A responsive MRI contrast agent to monitor functional cell status

It has been shown that insoluble Gd chelates are suitable MRI contrast agents for conditional activation by intracellular lipases. The DTPA-based, insoluble, inactive contrast agent was internalized into dendritic cells by phagocytosis. Cleavage of long aliphatic side chains by intracellular lipase activity leads to the contrast agents solubility and hereby its activation depending on the enzyme expression. Uptake and activation of the contrast agent was much reduced in Flt3+ CD11b+ progenitor cells. Detectability limits in the T(1)-weighted MR images were estimated in phantoms and in vivo in the rat brain. Marginal toxic effects were only observed at very high concentrations of the contrast agent. The chelate can easily be modified to be targeted by enzymes expressed during specific change of cell status like activation or differentiation. Such a system is suitable for functional cellular in vivo MR imaging.     

Comparative Survival among Older Adults with Advanced Kidney Disease Managed Conservatively Versus with Dialysis

Background and objectives

Outcomes of older patients with ESRD undergoing RRT or conservative management (CM) are uncertain. Adequate survival data, specifically of older patients, are needed for proper counseling. We compared survival of older renal patients choosing either CM or RRT.

Design, setting, participants, & measurements

A retrospective survival analysis was performed of a single-center cohort in a nonacademic teaching hospital in The Netherlands from 2004 to 2014. Patients with ESRD ages ≥70 years old at the time that they opted for CM or RRT were included. Patients with acute on chronic renal failure needing immediate start of dialysis were excluded.

Results

In total, 107 patients chose CM, and 204 chose RRT. Patients choosing CM were older (mean±SD: 83±4.5 versus 76±4.4 years; P<0.001). The Davies comorbidity scores did not differ significantly between both groups. Median survival of those choosing RRT was higher than those choosing CM from time of modality choice (median; 75th to 25th percentiles: 3.1, 1.5–6.9 versus 1.5, 0.7–3.0 years; log-rank test: P<0.001) and all other starting points (P<0.001 in all patients). However, the survival advantage of patients choosing RRT was no longer observed in patients ages ≥80 years old (median; 75th to 25th percentiles: 2.1, 1.5–3.4 versus 1.4, 0.7–3.0 years; log-rank test: P=0.08). The survival advantage was also substantially reduced in patients ages ≥70 years old with Davies comorbidity scores of ≥3, particularly with cardiovascular comorbidity, although the RRT group maintained its survival advantage at the 5% significance level (median; 75th to 25th percentiles: 1.8, 0.7–4.1 versus 1.0, 0.6–1.4 years; log-rank test: P=0.02).

Conclusions

In this single–center observational study, there was no statistically significant survival advantage among patients ages ≥80 years old choosing RRT over CM. Comorbidity was associated with a lower survival advantage. This provides important information for decision making in older patients with ESRD. CM could be a reasonable alternative to RRT in selected patients.     

Ex vivo expansion of cord blood‐CD34+ cells using IGFBP2 and Angptl‐5 impairs short‐term lymphoid repopulation in vivo

Cord blood‐derived haematopoietic stem cells (CB‐HSCs) are an attractive source for transplantation in haematopoietic disorders. However, the yield of CB‐HSCs per graft is limited and often insufficient, particularly for the treatment of adult patients. Here we compare the capacity of three cytokine cocktails to expand CB‐CD34⁺ cells. Cells were cultured for 5 or 14 days in media supplemented with: (a) SCF, FL, IL‐3 and IL‐6 (SFLIL3/6); (b) SCF, TPO, FGF‐1 and IL‐6 (STFIL6); and (c) SCF, TPO, FGF‐1, IGFBP₂ and Angptl‐5 (STFAI). We observed that STFAI‐culture expansion sustained the most vigorous cell proliferation, maintenance of CD34⁺ phenotype and colony‐forming unit counts. In addition, STFAI‐cultured cells had a potent ex vivo migration activity. STFAI‐expanded cells were able to engraft NSG mice. However, no significant difference in overall engraftment was observed among the expansion cocktails. Assessment of short‐term reconstitution using multilineage markers demonstrated that the STFAI cocktail for HSCs expansion greatly improved total cell expansion but may impair short‐term lymphoid repopulation. Copyright © 2012 John Wiley & Sons, Ltd.     

Variation at the paraoxonase gene locus contributes to carotid arterial wall thickness in subjects with familial hypercholesterolemia

OBJECTIVES: Paraoxonase (PON1) is a potent enzyme, physically associated with the high-density lipoprotein particle. PON1 may protect against cardiovascular disease (CVD), since it is capable of hydrolyzing oxidized LDL-cholesterol, thereby negating the detrimental effects of this lipoprotein on the arterial wall. DESIGN AND METHODS: In 187 patients with familial hypercholesterolemia, we studied the seven most common single nucleotide polymorphisms (SNPs) in both the coding and promoter sequences of PON1 (L55M, Q192R, T-107C, C-126G, G-162A, G-824A, and C-907G) in terms of PON1 activity and intima media thickness (IMT) of the carotid arterial wall, a validated surrogate marker for CVD. RESULTS: In concordance with several previous studies, we observed that the L55M, T-107C, G-162A, G-824A, and C-907G SNPs conferred PON1 activity towards phenylacetate, while this was not the case for the Q192R and C-126G SNPs. Importantly, in a multivariate regression analysis, G-824A proved to be an independent predictor of carotid IMT. Additionally, the two fully discordant homozygous haplotypes, C-907/G-824/G-162/C-126/T-107/55M versus -907G/-824A/-162A/-126G/-107C/L55, differed by 22% in carotid IMT (P = 0.007). CONCLUSIONS: Genetic variation at the PON1 locus has a strong influence on PON1 activity as well as on carotid IMT. These data indicate that PON1 is indeed involved in the pathogenesis of atherosclerosis. Whether this also translates into a role for PON1 in the occurrence of CVD events needs to be confirmed by large prospective studies in the general population.     

Adipose tissue‐derived extracellular matrix hydrogels as a release platform for secreted paracrine factors

Fat grafting is an established clinical intervention to promote tissue repair. The role of the fat's extracellular matrix (ECM) in regeneration is largely neglected. We investigated in vitro the use of human adipose tissue‐derived ECM hydrogels as release platform for factors secreted by adipose‐derived stromal cells (ASCs). Lipoaspirates from nondiabetic and diabetic donors were decellularized. Finely powdered acellular ECM was evaluated for cell remainders and DNA content. Acellular ECM was digested, and hydrogels were formed at 37°C and their viscoelastic relaxation properties investigated. Release of ASC‐released factors from hydrogels was immune assessed, and bio‐activity was determined by fibroblast proliferation and migration and endothelial angiogenesis. Acellular ECM contained no detectable cell remainders and negligible DNA contents. Viscoelastic relaxation measurements yielded no data for diabetic‐derived hydrogels due to gel instability. Hydrogels released several ASC‐released factors concurrently in a sustained fashion. Functionally, released factors stimulated fibroblast proliferation and migration as well as angiogenesis. No difference between nondiabetic and diabetic hydrogels in release of factors was measured. Adipose ECM hydrogels incubated with released factors by ASC are a promising new therapeutic modality to promote several important wound healing‐related processes by releasing factors in a controlled way.