Clinical characteristics, diagnosis, treatment, and outcome of patients with liver abscess due to Aspergillus spp: a systematic review of published cases

BACKGROUND

Aspergillus spp liver abscess is a relatively rare entity and thus far no systematic review has been performed examining patients' demographics, clinical manifestations, diagnosis, management, and outcome.

METHODS

We performed a systematic review of the literature using MEDLINE and LILACS databases. We searched for articles published in the period from January 1990 to December 24, 2022, to identify patients who developed liver abscesses due to Aspergillus spp.

RESULTS

Our search yielded 21 patients all of whom had invasive aspergillosis confirmed on liver biopsy. Of these patients 81% were adults, and 60% were males. The majority (86%) of patients were immunocompromised and 95% had symptomatic disease at the time of diagnosis. The most common symptoms were fever (79%), abdominal pain (47%), and constitutional symptoms (weight loss, chills, night sweats, fatigue) (38%). Liver enzymes were elevated in 50%, serum galactomannan was positive in 57%, and fungal blood cultures were positive in only 11%. Co-infection with other pathogens preceded development of apsergillosis in one-third of patients, and the majority of the abscesses (43%) were cryptogenic. In the remaining patients with known source, 28% of patients developed liver abscess through dissemination from the lungs, 19% through the portal vein system, and in 10% liver abscess developed through contiguous spread. The most common imaging modality was abdominal computerized tomography done in 86% of patients. Solitary abscess was present in 52% of patients while 48% had multiple abscesses. Inadequate initial empiric therapy was prescribed in 60% of patients and in 44% of patients definite treatment included combination therapy with two or more antifungal agents. Percutaneous drainage of the abscesses was done in 40% of patients, while 20% required liver resection for the treatment of the abscess. Overall mortality was very high at 38%.

CONCLUSION

Further studies are urgently needed for a better understanding of pathophysiology of liver aspergillosis and for developement of newer blood markers in order to expedite diagnosis and decrease mortality.

Chk1 phosphorylation of Metnase enhances DNA repair but inhibits replication fork restart

Chk1 both arrests replication forks and enhances repair of DNA damage by phosphorylating downstream effectors. Although there has been a concerted effort to identify effectors of Chk1 activity, underlying mechanisms of effector action are still being identified. Metnase (also called SETMAR) is a SET and transposase domain protein that promotes both DNA double-strand break (DSB) repair and restart of stalled replication forks. In this study, we show that Metnase is phosphorylated only on Ser495 (S495) in vivo in response to DNA damage by ionizing radiation. Chk1 is the major mediator of this phosphorylation event. We had previously shown that wild-type (wt) Metnase associates with chromatin near DSBs and methylates histone H3 Lys36. Here we show that a Ser495Ala (S495A) Metnase mutant, which is not phosphorylated by Chk1, is defective in DSB-induced chromatin association. The S495A mutant also fails to enhance repair of an induced DSB when compared with wt Metnase. Interestingly, the S495A mutant demonstrated increased restart of stalled replication forks compared with wt Metnase. Thus, phosphorylation of Metnase S495 differentiates between these two functions, enhancing DSB repair and repressing replication fork restart. In summary, these data lend insight into the mechanism by which Chk1 enhances repair of DNA damage while at the same time repressing stalled replication fork restart.