Effectiveness of Targeted Antidandruff Shampoos: Clinical, Instrumental and Metagenomic Analysis
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Presented by: Sandrine Bessou-Touya
Introduction & Objectives:
It is accepted that dandruff (D) states are associated with an imbalance of the fungal and bacterial flora, a change in scalp hydration, pH and cutaneous barrier function, and various discomfort sensations.
In addition to the known clinical differences between oily and dry dandruff conditions, previous work found differences in terms of lipid and hydration levels, and microbiota, justifying the formulation of products specifically adapted to each type of dandruff for a targeted effectiveness and scalp friendly.
We wanted to assess the effectiveness of 2 shampoos targeting oily or dry dandruff (OD, DD) and the persistence of this effect 4 weeks after stopping use.
Material and Method:
33 subjects with mild to moderate dandruff scalp (16 OD and 17 DD) completed this 2-steps study: 4-weeks anti dandruff shampoo followed by a for 4 weeks neutral shampoo use, shampoos being used thrice a week.
These anti dandruff shampoos were formulated with natural active ingredients, among them a common anti Malassezia ginger extract. Others ingredients were selected regarding the type of scalp dandruff (OD or DD).
Efficacy was assessed from measurements done at W0, W2, W4, and W8:
Clinically: Overall Clinical Dandruff Score, global efficacy, itching and discomfort sensations, satisfaction rated by investigator and/or subject
Instrumentally: scalp hydration (HI), pH, barrier function (TEWL), lipids (LI)
Microbiologically, from swab samples analysed by droplet digital Polymerase Chain Reaction (ddPCR) for 4 microbial species in OD scalp (S) and sequencing of the fungal and bacterial flora in DD scalp (excepted W8).
Statistical analysis was done by ANCOVA, paired Student or Wilcoxon tests, according to the nature of data. For metagenomic statistical analysis, Alpha and Beta diversity analysis were carried out after normalization by rarefaction and differential analysis was used to identify genus or species that changed during the treatment.
Results:
Both shampoos showed a significant improvement in clinical signs during the treatment phase, with decrease in dandruff, itching, discomfort scores observed from W2. These changes were maintained during the persistence phase.
With the ODS, HI, LI, TEWL increased and pH decreased during treatment phase. These changes, while significant, were slight and remained in the normal range of values. Only the increase oh HI remained 4 weeks after stopping shampoo, other parameters returning to baseline. ddPCR results showed a significant decrease of the ratio Malassezia restricta to Cutibacterium acnes as a result of a rebalancing of the microflora (increase in C. acnes at the expense of M. Restricta).
With the DDS, HI increased only at W2, then returned to baseline, LI, pH and TEWL remained stable. ddPCR results showed a decrease in Malassezia restricta and an increase in C. acnes populations. Metagenomic analysis done for DD scalp showed significant changes in microbiota composition from W2, with a significant increase of richness and equitability, reflecting a rebalance of fungi and bacterial populations.
Conclusion:
These results show the efficacy on clinical signs and the soothing effect of anti-dandruff shampoo during the treatment period, confirmed by the perception of the investigator and the subject, and the persistence of the clinical effects for at least 4 weeks after stopping treatment.
These shampoos also helped to rebalance significantly the skin scalp microflora
A formulation specially adapted to the dandruff state (greasy/dry) makes it possible to target the effectiveness and to limit the undesirable effects which could occur with a less specific product, such as dryness/tugging or discomfort for dry scalps frequently encountered when using non-specific anti-dandruff shampoos.
It is accepted that dandruff (D) states are associated with an imbalance of the fungal and bacterial flora, a change in scalp hydration, pH and cutaneous barrier function, and various discomfort sensations.
In addition to the known clinical differences between oily and dry dandruff conditions, previous work found differences in terms of lipid and hydration levels, and microbiota, justifying the formulation of products specifically adapted to each type of dandruff for a targeted effectiveness and scalp friendly.
We wanted to assess the effectiveness of 2 shampoos targeting oily or dry dandruff (OD, DD) and the persistence of this effect 4 weeks after stopping use.
Material and Method:
33 subjects with mild to moderate dandruff scalp (16 OD and 17 DD) completed this 2-steps study: 4-weeks anti dandruff shampoo followed by a for 4 weeks neutral shampoo use, shampoos being used thrice a week.
These anti dandruff shampoos were formulated with natural active ingredients, among them a common anti Malassezia ginger extract. Others ingredients were selected regarding the type of scalp dandruff (OD or DD).
Efficacy was assessed from measurements done at W0, W2, W4, and W8:
Clinically: Overall Clinical Dandruff Score, global efficacy, itching and discomfort sensations, satisfaction rated by investigator and/or subject
Instrumentally: scalp hydration (HI), pH, barrier function (TEWL), lipids (LI)
Microbiologically, from swab samples analysed by droplet digital Polymerase Chain Reaction (ddPCR) for 4 microbial species in OD scalp (S) and sequencing of the fungal and bacterial flora in DD scalp (excepted W8).
Statistical analysis was done by ANCOVA, paired Student or Wilcoxon tests, according to the nature of data. For metagenomic statistical analysis, Alpha and Beta diversity analysis were carried out after normalization by rarefaction and differential analysis was used to identify genus or species that changed during the treatment.
Results:
Both shampoos showed a significant improvement in clinical signs during the treatment phase, with decrease in dandruff, itching, discomfort scores observed from W2. These changes were maintained during the persistence phase.
With the ODS, HI, LI, TEWL increased and pH decreased during treatment phase. These changes, while significant, were slight and remained in the normal range of values. Only the increase oh HI remained 4 weeks after stopping shampoo, other parameters returning to baseline. ddPCR results showed a significant decrease of the ratio Malassezia restricta to Cutibacterium acnes as a result of a rebalancing of the microflora (increase in C. acnes at the expense of M. Restricta).
With the DDS, HI increased only at W2, then returned to baseline, LI, pH and TEWL remained stable. ddPCR results showed a decrease in Malassezia restricta and an increase in C. acnes populations. Metagenomic analysis done for DD scalp showed significant changes in microbiota composition from W2, with a significant increase of richness and equitability, reflecting a rebalance of fungi and bacterial populations.
Conclusion:
These results show the efficacy on clinical signs and the soothing effect of anti-dandruff shampoo during the treatment period, confirmed by the perception of the investigator and the subject, and the persistence of the clinical effects for at least 4 weeks after stopping treatment.
These shampoos also helped to rebalance significantly the skin scalp microflora
A formulation specially adapted to the dandruff state (greasy/dry) makes it possible to target the effectiveness and to limit the undesirable effects which could occur with a less specific product, such as dryness/tugging or discomfort for dry scalps frequently encountered when using non-specific anti-dandruff shampoos.