Reconstruction of hepatic stellate cell‐incorporated liver capillary structures in small hepatocyte tri‐culture using microporous membranes

In liver sinusoids, hepatic stellate cells (HSCs) locate the outer surface of microvessels to form a functional unit with endothelia and hepatocytes. To reconstruct functional liver tissue in vitro, formation of the HSC‐incorporated sinusoidal structure is essential. We previously demonstrated capillary formation of endothelial cells (ECs) in tri‐culture, where a polyethylene terephthalate (PET) microporous membrane was intercalated between the ECs and hepatic organoids composed of small hepatocytes (SHs), i.e. hepatic progenitor cells, and HSCs. However, the high thickness and low porosity of the membranes limited heterotypic cell–cell interactions, which are essential to form HSC–EC hybrid structures. Here, we focused on the effective use of the thin and highly porous poly( d , l ‐lactide‐co‐glycolide) (PLGA) microporous membranes in SH–HSC–EC tri‐culture to reconstruct the HSC‐incorporated liver capillary structures in vitro. First, the formation of EC capillary‐like structures was induced on Matrigel‐coated PLGA microporous membranes. Next, the membranes were stacked on hepatic organoids composed of small SHs and HSCs. When the pore size and porosity of the membranes were optimized, HSCs selectively migrated to the EC capillary‐like structures. This process was mediated in part by platelet‐derived growth factor (PDGF) signalling. In addition, the HSCs were located along the outer surface of the EC capillary‐like structures with their long cytoplasmic processes. In the HSC‐incorporated capillary tissues, SHs acquired high levels of differentiated functions, compared to those without ECs. This model will provide a basis for the construction of functional, thick, vascularized liver tissues in vitro. Copyright © 2012 John Wiley & Sons, Ltd.     

Ultrasound-guided infraclavicular axillary vein puncture is effective to avoid pinch-off syndrome: a long-term follow-up study

Purpose

Pinch-off syndrome (POS) is a serious complication encountered during the long-term management of totally implantable access ports (TIAPs). The aim of this study was to examine the effect of ultrasound-guided infraclavicular axillary vein puncture to avoid POS in patients with long-term use of a TIAP.

Methods

This was a retrospective review of 207 consecutive TIAPs: one hundred devices implanted using an anatomical landmark technique were used as historical controls (Landmark group), while 107 devices were implanted using an ultrasound (US)-guided puncture method (US group). The pinch-off grade (POG) was determined using chest X-ray findings following the definition of Hinke, and the progression of POG during the follow-up period of the Landmark and US groups was compared.

Results

Sixteen cases in the Landmark group were POG-1 and 3 were POG-2, while all cases in the US group were POG-0 at the time of venipuncture (p < 0.001). Eleven patients in the Landmark group showed some degree of progression of the POG during the follow-up period. In contrast, there were no cases showing progression of the POG in the US group (p = 0.002).

Conclusions

US-guided infraclavicular axillary vein puncture was found to effectively make it possible to avoid POS for the long-term management of TIAPs, as well as at the time of implantation.