Interleukin-6 and Interleukin-8 Gene Expressions Differ Between Male and Female Patients at Time of Hip Arthroscopy for Femoroacetabular Impingement Syndrome

Abstract

Purpose: To identify key molecular components within the femoroacetabular impingement hip and compare the findings between male and female patients across varying age groups.

Methods: All patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS) without hip dysplasia were included. During hip arthroscopy, performed at University of Wisconsin Health, loose articular cartilage, excess synovium, damaged labral tissue, and minimal adipose tissue were debrided only as needed for visualization and tissue repair purposes and collected. Tissue was processed and used for quantitative polymerase chain reaction (qPCR). Genes were selected for qPCR on the basis of their associated function in inflammation and/or extracellular matrix remodeling during the progression of osteoarthritis.

Results: A total of 91 male (M) and female (F) patients 15 to 58 years old were included in the study. qPCR results indicated that Interleukin-6 (P < .05, 95% confidence interval [CI] 0.047-0.083 F, 0.070-0.12 M) and Interleukin-8 (P = .04, 95% CI 0.059-0.10 F, 0.082-0.18 M) were significantly greater in male patients compared with female patients regardless of age, and IL6 (P = .02, 95% CI [0.026-0.070] F, [0.067-0.17] M), Interleukin-1ß (P < .01 95% CI [0.013-0.063] F, [0.073-0.25] M), and Matrix metalloproteinase-13 (P = .047, 95% CI [0.0051-0.017] F, [0.0084-0.052] M) were significantly greater in male patients younger than 20 years old compared with female patients younger than 20 years old.

Conclusions: In patients with FAIS, there are significant differences between male and female patients in the biomarkers present in the affected hip at the time of surgery. Male patients have greater levels of IL6 and IL8 and male patients younger than 20 years of age have greater levels of IL1β, IL6, and MMP13 compared with age-matched female patients.

Clinical relevance: A better understanding of the molecular markers present during varying stages of FAIS and in patients of different ages will help characterize the pathologic process behind FAIS. This may also help define future methods of targeted treatment and prevention of disease progression.

Fig 1

Representative intraoperative images of a patient with femoroacetabular impingement syndrome. Image depicts a left hip in an 18-year-old male patient. This image demonstrates the frayed and damaged cartilage at the chondrolabral junction will be debrided by the shaver as viewed through the accessory medial portal (A) and as viewed through the anterolateral portal (B).

Fig 2

(A) and (B) show the intraoperative orientation of the filter device (circled in yellow) used to collect tissue debrided from the central compartment of the hip joint. (C) The filter device was detached after labral repair and necessary cartilage debridement were complete, and samples (circled in black) immediately transported to the laboratory via appropriate storage and transport protocols.

Fig 3

Inflammatory biomarker results comparing sexes and age groups in a cohort of patients with femoroacetabular impingement syndrome (FAIS). Quantitative polymerase chain reaction results of inflammatory and cell senescent factors of tissue remnants obtained during hip arthroscopy to correct for FAIS. Results indicate that IL6 (A) and IL8 (B) expression levels were significantly greater in male than female subjects. No significance was noted in IL1β (C). Analysis of specific age groups further indicated that expression levels of IL1β (D) and IL6 (E) were greater in male patients <20 years old compared with <20-year-old female subjects. (F) No differences between age groups were noted with IL8 expression. (G and H) The cell senescent factor P21 was not significantly different between sexes. (H) Although male subjects <20 years old expressed greater levels of P21 compared with female subjects <20 years old, only a trend was noted. There were no significant differences for data grouped by age and not sex. Data are expressed as mean ± standard error of the mean. Data are considered significant if P ≤ .05. (IL1β, interleukin-1β; IL6, interleukin-6; IL8, interleukin-8.)

Fig 4

Anabolic and catabolic biomarker results compared between sexes and age groups in a cohort of patients with femoroacetabular impingement syndrome (FAIS). Quantitative polymerase chain reaction results of anabolic and catabolic factors expressed in tissue remnants obtained during hip arthroscopy to correct for FAIS. Results indicate that ACAN (A and B), COL2A1 (C and D), and COMP (E and F) were not significantly different between samples. COL2A1 was greater in >40-year-old male patients compared with age-matched female patients (P = .07). (G-L) No differences were noted with the catabolic factors, MMP13, ADAMTS1, or ADAMSTS5, although an increase in ADAMTS5 was noted between male subjects <20 years of age compared with their aged female counterparts. There were no significant differences for data grouped by age and not sex. Data are expressed as mean ± standard error of the mean. Data are considered significant if P ≤ .05. (ACAN, aggrecan; ADAMTS1, a disintegrin and metalloproteinase with thrombospondin motifs-1; ADAMTS5, a disintegrin and metalloproteinase with thrombospondin motifs-5; COL2A1, collagen type II; COMP, cartilage oligomeric matrix protein; MMP13, matrix metalloproteinase-13.)