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"IN VITRO" TEST
Effects of Crescina® on human primary epidermal and dermal cells -
Investigators: V C Biotechnology
Aim of project
It has been tested a preparation formed by the nucleus of Crescina hair treatment active principles in an aqueous solution and with the following composition: aqua, glycerin, lysine hydrochloride, acetyl cysteine, glycoproteins.
The objectives of this project were the following:
Objective 1
We investigated effects of Crescina on human primary keratinocytes and fibroblast cell proliferation
Objective 2
We investigated the effects of Crescina on protein synthesis in human in primary human keratinocytes and fibroblasts.
Abbreviations used
NHEK: Normal human epidermal keratinocytes
NHDF: Normal human dermal fibroblasts
SD: Standard deviation
MV: Mean value
Study protocol
Objective 1
Cell Cultures. Primary human keratinocytes and fibroblasts were obtained from Promocell (Heidelberg, Germany). Cells were maintained in specific growth medium supplemented with growth factors and seeded in 96 well plates (10 000 cells/well) for determination of cell proliferation and in 24 well plates for protein synthesis. Cells were treated for different period of time (24, 48 and 72 hours) with increasing concentrations (0.031, 0.062, 0.125, 0.25, 0.5% w/v = 310 µg/ml, 620.5 µg/ml, 1.25 mg/ml, 2.5 mg/ml, 5 mg/ml provided as 0.31 µl, 0.62 µl, 1.25 µl, 2.5 µl, 5 µl) of a solution of Crescina. Medium was removed before stimulation and replaced by fresh medium without growth factors. The growth factor supplements, as well as the growth factors PDGF (platelet derived growth factor) and FGF (fibroblast growth factor), were used as positive controls. Not-treated cells have been used as negative control.
Determination of cell proliferation.
Fibroblasts or keratinocytes were incubated with Crescina for 24 h, 48 h, and 72h. Each dose (see above) was tested 16 times (8 wells on 2 plates with two different methods).
Proliferation of primary fibroblasts/keratinocytes was determined by:
| 1) |
Determination of DNA incorporation (dBrU) using a cell proliferation assay from Amersham-Pharmacia .
Incorporation of 5-bromo-2'-deoxyuridine (BrdU) into newly synthesized DNA permits indirect detection of proliferating cells with labelled anti-BrdU antibodies thereby facilitating the identification of cells that have progressed through the S-phase of the cell cycle during the BrdU labelling period. The BrdU labelling method is a widely used method to measure proliferation of keratinocytes (Yano et al., 2004) and fibroblasts (Nasonova et al., 2004). |
| 2) |
AlamarBlue staining (Biosource). AlamarBlue is a redox indicator that yields a colorimetric change and a fluorescent signal in a response to a metabolic activity. The compound is non-toxic, soluble and stable in tissue culture medium, and is used for the quantitative measurement of proliferation and viability of cells. The AlamarBlue assay incorporates a fluorometric/colorimetric growth indicator based on detection of metabolic activity. Specifically, the system incorporates an oxidation-reduction (REDOX) indicator that both fluoresces and changes colour in response to chemical reduction of growth medium resulting from cell growth. As cells grow, innate metabolic activity results in a chemical reduction of AlamarBlue. Continued growth maintains a reduced environment while inhibition of growth maintains an oxidized environment. Reduction related to growth causes the REDOX indicator to change from oxidized (non-fluorescent, blue) form to reduced (fluorescent, red) form.
This colorimetric reaction was determined by an ELISA reading measuring the intensity of the red colour as marker of the increased AlamarBlue reaction. This colorimetric determination of colour intensity is expressed as arbitrary units, since there is no direct transaction to other metric systems possible. The increase of cell proliferation or metabolism has then to be expressed in comparison to untreated control cells. The AlamarBlue method is commonly used to determine proliferation (Voytik-Harbin et al., 1998) and cell viability (Ihalin et al., 2003) of keratinocytes and fibroblasts. |
Objective 2:
Determination of protein content.
Human primary keratinocytes or fibroblasts from human skin origin were seeded in 24 or 6 well plates and incubated with the Crescina (5 doses see above) for different times (24, 48 and 72 hours) with n = 4. After cell treatment, cells will be washed with phosphate buffered saline (PBS) and lysed in 1.3 x SDS (sodium dodecyl sulfate)-containing sample buffer without DTT containing 100 µM orthovanadate (Laemmli, 1970). Lysates will be homogenized by repeated passage through a 26-gauge-needle. Protein contents will be measured using the bicinchoninic acid method (BCA protein determination kit from Pierce, distributed by KFC Chemikalien, München, Germany) according to the manufacturer’s instructions (standards (bovine serum albumine, Sigma) ranging form 0.2 µg/µl to 4 µg/µl; optical density read at 570 nm). This method is a well established method to determine protein content and was part of at least 20 high impact publications from our group (e.g. Akundi et al., 2004).
Deviations:
To obtain more valid data in fibroblasts, additional experiments were performed using less cell numbers (1 000 and 5 000), and two additional time points.
Results and Discussion
Determination of cell proliferation.
On human keratinocytes experiments, at all tested time points 24, 48 and 72 h, Crescina had no effect on DNA synthesis as measured by dBrdU incorporation.
In contrast, Crescina revealed to increase the reaction of AlamarBlue. This effect was significant, suggesting that Crescina has an effect on cell viability (underlining values > 100% of metabolic activity) compared to non-treated cells (negative control) which cell vitality was considered as 100%. The effects were especially evident with 0.5% of the product Crescina with a maximum value of + 55% at 24 h (Fig. 4) and with 0.25% of the product Crescina with maximum values of + 56.3% at 48 h (Fig. 5) and + 61.6% at 72 h. Furthermore, our data suggest, that Crescina increases the metabolic activity of cells by increasing cellular energy levels.
At all tested time points fibroblastic DNA synthesis was not affected by Crescina, even if it’s possible to notice a quite moderate effect on DNA synthesis as measured by dBrdU incorporation (maximum value + 5.1% with 0.25% of the product Crescina after 48 h) in comparison with non-treated cells.
In the fibroblast experiments using the AlamarBlue method, additional experiments were performed using an inferior number of cells (1 000 and 5 000 cells/well) and two additional time points (4 and 6 h) just to obtain data of major validity. The use of 10 000 cells as starting point did not gain significant data since the fibroblasts are rapid proliferating cells and therefore cell proliferation and metabolism was probably maximal and not further increasable with this amount of cells suggesting that cell metabolism was already decreased due to cell to cell interaction lowering the proliferation rate of the cells.
In the AlamarBlue assays with 1 000 cells/well, Crescina showed a quite moderate increase of metabolic activity, compared to the negative control, after 4 and 6 h with maximal values of + 14.5 % and + 20.5% respectively, both with 0.5% of Crescina.
Very potent effects were obtained after 24, 48, and 72 h (Figs. 13-14) with maximal increase in the metabolic activity of + 58.5% with 0.125% of Crescina at 24 h, + 111.4% with 0.25% of Crescina at 48 h and + 195.7% with 0.5% of Crescina at 72 h, compared to negative control.
Furthermore, in the AlamarBlue assays determining the Crescina effects on cell proliferation with 5 000 cells/well, Crescina showed an increase in the metabolic activity, compared to non-treated cells (negative control), 4 and 6 h with maximal values of + 33.1% and + 36.5% both with 0.5% of Crescina.
Very potent effects were detected after 24, 48, and 72 h (Figs. 18-19) showing an increase in metabolic activity of + 80.3% with 0.0625% of Crescina at 24 h, + 119.3% with 0.5% of Crescina at 48 h, and + 91.4% with 0.5% of Crescina at 72 h, all of them compared to negative control.
In this way, Crescina increased AlamarBlue reactivity when 5 000 cells were seeded but not as potent as with 1 000 cells per well.
Only slight effects were visible after 24 h, when 10 000 cells where seeded (+ 20.2% with 0.5% of Crescina), and no effects after 48 and 72 h (Fig. 20), suggesting that the proliferation and the viability of cells is not further increasable after later time points. This indicated, that the number of cells is critical for obtaining effects of Crescina and that the number of 10 000 cells is to high to induce cell viability by possible cell to cell interactions occurring in confluent cell layers.
Determination of protein content.
Determination of protein content performed using keratinocytes revealed that, compared to non-treated cells, Crescina increased protein content (+ 160.3%) at the dose of 0.125% of Crescina at 24 h, at the doses of 0.0625% (+ 242.1%) and 0,125% (+ 206.8%) after 48 h and, at least, after 72 h with 0.25% of Crescina it’s possible to notice an increase of protein content of + 73.9% (Fig. 23, 24).
No increase in protein content was visible in fibroblasts after 24 h, but a slight increasing effect after 72 h: + 51.4% with the exposition at 0.125% of Crescina.
Conclusions
Determination of cell proliferation.
Using human keratinocytes, the preparation Crescina had no effects on DNA synthesis as measured by dBrdU incorporation at all tested time points 24, 48 and 72 h.
However, Crescina increased the metabolic activity of cells by increasing cellular energy levels as revealed by the reaction of AlamarBlue.
Using human fibroblasts, Crescina had no effect on DNA synthesis as measured by dBrdU incorporation at all tested time points 24, 48 and 72 h.
In the AlamarBlue assays, very potent effects were obtained after 24, 48, and 72 h with an increase in the metabolic activity compared to non-treated cells .
Our data suggest that due to its positive effects on cell viability and metabolism as shown by the AlamarBlue assays, Crescina should also increase the cell number. Furthermore, we conclude that the treatment with Crescina increases cell life, finally resulting in increased cell numbers, if compared to untreated cells, which have a more rapid cell turnover. This increase in cell numbers in Crescina treated cells, will not increase DNA synthesis as observed in this study.
Determination of protein content.
Determination of protein content in keratinocytes revealed that Crescina increased protein content considerably after 24 h (+ 160.3%) and 48 h (+ 242.1%) compared to negative control.
In fibroblasts, a slight increasing effect was visible after 72 h (+ 51.4%) compared to non-treated cells.
The difference in the total protein content between keratinocytes and fibroblasts is due to the differences in the total cell volume between the epithelial keratinocytes and the smaller fibroblasts.
Therefore, the protein content has not increased in consequence of the pro-proliferative effect of Crescina, but it might be increased due to increased cell viability. This fits to the hypothesis that Crescina promotes cellular metabolism.
Finally, we demonstrated that preparation Crescina increased cell metabolism and therefore might act as a cell protective and energizing hair treatment.
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