, HFD rats showed cardiac and vascular fibrosis and enhanced levels of superoxide anion (O2(-)), collagen I and transforming growth factor ß (TGF-ß) in heart and aorta and connective tissue growth factor (CTGF) in aorta, effects that were attenuated by LOX inhibition. Interestingly, BAPN also prevented the increase in circulating leptin levels detected in HFD fed animals. Leptin increased protein levels of collagen I, TGF-ß and CTGF, Akt phosphorylation and O2(-) production in both cardiac myofibroblasts and vascular smooth muscle cells in culture, while LOX inhibition ameliorated these alterations. LOX knockdown also attenuated leptin-induced collagen I production in cardiovascular cells. Our findings indicate that LOX inhibition attenuates the fibrosis and the oxidative stress induced by a HFD on the cardiovascular system. The reduction of leptin levels by BAPN in vivo and the ability of this compound to inhibit leptin-induced profibrotic mediators and ROS production in cardiac and vascular cells suggest that interactions between leptin and LOX regulate downstream events responsible for myocardial and vascular fibrosis in obesity.

Inhibition of Lysyl Oxidase and Lysyl Oxidase-Like Enzymes Has Tumour-Promoting and Tumour-Suppressing Roles in Experimental Prostate Cancer.

Lysyl oxidase (LOX) and LOX-like (LOXL) enzymes are key players in extracellular matrix deposition and maturation. LOX promote tumour progression and metastasis, but it may also have tumour-inhibitory effects. Here we show that orthotopic implantation of rat prostate AT-1 tumour cells increased LOX and LOXLs mRNA expressions in the tumour and in the surrounding non-malignant prostate tissue. Inhibition of LOX enzymes, using Beta-aminopropionitrile (BAPN), initiated before implantation of AT-1 cells, reduced tumour growth. Conversely, treatment that was started after the tumours were established resulted in unaffected or increased tumour growth. Moreover, treatment with BAPN did not suppress the formation of spontaneous lymph node metastases, or lung tumour burden, when tumour cells were injected intravenously. A temporal decrease in collagen fibre content, which is a target for LOX, was observed in tumours and in the tumour-adjacent prostate tissue. This may explain why early BAPN treatment is more effective in inhibiting tumour growth compared to treatment initiated later. Our data suggest that the enzymatic function of the LOX family is context-dependent, with both tumour-suppressing and tumour-promoting properties in prostate cancer. Further investigations are needed to understand the circumstances under which LOX inhibition may be used as a therapeutic target for cancer patients.

Cardioprotective effects of lysyl oxidase inhibition against volume overload-induced extracellular matrix remodeling.

A hallmark of heart failure (HF) is adverse extracellular matrix (ECM) remodeling, which is regulated by the collagen cross-linking enzyme, lysyl oxidase (LOX). In this study, we evaluate the efficacy of LOX inhibition to prevent adverse left ventricular (LV) remodeling and dysfunction using an experimental model of HF. Sprague-Dawley rats were subjected to surgically induced volume overload (VO) by creation of aortocaval fistula (ACF). A LOX inhibitor, beta-aminopropionitrile (BAPN; 100 mg/kg/day), was administered to rats with ACF or sham surgery at eight weeks postsurgery. Echocardiography was used to assess progressive alterations in cardiac ventricular structure and function. Left ventricular (LV) catheterization was used to assess alterations in contractility, stiffness, LV pressure and volume, and other indices of cardiac function. The LV ECM alterations were assessed by: (a) histological staining of collagen, (b) protein expression of collagen types I and III, (c) hydroxyproline assay, and (d) cross-linking assay. LOX inhibition attenuated VO-induced increases in cardiac stress, and attenuated increases in interstitial myocardial collagen, total collagen, and protein levels of collagens I and III. Both echocardiography and catheterization measurements indicated improved cardiac function post-VO in BAPN treated rats vs. untreated. Inhibition of LOX attenuated VO-induced decreases in LV stiffness and cardiac function. Overall, our data indicate that LOX inhibition was cardioprotective in the volume overloaded heart.

Lysyl oxidase activity contributes to collagen stabilization during liver fibrosis progression and limits spontaneous fibrosis reversal in mice.

Collagen stabilization through irreversible cross-linking is thought to promote hepatic fibrosis progression and limit its reversibility. However, the mechanism of this process remains poorly defined. We studied the functional contribution of lysyl oxidase (LOX) to collagen stabilization and hepatic fibrosis progression/reversalin vivousing chronic administration of irreversible LOX inhibitor ß-aminopropionitrile (BAPN, or vehicle as control) in C57Bl/6J mice with carbon tetrachloride (CCl4)-induced fibrosis. Fibrotic matrix stability was directly assessed using a stepwise collagen extraction assay and fibrotic septae morphometry. Liver cells and fibrosis were studied by histologic, biochemical methods and quantitative real-time reverse-transcription PCR. During fibrosis progression, BAPN administration suppressed accumulation of cross-linked collagens, and fibrotic septae showed widening and collagen fibrils splitting, reminiscent of remodeling signs observed during fibrosis reversal. LOX inhibition attenuated hepatic stellate cell activation markers and promoted F4/80-positive scar-associated macrophage infiltration without an increase in liver injury. In reversal experiments, BAPN-treated fibrotic mice demonstrated accelerated fibrosis reversal after CCl4withdrawal. Our findings demonstrate for the first time that LOX contributes significantly to collagen stabilization in liver fibrosis, promotes fibrogenic activation of attenuated hepatic stellate cells, and limits fibrosis reversal. Our data support the concept of pharmacologic targeting of LOX pathway to inhibit liver fibrosis and promote its resolution.-Liu, S. B., Ikenaga, N., Peng, Z.-W., Sverdlov, D. Y., Greenstein, A., Smith, V., Schuppan, D., Popov, Y. Lysyl oxidase activity contributes to collagen stabilization during liver fibrosis progression and limits spontaneous fibrosis reversal in mice.

Bone fracture toughness and strength correlate with collagen cross-link maturity in a dose-controlled lathyrism mouse model.

Collagen cross-linking is altered in many diseases of bone, and enzymatic collagen cross-links are important to bone quality, as evidenced by losses of strength after lysyl oxidase inhibition (lathyrism). We hypothesized that cross-links also contribute directly to bone fracture toughness. A mouse model of lathyrism using subcutaneous injection of up to 500 mg/kg ß-aminopropionitrile (BAPN) was developed and characterized (60 animals across 4 dosage groups). Three weeks of 150 or 350 mg/kg BAPN treatment in young, growing mice significantly reduced cortical bone fracture toughness, strength, and pyridinoline cross-link content. Ratios reflecting relative cross-link maturity were positive regressors of fracture toughness (HP/[DHLNL + HLNL] r(2) = 0.208, p < 0.05; [HP + LP]/[DHNL + HLNL] r(2) = 0.196, p < 0.1), whereas quantities of mature pyridinoline cross-links were significant positive regressors of tissue strength (lysyl pyridinoline r(2) = 0.159, p = 0.014; hydroxylysyl pyridinoline r(2) = 0.112, p < 0.05). Immature and pyrrole cross-links, which were not significantly reduced by BAPN, did not correlate with mechanical properties. The effect of BAPN treatment on mechanical properties was dose specific, with the greatest impact found at the intermediate (350 mg/kg) dose. Calcein labeling was used to define locations of new bone formation, allowing for the identification of regions of normally cross-linked (preexisting) and BAPN-treated (newly formed, cross-link-deficient) bone. Raman spectroscopy revealed spatial differences attributable to relative tissue age and effects of cross-link inhibition. Newly deposited tissues had lower mineral/matrix, carbonate/phosphate, and Amide I cross-link (matrix maturity) ratios compared with preexisting tissues. BAPN treatment did not affect mineral measures but significantly increased the cross-link (matrix maturity) ratio compared with newly formed control tissue. Our study reveals that spatially localized effects of short-term BAPN cross-link inhibition can alter the whole-bone collagen cross-link profile to a measureable degree, and this cross-link profile correlates with bone fracture toughness and strength. Thus, cross-link profile perturbations associated with bone disease may provide insight into bone mechanical quality and fracture risk.

[Effect of lysyl oxidase on migration and adhesion of human gastric cancer HGC-27 cells in vitro].

OBJECTIVE: To study the effects of lysyl oxidase (LOX) on the migration and adhesion of the human gastric cancer cell line HGC-27 cells in vitro. METHODS: The human gastric cancer cell line HGC-27 cells were cultured in vitro, and treated with different concentration of ß-aminopropionitrile (BAPN). The ability of migration was assessed by wound-healing assay. The ability of adhesion was detected by homogenous and heterogeneous adhesion experiments. RESULTS: Compared that with 0 mmol/L BAPN, the ability of migration of the cells after treatment with 0.2 mmol/L BAPN was descended at 8, 24, 32 and 48 h; the number of cells with homogeneous adhesion was increased from (6.97 ± 0.07) × 10(3)/ml to (7.78 ± 0.11) × 10(3)/ml; and the number of cells with heterogeneous adhesion was decreased from (8.98 ± 0.15) × 10(3)/ml to (8.35 ± 0.10) × 10(3)/ml, both < 0.05. Compared with that of cells treated with 0 mmol/L and 0.2 mmol/L BAPN, the migration ability of cells after treatment with 0.3 mmol/L BAPN was descended at 8, 24, 32 and 48 h; the number of cells with homogeneous adhesion was raised to (8.02 ± 0.11) × 10(3)/ml and the number of cells with heterogeneous adhesion was down to (7.93 ± 0.07) × 10(3)/ml (P < 0.05). CONCLUSION: LOX may promote the metastasis of cancer cells by enhancing invasion, increasing heterogeneous adhesion and decreasing homogeneous adhesion.

The effect of lathyrism on dentin structure of the rat incisors: a morphometric and scanning electron microscopic investigation.

BACKGROUND: The present study was designed to study the effect of beta-aminopropionitrile (beta-APN), present in Lathyrus sativus grass pea consumed in drought prone areas, on dentin of the continuously erupting rat incisors. METHODS: Eighteen adult male rats were used. In the experimental group (18 rats), lathyrism was induced by a once daily subcutaneous administration of beta-APN for 40 days. The maxillary and mandibular incisors were examined ultrastructurally and morphometrically. RESULTS: The mean number of patent tubules, the mean area, perimeter and the area percent of the tubules were analyzed. Ultrastructurally, the dentinal tubules of both coronal and radicular dentin in the lathyritic group were narrower or even obliterated compared with those in the control. The coronal and radicular dentin of the lathyritic group exhibited an irregular lattice of non-mineralized small branching collagen fibrils obliterating the dentinal tubules. The mean number of patent tubules in the control and lathyritic groups revealed an insignificant difference. The mean area of the tubules showed a statistically significant difference in lathyritic radicular dentin (P = 0.0353). The percentage of the total surface area of the dentinal tubules significantly decreased in the radicular dentin of the lathyritic group (P = 0.024). CONCLUSIONS: These findings indicated a deleterious effect of lathyrism on dentin, with a possible negative impact on developing teeth integrity.

Inhibition of breast adenocarcinoma growth by intratumoral injection of lipophilic long-acting lathyrogens.

Prevention of the formation of crosslinks and/or disintegration of already formed collagen fibrils in the tumor by known lathyrogens, beta-aminopropionitrile or D-penicillamine, may result in the weakening of tumor support, decreasing angiogenesis and promoting tumor regression. This paper reviews our studies with a single intratumoral injection of lipophilic lathyrogens and others, using a systemic administration to investigate the effect of both lathyrogens. Details of our experimental results are also given.

Effect of beta-aminopropionitrile and hyaluronic acid on repair of collagenase-induced injury of the rabbit Achilles tendon.

Collagenase was injected into the Achilles tendon of both hind legs of 10 clinically normal adult male New Zealand white rabbits. One month after induction of the injury, beta-aminoproprionitrile (BAPN) or hyaluronic acid (HA) was injected into the tendon core of the right hind leg of each rabbit, the left hind leg being left untreated. The treatment effects were evaluated by electron microscopy and analysis of the glycosaminoglycan (GAG) content of samples at 2 and 6 months post-treatment. At 2 months, collagen fibrils in tendons from both hind legs were relatively small in diameter, irregularly arranged, and interspersed with abundant active tenocytes as compared with those in normal tendon uninjured by collagenase. In the matrix, the amount of HA increased, but chondroitin-6-sulphate was eliminated. At 6 months, BAPN-treated tendons had small-diameter, regularly arranged collagen fibrils. HA-treated tendons, on the other hand, had large diameters, as well as regularly arranged collagen fibrils by comparison with non-treated tendon. The results suggest that HA, unlike BAPN, promoted healing.

The effects of 17 alpha-methyltestosterone on myocardial function in vitro.

Testosterone analogs have been used as performance enhancers by athletes for more than 40 yr. We asked whether the anabolic steroid 17 alpha-methyl-4-androstene-17-ol-3-one (17 alpha-MT) would affect intrinsic contractile function of the heart. Male Sprague-Dawley rats, 125-150 g, were treated with 17 alpha-MT either parenterally or orally for up to 8 wk. Intrinsic contractile function of the hearts was assessed utilizing both the isolated working heart and isovolumic perfused heart preparations. Isolated working hearts from 17 alpha-MT-treated rats had a 45% decrease in heart work attributable largely to a similarly decreased stroke volume. Isovolumic perfused hearts from treated animals had elevated left ventricular systolic and diastolic pressures at similar interventricular volumes compared to controls. Rates of ventricular pressure development (+dP/dT) or relaxation (-dP/dT) were unchanged as a result of the treatment. However, static elastance was reduced in potassium-arrested hearts from the 17 alpha-MT treatment (63% increase in interventricular pressure), consistent with a limitation being imposed on stroke volume by a decreased myocardial compliance. Hydroxyproline content of the hearts was not altered by 17 alpha-MT treatment suggesting that increased stiffness was not a consequence of collagen proliferation. Treatment of the steroid rats with beta-aminopropionitrile, a compound that inhibits lysyl oxidase, restored the left ventricular volume-pressure relationship (elastance curve) to that of control hearts. Thus, chronic treatment with anabolic steroids appears to reduce left ventricular compliance, possibly related to an enhanced activity of lysyl oxidase, and results in increased crosslink formation between collagen strands in the extracellular matrix.

Influence of dietary osteolathyrogens on the eggshell quality of laying hens.

1. Laying hens were fed osteolathyrogens, either semicarbazide hydrochloride at 0.3 or 0.4 g/kg or beta-aminopropionitrile fumarate at 0.5 or 0.6 g/kg diet to examine their effects on eggshell quality. 2. Shell quality characteristics considered for evaluation were shell surface area, shell thickness, shell weight, percentage shell, shape index and the specific gravity of eggs. Measurement of shell quality traits revealed that the hens fed osteolathyrogens laid eggs with significantly lower specific gravities and proportion of shell by weight. These differences were not explained by differences in shell thickness or weight or the shape index of eggs. 3. It was concluded that osteolathyrogens cause hens to lay eggs with poor shell quality and such eggs are weak and fragile.

Impact of antifibrotic treatment on the course of Schistosoma mansoni infection in murime model

Administration of an antifibrotic agent as an adjunct to antihelmintic treatment with the objective of morbidity reduction was investigated in the nurine schistosomiasis mansoni model. Antifibrotic, ß-aminopropionitrile treatment has a profound effect on the cellular composition of the liver granuloma of Schistosoma mansoni infected mice when given alone, resulting in increase macrophage infiltration. These macrophages, in response to stimulation with soluble egg antigen or lipopolysaccharide produced elevated levels of nitric oxide but low levels of tumor necrosis factor alpha compared to untreated infected mice. This also correlated with reduced liver granuloma size. In spite of low numbers of eggs in the liver, mice receiving a combine treatment had a high level of resistance to a challenge infection compared with mice receiving only praziquantel. Those mice also exhibited a reduced lymphocyte proliferative response, similar to that of infected untreated mice. Antifibrotic treatment has an impact on the dynamic of the cellular nature of granulomas and impacts on the host immunity to infection.

Effects of vitamin B6 on beta-aminoproprionitrile-induced palatal cleft formation in the rat.

OBJECTIVE: This study was conducted to evaluate the effects of beta-aminoproprionitrile and vitamin B6 on palatal clefting. METHOD: In four groups of pregnant Sprague-Dawley rats, beta-aminoproprionitrile (BAPN; 600 mg/kg b.w.) was given by gavage on embryonal day 15, 7 hours to induce palatal clefts. Vitamin B6 (10 mg/kg b.w., IM) was given twice on embryonal day 14, 7 hours and on day 15, 7 hours. The possibility that the food's content of vitamin B6 affected the results was also tested. Palatal cleft formation was divided into four different grades, ranging from no cleft formation to total cleft formation. RESULTS/CONCLUSION: It was found that BAPN induces cleft palate in rat fetuses and that this defect can be prevented both in number and severity by administration of vitamin B6 before and simultaneously with BAPN.

In vitro measurement of orthodontic tooth movement in rats given beta-aminopropionitrile or hydrocortisone using a time-lapse videotape recorder.

In vitro tooth movement of rat molars in response to an orthodontic force was recorded using a time-lapse videotape recorder and analysed by a computer system. Rats received daily s.c. injections of beta-aminopropionitrile (BAPN, 300 mg/kg/day) or hydrocortisone (10 mg/kg/day) for a period of 7 days. After drug administration, the animals were killed and the mandibles dissected. The jaw was then held under a stereomicroscope with a haemostatic clamp and an elastic band was inserted between the first and second molars. The movements of reference points on the occlusal surfaces of the first and second molars were recorded for 20 hours using a time-lapse videotape recorder. Mesiolingual movement of the first molar and distobuccal movement of the second molar were observed. During the experimental period, the greatest amount of total tooth movement in the first and second molars was seen in the group pretreated with BAPN, less movement was observed in the control group, and the group pretreated with hydrocortisone exhibited the least amount of movement. The highest rates of tooth movement were observed during the initial hour in each of the groups, and decreased thereafter. The initial rates of movement were also greatest in the BAPN group, less in the control group, and least in the hydrocortisone group. These results indicate that treatment with BAPN accelerated experimental tooth movements in vitro and hydrocortisone treatment inhibited the movements, suggesting that, although a part of the tooth movement measured in this experiment was due to deformation of the alveolar bone, the mechanical properties of the periodontal ligament play an important role in the regulation of orthodontic tooth movement.