The significance and challenges of monocyte impairment: for the ill patient and the surgeon

Galbraith, N. , Walker, S., Galandiuk, S., Gardner, S. and Polk, H. C. (2016) The significance and challenges of monocyte impairment: for the ill patient and the surgeon. Surgical Infections, 17(3), pp. 303-312. (doi: 10.1089/sur.2015.245) (PMID:26958709)

Abstract

Background: Trauma, major elective surgery, and overt sepsis can lead to a cascade of immunological change. A subset of these patients will have a degree of immune suppression that leads to hyporesponsive innate defenses, increasing the risk of infective co-morbidity and death. This article is an overview of monocyte impairment in the high-risk surgical patient. Specifically, our primary focus is on observations made pertaining to monocyte function and pathophysiological mechanisms underpinning this impairment. Clinical factors influencing monocyte function are also discussed. Methods: A Pubmed search was conducted to review aspects of monocyte impairment in the surgical patient. Search terms included “monocyte impairment,” “immunoparalysis,” and “endotoxin tolerance” cross-referenced against terms including “trauma,” “major surgery,” and “sepsis.” Results: Findings revealed a broad variety of monocyte defects reported in surgical patients. They ranged from altered cytokine responses, particularly ex vivo TNF-α production, to impaired antigen presentation such as depressed HLA-DR expression. The latter is the most commonly described marker of secondary infection and death. Studies of underlying mechanisms have commonly utilized a model of endotoxin tolerance with in vitro monocytes, revealing a complex array of dysregulated pathways. For our purposes, endotoxin tolerance and monocyte impairment are sufficiently similar entities to permit further study as a single subject. In the high risk patient, microRNAs (also referred to as miRNA or miR) are emerging as potential biomarkers that may modify such pathways. Creation of a reliable impaired human monocyte model could be important to all such considerations. Conclusion: Impairment of monocyte function continues to be predictive of nosocomial infection, multi-organ failure, and death in some surgical patients. However, the optimal marker that could identify a patient as high risk early enough, and whether it might guide potential therapy, still is yet to be proven.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Galbraith, Dr Norman
• Authors: Galbraith, N., Walker, S., Galandiuk, S., Gardner, S., and Polk, H. C.
• College/School: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
• Journal Name: Surgical Infections
• Publisher: Mary Ann Liebert
• ISSN: 1096-2964
• ISSN (Online): 1557-8674
• Published Online: 09 March 2016