Local aldosterone release and CYP11B2 expression in response to angiotensin peptides, glucose, and potassium - an ex vivo study on murine colon.

We have previously described local aldosterone synthesis in mouse colon. In the renin-angiotensin-aldosterone system (RAAS), angiotensin II (Ang II) peptide is the physiological factor which stimulates aldosterone synthesis in the adrenal glands. We have recently demonstrated that Ang II stimulates aldosterone synthesis also in mouse colon. Here, we conducted a 75-min ex vivo incubation of murine colonic tissue and evaluated the effects of three other Ang peptides, Ang I (1 µM), Ang III (0.1 µM) and Ang (1-7) (0.1 µM) on aldosterone synthesis. As a possible mechanism, their effects on tissue levels of the rate-limiting enzyme, aldosterone synthase (CYP11B2) were measured by ELISA and Western blot. Ang III significantly elevated the amount of tissue CYP11B2 protein in colon. The values of released aldosterone in colon tissue incubation were increased over the control in the presence of Ang I, II or III, however, being statistically non-significant. In Western blot analysis, the values of tissue CYP11B2 protein content were elevated by Ang I and II. Ang (1-7) alone in colon did not influence CYP11B2 protein levels in the incubation experiment but showed higher aldosterone release without statistical significance. Ang (1-7) showed an antagonistic effect towards Ang II in release of aldosterone in adrenal gland. An overall estimation of a single peptide (three measured variables), the results were always in an increasing direction. The responses of aldosterone synthesis to high levels of glucose (44 mM) and potassium (18.8 mM) as physiological stimulators in vivo were investigated in the colon incubation. Glucose, equal to four times the concentration of the control buffer in the incubation, showed higher values of aldosterone release in colon than control without statistical significance similarly to the effect seen in adrenal glands. Increasing the concentration of potassium in the incubation buffer exerted no effect on colonic aldosterone production. Intriguingly, no correlation was found between aldosterone release and the tissue CYP11B2 protein content in colon. In summary, the response of colonic aldosterone synthesis to different Ang peptides resembles, but is not identical to, the situation in the adrenal glands.

Intestinal aldosterone synthase activity and aldosterone synthesis in mouse.

Aldosterone is the most important mineralocorticoid hormone regulating water and electrolyte absorption in the distal convoluted tubule of the kidney. Recently, we detected the presence of the whole chain of aldosterone production from the precursor corticosterone, transcription factor liver receptor homologue-1 (LRH-1), the aldosterone synthase enzyme protein (CYP11B2) as well as the gene to the final product aldosterone in murine large intestine. Here, we decided to correlate the amount of this synthase protein with its enzymatic activity in different parts of gastrointestinal tract and also with the aldosterone concentration in the respective tissue. Considering the physiological behavior of the animals in light and dark environment, we measured these variables at four time points - two in the light, the others during darkness. In vitro activity of CYP11B2 was measured as the amount of aldosterone formed from the precursor deoxycorticosterone using enzyme preparations from homogenized intestinal sections. CYP11B2 enzyme activity was higher in the large than in the small intestine. In ileum and colon, the CYP11B2 activity increased in the dark time. The highest aldosterone concentration was detected in the dark in the large intestine. In summary, enzyme activity of CYP11B2 was present in all parts of intestine; the large intestine formed more aldosterone during the darkness. No difference was seen in any of the variables between the early and late light hours.

Evidence for local aldosterone synthesis in the large intestine of the mouse.

Aldosterone, the main physiological mineralocorticoid, regulates sodium and potassium balance in the distal convoluted tubule of the kidney. Aldosterone is synthesized from cholesterol in the adrenal cortex in a sequence of enzymatic steps. Recently however, several tissues or cells e.g. brain, heart, blood vessels, kidneys and adipocytes have been shown to possess capability to produce aldosterone locally, and there is some evidence that this occurs also in the intestine. Colon expresses mineralocorticoid receptors and is capable of synthesizing corticosterone, the second last intermediate on the route to aldosterone from cholesterol. Based on such reports and on our preliminary finding, we hypothesized that aldosterone could be synthesized locally in the intestine and therefore we measured the concentration of aldosterone as well as the protein and gene expression of aldosterone synthase (CYP11B2), an enzyme responsible on aldosterone synthesis, from the distal section of the gastrointestinal tract of 10-week-old Balb/c male mice. It is known that sodium deficiency regulates aldosterone synthesis in adrenal glands, therefore we fed the mice with low (0.01%), normal (0.2%) and high-sodium (1.6%) diets for 14 days. Here we report that, aldosterone was detected in colon and cecum samples. Measurable amounts of CYP11B2 protein were detected by Western blot and Elisa analysis from both intestinal tissues. We detected CYP11B2 gene expression from the large intestine along with immunohistochemical findings of CYP11B2 in colonic wall. Sodium depletion increased the aldosterone concentration in plasma compared to control and high-sodium groups as well as in the intestine compared to mice fed with the high-sodium diet. To summarize, this study further supports the presence of aldosterone and the enzyme needed to produce this mineralocorticoid in the murine large intestine.

Detection of immunoreactive aldosterone in murine gastrointestinal tract.

The adrenocortical steroid hormone, aldosterone, regulates water and electrolyte transport in the distal tubules and collecting ducts of the nephrons in the kidney. Evidence has accumulated that it participates also in epithelial sodium absorption and potassium excretion in the colon acting via mineralocorticoid receptors. However, it is unclear whether aldosterone, like corticosterone, can be synthetized locally in the gut epithelium. Here we describe for the first time the expression of immunoreactive aldosterone in different sections of the murine gastrointestinal tract, with highest levels in the caecum. If similar findings can be verified in humans, this intestinal aldosterone might not only be of compensatory significance in severe renal failure, but also have a role in inflammatory bowel diseases as well as contributing to the development of salt-related hypertension.

Age-related changes in the local intestinal renin-angiotensin system in normotensive and spontaneously hypertensive rats.

Local renin-angiotensin systems (RAS) are found in many tissues. The main physiological effects of RAS are driven by the balance between two pathways: the angiotensin-converting enzyme I - angiotensin II receptor type 1 (ACE1-AT1R) axis and the angiotensin-converting enzyme 2 - Mas-receptor (ACE2-MAS) axis. The local intestinal RAS functions both as a paracrine regulator and as a regulator of inflammation. The expression of local RAS is known to change with age in many tissues, but age-related changes in the intestinal RAS have not been studied comprehensively. The present study characterized age-related changes in two main pathways of local RAS in the jejunum and colon of young and adult rats, in normotensive and hypertensive strains. The main finding was that 33-week-old rats exhibit an increased ratio of ACE1/ACE2 activities and protein quantity ratios compared to young rats. As the relationship of ACE1 and ACE2 mediated pathways drives the total physiological effects of RAS, the results indicate that the function of intestinal RAS changes with age. It is possible that age-related increase in ACE1-AT1R axis introduces more pro-inflammatory and fibrogenic conditions in the intestine.

Beneficial anti-inflammatory effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker in the treatment of dextran sulfate sodium-induced colitis in mice.

The renin-angiotensin system (RAS) in the intestine is involved in the regulation of inflammation, apoptosis and tissue fibrosis in experimental models of colitis; the inhibition of local RAS by pharmacologic interventions has been claimed to prevent and alleviate colitis. In this study, we compared the benefits of an angiotensin-converting enzyme (ACE) inhibitor, enalapril, an angiotensin receptor blocker, losartan and their combination in dextran sodium sulfate (DSS)-induced colitis in mice by assessing the histopathological and macroscopic changes in the colon, and by measuring the expression of the pro-inflammatory interleukin 1beta (IL-1ß) and tumor necrosis factor alpha (Tnf-α) genes. We also examined the consequences of these interventions on colonic angiotensin-converting enzyme protein and its ectodomain shedding as well as gene expression of RAS components, Agt and Ace, and corticosterone synthesis and its components, Lrh-1 and Cyp11b1. Both enalapril and losartan alleviated colitis by reducing the inflammatory cell infiltrate in colon. In addition, enalapril downregulated the pro-inflammatory IL-1ß expression whereas losartan treatment resulted in lower macroscopic scores, but the effects of the medications were not synergistic when the drugs were combined. ACE-ectodomain shedding was enhanced in the distal colon in DSS colitis. We found no evidence that ACE inhibition or angiotensin receptor blockade altered intestinal RAS or corticosterone synthesis. We conclude that some of the benefits of ACE inhibition and angiotensin receptor blockade might differ in the treatment of colitis, but their combination is unlikely to confer additional benefits.

Orally administered angiotensin-converting enzyme-inhibitors captopril and isoleucine-proline-proline have distinct effects on local renin-angiotensin system and corticosterone synthesis in dextran sulfate sodium-induced colitis in mice.

The effects of angiotensin-converting enzyme (ACE) inhibition by an antihypertensive drug, captopril, and milk casein-derived ACE-inhibiting bioactive tripeptide isoleucine-proline-proline (Ile-Pro-Pro), on local renin-angiotensin system (RAS) and glucocorticoid production in the intestine were studied in the dextran sodium sulfate induced colitis in mice. Mice received water or 3% dextran sodium sulfate with or without either 15.7 mg/l captopril or 833 mg/l Ile-Pro-Pro for 7 days. Captopril and Ile-Pro-Pro were found to have distinct effects on local renin-angiotensin system and mRNA expression of glucocorticoid synthesis components in colon in vitro. Captopril reduced intestinal mRNA expression of angiotensin-converting enzyme, angiotensinogen and Cyp11b1, whereas Ile-Pro-Pro reduced angiotensin-converting enzyme protein shedding from colon. Neither captopril nor Ile-Pro-Pro changed the expression of glucocorticoid-synthesis driving transcription factor Lrh-1 expression or intestinal glucocorticoid production. Contrary to previous studies, captopril did not alleviate DSS-induced colitis. Furthermore, Ile-Pro-Pro was mildly pro-inflammatory as exhibited by increased pro-inflammatory cytokine interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) levels in colon. The nutritional component Ile-Pro-Pro had different effect on intestinal RAS and glucocorticoid (GC) synthesis pathway than ACE inhibitor captopril, which suggests that the bioactivity of Ile-Pro-Pro is not limited to inhibition of ACE.

Long-term feeding with bioactive tripeptides in aged hypertensive and normotensive rats: special focus on blood pressure and bradykinin-induced vascular reactivity.

Bradykinin is the main player of the kallikrein-kinin system. Bradykinin-induced vasodilatation is age-dependent; this is believed to be associated with the level of expression of the two bradykinin receptors (BR1 and BR2) in the vasculature. The aim of this study was to clarify bradykinin-induced vascular reactivity of spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY) after 6 weeks' consumption of a drink containing bioactive tripeptides (Ile-Pro-Pro, Val-Pro-Pro and Leu-Pro-Pro). Two age groups were used: young (10 weeks at the end of experiment) and old (24 weeks). Blood pressure was monitored weekly by the tail-cuff method. After six weeks, vascular reactivity was assessed in vitro in mesenteric artery rings focusing on bradykinin induced activity. Blood pressure was lowered in old SHR after 6 weeks' tripeptide consumption compared to water drinking controls (P < 0.05). Blood pressure was lowered by peptide consumption also in old WKY (P < 0.05) but tripeptide consumption exerted no effect on the blood pressure of young animals. Old SHR suffered from endothelial and smooth muscle dysfunction which was not improved by these tripeptides. Interestingly, bradykinin caused vasoconstriction even in young SHR; this was blocked by a non-selective cyclooxygenase (COX) inhibitor but not by a B1 and B2 receptor antagonist. The expressions of mRNA of COX-1 and COX-2 in aorta were slightly upregulated in old SHR. ACE-1 activity in aorta and protein level in kidney, but not ACE-1 mRNA expression was upregulated in old animals (P < 0.05). To conclude, long-term feeding with a drink containing tripeptides lowers or prevents the age-associated increase in blood pressure in hypertensive and normotensive animals. ACE-1 activity, protein level but not mRNA expression are elevated in old animals. We also demonstrated that the vascular inflammation and dysfunction present in aged hypertensive animals cause bradykinin to induce vasoconstriction; this is not prevented by tripeptide feeding but involves the prostaglandin pathway.

Bradykinin -induced vasodilatation: Role of age, ACE1-inhibitory peptide, mas- and bradykinin receptors.

Bradykinin exerts its vascular actions via two types of receptors, the non-constitutively expressed bradykinin receptor type 1 (BR1) and the constitutive type 2 receptor (BR2). Bradykinin-induced vasorelaxation is age-dependent, a phenomenon related to the varying amounts of BR1 and BR2 in the vasculature. Isoleucine-proline-proline (Ile-Pro-Pro), a bioactive tripeptide, lowers elevated blood pressure and improves impaired endothelium-dependent vasorelaxation in hypertensive rats. It inhibits angiotensin converting enzyme 1 (ACE1). Other mechanisms of action have also been postulated. The aims of the study were to clarify the underlying mechanisms of the age-dependency of bradykinin-induced vasodilatation such as the roles of the two bradykinin receptors, the mas-receptor and synergism with Ile-Pro-Pro. The vascular response studies were conducted using mesenteric artery and aorta rings from normotensive 6 wk. (young) and 22 wk. (old) Wistar rats. Cumulative dosing of acetylcholine, bradykinin and angiotensin(1-7) (Ang(1-7))were tested in phenylephrine-induced vasoconstriction with or without 10min pre-incubation with antagonists against BR1-, BR2- or mas-receptors, Ang(1-7) or ACE1-inhibitors captopril and Ile-Pro-Pro. The bradykinin-induced vasorelaxation in vitro was age-dependent and it was improved by pre-incubation with Ile-Pro-Pro, especially in old rats with endothelial dysfunction. The mas-receptor antagonist, D-Pro7-Ang(1-7) abolished bradykinin-induced relaxation totally. Interestingly, BR1 and BR2 antagonists only slightly reduced bradykinin-induced vasorelaxation, as an evidence for the involvement of other mechanisms in addition to receptor activation. In conclusion, bradykinin-induced vasorelaxation was age-dependent and Ile-Pro-Pro improved it. Mas receptor antagonist abolished relaxation while bradykinin receptor antagonist only slightly reduced it, suggesting that bradykinin-induced vasorelaxation is regulated also by other mechanisms than the classical BR1/BR2 pathway.

The expression of Mas-receptor of the renin-angiotensin system in the human eye.

PURPOSE: The local renin-angiotensin system has been held to be expressed in many organs, including the eye. It has an important role in the regulation of local fluid homeostasis, cell proliferation, fibrosis, and vascular tone. Mas-receptor (Mas-R) is a potential receptor acting mainly opposite to the well-known angiotensin II receptor type 1. The aim of this study was to determine if Mas-R is expressed in the human eye. METHODS: Seven enucleated human eyes were used in immunohistochemical detection of Mas-R and its endogenous ligand angiotensin (1-7) [Ang(1-7)]. Both light microscopy and immunofluorescent detection methods were used. A human kidney preparation sample was used as control. RESULTS: The Mas-R was found to have nuclear localization, and localized in the retinal nuclear layers and in the structures of the anterior segment of the eye. A cytoplasmic immunostaining pattern of Ang(1-7) was found in the inner and outer nuclear and plexiform layers of the retina and in the ciliary body. CONCLUSION: To the best of our knowledge, this is the first report showing Mas-R expression in the human eye. Its localization suggests that it may have a role in physiological and pathological processes in the anterior part of the eye and in the retina.

Effects of milk casein derived tripeptides on endothelial enzymes in vitro; a study with synthetic tripeptides.

In the fermentation of milk by certain lactic acid bacteria, casein is degraded into bioactive tripeptides shown to lower blood pressure in experimental animal models and in mildly hypertensive humans. This effect is suggested to result mainly in inhibition of angiotensin converting enzyme 1 (ACE-1).Due to the complexity of renin-angiotensin system (RAS), several other enzymes than ACE-1 can participate in the production of vasoactive components. Therefore, in the present study we investigated effects of tripeptides isoleucine-proline-proline (IPP), valine-proline-proline (VPP) and leucine-proline-proline (LPP) on some endothelial enzymes that are important in RAS or otherwise have a role in the endothelial function. The enzymes investigated were renin, chymase, neutral endopeptidase (NEP), prolyl oligopeptidase (POP), cathepsin G, endothelin converting enzyme 1 (ECE-1), and cyclooxygenase 1 and 2 (COX -1 and COX-2).The tripeptides inhibited prolyl oligopeptidase (POP) dose-dependently. IPP was the most potent inhibitor (IC50 486±95 µM). Contrary, cathepsin G was activated by IPP, VPP and LPP as well as the amino acids proline and isoleucine. The other investigated enzymes were not affected. Inhibition of POP and activation of cathepsin G do not explain the blood pressure lowering effects of the tripeptides. Thus the inhibition of ACE-1 remains the most plausible mechanism of the antihypertensive effects of the tripeptides.

Effects of long-term intake of lactotripeptides on cardiovascular risk factors in hypertensive subjects.

BACKGROUND/OBJECTIVES: Lactobacillus helveticus LBK-16H-fermented milk products containing tripeptides isoleucine-proline-proline and valine-proline-proline lower blood pressure in hypertensive subjects using office and home blood pressure registration. The present study was aimed to evaluate the effects of two doses of these lactotripeptides on 24-h ambulatory blood pressure and lipidomics profiles in mildly hypertensive subjects. SUBJECTS/METHODS: In a randomized, double-blind, placebo-controlled parallel group study, 89 mildly hypertensive subjects ingested, after a 1-month run-in period, a fermented milk drink with 5 mg per day of lactotripeptides during 3 months, and a milk drink with 50 mg per day of lactotripeptides for the following 3 months, or a placebo milk drink without lactotripeptides. Ambulatory blood pressure (24 h) was recorded at baseline and at the end of the intervention periods. Lipidomics profiles were characterized before and after the 6-month intervention. RESULTS: After the second intervention period (50 mg per day of lactotripeptides), systolic and diastolic 24-h blood pressures decreased significantly in the peptide, but not in the placebo group. However, the treatment effects -2.6 mm Hg (95% confidence interval (CI): -5.7 to 0.4) in systolic and -1.3 mm Hg (95% CI: -3.4 to 0.8) in diastolic blood pressure did not reach statistic significance. Ingestion of 5 mg per day of lactotripeptides for 3 months did not lower blood pressure. The peptide group was dominated by decrease in multiple phospholipids (PL). CONCLUSIONS: Ingestion of fermented milk with daily dose of 50 mg of lactotripeptides appears to lower elevated blood pressure slightly from the baseline, but not significantly compared with the placebo group and to induce significant decreases in multiple PL.

Long-term intervention with Lactobacillus helveticus fermented milk reduces augmentation index in hypertensive subjects.

BACKGROUND: The milk casein-derived biologically active tripeptides, isoleucyl-prolyl-proline (Ile-Pro-Pro) and valyl-prolyl-proline (Val-Pro-Pro), have documented antihypertensive effect probably related to reduced angiotensin formation. It has been suggested that these tripeptides may reduce arterial stiffness and improve endothelial function. Our aim was to evaluate whether the milk-based drink containing Ile-Pro-Pro and Val-Pro-Pro influence arterial stiffness, measured as augmentation index (AIx), and endothelial function in man. METHODS: In a double-blind parallel group intervention study, 89 hypertensive subjects received daily peptide milk containing a low dose of tripeptides (5 mg/day) for 12 weeks and a high dose (50 mg/day) for the following 12 weeks, or a placebo milk drink to titrate the dose-response effect. Arterial stiffness was assessed by pulse wave analysis at the beginning and end of each intervention period. Endothelial function was tested by examining pulse wave reflection response to sublingual nitroglycerin and salbutamol inhalation. Blood pressure was measured by using office and 24-h ambulatory blood pressure measurement. RESULTS: At the end of the second intervention period, AIx decreased significantly in the peptide group compared with the placebo group (peptide group -1.53% (95% confidence interval (CI) -2.95 to -0.12), placebo group 1.20% (95% CI 0.09-2.32), P=0.013). No change in endothelial function index was observed (peptide group 0.02 (95% CI -0.06 to 0.08), placebo group 0.04 (95% CI -0.04 to 0.12), P=0.85). There were no statistically significant differences between the effects of the peptide and placebo treatment on office and 24-h ambulatory blood pressure. CONCLUSIONS: Long-term treatment with Lactobacillus helveticus-fermented milk containing bioactive peptides reduces arterial stiffness expressed as AIx in hypertensive subjects.

Cardiovascular activity of milk casein-derived tripeptides and plant sterols in spontaneously hypertensive rats.

The effect of chronic treatment with fermented milk products containing bioactive tripeptides and plant sterols on blood pressure and vascular function was investigated in spontaneously hypertensive rats (SHR). Six-weeks old male SHR (n=36) were randomized into 4 groups by body weight and blood pressure to receive either Lactobacillus helveticus fermented standard milk product (containing tripeptides Ile-Pro-Pro, Val-Pro-Pro and Leu-Pro-Pro), test product with enzymatically produced tripeptides without or with plant sterols or control product without the active constituents for 8 weeks. Systolic blood pressure (SBP) was measured weekly using the tail-cuff method. Thoracic aorta and mesenteric artery were excised for vascular response measurements. At the end, SBP values vs. control product group were: standard product group -14 mmHg (P<0.05), test product group -12 mmHg and test product +sterols group -7 mmHg. The average daily tripeptide dose was 2.8-5.2 mg/kg. Total serum cholesterol in the test product +sterols group tended to be lower than in the test product group (P=0.10) whereas serum plant sterol (campesterol, sitosterol) concentrations were higher (P<0.001). In conclusion, bioactive tripeptide-containing milk products attenuated the blood pressure development in SHR. The plant sterols did not improve this effect. Vascular responses did not markedly differ between the groups, except that endothelium-derived hyperpolarizing factor (EDHF) -related aortic relaxation was demonstrated in the test product +sterols group.

Effects of multispecies probiotic combination on helicobacter pylori infection in vitro.

Probiotic bacteria alleviate many gastrointestinal symptoms, but the current trend of combining bacteria for additional benefit may make their effects more complex. We characterize four probiotics and their combination in terms of pathogen adhesion, barrier function, cell death, and inflammatory response in Helicobacter pylori-infected epithelial cells. H. pylori-infected Caco-2 cells were pretreated with Lactobacillus rhamnosus GG, Lactobacillus rhamnosus Lc705, Propionibacterium freudenreichii subsp. shermanii Js, Bifidobacterium breve Bb99, or all four organisms in combination. We evaluated the adhesion of H. pylori by in situ immunofluorescence; epithelial barrier function by measurement of transepithelial resistance; apoptosis by measurement of caspase 3 activation; cell membrane leakage by measurement of lactate dehydrogenase release; and inflammation by measurement of interleukin-8 (IL-8), IL-10, prostaglandin E(2) (PGE(2)), and leukotriene B(4) (LTB(4)) release. All probiotics inhibited H. pylori adhesion. L. rhamnosus GG, L. rhamnosus Lc705, P. freudenreichii subsp. shermanii Js, and the combination inhibited H. pylori-induced cell membrane leakage. L. rhamnosus GG, L. rhamnosus Lc705, and the combination initially improved epithelial barrier function but increased the H. pylori-induced barrier deterioration after incubation for 24 to 42 h. L. rhamnosus GG, L. rhamnosus Lc705, and P. freudenreichii subsp. shermanii Js inhibited H. pylori-induced IL-8 release, whereas L. rhamnosus GG, L. rhamnosus Lc705, and B. breve Bb99 suppressed PGE(2) release. None of these anti-inflammatory effects persisted when the probiotics were used in combination. The combination thus increased the levels of IL-8, PGE(2), and LTB(4) released from H. pylori-infected epithelial cells. The proinflammatory actions of the individual components dominated the anti-inflammatory effects when the probiotic bacteria were used in combination. Our results stress that the therapeutic response can be optimized if probiotic strains are characterized before they are used in combination.

Is there a relationship between blood pressure and intraocular pressure? An experimental study in hypertensive rats.

PURPOSE: Evaluation of relation between blood pressure (BP) and intraocular pressure (IOP) in two hypertensive rat strains: spontaneously hypertensive rats (SHR) and double transgenic (dTGR) (harboring human renin and angiotensinogen genes) rats, and in their normotensive control Wistar Kyoto and Sprague Dawley rats, respectively. METHODS: Each rat strain was divided into medicated and non-medicated groups. Medicated rats were treated orally with an angiotensin II receptor type 1 blocker. IOP was measured using a specific rebound tonometer and BP by a tail-cuff method. Both parameters were determined in conscious animals every second week. For comparison, at the end of the study, IOP was measured in conscious and anesthetized rats. RESULTS: The baseline IOP was higher in hypertensive rats vs their normotensive controls. Eight weeks of treatment with an angiotensin type 1 receptor blocker did not prevent a slight increase in IOP, although it abolished the development of hypertension in SHR. The markedly elevated IOP was reduced in medicated and non-medicated dTGR animals during the short follow-up period. General anesthesia reduced IOP significantly. CONCLUSION: The results suggest a positive relation between BP and IOP in hypertensive rats.

Clinical trial: multispecies probiotic supplementation alleviates the symptoms of irritable bowel syndrome and stabilizes intestinal microbiota.

BACKGROUND: Irritable bowel syndrome is the most common diagnosis in gastroenterology. Trials suggest certain probiotics to be beneficial. AIM: To investigate the effects of multispecies probiotic supplementation (Lactobacillus rhamnosus GG, L. rhamnosus Lc705, Propionibacterium freudenreichii ssp. shermanii JS and Bifidobacterium animalis ssp. lactis Bb12) on abdominal symptoms, quality of life, intestinal microbiota and inflammatory markers in irritable bowel syndrome. METHODS: Eighty-six irritable bowel syndrome patients (Rome II criteria) participated in this randomized, placebo-controlled 5-month intervention. Patients were randomized to receive daily either multispecies probiotic supplementation or placebo. Irritable bowel syndrome symptoms, quality of life, microarray-based intestinal microbiota stability (n = 20), serum cytokines and sensitive C-reactive protein were monitored. RESULTS: The composite irritable bowel syndrome score had at 5 months decreased 14 points (95% CI: -19 to -9) from baseline with the multispecies probiotic vs. three points (95% CI: -8 to 1) with placebo (P = 0.0083). Especially, distension and abdominal pain were affected. A stabilization of the microbiota was observed, as the microbiota similarity index increased with the probiotic supplementation (1.9 +/- 3.1), while it decreased with placebo (-2.9 +/- 1.7). No differences were seen in C-reactive protein. CONCLUSIONS: This multispecies probiotic seems to be an effective and safe option to alleviate symptoms of irritable bowel syndrome, and to stabilize the intestinal microbiota.

Prophylactic potential of montelukast against mild colitis induced by dextran sulphate sodium in rats.

Cysteinyl leukotrienes play a part in inflammatory processes such as inflammatory bowel diseases. The present study aimed to evaluate the effects of the cys-LT-1 receptor antagonist montelukast on a mild colitis model in rats. Colitis was induced by administrating 4% dextran sulphate sodium (DSS, MW 45,000) in drinking water for 9 days. Montelukast (10 mg/kg/day) or vehicle was given by gastric gavage once daily simultaneously with DSS administration. A healthy control group receiving water as drinking fluid and vehicle by gastric gavage was included. Body weight loss, consistency of faeces (loose/diarrhoea) and occult blood in the faeces/ gross bleeding were assessed on days 6 - 9. After sacrifice, the following were assessed: colonic histology, the expression of inducible nitric oxide synthase, macrophage/monocyte marker ED1, cyclooxygenase-1 and cyclooxygenase-2, as well as the production of leukotriene B(4) and E(4), prostaglandin E(2), its metabolite bicyclic-prostaglandin E(2) and thromboxane B(2) in the colonic tissue incubation in vitro. Rats receiving DSS exhibited bloody diarrhoea from day 6 onwards. Montelukast significantly reduced the occult blood in the faeces/ gross bleeding, maintained normal body weight gain and tended to decrease the ratio of leukotriene B(4)/ prostaglandin E(2) production in the colon in vitro. The results indicate that montelukast has some potential to ameliorate mild experimental colitis induced by DSS.

Probiotic intervention decreases serum gastrin-17 in Helicobacter pylori infection.

BACKGROUND: Previously we showed that a probiotic combination with L. rhamnosus GG was beneficial as an adjuvant therapy during H. pylori eradication. AIM: To evaluate whether probiotic combination with LGG adheres to the upper gastrointestinal mucosa and modifies H. pylori colonisation and H. pylori induced inflammation. METHODS: Thirteen patients referred for gastroduodenoscopy received a drink consisting of equal doses (2.5x10(9)CFU) of LGG, L. rhamnosus LC705, Propionibacterium freudenreichii JS and Bifidobacterium lactis Bb12 daily. Recovery of probiotics in biopsies (antrum, corpus, duodenum) and faecal samples was evaluated by strain-specific quantitative polymerase chain reaction. H. pylori colonization and gastric inflammation was investigated by urease activity ((13)C-urea breath test), histology and serum pepsinogen I, II and gastrin-17 measurements. RESULTS: Twelve patients were fully investigated; of these three of the patients had LGG adhering to the biopsies at end of the intervention. Other probiotic strains were not detected, even though the recovery of all individual probiotic strains from the faeces was significantly increased (p<0.01). After the treatment, the level of (13)C-urea breath test (p=0.063) and gastrin-17 (p=0.046) decreased. CONCLUSIONS: The decreases in (13)C-urea breath test and gastrin-17 indicate that the probiotic combination exerts a beneficial effect on gastric mucosa in H. pylori infected patients. LGG showed marginal ability to adhere to the upper gastrointestinal tract mucosa.