| "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.
Figures









|