PREVENTION OF STRETCH MARKS : A RANDOMIZED DOUBLE BLIND CLINICAL STUDY VERSUS PLACEBO
P.Msika (1), C.Gavaud-Kennedy (2), M.Pitiot (2), E.Camel (2), L.Arnaud-Boissel (2), JP.Guillot (2)
(1) R&D Center, Laboratoires PharmascienceTM, Epernon, France (3) Institut d'Expertise Clinique, Lyon, France pmsika@expanscience.com
Striae distensae, commonly referred to as stretch marks, occur on the abdomen and/or breast in 90% of all pregnant women (striae gravidarum), after the sixth month of pregnancy. They are the result of extrinsic factors (ie, mechanical stress), but more important of intrinsic factors (eg, hormones/steroids, genetic predisposition and physiological stress) that interact to produce these lesions. They are generally 2 to 5 mm in width. During the earliest stages, women may describe minor pruritus or irritation. The lesions are frequently seen over the peri-umbilical area, the thighs, buttocks and breasts. After delivery, they gradually fade in colour and appear as white, atrophic, depressed lesions, often with a wrinkled surface. Although only partially understood, recent works, with electronic microscopy and immuno-histochemistry, have demonstrated at least three essential factors for the development of striae distensae : cutaneous stretching, hormonal impact and inflammation. These three factors led to the inhibition of collagen and elastic fibers synthesis by dermal fibroblasts and to the induction of collagenases ans elastases (MMP=Matricial Metallo Proteases). The final result is a desorientation of dermal fibers with a re-orientation following the stretching lines and the clinical pseudo-scar aspect. The following trial involves a marketed product containing 10% lactic acid (pH 3.5) associated with a soya peptide, biofermented by Lactobacillus, which activates the production of all matrix proteins ex vivo. The association of an alpha-hydroxyacid to the soya peptide potentiates its activity and provokes a synergistic effect in preventing and/or treating stretch marks.

Introduction

This randomized, double-blind trial versus placebo has been conducted under gynecologic and dermatologic control. 74 women have been included, during their third, fourth or fifth month of pregnancy. They randomly received either the patented product (36 women, 22 to 37 years old) or the placebo (emulsion O/W, 38 women, 23 to 39 years old). They applied the tested products (VDA) twice daily on the thighs, the hips and the peri-umbilical area until the end of the first month post-delivery.

Protocole

Evaluations were performed at T0, T+3 months, T+5 months and Tpp (1 month post-partum). Clinical evaluation by a dermatologist and auto evaluation by women were performed at each time, on 5 criteria : presence, length, width, colour and relief, with an analogic scale in 10 points. Macrophotographies (Nikon F-801S, 105MM) of the thighs and the peri-umbilical area were achieved at each visit. Statistical analysis used Wilcoxon test and U test (Mann Whitney).
The results at T+5 and Tpp showed that the patented association was efficient versus placebo : New striae distensae (Figure 1) : The development of stretch marks was largely reduced (-50%) under VDA compared to placebo. Their rate of appearance was slower (p<0.05) ie, the statistically significant increase of striae distensae number was reached at Tpp under patented product and earlier at T+5 under placebo.

Placebo VDA

Results
Macrophotos : Here are some characteristic evolutions of striae distensae with VDA and with placebo (Figure 4).
Development of stretch marks (%)
T0 T + 3 months T + 5 months Tpp
Figure 1 : Compared to the placebo, the twice daily application of VDA reduces by 50% the development of striae distenseae on the abdomen.
T0, placebo [volunteer 55]
T+3 months, placebo [volunteer 55]
Clinical dermatologic evaluations (Figures 2, A&B) : The new stretch marks observed were 1.5 time less important, 2 times less inflamed (p=0.03), 2 times less red (p=0.03), 1.5 time less reliefed (p=0.1) and less long (p=0.03).

Placebo

WIDTH LENGTH COLOUR RELIEF 0 WIDTH LENGTH COLOUR RELIEF
T+5 months, placebo [volunteer 55]
Tpp, placebo [volunteer 55]
Figure 2 : Evolution of the striae distensae parameters. Dermatological evaluation at T+5 months (A) and Tpp (B).*Statistically significant compared to placebo.
Auto-evaluations (Figure 3) : Volunteers have noted similar efficacy on stretch-marks about their length, width, colour and relief. They also noted a real improvement of hydration (78% good or very good), firmness (78%), tonicity (86%), elasticity (94%) and suppleness (92%) at T+5. WIDTH

LENGTH

T0, VDA [volunteer 14]

T + 5 months Tpp

T+3 months, VDA [volunteer 14]

T + 5 months

COLOUR

RELIEF

Figure 3 : Clinical evaluation of the stretch marks parameters by the volunteers.
Stretch-marks are very common problems during pregnancy and remain very difficult to treat. Prevention is the best way to act, because curative treatment remains deceptive. Retinoic acid has been tested on stria distensae with some results but remains very irritant in the locations of stretch marks (breast, thighs) and is contre-indicated during pregnancy. Cosmetic products are numerous but very few have been tested with pertinent clinical assays, ie randomised double-blind studies versus placebo. This was the fact with a new patented product containing lactic acid and soya peptides which targets are dermal collagen and elastic fibers. The present study on 73 pregnant women have demonstrated that prevention of stretch-marks during pregnancy is possible : Speed of development is reduced, number divided by 2, lesions less visible because less red and surface less prominent. These performances have been evaluated both by dermatologists and by the volunteers themselves.
T+5 months, VDA [volunteer 14]

Tpp, VDA [volunteer 14]

Figure 4 : Illustration of the evolution of the stretch marks for one volunteer using VDA [14] and one volunteer using the placebo [55]. VDA>PLACEBO.

Conclusion

The majority of these women have judged that this new product represents an efficient tool against striae distensae. They also positively judged its cosmetic properties : consistence, texture, perfume The tolerance has been good to excellent in all cases with no significant difference with the placebo. References :
1-Zheng P et al : Br J dermatol 1985, 112 : 185-193 2-P.Nigam :Int J Dermatol 1989, 2,7 :426-428 3-R.Watson et al : Br J Dermatol, 1998, 138 : 931-937 4-T.Tsuji et al : J Cutan Pathol 1988, 15 : 215-222 5-A.Jarrett : J Appl Cosmetol 1989, 7 : 89-91