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The use of subatmospheric pressure to promote wound healing has increased in popularity during the last several years. The original studies on granulation tissue formation used a 125-mmHg vacuum. The use of alternative sources of subatmospheric pressure has led to many questions regarding efficacy or risk. In this report a swine model is used to quantify and compare the effects of low vacuum suction (25 mmHg) and high vacuum suction (500 mmHg) produced by various vacuum pumps and wall suction systems with the standard 125-mmHg vacuum. Additionally, the effects of an unregulated air leak in the sealing system were examined. All four wound treatments were examined on each of 4 pigs. Wounds were treated until one of the wounds had granulated to a level flush with the surrounding tissue. Wounds treated with the standard 125-mmHg vacuum had filled with granulation tissue by day 8. At this time wounds treated with 25 mmHg had filled 21.2% with new granulation tissue, and wounds treated with 500 mmHg had filled 5.9% with new tissue. Wounds treated with 125 mmHg with a hole in the sealing drape had increased in size 197% because of the debridement of necrotic tissue. In conclusion, wounds treated with a 125-mmHg vacuum exhibited a significant (p< 0.0001) increase in the rate of granulation tissue formation compared with treatment at 25 mmHg or 500 mmHg. The presence of an unregulated air leak in the sealing drape results in significant progression (p < 0.0001) of the wound secondary to dehydration and progressive necrosis.

Common genetic variants can have profound effects on cellular function, but studying these effects in primary human tissue samples and during development is challenging. Human induced pluripotent stem cell (iPSC) technology holds great promise for assessing these effects across a range of differentiation contexts. Here, we use an efficient multiplexing strategy to differentiate 215 iPS cell lines towards a midbrain neural fate, including dopaminergic neurons, and profile over 1 million cells sampled across three differentiation timepoints using single cell RNA sequencing. We find that the proportion of neuronal cells produced by each cell line is highly reproducible over different experimental batches, and identify robust molecular markers in pluripotent cells that predict line-to-line differences in cell fate. We identify expression quantitative trait loci (eQTL) that manifest at different stages of neuronal development, and in response to rotenone-induced oxidative stress. We find 1,284 eQTL that colocalise with a known risk locus for a neurological trait, 46% of which are not found in the GTEx catalogue. Our study illustrates how coupling single cell transcriptomics with long-term iPSC differentiation can profile mechanistic effects of human trait-associated genetic variants in otherwise inaccessible cell states.