Strategies for intra-amniotic administration of fetal therapy in a rabbit model of intrauterine growth restriction.

Intrauterine growth restriction affects up to 10% of all pregnancies, leading to fetal programming with detrimental consequences for lifelong health. However, no therapeutic strategies have so far been effective to ameliorate these consequences. Our previous study has demonstrated that a single dose of nutrients administered into the amniotic cavity, bypassing the often dysfunctional placenta via intra-amniotic administration, improved survival at birth but not birthweight in an intrauterine growth restriction rabbit model. The aim of this study was to further develop an effective strategy for intra-amniotic fetal therapy in an animal model. Intrauterine growth restriction was induced by selective ligation of uteroplacental vessels on one uterine horn of pregnant rabbits at gestational day 25, and fetuses were delivered by cesarean section on GD30. During the five days of intrauterine growth restriction development, three different methods of intra-amniotic administration were used: continuous intra-amniotic infusion by osmotic pump, multiple intra-amniotic injections, and single fetal intraperitoneal injection. Technical feasibility, capability to systematically reach the fetus, and survival and birthweight of the derived offspring were evaluated for each technique. Continuous intra-amniotic infusion by osmotic pump was not feasible owing to the high occurrence of catheter displacement and amnion rupture, while methods using two intra-amniotic injections and one fetal intraperitoneal injection were technically feasible but compromised fetal survival. Taking into account all the numerous factors affecting intra-amniotic fetal therapy in the intrauterine growth restriction rabbit model, we conclude that an optimal therapeutic strategy with low technical failure and positive fetal impact on both survival and birthweight still needs to be found.

Intraperitoneal Oil Application Causes Local Inflammation with Depletion of Resident Peritoneal Macrophages.

Oil is frequently used as a solvent to inject lipophilic substances into the peritoneum of laboratory animals. Although mineral oil causes chronic peritoneal inflammation, little is known whether other oils are better suited. We show that olive, peanut, corn, or mineral oil causes xanthogranulomatous inflammation with depletion of resident peritoneal macrophages. However, there were striking differences in the severity of the inflammatory response. Peanut and mineral oil caused severe chronic inflammation with persistent neutrophil and monocyte recruitment, expansion of the vasculature, and fibrosis. Corn and olive oil provoked no or only mild signs of chronic inflammation. Mechanistically, the vegetal oils were taken up by macrophages leading to foam cell formation and induction of cell death. Olive oil triggered caspase-3 cleavage and apoptosis, which facilitate the resolution of inflammation. Peanut oil and, to a lesser degree, corn oil, triggered caspase-1 activation and macrophage pyroptosis, which impair the resolution of inflammation. As such, intraperitoneal oil administration can interfere with the outcome of subsequent experiments. As a proof of principle, intraperitoneal peanut oil injection was compared with its oral delivery in a thioglycolate-induced peritonitis model. The chronic peritoneal inflammation due to peanut oil injection impeded the proper recruitment of macrophages and the resolution of inflammation in this peritonitis model. In summary, the data indicate that it is advisable to deliver lipophilic substances, like tamoxifen, by oral gavage instead of intraperitoneal injection. IMPLICATIONS: This work contributes to the reproducibility of animal research by helping to understand some of the undesired effects observed in animal experiments.

Repeated Intraperitoneal Administration of Low-Concentration Methylcellulose Leads to Systemic Histologic Lesions Without Loss of Preclinical Phenotype.

Methylcellulose (MC; 0.5% concentration) is commonly used when evaluating investigational agents for efficacy in preclinical models of disease. When administered by the oral (PO) route, MC is considered a Food and Drug Administration "generally recognized as safe" compound. Yet, there is limited data pertaining to the tolerability and impact on model fidelity of repeated intraperitoneal administration of 0.5% MC. Chronic administration of high-concentration MC (2%-2.5%) has been used to induce anemia, splenomegaly, and lesions in multiple organ systems in several preclinical species. Histopathological findings from a diagnostic pathologic analysis of a single mouse from our laboratory with experimentally induced chronic seizures that had received repeated intraperitoneal administration of antiseizure drugs delivered in MC revealed similar widespread lesions. This study thus tested the hypothesis that chronic administration of intraperitoneal, but not PO, MC incites histologic lesions without effects on preclinical phenotype. Male CF-1 mice (n = 2-14/group) were randomized to receive either 6 weeks of twice weekly 0.5% MC or saline (intraperitoneal or PO) following induction of chronic seizures. Histology of a subset of mice revealed lesions in kidney, liver, mediastinal lymph nodes, mesentery, aorta, and choroid plexus only in intraperitoneal MC-treated mice (n = 7/7). Kindled mice that received MC PO (n = 5) or saline (intraperitoneal n = 6, PO n = 3) had no lesions. There were no effects of intraperitoneal MC treatment on body weight, appearance, seizure stability, or behavior. Nonetheless, our findings suggest that repeated intraperitoneal, but not PO, MC elicits systemic organ damage without impacting the model phenotype, which may confound interpretation of investigational drug-induced histologic lesions. SIGNIFICANCE STATEMENT: Methylcellulose (0.5% concentration) is commonly used when evaluating investigational agents for efficacy in preclinical models of disease. Herein, we demonstrate that repeated administration of 0.5% methylcellulose by the intraperitoneal, but not oral, route results in systemic inflammation and presence of foam-laden macrophages but does not impact the behavioral phenotype of a rodent model of neurological disease.

The Global End-Diastolic Volume (GEDV) Could Be More Appropiate to Fluid Management Than Central Venous Pressure (CVP) During Closed Hyperthermic Intrabdominal Chemotherapy with CO2 Circulation.

BACKGROUND: Closed hyperthermic intraperitoneal chemotherapy (HIPEC) may increase abdominal pressure and effects of hemodynamic changes due to maintenance hyperthermia. Our aim was to analyze the safety and effectiveness of our closed technique with CO2 circulation in management fluid status and hemodynamic parameters by means of cardiac preload control measured by Global End Diastolic Values (GEDV) and a gas exchanger. MATERIAL AND METHODS: A Pilot Clinical Study that included 18 advanced ovarian cancer patients undergoing citoreductive surgery and HIPEC. We used a closed-perfusion system (PRS Combat®) that includes CO2 circulation and a gas exchanger. Transpulmonary thermodilutions and hemodynamic measurements (PiCCO2®) were performed after citoreductive surgery (Pre-HIPEC); At half time of the HIPEC (Intra-HIPEC); After HIPEC (Post-HIPEC). RESULTS: No significant hemodynamic measurements changes in the three thermodilutions values of Cardiac Index (CI) (p = 0.227), Global End Diastolic Values (GEVD) (p = 0.966), Stroke Volume Variation (SVV) (p = 0,884) and Systemic Vascular Resistance Index (SVRI) (p = 0.082). No correlation between central venous pressure (CVP) and GEDV (Pre-HIPEC: r = 0.164, p = 0.211; Intra-HIPEC: r = 0.015, p = 0.900; Post-HIPEC: r = 0.018, p = 0.890). There was better correlation between GEDV and CI (Pre-HIPEC: r = 0.432, p = 0.071; Intra-HIPEC: r = 0.418, p = 0.074; Post-HIPEC: r = 0.411, p = 0.080). CONCLUSIONS: Closed intrabdominal chemotherapy with CO2 circulation model may be a safe model for HIPEC by means of a gas exchanger. GEDV and its changes significantly correlated to CI, and not observed for CVP. GEDV values may be more appropriate for monitoring cardiac preload, blood loss limitation and to predict changes in intravascular volume status during intraperitoneal chemotherapy.

Studies on the antibody response and side effects after intramuscular and intraperitoneal injection of Atlantic lumpfish (Cyclopterus lumpus L.) with different oil-based vaccines.

Atlantic lumpfish (Cyclopterus lumpus L.) is used as a biological delousing agent for sea lice (Lepeophtheirus salmonis K.) infestations in Norwegian aquaculture. Here, we present a study on the antibody response and vaccine side effects after intramuscular and intraperitoneal injection of lumpfish with two vaccines. Both vaccines contained bacterial antigens from atypical Aeromonas salmonicida A-layer types V and VI, Vibrio anguillarum serotype O1 and Moritella viscosa sp., but one vaccine contained a vegetable oil-based adjuvant, while the other contained a mineral oil-based adjuvant. Intramuscular injection of the mineral oil-based vaccine caused a high acute mortality of fish within 48 hr after immunization. Intraperitoneal injection of the mineral oil-based vaccine resulted in a lower severity of intra-abdominal side effects than the vegetable oil-based vaccine. Intramuscular injection of the mineral oil-based vaccine resulted in a significantly higher antibody response against A. salmonicida when compared to controls and the vegetable oil-based vaccine group. The antibody response was poor against V. anguillarum and M. viscosa for all groups. Our results indicate that intramuscular injection of oil-based vaccines might be feasible for providing immunological protection for Atlantic lumpfish against bacterial diseases, especially atypical A. salmonicida, but more work is required to identity optimal adjuvants.

Intraperitoneal perfusion chemotherapy with hyperthermia in some malignant ascites.

Intraperitoneal administration of chemotherapeutic drugs with hyperthermia (HIPEC) increases their local effect on malignant peritoneal diseases and reduces systemic cytotoxicity. The most commonly used are cisplatin, doxorubicin, and mitomycin C. A major disadvantage of intraperitoneal chemotherapy is limited penetration of the drug in the tumor lesion depth (1-3 mm). Extended exposure and increased pressure in the abdominal cavity solution increases penetration of the agent into the tumor and hyperthermia has synergy with cytostatic agent on the permeability of cell membranes and metabolism of the drug. Real clinical hyperthermia is achieved at 41 degrees C. Of greatest importance is the concentration of the drug, but crucial for the prognosis is complete cytoreductive surgery. A major disadvantage of the closed technique is the uneven distribution of the perfusion solution in the peritoneal cavity, and the main advantage is better control of the perfusion, keeping of constant hyperthermia of the solution and regular repetition of manipulation, like intravenous chemotherapy. Laparoscopy determines the stage of the tumor process, refines the indications and preoperative selection for HIPEC, monitors the effects of treatment and determines locations for introducing catheters. In the review the results of the inraperitoneal chemotherapy with hyperthermia in gastric, colorectal, ovarian and other cancers are discussed as well as in diffuse malignant peritoneal mesothelioma and others.

Safety evaluation of ABELCET, an amphotericin B lipid complex (ABLC): toxicity studies in rats.

ABELCET (ABLC) is a widely used amphotericin B lipid complex formulation that is approved for use in the treatment of invasive fungal infections in patients who are refractory or intolerant of conventional amphotericin B (AmB). The safety profile of ABLC has been characterized in two acute and two repeat-dose toxicity studies in rats. The acute toxicity studies indicated that single intravenous doses of ABLC are at least 20 times less toxic than conventional amphotericin B doses without the lipid formulation, Fungizone. Intravenous doses of 0, 1, 3, or 10 mg/kg/day to groups of rats (10 to 15 rats/sex/group) for 31 days elicited no mortality or overt clinical signs of toxicity, whereas alternate intravenous/intraperitoneal doses (three each per week) for 6 months, produced one death in the control group, one in the intermediate-dose group, and two in the high-dose group. Clinical signs (predominantly piloerection and hunched posture at 10 mg/kg/day) were attributed to granulomatous inflammatory lesions in the abdominal wall, mesentery, and omentum, which were produced by the intraperitoneal injections of ABLC. Feed consumption and body weight gains decreased in high-dose male rats in the one-month study and were significantly lower in male rats at 3 and 10 mg/kg/day in the 6-month study. In contrast, water consumption increased in male and female rats in both studies. Trends of minimal to moderate, dose-related increases in relative kidney, liver and spleen weights, and histological evidence of hypertrophy and hyperplasia of reticuloendothelial cells in the liver and spleen and mild, dose-related impairment of renal function occurred in both the 1- and 6-month studies. Examination of high-dose rats following a recovery period of 28 days after completion of 31 days of dosing suggested that treatment-related changes were reversible. The observed changes for ABLC are similar to those for other amphotericin B lipid formulations, such as AmBisome (LAmB), except for the hepatoxicity, which was observed for LAmB, but not for ABLC.

Targeting pain-suppressed behaviors in preclinical assays of pain and analgesia: effects of morphine on acetic acid-suppressed feeding in C57BL/6J mice.

UNLABELLED: Pain increases the rate, frequency, or intensity of some behaviors (eg, withdrawal responses) and suppresses other behaviors (eg, feeding). Our laboratories are developing assays to test analgesic drug candidates using measurements of pain-suppressed rather than pain-elicited behaviors. Such assays may model important aspects of clinical pain and provide a means for distinguishing true analgesics from drugs that produce motor impairment. The present study compared effects of the mu opioid analgesic morphine and the nonanalgesic neuroleptic haloperidol on intraperitoneal acetic acid-induced writhing (a pain-elicited behavior) and suppression of feeding behavior (a pain-suppressed behavior). In feeding studies, C57BL/6J mice were given access to a dish containing 8 mL Ensure(trade mark) liquid food (0-100% in water) during daily sessions (7.5-120 min). Levels of consumption were dependent on both Ensure concentration and session duration. Intraperitoneal injection of acetic acid (0.10-0.56%) produced a time- and concentration-dependent decrease in Ensure consumption. Morphine (1 mg/kg) prevented both acid-induced writhing and acid-induced suppression of feeding, whereas the dopamine antagonist haloperidol inhibited writhing without preventing acid-induced suppression of feeding. The effects of morphine were time-dependent, selective for acid-suppressed feeding, and naltrexone-reversible. These results suggest that assays of pain-suppressed behaviors may complement assays of pain-elicited behaviors in preclinical studies of candidate analgesics. PERSPECTIVE: This paper presents a new preclinical strategy for assessing pain and analgesia in mice that is congruent with current methods of pain assessment in the clinic. This strategy may therefore be a useful complement to more traditional procedures for assessing pain and analgesia.

Intraperitoneal heated chemotherapy affects healing of experimental colonic anastomosis: an animal study.

BACKGROUND: The peritoneal spread of cancer is a well-known entity carrying a dismal prognosis. A new therapeutic approach is the combination of cytoreduction with heated intraperitoneal chemotherapy (HIPC). The risk of an intra-abdominal anastomosis in the presence of such chemotherapy is recognized clinically but the experimental data on the subject are lacking. The aim of this study is to examine the influence of chemotherapy and hyperthermia on the healing of colonic anastomosis. MATERIALS AND METHODS: Colonic anastomosis were performed in four groups of male Wistar rats: (1) control (operation only), (2) HIPC with saline, (3) with mitomycin C (MMC), and (4) with cisplatinum. HIPC was performed using a closed circulation system at 40 degrees C over 20 min. Anastomotic strength was tested on day 4, 7, 10, and 21. RESULTS: The bursting pressure of anastomoses in rats treated by HIPC was significantly lower than in controls. On day 4, it was 54.8 mm Hg, 38 mm Hg, 18 mm Hg, and 14.8 mm Hg in groups 1-4, respectively, while on day 7 it was 170 mm Hg, 188 mm Hg, 83 mm Hg, and 19 mm Hg, respectively (P < 0.01). The difference decreased on day 10 and almost vanished on day 21. HIPC with cisplatinum had the worst effect on anastomotic healing during the early postoperative period. CONCLUSIONS: Cytoreduction and HIPC are gaining popularity. However, the use of heated chemotherapy has a detrimental effect on the strength of colonic anastomosis, especially during the early postoperative period (until day 10). This may cause anastomotic failure and postoperative morbidity. Therefore, careful selection and avoidance of unnecessary anastomoses are mandatory.

Visceral antinociception produced by bee venom stimulation of the Zhongwan acupuncture point in mice: role of alpha(2) adrenoceptors.

The goal of the present study was to determine whether bee venom (BV) injection into the Zhongwan acupoint (CV12), compared to injection into a non-acupoint, produced antinociception in an acetic acid-induced visceral pain model. This was accomplished by injecting BV subcutaneously into the Zhongwan acupoint or into a non-acupoint 30 min before intraperitoneal injection of acetic acid in ICR mice. BV injection into the acupoint produced a dose dependent suppression of acetic acid-induced abdominal stretches and of acetic acid-induced Fos expression in the spinal cord and the nucleus tractus solitarii. In contrast BV injection into the non-acupoint only produced antinociception at the highest dose of BV tested. Naloxone pretreatment did not alter the antinociceptive effect of BV acupoint injection on the abdominal stretch reflex. On the other hand, pretreatment with the alpha 2-adrenoceptor antagonist, yohimbine completely blocked the antinociceptive effect of BV acupoint injection. These results imply that BV acupoint stimulation can produce visceral antinociception that is associated with activation of alpha 2-adrenoceptors, but not with naloxone-sensitive opioid receptors.