Real-World Outcomes in Patients with Diabetic Macular Edema Treated Long Term with Ranibizumab (VISION Study).

AIM: Evaluate long-term real-world treatment patterns and associated effectiveness and safety outcomes in patients with diabetic macular edema (DME) treated ≥36 months with 0.5mg ranibizumab. METHODS: Open-label observational effectiveness study in 9 Belgian clinics. Included were primary treated eyes of 55 DME patients between August 2014 and March 2015 and followed for 3.5±1.8 years. Eyes were 21.8% treatment (TX)-naïve, 9.1% non-naïve with exclusive prior anti-VEGF treatment (PRIOR-anti-VEGF), and 63.6% non-naïve with other prior treatments (PRIOR-other). Intravitreal injections with ranibizumab were administered per ophthalmologists' best clinical judgment. Trend testing of changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) over time occurred using mixed regression analysis. RESULTS: The mean±SD number of treatments in the first year was 5.1±3.0 (TX-naïve), 4.5±2.7 (PRIOR-anti-VEGF) and 5.6±3.1 (PRIOR-other). At 12 months, BCVA increased by 8.9±16.4 letters from 59.7±9.3 at baseline in TX-naïve (p<0.0001), by 11.8±9.9 from 61.6±8.5 in PRIOR-anti-VEGF (p=0.03), and by 4.2±10.6 from 58.2±14.6 in PRIOR-other groups (p=0.0002). BCVA remained stable for the remainder of follow-up in all groups. CRT decreased over the first 2 months by monthly rates of -43.8µm in TX-naïve (p=0.04), -75.7µm in PRIOR-anti-VEGF (p=0.02), and -65.8µm in PRIOR-other eyes (p=0.0003), showing stability afterwards. No unknown adverse events were recorded; a painful eye following injection was registered with a possible relationship to the treatment. CONCLUSION: This real-world study confirms the effectiveness of ranibizumab in preventing a decline in BCVA and demonstrated initial improvement and subsequent retention of BCVA in DME patients ≥36 months. Ranibizumab initially reduced and then maintained CRT. However, these data reveal that treatment intensity and BCVA and CRT outcomes are lower than those found in early efficacy trials. Under-treatment likely accounts for this efficacy-effectiveness gap. Yet, intravitreal ranibizumab is an effective and safe long-term treatment for DME under conditions of significant heterogeneity in patients and treatment patterns.

Long-Term Ranibizumab Treatment in Neovascular Age-Related Macular Degeneration: A Belgian Subanalysis from the Global Real-World LUMINOUSTM Study.

PURPOSE: To evaluate long-term, real-world treatment patterns and outcomes of ranibizumab 0.5 mg for neovascular age-related macular degeneration (nAMD) in a Belgian cohort. PATIENTS AND METHODS: This Belgian (BE) cohort of the 5-year global observational LUMINOUS study included 229 patients with nAMD. Outcomes included visual acuity (VA), central retinal thickness (CRT) and safety. RESULTS: The mean age was 79.5±7.7 years. The majority of patients (67.7%) were female and all patients were Caucasian. Most patients previously received ranibizumab with only 17.5% of patients being treatment-naïve. The injection frequency declined over time irrespective of prior treatment status (p<0.0001), with treatment-naïve eyes receiving a mean of 4.2±2.9 yearly injections and prior-ranibizumab eyes 3.6±2.7. Regression analysis confirmed first-year VA increases for treatment-naïve eyes (p=0.002) followed by a slight decrease of -1.8 letters per year. For prior-ranibizumab eyes, the visual changes over 1 year were statistically non-significant (p=0.90) but declined slightly after year one (p<0.0001). Anatomically, the CRT of treatment-naïve eyes decreased over time from baseline (p<0.0001), whereas the CRT of prior-ranibizumab eyes remained stable (p=0.43). No new safety findings were identified. CONCLUSION: LUMINOUS-BE reconfirms the well-characterized benefit-risk profile of ranibizumab for nAMD treatment. The observed low injection frequency reflects a need for more rigorous treatment in real-world settings. CLINICAL TRIAL REGISTRATION: NCT01318941.

Effects of Trichostatin A on drug uptake transporters in primary rat hepatocyte cultures.

The present study was set up to investigate the effects of Trichostatin A (TSA), a prototypical epigenetic modifier, on the expression and activity of hepatic drug uptake transporters in primary cultured rat hepatocytes. To this end, the expression of the sinusoidal transporters sodium-dependent taurocholate cotransporting polypeptide (Ntcp) and organic anion transporting polypeptide 4 (Oatp4) was monitored by real-time quantitative reverse transcriptase polymerase chain reaction analysis and immunoblotting. The activity of the uptake transporters was analyzed using radiolabeled substrates and chemical inhibitors. Downregulation of the expression and activity of Oatp4 and Ntcp was observed as a function of the cultivation time and could not be counteracted by TSA. In conclusion, the epigenetic modifier TSA does not seem to exert a positive effect on the expression and activity of the investigated uptake transporters in primary rat hepatocyte cultures.

Immortalized Human Hepatic Cell Lines for In Vitro Testing and Research Purposes.

The ubiquitous shortage of primary human hepatocytes has urged the scientific community to search for alternative cell sources, such as immortalized hepatic cell lines. Over the years, several human hepatic cell lines have been produced, whether or not using a combination of viral oncogenes and human telomerase reverse transcriptase protein. Conditional approaches for hepatocyte immortalization have also been established and allow generation of growth-controlled cell lines. A variety of immortalized human hepatocytes have already proven useful as tools for liver-based in vitro testing and fundamental research purposes. The present chapter describes currently applied immortalization strategies and provides an overview of the actually available immortalized human hepatic cell lines and their in vitro applications.

Development and characterization of a new human hepatic cell line.

The increasing demand and hampered use of primary human hepatocytes for research purposes have urged scientists to search for alternative cell sources, such as immortalized hepatic cell lines. The aim of this study was to develop a human hepatic cell line using the combined overexpression of TERT and the cell cycle regulators cyclin D1 and mutant isoform CDK4R24C. Following transduction of adult human primary hepatocytes with the selected immortalization genes, cell growth was triggered and a cell line was established. When cultured under appropriate conditions, the cell line expressed several hepatocytic markers and liver-enriched transcription factors at the transcriptional and/or translational level, secreted liver-specific proteins and showed glycogen deposition. These results suggest that the immortalization strategy applied to primary human hepatocytes could generate a novel hepatic cell line that seems to retain some key hepatic characteristics.

Strategies for immortalization of primary hepatocytes.

The liver has the unique capacity to regenerate in response to a damaging event. Liver regeneration is hereby largely driven by hepatocyte proliferation, which in turn relies on cell cycling. The hepatocyte cell cycle is a complex process that is tightly regulated by several well-established mechanisms. In vitro, isolated hepatocytes do not longer retain this proliferative capacity. However, in vitro cell growth can be boosted by immortalization of hepatocytes. Well-defined immortalization genes can be artificially overexpressed in hepatocytes or the cells can be conditionally immortalized leading to controlled cell proliferation. This paper discusses the current immortalization techniques and provides a state-of-the-art overview of the actually available immortalized hepatocyte-derived cell lines and their applications.

Primary hepatocyte cultures as prominent in vitro tools to study hepatic drug transporters.

Before any drug can be placed on the market, drug efficacy and safety must be ensured through rigorous testing. Animal models are used for this purpose, though currently increasing attention goes to the use of alternative in vitro systems. In particular, liver-based testing platforms that allow the prediction of pharmacokinetic (PK) and pharmacotoxicological properties during the early phase of drug development are of interest. They also enable the screening of potential effects on hepatic drug transporters. The latter are known to affect drug metabolism and disposition, thereby possibly underlying drug-drug interactions, which, in turn, may result in liver toxicity. Clearly, stable in vivo-like functional expression of drug transporters in hepatic in vitro settings is a prerequisite to be applicable in routine PK and pharmacotoxicological testing. In the first part of the article, an updated overview of hepatic drug transporters is provided, followed by a state-of-the-art review of drug-transporter production and activity in primary hepatocyte cultures (PHCs), being the gold-standard in vitro system. Specific focus is hereby put on strategies to maintain long-term functional expression, in casu of drug transporters, in these systems. In the second part, the use of PHCs to assess hepatobiliary transport and transporter-mediated interactions is outlined.

Evaluation of the multipotent character of human adipose tissue-derived stem cells isolated by Ficoll gradient centrifugation and red blood cell lysis treatment.

In the present study, the multipotent potential of two differential isolated human adipose-derived stem cell (hADSC) populations was evaluated. More specifically, hADSC isolated by means of classical Ficoll (F) gradient centrifugation were compared to hADSC isolated by means of red blood cell (RBC) lysis treatment and subsequent cultivation as 3D spheres. No significant difference in the genotypic expression of the multipotent markers Oct-4, Sox-2, Nanog, Klf-4 and cMyc could be observed between both isolation methods. Upon adipogenic and osteogenic differentiation, both hADSC populations showed lipid droplet accumulation and mineral deposition, respectively. Although, a more pronounced mineral deposition was observed in hADSC-RBC, suggesting a higher osteogenic potential. Upon exposure to keratinogenic media, both hADSC populations expressed the keratinocyte markers filaggrin and involucrin, evidencing a successful keratinogenic differentiation. Yet, no differences in expression were observed between the distinctive isolation procedures. Finally, upon exposure to neurogenic differentiation media, a significant difference in marker expression was observed. Indeed, hADSC-RBC only expressed vimentin and nestin, whereas hADSC-F expressed vimentin, nestin, NF-200, MBP and TH, suggesting a higher neurogenic potential. In summary, our data suggest that the choice of the most efficient isolation procedure of hADSC depends on the differentiated cell type ultimately required.

Characterization of spontaneous cell death in monolayer cultures of primary hepatocytes.

Monolayer cultures of primary hepatocytes, isolated from freshly removed livers, represent widely used in vitro tools in the area of liver physiology and pathology, pharmacology and toxicology. However, a major shortcoming of these systems is that they cope with dedifferentiation, which is accompanied by spontaneous cell death. The goal of the present study was to elucidate the mechanisms that drive the process of self-generated cell demise in primary hepatocyte cultures. For this purpose, isolated rat hepatocytes were cultivated under conventional conditions, and the occurrence of apoptosis and necrosis was monitored during 4 days by performing a set of acknowledged cell death assays. These included examination of cell morphology by light microscopy, quantification of apoptotic and necrotic cell populations by Hoechst 33342 and propidium iodide in situ staining, assessment of apoptotic and necrotic activities by measuring caspase 3-like activity and extracellular leakage of lactate dehydrogenase, and studying the expression of apoptosis regulators through immunoblot analysis. In essence, two cell death peaks were observed, namely shortly after cell seeding and in the final stages of the cultivation period, both involving apoptotic and necrotic actions. The outcome of this study not only sheds new light onto the molecular processes that underlie spontaneous cell death in primary hepatocyte cultures, but also opens perspectives for the establishment of strategies to increase cell survival in these popular in vitro systems.

Evaluation of the multipotent character of human foreskin-derived precursor cells.

In the present study, the trilineage differentiation capacity of human foreskin-derived precursor cells (hSKP) was evaluated upon exposure to various (non)commercial (i and ii) ectodermal, (iii) mesodermal and (iv) endodermal differentiation media. (i) Upon sequential exposure of the cells to keratinocyte growth (CnT-07® or CnT-057®) and differentiation (CnT-02® or Epilife®) media, keratinocyte-like cells (filaggrin(+)/involucrin(+)) were obtained. The preferred keratinocyte differentiation strategy was exposure to CnT-07®. (ii) When hSKP were subsequently exposed to NeuroCult® media, cells underwent a weak neuro-ectodermal differentiation expressing nestin, myelin binding protein (MBP), vimentin and alpha-foetoprotein (AFP). Sequential exposure to NPMM® and NPDM® generated cells with an inferior neuro-ectodermal phenotype (nestin(+)/vimentin(+)/MBP(-)/AFP(-)). (iii) Upon exposure of hSKP to insulin-transferrin-selenite (ITS) and dexamethasone, small lipid droplets were observed, suggesting their differentiation potential towards adipocyte-like cells. (iv) Finally, after sequential exposure to hepatogenic growth factors and cytokines, an immature hepatic cell population was generated. The presence of pre-albumin suggests that a sequential exposure strategy is here superior to a cocktail approach. In summary, a considerable impact of different (non)commercial media on the lineage-specific differentiation efficiency of hSKP is shown. In addition, we demonstrate here for the first time that, in a suitable keratinocyte stimulating micro-environment, hSKP can generate keratinocyte-like progeny in vitro.