Engineering 3D-Printed Bioresorbable Scaffold to Improve Non-Vascularized Fat Grafting: A Proof-of-Concept Study

Autologous fat grafting is the gold standard for treatment in patients with soft-tissue defects. However, the technique has a major limitation of unpredictable fat resorption due to insufficient blood supply in the initial phase after transplantation. To overcome this problem, we investigated the capability of a medical-grade poly L-lactide-co-poly ε-caprolactone (PLCL) scaffold to support adipose tissue and vascular regeneration. Deploying FDM 3D-printing, we produced a bioresorbable porous scaffold with interconnected pore networks to facilitate nutrient and oxygen diffusion. The compressive modulus of printed scaffold mimicked the mechanical properties of native adipose tissue. In vitro assays demonstrated that PLCL scaffolds or their degradation products supported differentiation of preadipocytes into viable mature adipocytes under appropriate induction. Interestingly, the chorioallantoic membrane assay revealed vascular invasion inside the porous scaffold, which represented a guiding structure for ingrowing blood vessels. Then, lipoaspirate-seeded scaffolds were transplanted subcutaneously into the dorsal region of immunocompetent rats (n = 16) for 1 or 2 months. The volume of adipose tissue was maintained inside the scaffold over time. Histomorphometric evaluation discovered small- and normal-sized perilipin+ adipocytes (no hypertrophy) classically organized into lobular structures inside the scaffold. Adipose tissue was surrounded by discrete layers of fibrous connective tissue associated with CD68+ macrophage patches around the scaffold filaments. Adipocyte viability, assessed via TUNEL staining, was sustained by the presence of a high number of CD31-positive vessels inside the scaffold, confirming the CAM results. Overall, our study provides proof that 3D-printed PLCL scaffolds can be used to improve fat graft volume preservation and vascularization, paving the way for new therapeutic options for soft-tissue defects.

Left ventricular remodeling: is there a real impact of cardiac rehabilitation?

Funding Acknowledgements

Type of funding sources: None.

Introduction

A number of randomized controlled trials have examined the effect of exercise training on left ventricle (LV) remodeling in individuals with cardiovascular disease. However, the results of these trials have been inconclusive. 

Purpose

Evaluation of the impact of a cardiac rehabilitation program (CRP) on left ventricle remodelling evaluated by echocardiogram. 

Methods

Observational single centre study including consecutive patients, undergoing structured CRP since June 2016 until February 2020. Phase II CRP included 3 months of exercise training, aerobic and strength exercise, individually prescribed, 3 times a week, 60 minutes sessions. All patients were submitted to a clinical evaluation, echocardiogram, and cardiopulmonary exercise test before and after the CRP.

Results

205 patients (62.6 ± 11 years, 83.4% men, 82.3% ischemic disease) were included in a phase II CRP. Most patients had ischemic disease (82.3%) and 23.5% of patients had left ventricular ejection fraction (LVEF) <40%. Of the cardiovascular risk factors, hypertension was the most prevalent (76%), followed by dyslipidaemia (67.4%), active smoking (45.9%) and diabetes (26.9%). 

After the CRP, there was a significant improvement of LVEF (from 48.3 ± 13 to 52 ± 11.6 %, p = 0.001) and a significant reduction of LV volumes (LV end-diastolic volume, LVEDV , decreased from 140 ± 81 to 121 ± 57, p = 0.002; LV end-systolic volume , LVESV , reduced from 80 ± 75 to 64 ± 48, p = 0.004). Considering only the patients with LVEF < 40% (n = 38), the improvement was even greater: LVEF increased from 30 ± 8 to 39 ± 13 (p = 0.002); LVEDV reduced from 206 ± 107 to 159 ± 81 (p = 0.001) and LVESV reduced from 142 ± 99 to 101 ± 66 (p = 0.002). 63.6%(n = 14) of these patients improved at least 10% of LVEF and only 1 of them had a cardiac resynchronization therapy device. 

Conclusions

A phase II CR program was associated with significant improvements in left ventricular reverse remodelling irrespective of baseline EF classification. Those with reduced baseline EF derived an even greater improvement, highlighting the great importance of CR in this subgroup of patients.

Autoradiographic, electrophoretic, and immunocytochemical studies of glycoproteins of the rabbit iris

L-[3H]fucose was injected either intravitreally or intra-aqueously into adult rabbits which were killed at several time points after injection. SDS-polyacrylamide gel electrophoresis and fluorography of iris extracts revealed that most of the proteins are glycoproteins containing fucose residues. Autoradiography of semi-thin histologic sections demonstrated that glycoprotein synthesis was most prominent in the epithelium of the iris, while little protein synthesis was evident in the stroma of the iris. The results of these experiments indicated that the glycoproteins of the iris undergo renewal. The protein band pattern of the iris extracts was very similar to that of extracts of the ciliary body. The high-molecular-weight cartilage matrix glycoprotein (CMGP), an intrinsic component of the ciliary body, vitreous, and aqueous humor, was detected by immunohistologic studies only in the stroma of the iris. The results of immunohistochemical analyses of the eyes of young rabbits (1-21 days old), in addition to the autoradiographic findings, strongly suggest that CMGP is not an intrinsic glycoprotein of the iris stroma, at least in this species.