Effects of intracerebroventricular injection of indomethacin on adaptive gastric cytoprotection in the conscious rat

Brainstem inflammation modulates the ventilatory pattern and its variability after acute lung injury in rodents

KEY POINTS

Compared with sham rats, rats a week after acute lung injury (ALI) express more pro-inflammatory cytokines in their brainstem respiratory control nuclei, exhibit a higher respiratory frequency (fR) and breathe with a more predictable pattern. These characteristics of the respiratory pattern persist in in situ preparations even after minimizing pulmonary and chemo-afferent inputs. Interleukin (IL)-1β microinjected in the nucleus tractus solitarii increases fR and the predictability of the ventilatory pattern similar to rats with ALI. Intracerebroventricular infusion of indomethacin, an anti-inflammatory drug, mitigates the effect of ALI on fR and ventilatory pattern variability. We conclude that changes in the ventilatory pattern after ALI result not only from sensory input due to pulmonary damage and dysfunction but also from neuro-inflammation.

ABSTRACT

Acute lung injury (ALI) increases respiratory rate (fR) and ventilatory pattern variability (VPV), but also evokes peripheral and central inflammation. We hypothesized that central inflammation has a role in determining the ventilatory pattern after ALI. In rat pups, we intratracheally injected either bleomycin to induce ALI or saline as a sham control. One week later, we recorded the ventilatory pattern of the rat pups using flow-through plethysmography, then formed in situ preparations from these pups and recorded their 'fictive' patterns from respiratory motor nerves. Compared with the ventilatory pattern of the sham rat pups, injured rat pups had increased fR and predictability. Surprisingly, the fictive patterns of the in situ preparations from ALI pups retained these characteristics despite removing their lungs to eliminate pulmonary sensory inputs and perfusing them with hyperoxic artificial cerebral spinal fluid to minimize peripheral chemoreceptor input. Histological processing revealed increased immunoreactivity of the pro-inflammatory cytokine Interleukin-1β (IL-1β) in the nucleus tractus solitarii (nTS) from ALI but not sham rats. In subsequent experiments, we microinjected IL-1β in the nTS bilaterally in anaesthetized naïve adult rats, which increased fR and predictability of ventilatory pattern variability (VPV) after 2 h. Finally, we infused indomethacin intracerebroventricularly during the week of survival after ALI. This did not affect sham rats, but mitigated changes in fR and VPV in ALI rats. We conclude that neuro-inflammation has an essential role in determining the ventilatory pattern of ALI rats.

Clinical and histologic features of Azathioprine-induced hepatotoxicity

BACKGROUND

Hepatoxicity is a relative uncommon complication related with Azathioprine, however most studies were performed in inflammatory bowel diseases patients. The aim of this study is to report the clinical profile of patients with Azathioprine-induced hepatotoxicity.

METHODS

All medical records of patients received Azathioprine from 2010 to 2015 were retrospectively reviewed. Hepatotoxicity was defined as serum alanine aminotransferase (ALT) or aspatate aminotransferase (AST) or total bilirubin >2 times upper limit normal. Other causes of liver diseases were excluded. All subjects were followed until the resolution of liver injury.

RESULTS

Two-hundred and ninety-three patients receiving Azathioprine were retrospectively reviewed. Eight patients (2.7%) were diagnosed with Azathioprine-induced hepatotoxicity. The median age was 45 year with female preponderance. The latency to onset of liver injury ranged from 7 to 236 d, and 4 patients were symptomatic. Median peak levels were ALT 295 U/L, alkaline phosphatase 169 U/L, and total bilirubin 1 mg/dl. According to R-ratio, mixed pattern (50%) was more frequent than cholestatic (37.5%) and hepatocellular pattern (12.5%). Liver biopsies were performed in 2 patients, and showed hepatocellular and canalicular cholestasis with mild portal and peri-portal inflammation. All patients recovered fully with a median time of 41.3 days. Two patients developed prolonged cholestasis >2 months, hence none had liver failure or required liver transplantation.

CONCLUSION

Hepatotoxicity is relative uncommon in patients receiving Azathioprine, and predominantly is mixed hepatocellular and cholestatic in nature. Even though all patients recover fully after drug withdrawal, severe cholestasis can occur.

Morphologische Veränderungen der medikamenteninduzierten Leberschädigung

Hepatotoxicity is a significant complication of therapeutic drug use. As ist can imitate nearly all hepatopathies, the diagnosis of drug-induced liver disease is difficult. Most often, it is a diagnosis of exclusion. The following morphological changes are known, dependent on the target cell type: acute and chronic hepatitis, granuloma formation, and fatty liver disease, cholestatic type acute and chronic liver damage with or without inflammation,or mixed forms of liver injury. Portal or perisinusoidal fibrosis can occur following each type of liver damage. Vascular changes or neoplasms are rare. Drug induced liver injuries are more likely induced by type B damage, which is not expected and cannot be reproduced in animal testing. Type A damage, which is known from toxicity assays, is less likely. A specific therapeutic regime is not available. Therefore, early recognition and cessation of the use of the drug is necessary.

Cyclooxygenase inhibition in the dorsal vagal complex of the rat evokes increases in gastric motor function

To characterize the involvement of brainstem cyclooxygenase (COX) in the vagal control of gastric motor function, tolmetin, a reversible COX inhibitor, was applied to the surface of the dorsal medulla oblongata or microinjected into the dorsal vagal complex (DVC) in alpha-chloralose anesthetized rats, while intragastric pressure and contractile activity of the pyloric circular and greater curvature longitudinal muscle were monitored. Tolmetin, applied to the surface of the medulla oblongata, increased intragastric pressure and stimulated contractile activity of gastric smooth muscle. Comparable gastric motor effects were observed after microinjection of tolmetin into the DVC. All the effects of tolmetin were abolished by bilateral vagotomy at the midcervical level. These results demonstrate for the first time that COX inhibition evokes vagally-mediated gastric motor effects in the DVC of the rat and support a role for COX products in gastrointestinal regulation.

Application of International Consensus Meeting Criteria for classifying drug-induced liver disorders

OBJECTIVE

To report a patient with 2 consecutive reversible drug-induced liver disorders and the application of International Consensus Meeting Criteria for the screening and diagnosis of drug-induced liver disorders.

CASE SUMMARY

An 88-year-old man in a chronic care institution developed abdominal discomfort and jaundice after finishing a 10-day course of trimethoprim/sulfamethoxazole therapy for a urinary tract infection (UTI). The jaundice and the symptoms resolved spontaneously and the final diagnosis was symptomatic drug-induced liver injury, mixed type. After 1 month, the same patient received a course of cefadroxil therapy for another UTI. He developed an asymptomatic drug-induced liver injury, mixed type. Six months later, the patient received oral penicillin therapy and then ciprofloxacin, with no change in his liver function test results.

DISCUSSION

To our knowledge, there are only a few other reports in the literature of a drug-induced liver injury with cefadroxil therapy; more cases are reported with trimethoprim/sulfamethoxazole than with cefadroxil. The criteria of an International Consensus Meeting were helpful to evaluate both incidences of liver injury in this patient with the aim of establishing the diagnosis and causality assessment. Additionally, the criteria were used to show that the patient had 2 separate liver injuries.

CONCLUSIONS

Screening and diagnosis of drug-induced liver disorders depend on careful history taking and 5 specific biochemical liver tests. The evolution of the liver disorder induced by cefadroxil therapy probably was interrupted because of its early detection. Appropriate screening was done with the subsequent administration of new potentially hepatotoxic drugs.