pH in nature, humans and skin

  title={pH in nature, humans and skin},
  author={Ehrhardt Proksch},
  journal={The Journal of Dermatology},
  • E. Proksch
  • Published 4 June 2018
  • Biology
  • The Journal of Dermatology
The pH plays an important physiological role in nature and humans. pH varies from 1 to 8 in human organs with tight regulation in blood and epithelia of barrier organs. The physiological pH of the stratum corneum is 4.1–5.8 and several mechanisms contribute to its formation: filaggrin degradation, fatty acid content, sodium‐hydrogen exchanger (NHE1) activation and melanosome release. First, the acidic pH of the stratum corneum was considered to present an antimicrobial barrier preventing… 

Influence of Buffers of Different pH and Composition on the Murine Skin Barrier, Epidermal Proliferation, Differentiation, and Inflammation

Application of the pH 7 buffer led to a significant increase in the skin pH, TEWL, epidermal thickness, and inflammation, which is important for the formulation of topical products for effective acidification in pathological skin conditions.

Towards Optimal pH of the Skin and Topical Formulations: From the Current State of the Art to Tailored Products

Acidic pH of the skin surface has been recognized as a regulating factor for the maintenance of the stratum corneum homeostasis and barrier permeability. The most important functions of acidic pH

Ambient pH regulates secretion of lipases in Malassezia furfur.

The qPCR results revealed that a set of functional lipase genes, LIP3-6, were constitutively expressed regardless of pH conditions or exposure time, concluding that the external pH plays a promotional role in the secretion of lipases but exerts less effect on transcription of the genes and morphology in M. furfur.

Cytokinocytes: the diverse contribution of keratinocytes to immune responses in skin

The skin serves as the primary interface between the authors' body and the external environment and acts as a barrier against entry of physical agents, chemicals, and microbes and keratinocytes actively participate in maintaining tissue homeostasis.

The Keratinocyte as a Crucial Cell in the Predisposition, Onset, Progression, Therapy and Study of the Atopic Dermatitis

The genetic predisposing and environmental factors, inflammatory molecules and signaling pathways of the KC that participate in the physiopathology of the AD are provided and the link among the KC, the microbiota and the inflammatory response underlying acute and chronic skin AD lesions is analyzed.

Skin acidification with a water‐in‐oil emulsion (pH 4) restores disrupted epidermal barrier and improves structure of lipid lamellae in the elderly

Evidence is provided that topical application of a w/o emulsion with pH 4 reacidifies the skin in elderly and has beneficial effects on skin moisturization, regeneration of lipid lamellae and lipid content.

Overcoming pH defenses on the skin to establish infections

A brief overview of skin barrier function and skin surface composition from the perspective of how the most common skin pathogen, Staphylococcus aureus, combats acid stress is provided.

Innate Antimicrobial Defense of Skin and Oral Mucosa

The various antimicrobial factors determine the microbiomes of the skin surface and the oral cavity, and Alterations of these factors can result in colonization by opportunistic pathogens, and this may lead to infection.

Molecular Mechanism of Epidermal Barrier Dysfunction as Primary Abnormalities

  • Ai-Young Lee
  • Medicine, Biology
    International journal of molecular sciences
  • 2020
The molecular mechanism involved in epidermal barrier dysfunction has been mostly episodic and research into the relationship between the causative molecules has been gradually increasing, but further evidence-based systematic data of target molecules and their interactions would probably be helpful for a better understanding.



The pH of the Skin Surface and Its Impact on the Barrier Function

The ‘acid mantle’ of the stratum corneum seems to be important for both permeability barrier formation and cutaneous antimicrobial defense. However, the origin of the acidic pH, measurable on the

The Acidic Milieu of the Horny Layer

Changes in the pH and the organic factors influencing it appear to play a role, not only in the pathogenesis, prevention and treatment of irritant contact dermatitis, but also of atopic dermatitis and ichthyosis and in wound healing.

sPLA2 and the epidermal barrier.

Is the filaggrin-histidine-urocanic acid pathway essential for stratum corneum acidification?

An acidic SC is important in regulating the metabolism and function of the SC, and alterations in SC pH could have numerous adverse effects.

NHE1 Regulates the Stratum Corneum Permeability Barrier Homeostasis

A role for NHE1 is demonstrated in the generation of acidic extracellular domains of the lower SC, thus providing the acidification of deep SC interstices necessary for lipid processing and barrier homeostasis.

Evidence for the existence of a self-regulated enzymatic process within the human stratum corneum -an unexpected role for urocanic acid.

Data analysis suggests that three groups characterized by different skin surface pH values depend on urocanic acid production rate within the stratum corneum and that this production rate is self-regulated by its uro canic acid content.

Stratum corneum acidification in neonatal skin: secretory phospholipase A2 and the sodium/hydrogen antiporter-1 acidify neonatal rat stratum corneum.

A neonatal model is described, in which the development of an acidic surface pH can be ascribed, in part, to progressive SC acidification by two endogenous mechanisms, namely, sPLA2 and NHE1, which are known to be important for acidification of adult rodent SC.

Generation of free fatty acids from phospholipids regulates stratum corneum acidification and integrity.

The importance of phospholipid-to-free-fatty-acid processing for normal stratum corneum acidification is demonstrated and the potentially important role of this pathway not only for barrier homeostasis but also for the dual functions of stratum Corneum integrity and cohesion is demonstrated.

Acute acidification of stratum corneum membrane domains using polyhydroxyl acids improves lipid processing and inhibits degradation of corneodesmosomes.

As SC hyperacidification improves the structure and function, even of normal epidermis, these studies lay the groundwork for an assessment of the potential utility of SC acidification as a therapeutic strategy for inflammatory dermatoses, characterized by abnormalities in barrier function, cohesion, and surface pH.

Stratum corneum acidification: how and why?

  • P. Elias
  • Biology
    Experimental dermatology
  • 2015
The acidic pH of darkly pigmented skin dictates the superior function in such individuals, because acidification of lightly pigmented human skin ‘resets’ functions to darkly Pigmented skin, and it is likely that one additional mechanism contributes to SC acidification.