The association between gut microbiome and growth in infants with cystic fibrosis

BACKGROUND

In cystic fibrosis (CF), pathophysiologic changes in the gastrointestinal tract lead to malnutrition and altered gut microbiome. Microbiome alterations have been linked to linear growth, gut inflammation and respiratory manifestations. Elucidating these gut microbiome alterations may provide insight into future nutritional management in CF.

METHODS

Infants were followed for 12-months at four sites in the United States (US-CF) and Australia (AUS-CF). 16S rRNA gene sequencing was performed on longitudinal stool samples. Associations between microbial abundance and age, antibiotic prophylaxis, malnutrition, and breast feeding were evaluated using generalized linear mixed models. Taxonomic and predictive functional features were compared between groups.

RESULTS

Infants with CF (N = 78) were enrolled as part of a larger study. AUS-CF infants had higher mean weight-for-age z-scores than US-CF infants (p = 0.02). A subset of participants (CF N = 40, non-CF disease controls N = 10) provided stool samples for microbiome analysis. AUS-CF infants had lower stool alpha diversity compared to US-CF infants (p < 0.001). AUS-CF infants had higher relative abundance of stool Proteobacteria compared to US-CF infants which was associated with antibiotic prophylaxis (p < 0.001). Malnutrition (weight-for-age <10th percentile) was associated with depleted Lactococcus (p < 0.001). Antibiotic prophylaxis (p = 0.002) and malnutrition (p = 0.012) were linked with predicted decreased activity of metabolic pathways responsible for short chain fatty acid processing.

CONCLUSIONS

In infants with CF, gut microbiome composition and diversity differed between the two continents. Gut microbial diversity was not linked to growth. The relationship between malnutrition and antibiotic prophylaxis with reduced SCFA fermentation could have implications for gut health and function and warrants additional investigation.

SAT0572 CONSTRUCTIVE VALIDITY OF MUSKULOSKELETAL ULTRASOUND MEASUREMENT OF CARTILAGE THICKNESS IN PATIENTS WITH KNEE OSTEOARTHRITIS

Background:

Cartilage thickness is one important measure in describing both OA development and progression. Based on current knowledge, conventional radiography (CR) and magnetic resonance imaging (MRI) have not been demonstrated to be superior over one another. Because of disadvantages of MRI and CR neither can be use in routine daily clinical practice for follow up of OA patients. Diagnostic ultrasound assessment (US) of cartilage thickness offers an alternative measure as a clinically available and more cost-effective source of knee articular cartilage imaging.

Objectives:

Our objective was to determine the relationship between US and CR measures of femoral cartilage thickness in patients with knee osteoarthritis because systematic feature- and site-specific cross-comparison between this two methods is still missing in the current literature.

Methods:

120 patients with knee osteoarthritis (240 knees) are recruited for this study. The joint space width (JSW) and Kellgren and Lawrence (K&L) grade were measured using weight-bearing anteroposterior 30° knee semi-flexion knee radiography (with inclusion criteria K&L grade 1-4). Femoral cartilage thickness was measured three times in supine position and with a suprapatellar transverse scan with the knee in maximal flexion at the lateral condyle (LC), medial condyle (MC) and intercondylar notch (IN) by one rheumatologist and arithmetic mean is taken. Pain and functionality are measured with VAS pain scale, Womac, Lysholm and SF 36 score. The agreement between two methods was evaluated with Bland-Altman analysis.

Results:

We found a statistically significant low level of rank correlation between CR and US measurements of mean cartilage thickness; ρ (rho) values between modalities were low (0.263 and 0.273 depending on side (right/left), p=0.005 and p=0.007 respectively). In Bland – Altman analysis, US measurement showed bad agreement with CR. Presence or absence of US features of OA (effusion, synovial hypertrophy, osteophytes and popliteal cysts) didn’t influence on cartilage thickness assessed by US (p>0.05). For US assessment, we found correlation only between cartilage thickness and VAS pain scale (ρ (rho) -0.281, p=0.004). We didn’t found any statistically significant correlation between CR thickness measures and pain/functionality/HRQoL scores (p>0.05).

Conclusion:

These results suggest that ultrasound may be a useful clinical tool to assess relative cartilage thickness. However, the absolute validity of the ultrasound measure is called into question due to the larger CR-based thickness measures and low level of agreement according to Bland-Altman analysis. The use of ultrasound as a complementary imaging tool along with CR may enable more accurate and cost-effective detection, prognosis and follow-up of knee osteoarthritis in routine clinical practice.

References:

[1]Mehta N, Duryea J, Badger GJ, et al. Comparison of 2 Radiographic Techniques for Measurement of Tibiofemoral Joint Space Width.Orthop J Sports Med. 2017;5:2325967117728675.

[2]Schmitz RJ, Wang HM, Polprasert DR, Kraft RA, Pietrosimone BG. Evaluation of knee cartilage thickness: A comparison between ultrasound and magnetic resonance imaging methods.Knee. 2017;24:217–223.

[3]Podlipská J, Guermazi A, Lehenkari P, et al. Comparison of Diagnostic Performance of Semi-Quantitative Knee Ultrasound and Knee Radiography with MRI: Oulu Knee Osteoarthritis Study.Sci Rep. 2016;6:22365

[4]Razek AA, El-Basyouni SR. Ultrasound of knee osteoarthritis: interobserver agreement and correlation with Western Ontario and McMaster Universities Osteoarthritis.Clin Rheumatol. 2016;35:997–1001.

[5]Oo WM, Bo MT. Role of Ultrasonography in Knee Osteoarthritis.J Clin Rheumatol. 2016;22:324–329.

Disclosure of Interests:

None declared

Evaluation of Prognostic Immune Signatures in Patients with Breast, Colorectal and Pancreatic Cancer Receiving Chemotherapy

BACKGROUND

CD97 is a member of the epidermal growth factor-seven transmembrane (EGF-TM7) receptor family and is dominantly expressed on immune cells and in a variety of malignant diseases. B7-H1 and B7-H3 are transmembrane proteins that are involved in suppression of the immune system. The aim of this study was to evaluate if these molecules are up-regulated in patients with cancer and change during chemotherapy.

MATERIALS AND METHODS

We analyzed cluster of differentiation (CD) protein expression levels on tumor cell lines and in blood samples of 37 patients with solid tumors at baseline and during chemotherapy; we correlated the serum levels of CD proteins with survival outcome.

RESULTS

Levels of soluble CD97 proteins were significantly elevated in all three cancer types compared to healthy controls. Patients with colorectal cancer and those with high CD97 levels had a significantly worse prognosis.

CONCLUSION

This study showed a marked elevation of soluble CD97 expression in patients with certain cancer types and demonstrated definite changes in CD protein expression during chemotherapy in one patient with metastatic breast cancer.