Preface to extracellular matrix and disease

Assessment of myocardial function by two-dimensional speckle tracking echocardiography in patients with Kawasaki disease: a mid-term follow-up study

BACKGROUND

Myocardial impairment proved by histological studies persists in late convalescent phase Kawasaki disease patients. Whether Kawasaki disease-induced myocardial lesions can be detected in an earlier time is not well explored. In this study, we aimed to evaluate left ventricular (LV) myocardial function by two dimensional speckle tracking echocardiography (2DSTE) in late convalescent phase Kawasaki disease patients.

METHODS

A total of 68 Kawasaki disease patients during mid-term phase including 47 with no coronary artery aneurysm (NCAA) and 21 with coronary artery aneurysm (CAA), and 60 controls with age matched were consecutively enrolled.

RESULTS

No significant differences on conventional echocardiographic LV systolic function indices were found among group comparison. Compared with controls, Kawasaki disease patients had lower global longitudinal stain (GLS) and global circumferential stain (GCS). In subgroup analysis, both those with CAA and without CAA had lower GLS, lower GCS, higher amino-terminal propeptide of type III procollagen (PIIINP) and higher carboxyterminal propeptide of procollagen type I (PIPC) than in controls. GLS had significantly negative correlations with PIIINP (r = -0.69, P = 0.002) and PIPC (r = -0.82, P = 0.000).

CONCLUSION

Subclinical myocardial dysfunction in mid-term follow-up Kawasaki disease patients existed regardless of coronary artery status despite normal measurements of LV systolic function by routine echocardiography, and myocardial fibrosis may play a contributed role in this subclinical myocardial function impairment. 2DSTE is a valuable imaging modality for detecting regional and global myocardial dysfunction in Kawasaki disease patients in an early time.

An image-based assay to quantify changes in proliferation and viability upon drug treatment in 3D microenvironments

BACKGROUND

Every biological experiment requires a choice of throughput balanced against physiological relevance. Most primary drug screens neglect critical parameters such as microenvironmental conditions, cell-cell heterogeneity, and specific readouts of cell fate for the sake of throughput.

METHODS

Here we describe a methodology to quantify proliferation and viability of single cells in 3D culture conditions by leveraging automated microscopy and image analysis to facilitate reliable and high-throughput measurements. We detail experimental conditions that can be adjusted to increase either throughput or robustness of the assay, and we provide a stand alone image analysis program for users who wish to implement this 3D drug screening assay in high throughput.

RESULTS

We demonstrate this approach by evaluating a combination of RAF and MEK inhibitors on melanoma cells, showing that cells cultured in 3D collagen-based matrices are more sensitive than cells grown in 2D culture, and that cell proliferation is much more sensitive than cell viability. We also find that cells grown in 3D cultured spheroids exhibit equivalent sensitivity to single cells grown in 3D collagen, suggesting that for the case of melanoma, a 3D single cell model may be equally effective for drug identification as 3D spheroids models. The single cell resolution of this approach enables stratification of heterogeneous populations of cells into differentially responsive subtypes upon drug treatment, which we demonstrate by determining the effect of RAK/MEK inhibition on melanoma cells co-cultured with fibroblasts. Furthermore, we show that spheroids grown from single cells exhibit dramatic heterogeneity to drug response, suggesting that heritable drug resistance can arise stochastically in single cells but be retained by subsequent generations.

CONCLUSION

In summary, image-based analysis renders cell fate detection robust, sensitive, and high-throughput, enabling cell fate evaluation of single cells in more complex microenvironmental conditions.

Abnormal Matrix Remodeling in Adolescents and Young Adults with Kawasaki Disease Late after Onset

Background: Patients with a history of Kawasaki disease (KD), have been found to have pericoronary and myocardial fibrosis. Serum biomarkers of fibrosis may be sensitive indices for detection of these late cardiac complications in KD patients.

Methods: We studied a cohort of 60 adolescents and young adults comprising 10 KD patients with persistent coronary artery lesions (CAL) occurring at a mean (SD) time of 14.5 (4.4) years after disease onset, 25 KD patients with no CAL after disease onset, and 25 healthy age-matched volunteers. We compared laboratory data from the patients and volunteers, including lipid profile, liver function, amino-terminal propeptide of type III procollagen (PIIINP), matrix metalloproteinase 9 (MMP-9), tissue inhibitor of metalloproteinase 1 (TIMP-1), and MMP-9:TIMP-1 ratios. Severity of CAL was determined on the basis of computed tomography determinations of the frequency of aneurysms and the extent of coronary stenosis/occlusion, thrombosis, and calcification.

Results: Increased PIIINP and decreased MMP-9 and TIMP-1 concentrations and decreased MMP-9:TIMP-1 ratios were found not only in KD patients with persistent CAL but also in KD patients without CAL, although to a lesser extent in the latter group. In KD patients, the concentrations of PIIINP were positively associated with the severity of coronary stenosis/occlusion (r = 0.72, P = 0.011) and with the extent of coronary thrombus (r = 0.64, P = 0.014). The concentrations of high-sensitivity C-reactive protein, however, did not differ across groups.

Conclusions: Our results demonstrate alterations in extracellular matrix biomarkers in KD patients, suggesting enhanced collagen synthesis and ameliorated degradation in adolescents and young adults late after the onset of KD. We also observed an association between the concentrations of PIIINP and the extent of coronary stenosis/occlusion or thrombosis in KD patients, a finding that needs confirmation in further studies.