Mitochondrial Side Effects of Surgical Prophylactic Antibiotics Ceftriaxone and Rifaximin Lead to Bowel Mucosal Damage.

Despite their clinical effectiveness, a growing body of evidence has shown that many classes of antibiotics lead to mitochondrial dysfunction. Ceftriaxone and Rifaximin are first choice perioperative antibiotics in gastrointestinal surgery targeting fundamental processes of intestinal bacteria; however, may also have negative consequences for the host cells. In this study, we investigated their direct effect on mitochondrial functions in vitro, together with their impact on ileum, colon and liver tissue. Additionally, their impact on the gastrointestinal microbiome was studied in vivo, in a rat model. Rifaximin significantly impaired the oxidative phosphorylation capacity (OxPhos) and leak respiration in the ileal mucosa, in line with increased oxidative tissue damage and histological changes following treatment. Ceftriaxone prophylaxis led to similar changes in the colon mucosa. The composition and diversity of bacterial communities differed extensively in response to antibiotic pre-treatment. However, the relative abundances of the toxin producing species were not increased. We have confirmed the harmful effects of prophylactic doses of Rifaximin and Ceftriaxone on the intestinal mucosa and that these effects were related to the mitochondrial dysfunction. These experiments raise awareness of mitochondrial side effects of these antibiotics that may be of clinical importance when evaluating their adverse effects on bowel mucosa.

Reduction in hypoxia-reoxygenation-induced myocardial mitochondrial damage with exogenous methane.

Albeit previous experiments suggest potential anti-inflammatory effect of exogenous methane (CH4 ) in various organs, the mechanism of its bioactivity is not entirely understood. We aimed to investigate the potential mitochondrial effects and the underlying mechanisms of CH4 in rat cardiomyocytes and mitochondria under simulated ischaemia/reperfusion (sI/R) conditions. Three-day-old cultured cardiomyocytes were treated with 2.2% CH4 -artificial air mixture during 2-hour-long reoxygenation following 4-hour-long anoxia (sI/R and sI/R + CH4 , n = 6-6), with normoxic groups serving as controls (SH and SH + CH4 ; n = 6-6). Mitochondrial functions were investigated with high-resolution respirometry, and mitochondrial membrane injury was detected by cytochrome c release and apoptotic characteristics by using TUNEL staining. CH4 admixture had no effect on complex II (CII)-linked respiration under normoxia but significantly decreased the complex I (CI)-linked oxygen consumption. Nevertheless, addition of CH4 in the sI/R + CH4 group significantly reduced the respiratory activity of CII in contrast to CI and the CH4 treatment diminished mitochondrial H2 O2 production. Substrate-induced changes to membrane potential were partially preserved by CH4 , and additionally, cytochrome c release and apoptosis of cardiomyocytes were reduced in the CH4 -treated group. In conclusion, the addition of CH4 decreases mitochondrial ROS generation via blockade of electron transport at CI and reduces anoxia-reoxygenation-induced mitochondrial dysfunction and cardiomyocyte injury in vitro.

Mitochondrial Consequences of Organ Preservation Techniques during Liver Transplantation.

Allograft ischemia during liver transplantation (LT) adversely affects the function of mitochondria, resulting in impairment of oxidative phosphorylation and compromised post-transplant recovery of the affected organ. Several preservation methods have been developed to improve donor organ quality; however, their effects on mitochondrial functions have not yet been compared. This study aimed to summarize the available data on mitochondrial effects of graft preservation methods in preclinical models of LT. Furthermore, a network meta-analysis was conducted to determine if any of these treatments provide a superior benefit, suggesting that they might be used on humans. A systematic search was conducted using electronic databases (EMBASE, MEDLINE (via PubMed), the Cochrane Central Register of Controlled Trials (CENTRAL) and Web of Science) for controlled animal studies using preservation methods for LT. The ATP content of the graft was the primary outcome, as this is an indicator overall mitochondrial function. Secondary outcomes were the respiratory activity of mitochondrial complexes, cytochrome c and aspartate aminotransferase (ALT) release. Both a random-effects model and the SYRCLE risk of bias analysis for animal studies were used. After a comprehensive search of the databases, 25 studies were enrolled in the analysis. Treatments that had the most significant protective effect on ATP content included hypothermic and subnormothermic machine perfusion (HMP and SNMP) (MD = -1.0, 95% CI: (-2.3, 0.3) and MD = -1.1, 95% CI: (-3.2, 1.02)), while the effects of warm ischemia (WI) without cold storage (WI) and normothermic machine perfusion (NMP) were less pronounced (MD = -1.8, 95% CI: (-2.9, -0.7) and MD = -2.1 MD; CI: (-4.6; 0.4)). The subgroup of static cold storage (SCS) with shorter preservation time (< 12 h) yielded better results than SCS ≥ 12 h, NMP and WI, in terms of ATP preservation and the respiratory capacity of complexes. HMP and SNMP stand out in terms of mitochondrial protection when compared to other treatments for LT in animals. The shorter storage time at lower temperatures, together with the dynamic preservation, provided superior protection for the grafts in terms of mitochondrial function. Additional clinical studies on human patients including marginal donors and longer ischemia times are needed to confirm any superiority of preservation methods with respect to mitochondrial function.

Detection of Intestinal Tissue Perfusion by Real-Time Breath Methane Analysis in Rat and Pig Models of Mesenteric Circulatory Distress.

OBJECTIVES: Methane (CH4) breath test is an established diagnostic method for gastrointestinal functional disorders. Our aim was to explore the possible link between splanchnic circulatory changes and exhaled CH4 in an attempt to recognize intestinal perfusion failure. DESIGN: Randomized, controlled in vivo animal study. SETTING: University research laboratory. SUBJECTS: Anesthetized, ventilated Sprague-Dawley rats (280 ± 30 g) and Vietnamese minipigs (31 ± 7 kg). INTERVENTIONS: In the first series, CH4 was administered intraluminally into the ileum before 45 minutes mesenteric ischemia or before reperfusion in non-CH4 producer rats to test the appearance of the gas in the exhaled air. In the porcine experiments, the superior mesenteric artery was gradually obstructed during consecutive, 30-minute flow reductions and 30-minute reperfusions achieving complete occlusion after four cycles (n = 6), or nonocclusive mesenteric ischemia was induced by pericardial tamponade (n = 12), which decreased superior mesenteric artery flow from 351 ± 55 to 182 ± 67 mL/min and mean arterial pressure from 96.7 ± 18.2 to 41.5 ± 4.6 mm Hg for 60 minutes. MEASUREMENTS AND MAIN RESULTS: Macrohemodynamics were monitored continuously; RBC velocity of the ileal serosa or mucosa was recorded by intravital videomicroscopy. The concentration of exhaled CH4 was measured online simultaneously with high-sensitivity photoacoustic spectroscopy. The intestinal flow changes during the occlusion-reperfusion phases were accompanied by parallel changes in breath CH4 output. Also in cardiac tamponade-induced nonocclusive intestinal ischemia, the superior mesenteric artery flow and RBC velocity correlated significantly with parallel changes in CH4 concentration in the exhaled air (Pearson's r = 0.669 or r = 0.632, respectively). CONCLUSIONS: we report a combination of in vivo experimental data on a close association of an exhaled endogenous gas with acute mesenteric macro- and microvascular flow changes. Breath CH4 analysis may offer a noninvasive approach to follow the status of the splanchnic circulation.

L-Alpha-glycerylphosphorylcholine can be cytoprotective or cytotoxic in neonatal rat cardiac myocytes: a double-edged sword phenomenon.

L-Alpha-glycerylphosphorylcholine (GPC) is a widely used food supplement. GPC has been shown to exert beneficial effects in several organs; however, the cardiac effects of GPC have yet to be investigated. The aim of the present study was therefore to map out the effects of GPC on cardiac myocytes, with or without ischemia-reperfusion insult. Neonatal rat cardiac myocytes were treated with GPC at 1, 10, 80, and 100 µM concentrations for 15 min, 3 h, or 24 h, respectively. Cell viability by calcein assay and the degree of oxidative stress by DHE (superoxide level) and H2DCF (total ROS accumulation) staining were measured. In separate experiments, cardiomyocytes were pre-treated with the optimal concentration of GPC for 3 h and then cells were exposed to 4 h of simulated ischemia followed by 2 h of reperfusion (SI/R). Cell viability was measured at the end of the SI/R protocol. In normoxic conditions, the 15-min and the 3-h GPC treatment did not affect cell viability, total ROS, and superoxide levels. Under SI/R conditions, the 3-h GPC treatment protected the cardiac myocytes from SI/R-induced cell death and did not alter the level of oxidative stress. The 24-h GPC treatment in normoxic conditions resulted in significant cell death and increased oxidative stress at each concentration. Here we provide the first evidence for the cytoprotective effect of short-term GPC treatment. However, long-term administration of GPC may exert cytotoxicity in a wide concentration range in cardiac myocytes. These results may draw attention to a comprehensive cardiac safety protocol for the testing of GPC.

Neuronal Nitric Oxide Mediates the Anti-inflammatory Effects of Intestinal Ischemic Preconditioning.

BACKGROUND: Ischemic preconditioning (IPC) can provide a defense against ischemia-reperfusion (IR)-induced acute inflammation and barrier dysfunction in many organs. Because nitric oxide (NO) has been implicated as a trigger or mediator in the IPC mechanism and because neuronal NO synthase (nNOS) is a dominant isoform of NOS in the gastrointestinal tract, our aim was to investigate the role of nNOS in IPC-induced protection after mesenteric IR. MATERIALS AND METHODS: Intestinal IR was induced in sodium pentobarbital-anesthetized dogs by clamping the superior mesenteric artery for 60 min followed by 2 h of reperfusion (IR group; n = 7). In further groups, IPC was used (three cycles of 5-min ischemia/5-min reperfusion periods) before IR in the presence or absence of selective inhibition of nNOS with 7-nitroindazole (5 mg/kg, intravenously, in a bolus 15 min before IPC, n = 6 each). Changes in mesenteric vascular resistance, intramucosal pH (pHi), and small bowel motility were monitored. Plasma nitrite/nitrate levels, intestinal NO synthase activity, leukocyte accumulation, mast cell degranulation, and histologic injury were also determined. RESULTS: Ischemia significantly decreased mesenteric vascular resistance and pHi, whereas IR induced a temporary bowel hypermotility and acute inflammatory reaction. IPC facilitated pHi recovery, attenuated motility dysfunction, elevated NOS-dependent NO production, and reduced leukocyte accumulation, mast cell degranulation, and mucosal injury. Pretreatment with 7-nitroindazole halted the IPC-induced increase in NO availability, pHi recovery, and the anti-inflammatory and morphologic effects. CONCLUSIONS: Our data demonstrate that NO generated by intestinal nNOS plays a pivotal role in IPC-linked tissue protection by inhibiting an IR-related acute inflammatory response.

Minimum Quality Threshold in Pre-Clinical Sepsis Studies (MQTiPSS): an international expert consensus initiative for improvement of animal modeling in sepsis.

PURPOSE: Pre-clinical animal studies precede the majority of clinical trials. While the clinical sepsis definitions and recommended treatments are regularly updated, a systematic review of pre-clinical models of sepsis has not been done and clear modeling guidelines are lacking. To address this deficit, a Wiggers-Bernard Conference on pre-clinical sepsis modeling was held in Vienna in May, 2017. The conference goal was to identify limitations of pre-clinical sepsis models and to propose a set of guidelines, defined as the "Minimum Quality Threshold in Pre-Clinical Sepsis Studies" (MQTiPSS), to enhance translational value of these models. METHODS: 31 experts from 13 countries participated and were divided into 6 thematic Working Groups (WG): (1) Study Design, (2) Humane modeling, (3) Infection types, (4) Organ failure/dysfunction, (5) Fluid resuscitation and (6) Antimicrobial therapy endpoints. As basis for the MQTiPSS discussions, the participants conducted a literature review of the 260 most highly cited scientific articles on sepsis models (2002-2013). RESULTS: Overall, the participants reached consensus on 29 points; 20 at "recommendation" (R) and 9 at "consideration" (C) strength. This Executive Summary provides a synopsis of the MQTiPSS consensus (Tables 1, 2 and 3). CONCLUSIONS: We believe that these recommendations and considerations will serve to bring a level of standardization to pre-clinical models of sepsis and ultimately improve translation of pre-clinical findings. These guideline points are proposed as "best practices" that should be implemented for animal sepsis models. In order to encourage its wide dissemination, this article is freely accessible in Shock, Infection and Intensive Care Medicine Experimental.

Correction to: Minimum Quality Threshold in Pre-Clinical Sepsis Studies (MQTiPSS): an international expert consensus initiative for improvement of animal modeling in sepsis.

The original version of this article unfortunately contained mistakes.

Capsaicin-induced rapid neutrophil leukocyte activation in the rat urinary bladder microcirculatory bed.

AIMS: This study was initiated to investigate the involvement of neutrophil leukocyte activation in neurogenic inflammation, a process also involved in human urinary pathologies, elicited in the rat urinary bladder by the local administration of capsaicin, the archetypal TRPV1 agonist. The contribution of afferent nerves and sensory neuropeptides to leukocyte activation in the urinary bladder microcirculatory bed was examined. METHODS: Following a 15-min topical application of capsaicin (50 µM), leukocyte-endothelial interactions were examined for an observation period of 45 min with intravital microscopy. Expression of adhesion molecules E-selectin and ICAM-1 implicated in these interactions was assessed by immunohistochemistry. Selective sensory denervation was performed by neonatal treatment with capsaicin. The role of the TRPV1 receptor and two sensory neuropeptides (CGRP and substance P [SP]) were studied using the selective antagonists capsazepine, CGRP8-37 and RP67580, respectively. RESULTS: Capsaicin induced rapid increases in leukocyte rolling and adhesion and increased the expression of E-selectin and ICAM-1 in the postcapillary venules. Sensory chemodenervation via capsaicin and also TRPV1 receptor antagonism effectively prevented these changes. A similar reduction was observed in leukocyte adhesion after topical application of CGRP8-34 or RP67580, but only CGRP8-34 reduced the capsaicin-evoked leukocyte rolling. CONCLUSIONS: Topical application of capsaicin induces early neurogenically mediated cellular microcirculatory inflammatory reactions via the activation of the TRPV1 receptor and the release of CGRP and SP from sensory nerves in the bladder. Co-administration of SP and CGRP receptor antagonists may ameliorate microcirculatory inflammatory changes elicited by capsaicin in the urinary bladder.

Acetylsalicylic acid-tris-hydroxymethyl-aminomethane reduces colon mucosal damage without causing gastric side effects in a rat model of colitis.

BACKGROUND: We have developed a novel compound from acetylsalicylic acid (ASA) and 2-amino-2-(hydroxymethyl)-1,3-propanediol (Tris) precursors with ASA-like anti-inflammatory efficacy and reduced the mucosa-damaging side-effects. Our aim was to examine local and remote consequences of ASA-Tris administration in 2-,4-,6-trinitrobenzene-sulfonic acid (TNBS)-induced colitis as compared to ASA or mesalamine (5-aminosalicylate) treatment. METHODS: Sprague-Dawley rats were randomized to five groups (n = 6, each), and TNBS enemas were performed. Group 1 was the negative control; group 2 was the untreated colitis group. 12 hour after colitis induction repeated doses of ASA, ASA-Tris (both 0.55 mmol/kg) and mesalamine (0.77 mmol/kg) were given 3 times daily for 3 days to groups 3-5. On day 3 of colitis, the in vivo histology of the colon and stomach was investigated. Tissue xanthine-oxidoreductase, myeloperoxidase, nitrite/nitrate changes, and circulating TNF-alpha levels were measured. In addition, liver mitochondria were examined with high-resolution respirometry to analyze alterations in the electron transport chain. RESULTS: TNBS enema significantly elevated inflammatory enzyme activities, NO production, TNF-alpha concentration, and induced morphological damage in the colon. ASA-treatment reduced the inflammatory marker levels and mucosal injury in the colon, but gastric tissue damage was present. ASA-Tris- and mesalamine-treatments significantly reduced the cytokine levels, inflammatory enzyme activities, and colonic mucosal damage without inducing gastric injury. Also, ASA significantly reduced the Complex IV-linked respiration of liver mitochondria, which was not observed after ASA-Tris-treatment. CONCLUSION: As compared to ASA, ASA-Tris conjugation provides significant protection against the colonic injury and cytokine-mediated progression of inflammatory events in experimental colitis without influencing the gastric epithelial structure.

EPR analysis of extra- and intracellular nitric oxide in liver biopsies.

PURPOSE: To develop an assay that can enable the quantification of intra- and extracellular nitric oxide (NO) levels in liver biopsies without application of potentially harmful exogenous NO traps. THEORY: Electron paramagnetic resonance (EPR) spectroscopy is currently the most appropriate method of measuring NO in biological samples due to the outstanding specificity resulting from the interaction of NO with exogenous NO traps. Because such traps are not allowed in clinical settings, we tested the reliability of endogenous NO traps for the determination of NO levels in blood and liver compartments. METHODS: Rats were injected with 0-8 mg/kg lipopolysaccharide (LPS) to gradually induce a systemic inflammatory response. Specific features of NO-hemoglobin and NO-Fe EPR signals were quantified using a specifically developed calibration procedure. RESULTS: Whereas both NO-hemoglobin (NO-HbLIVER BLOOD ) and NO-Fe (NO-FeLIVER ) complexes were detected in nonperfused liver tissue, only NO-Fe complexes were detected in perfused tissue and only NO-Hb complexes were detected in blood (NO-HbBLOOD ). The NO concentrations increased in the sequence NO-HbBLOOD < NO-FeLIVER < NO-HbLIVER BLOOD (9.4, 18.5, 27.9 nmol/cm3 , respectively at 2.5 mg/kg LPS). The detection limit of the method was 0.61 nmol/cm3 for NO-Hb and 0.52 nmol/cm3 for NO-Fe. CONCLUSION: The assay reported here does not influence natural NO pathways and enables the quantification of NO distribution in two liver compartments using a single liver biopsy. Magn Reson Med 77:2372-2380, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

The periosteal microcirculation in health and disease: An update on clinical significance.

Apart from its nutritive functions, the periosteum critically affects bone regeneration via its stem/osteoprogenitor cell content. Normal healing after bone fractures, trauma-orthopedic interventions and invasive dental procedures is critically linked to the reestablishment of the periosteal microcirculation, but the reconstruction, replacement or repair of lost tissues may also be performed with autologous periosteum. Besides the initiation of cell differentiation during bone repair and remodeling processes, the periosteum together with the endosteum plays significant roles in the pathogenesis of both hormone-related and trauma-induced osteoporotic alterations in the bone metabolism. Nevertheless, the axial bones, and in particular the jawbones, and the appendicular bones display differences not only in their blood supply and fracture healing characteristics, but also in respect of the development of osteoporosis and their reactions to treatment modalities (i.e. bisphosphonates). These reactions may also be linked to the differences in periosteal microcirculatory reactions. The present overview summarizes the relevant data of microcirculatory studies focusing on the periosteal reactions in different anatomical locations together with the optimal background methodologies, study models and the most significant observations.

Bladder Reconstruction with Human Amniotic Membrane in a Xenograft Rat Model: A Preclinical Study.

Background: Human amniotic membranes (HAMs) are assumed to have a number of unique characteristics including durability, hypoallergenic and anti-inflammatory properties. Materials and Methods: Multilayer HAMs from caesarian sections were applied to repair defined bladder defects in male Sprague-Dawley rats. The animals were sacrificed at 7, 21 and 42 days after implantation. Bladder volume capacity after grafting was measured. Histological analyses were performed to asses a number of parameters including HAM degradation, inflammatory reaction, graft rejection and smooth muscle ingrowth. Results: One rat died from sepsis in the treated group. No severe complications or signs of leakage were observed. Bladder capacity did not change over time. The initially increased inflammation in the HAM group diminished significantly over time (p<0.05). No signs of HAM degradation were observed and smooth muscle staining increased over time. Conclusions: HAMs appear to be durable and hypoallergenic grafts. The assumed suitability for the reconstruction of urinary tract justifies further research on detailed immunological process in larger grafts.

Human Amniotic Membrane Is Not Suitable for the Grafting of Colon Lesions and Prevention of Adhesions in a Xenograft Rat Model.

INTRODUCTION: New biological materials are needed for specific applications in reconstructive bowel surgery and for the prevention of adhesion formation. Amniotic membranes (AMs) are assumed to have a number of unique characteristics that enhance the ingrowth of the surrounding tissue. The aim of the present study was to provide proof of these qualities in a xenograft model. MATERIALS AND METHODS: A multilayer human AM (HAM) was applied to repair defined colon wall defects in Sprague-Dawley rats (n = 18). The control group was repaired with a suture (n = 6). The animals were killed humanely at 7, 21, and 42 days after implantation. Adhesions and perioperative complications were examined. Histological and immunohistological analyses were performed to assess a number of parameters, including degradation of the HAM, inflammation, graft rejection, and smooth muscle ingrowth. RESULTS: Two rats in the treated group died. No other severe complications were observed. Adhesion formation was more prominently visible in the HAM group ( P < .05). The initially increased inflammation in the HAM group reduced over time but remained significantly increased ( P < .05). The HAM degraded over time and a subtle transient glomerulitis could be observed. CONCLUSION: HAMs were found to increase adhesion formation and were not suitable for bowel augmentation in the presented xenograft model.

[Effects of complement C5a inhibitor therapy in animal models of non-occlusive mesenteric ischemia]. / Komplement C5a-antagonista-terápia hatása nem okklúzív mesenterialis ischaemia állatmodelljeiben.

INTRODUCTION: Non-occlusive mesenteric ischemia (NOMI) develops without anatomical causes. Early diagnosis is challenging and treatments are of questionable effectiveness. We investigated the role of complement activation in the pathophysiology of NOMI in animal models through the inhibition of complement C5a. MATERIALS AND METHODS: 60-min partial aortic occlusion (PAO; abdominal aorta, proximal to celiac trunk; mean arterial pressure: 30-40 mmHg) was established in Sprague-Dawley rats (n = 28) and 60-min cardiac tamponade in minipigs (n = 19; mean arterial pressure: 40-50 mmHg) to observe short- and long-term circulatory and inflammatory consequences of NOMI. Macro- and microhemodynamics, leukocyte infiltration, plasma levels of inflammatory mediators (endothelin, HMGB-1) were measured. C5a inhibitor (Acetyl-Peptid-A; 4 mg/kg iv) was administered at the 45th min of PAO or tamponade, respectively. RESULTS: Twenty-four hours after PAO systemic inflammatory response increased cardiac output and superior mesenteric artery flow (SMAF). C5a inhibition reduced the elevated cardiac output (203.1 ± 5 vs 269.6 ± 8.1 ml/min/kg) and SMAF and increased ileal microcirculation (833.5 ± 33.8 vs 441.9 ± 22.4 µm/s). In pigs, after the tamponade, C5a inhibition reduced the immediate hemodynamic disturbances, temporarily increased SMAF and permanently the ileal microcirculation. The Acetyl-Peptid-A treatment reduced leukocyte infiltration and plasma levels of inflammatory mediators in both NOMI models. CONCLUSIONS: Complement activation plays central role in the macro- and microcirculatory disturbance during NOMI. C5a inhibition reduces the inflammatory activation and influences the hemodynamic consequences of experimental NOMI.

[Experimental model for cardiogenic shock with pericardial tamponade]. / A cardiogen sokk modellezése pericardialis tamponáddal.

INTRODUCTION: Pericardial tamponade (PT) is a life-threatening condition, with low cardiac output. The hemodynamic consequences of PT can severely affect the circulation of all tissues, including the microcirculation of the kidneys and the intestinal mucosa. Our aim was to develop a hemodynamically stable and controllable large animal model of PT to study the consequences of cardiogenic shock. METHODS: Two groups of anesthetized vietnamese minipigs (n = 6, both groups) were used. Following laparotomy, a cannula was fixed into the pericardium through the diaphragm without thoracotomy. A sham-operated group served as control, in the second group 60-min PT was induced by intrapericardial injection of heparinised own blood. Throughout PT and 180-min reperfusion, macrohemodynamics, renal circulation and mesenteric macro- and microcirculation were monitored. Myeloperoxidase (MPO) activity was measured and in vivo histology was performed by confocal laser scanning endomicroscopy. RESULTS: The PT increased central venous pressure, heart rate and decreased mean arterial pressure, mesenteric flow (from 355.5 ± 112.4 vs 182.0 ± 59.1 ml/min) and renal arterial flow (from 159.63 ± 50.7 vs 35.902 ± 27.9 ml/min) and the microcirculation of the ileum. Elevated MPO activity (3.66 ± 1.6 vs 7.01 ± 1.44 mU/mg protein) and injury of the ileal mucosa were present also. SUMMARY: The reproducible large animal model is suitable for clinically relevant investigations of the hemodynamic and biochemical consequences of PT.

C5a inhibitor protects against ischemia/reperfusion injury in rat small intestine.

Acute mesenteric ischemia (AMI) is caused by considerable intestinal injury, which is associated with intestinal ischemia followed by reperfusion. To elucidate the mechanisms of ischemia/reperfusion injuries, a C5a inhibitory peptide termed AcPepA was used to examine the role of C5a anaphylatoxin, induction of inflammatory cells, and cell proliferation of the intestinal epithelial cells in an experimental AMI model. In this rat model, the superior mesenteric artery was occluded and subsequently reperfused (Induce-I/R). Other groups were treated with AcPepA before ischemia or reperfusion. Induce-I/R induced injuries in the intestine and AcPepA significantly decreased the proportion of severely injured villi. Induce-I/R induced secondary receptor for C5a-positive polymorphonuclear leukocytes in the vessels and CD204-positive macrophages near the injured site; this was correlated with hypoxia-induced factor 1-alpha-positive cells. Induction of these inflammatory cells was attenuated by AcPepA. In addition, AcPepA increased proliferation of epithelial cells in the villi, possibly preventing further damage. Therefore, Induce-I/R activates C5a followed by the accumulation of polymorphonuclear leukocyte and hypoxia-induced factor 1-alpha-producing macrophages, leading to villus injury. AcPepA, a C5a inhibitory peptide, blocks the deleterious effects of C5a, indicating it has a therapeutic effect on the inflammatory consequences of experimental AMI.

[Examination of liver mitochondria with respirometry]. / A májfunkció vizsgálata respirometriával.

Due to their diverse physiological functions, mitochondria can cause various acute and chronic liver diseases, thus being potential targets for therapies and diagnostics as well. In this study, the advantages of high-resolution respirometry are presented for the assessment of liver mitochondrial functions. During respitometry, the mitochondrial electron transport, the oxydative phosphorilation and the efficacy of the ADP synthesis can be calculated on the basis of oxygen consumption of freshly-taken tissue samples. Respirometry is a robust tool for the pre- or intraoperative analysis of liver mitochondrial functions and may increase the effectiveness of surgical interventions.

Protective effects of L-alpha-glycerylphosphorylcholine on ischaemia-reperfusion-induced inflammatory reactions.

PURPOSE: Choline-containing dietary phospholipids, including phosphatidylcholine (PC), may function as anti-inflammatory substances, but the mechanism remains largely unknown. We investigated the effects of L-alpha-glycerylphosphorylcholine (GPC), a deacylated PC derivative, in a rodent model of small intestinal ischaemia-reperfusion (IR) injury. METHODS: Anaesthetized Sprague-Dawley rats were divided into control, mesenteric IR (45 min mesenteric artery occlusion, followed by 180 min reperfusion), IR with GPC pretreatment (16.56 mg kg⁻¹ GPC i.v., 5 min prior to ischaemia) or IR with GPC post-treatment (16.56 mg kg⁻¹ GPC i.v., 5 min prior to reperfusion) groups. Macrohaemodynamics and microhaemodynamic parameters were measured; intestinal inflammatory markers (xanthine oxidoreductase activity, superoxide and nitrotyrosine levels) and liver ATP contents were determined. RESULTS: The IR challenge reduced the intestinal intramural red blood cell velocity, increased the mesenteric vascular resistance, the tissue xanthine oxidoreductase activity, the superoxide production, and the nitrotyrosine levels, and the ATP content of the liver was decreased. Exogenous GPC attenuated the macro- and microcirculatory dysfunction and provided significant protection against the radical production resulting from the IR stress. The GPC pretreatment alleviated the hepatic ATP depletion, the reductions in the mean arterial pressure and superior mesenteric artery flow, and similarly to the post-treatments with GPC, also decreased the xanthine oxidoreductase activity, the intestinal superoxide production, the nitrotyrosine level, and normalized the microcirculatory dysfunction. CONCLUSIONS: These data demonstrate the effectiveness of GPC therapies and provide indirect evidence that the anti-inflammatory effects of PC could be linked to a reaction involving the polar part of the molecule.

Periosteal microcirculatory reactions in a zoledronate-induced osteonecrosis model of the jaw in rats.

OBJECTIVES: Nitrogen-containing bisphosphonates induce osteonecrosis mostly in the jaw and less frequently in other bones. Because of the crucial role of periosteal perfusion in bone repair, we investigated zoledronate-induced microcirculatory reactions in the mandibular periosteum in comparison with those in the tibia in a clinically relevant model of bisphosphonate-induced medication-related osteonecrosis of the jaw (MRONJ). MATERIALS AND METHODS: Sprague-Dawley rats were treated with zoledronate (ZOL; 80 i.v. µg/kg/week over 8 weeks) or saline vehicle. The first two right mandibular molar teeth were extracted after 3 weeks. Various systemic and local (periosteal) microcirculatory inflammatory parameters were examined by intravital videomicroscopy after 9 weeks. RESULTS: Gingival healing disorders (∼100%) and MRONJ developed in 70% of ZOL-treated cases but not after saline (shown by micro-CT). ZOL induced significantly higher degrees of periosteal leukocyte rolling and adhesion in the mandibular postcapillary venules (at both extraction and intact sites) than at the tibia. Leukocyte NADPH-oxidase activity was reduced; leukocyte CD11b and plasma TNF-alpha levels were unchanged. CONCLUSION: Chronic ZOL treatment causes a distinct microcirculatory inflammatory reaction in the mandibular periosteum but not in the tibia. The local reaction in the absence of augmented systemic leukocyte inflammatory activity suggests that topically different, endothelium-specific changes may play a critical role in the pathogenesis of MRONJ. CLINICAL RELEVANCE: This model permits for the first time to explore the microvascular processes in the mandibular periosteum after chronic ZOL treatment. This approach may contribute to a better understanding of the pathomechanism and the development of strategies to counteract bisphosphonate-induced side effects.