Probiotic Research in Therapeutics: Volume 3: Probiotics and Gut Skin Axis–Inside Out and Outside In

Foreword by J. V. Yakhmi
Foreword by Manpreet Randhawa
Preface
Contents
About the Editors
1: Gut-Skin Axis: Role in Health and Disease
	1.1 Introduction
		1.1.1 Skin
		1.1.2 Development of Skin Microbiome
		1.1.3 Factors Affecting the Skin Microbiome
		1.1.4 Skin Microbiome: Composition and Distribution
			1.1.4.1 Bacteria
			1.1.4.2 Fungi
			1.1.4.3 Mites
			1.1.4.4 Viruses
	1.2 Gut-Skin Axis
	1.3 Microbial Association with ``Gut-Skin Axis´´
	1.4 ``Gut-Skin Axis´´ and Associated Disease
		1.4.1 Atopic Dermatitis
		1.4.2 Psoriasis
		1.4.3 Acne Vulgaris
		1.4.4 Other Skin Diseases
	1.5 ``Gut-Skin Axis´´ and Therapeutic Implications
		1.5.1 Diet: Probiotics and Prebiotics
			1.5.1.1 Atopic Dermatitis
			1.5.1.2 Acne
			1.5.1.3 Psoriasis
	1.6 Conclusion and Future Perspective
	References
2: Mechanistic Role of Probiotics in Improving Skin Health
	2.1 Introduction
	2.2 Probiotics as Elixir for Skin Ailments
		2.2.1 Chronic Skin Diseases
		2.2.2 Age-Related Skin Conditions
		2.2.3 Infectious Diseases
		2.2.4 General Skin Health
	2.3 Mechanism of Action
		2.3.1 Indirect Effects Generated via Oral Administration (Gut-Skin Axis and Gut-Brain-Skin Axis)
			2.3.1.1 Gut-Skin Cross-Talk (Alteration in Gut Bacteria Can Have Effects on Skin)
			2.3.1.2 Barrier Recovery and Hydration of Compromised Skin
			2.3.1.3 Regulating Skin Homeostasis
			2.3.1.4 Reducing Skin Inflammation
			2.3.1.5 Ameliorating Hair Growth
			2.3.1.6 Reduced Peripheral Tissue Response to Stress
		2.3.2 Direct Effects on Topical Application
			2.3.2.1 Pathogen Inhibition by Competitive Exclusion
			2.3.2.2 Production of Bacteriocins as Antimicrobials
			2.3.2.3 Maintenance of Skin Hydration and Elasticity
			2.3.2.4 Remodelling of Epidermal and Dermal Tissues
			2.3.2.5 Generation of Ceramide and Mucin
			2.3.2.6 Maintenance of Healthy Skin pH
			2.3.2.7 Effect of Probiotic Metabolites, Byproducts, and Structural Components
			2.3.2.8 Enhancement in Immune Function and Regulation of Production of Inflammatory Cytokines
			2.3.2.9 Cross-Talk Between Microbiota and the Skin Immune System
	2.4 Conclusion and Future Perspective
	References
3: Skin Microbiome and Host Immunity: Applications in Regenerative Cosmetics and Transdermal Drug Delivery
	3.1 Introduction
	3.2 Invasion of Cutaneous Pathogen and Response of Skin Ecosystem
	References
4: Probiotics and Their Various Forms Supporting Skin Health
	4.1 Introduction
		4.1.1 Definitions of Probiotics, Postbiotics, Parabiotics, and Prebiotics
		4.1.2 Definition of Probiotic Skin Care Products and Their Associated Challenges
		4.1.3 Briefly on Regulatory Environment for Probiotics in Skin Care Products
		4.1.4 Comparison of Skin and Gut Microbiota
		4.1.5 Skin Barrier Function
		4.1.6 Microbial Interactions in the Skin
	4.2 Effects of Oral Probiotics and Parabiotics on Skin Health
		4.2.1 Mechanisms Involved in the Gut-Skin Axis: Brief Overview
		4.2.2 In Vitro and In Vivo Research on Oral Probiotics and Parabiotics in Barrier Recovery and Hydration Related to Compromise...
		4.2.3 In Vitro and In Vivo Research on Oral Probiotics and Parabiotics in Effects Associated with Exposure to UV Radiation
		4.2.4 Conclusion of Oral Probiotic and Parabiotics Studies on Skin Health
	4.3 Topical Probiotics, Parabiotics, and Postbiotics on Skin Health
		4.3.1 Mechanisms of Topical Probiotics, Parabiotics, and Postbiotics in Skin Health
			4.3.1.1 Small Organic Acids Produced by Probiotics and Maintenance of pH in the Skin
			4.3.1.2 Pathogen Inhibition by Competitive Exclusion, as Well as by Production of Small Organic Acids and Bacteriocins
			4.3.1.3 Enhancement in Skin Barrier by Hyaluronic Acid and Lipid Production
			4.3.1.4 Enhancement in Immune Function by Bacterial Cell Wall Components and Bacterial DNA
		4.3.2 Effects of Topical Probiotics, Parabiotics, and Postbiotics on Skin Health
			4.3.2.1 Strain-Specificity and Dependence of the Application Form of Topical Probiotics
			4.3.2.2 Topical Probiotics, Parabiotics, and Postbiotics: Emerging Evidence of Health Benefits
		4.3.3 Conclusions of Topical Probiotic, Postbiotic, and Parabiotic Studies on Skin Health
	4.4 Manufacturing and Quality-Related Challenges of Postbiotics and Parabiotics
	4.5 Future Outlook: Need for Harmonization, Validated Methods, and Well-Designed Clinical Trials
	4.6 Concluding Remarks
	References
5: Topical Probiotics: Scope and Challenges
	5.1 Introduction
	5.2 In Vitro Assays to Determine the Efficacy of Probiotics Used in Topical Application
		5.2.1 Determining In Vitro Adhesion Characteristics of Probiotics
		5.2.2 Determining In Vitro Antimicrobial Characteristics of Probiotics
		5.2.3 Determining In Vitro Antibiofilm Activity of Probiotics
	5.3 In Vivo Studies to Determine the Efficacy of Probiotics Used in Topical Application
		5.3.1 Seborrheic Dermatitis
		5.3.2 Wound
		5.3.3 Psoriasis
		5.3.4 Atopic Dermatitis
		5.3.5 Acne
		5.3.6 Aging and Photoaging
		5.3.7 Allergic Contact Dermatitis
		5.3.8 Skin Cancer
	5.4 Future Challenges
	5.5 Conclusion
	References
6: Status of Using Probiotic Supplementation in Acne
	6.1 The Pathogenesis
	6.2 Factors Influencing Acne Pathogenesis
		6.2.1 Microbiota and Dysbiosis
			6.2.1.1 The Microbiota
			6.2.1.2 Microbial Secretions and Induced Secretions
		6.2.2 Lipids
		6.2.3 Hormones
		6.2.4 Diet and Nutrition
		6.2.5 Other Factors
	6.3 Acne Associated Psychological Effects
	6.4 Widely Used Treatment Strategies
	6.5 Probiotics
	6.6 Concluding Remarks
	References
7: Probiotic Effects on Skin Health: The Case of Photoprotection as a Model of Gut-Skin Dialog
	7.1 Introduction
	7.2 Probiotic Effects on Skin Health
		7.2.1 Changes of the Gut Microbiota in Skin Disorders
		7.2.2 Changes of the Cutaneous Microbiota in Skin Disorders
		7.2.3 Probiotics in the Treatment of Skin Disorders
	7.3 Ultraviolet Radiation Effects on Skin Health
		7.3.1 UV Radiation Acute Effects
		7.3.2 Chronic Effects
	7.4 Probiotic Modulation of UV-Induced Skin Damage
		7.4.1 Live Probiotics in Photoprotection
		7.4.2 Effects of Isolated Probiotic Components
			7.4.2.1 Functional and Structural Characteristics of LTA
			7.4.2.2 Effects of LTA Isolated from L. rhamnosus on Skin Damage
	7.5 Gut-Skin Dialog: Possible Mechanisms Involved
	7.6 Conclusions
	References
8: Relationship Between Probiotics and Gut-Skin Axis in Skin Wound Healing: A Recent Update
	8.1 Introduction
	8.2 Gut Microbiome Physiological Role
		8.2.1 Gut Microbiome Diversity in the Human Body
	8.3 The Implication of Probiotics in Skin Diseases
		8.3.1 Atopic Dermatitis (AD)
		8.3.2 Contact Dermatitis (CD)
		8.3.3 Psoriasis
		8.3.4 Acne
		8.3.5 Skin Aging
		8.3.6 Probiotics and Chronic Wounds
	8.4 Conclusion
	References
9: Probiotics for Atopic Dermatitis: An Update
	9.1 Introduction
		9.1.1 Gut Microflora
		9.1.2 Functions of Gut Microflora
		9.1.3 Gut Dysbiosis
	9.2 Atopic Dermatitis (AD)
		9.2.1 Epidemiology of AD
		9.2.2 Causes of AD
		9.2.3 Symptoms of AD
		9.2.4 Diagnosis of AD
			9.2.4.1 The Hanifin-Rajka Criteria of AD
			9.2.4.2 SCORAD Index
			9.2.4.3 Intensity and Severity Index
			9.2.4.4 Dermatology Quality-of-Life Index (DQLI)
		9.2.5 Pathophysiology of AD
			9.2.5.1 Genetic Variations
			9.2.5.2 Immune System Abnormalities
			9.2.5.3 Neuroimmunogenic Mechanism
			9.2.5.4 Epidermal Dysfunction
			9.2.5.5 Lipids
			9.2.5.6 Microbiome
		9.2.6 Current Approaches in Treatment of AD and Their Drawbacks
			9.2.6.1 First Line of Treatment (Basic Therapy)
			9.2.6.2 Second Line of Treatment (Mild Anti-inflammatory Treatment)
				Topical Steroids (TCS)
				Topical Calcineurin Inhibitors
				Antimicrobial Treatment
				Antihistamines
			9.2.6.3 Third Line of Treatment: Systemic Treatment
				Cyclosporine A (CsA)
				Methotrexate
				Azathioprine (AZA)
			9.2.6.4 Phototherapy
			9.2.6.5 Drawbacks of Currently Available Treatments
		9.2.7 Emerging Therapeutic Treatments in AD
		9.2.8 Alternative Treatment Options for AD
			9.2.8.1 Acupuncture
			9.2.8.2 Relaxation Therapy
			9.2.8.3 Psychotherapy
			9.2.8.4 Probiotics
	9.3 Probiotics in AD
		9.3.1 Probiotics in Skin Health
			9.3.1.1 Probiotics and Acne
			9.3.1.2 Probiotics and Wound Healing
			9.3.1.3 Probiotics and Skin Aging
			9.3.1.4 Probiotic and Psoriasis
		9.3.2 Microbiome in the Gut-Skin Axis in AD
			9.3.2.1 Mechanism of Action
				Immunomodulatory Mechanism
				Metabolic Pathway
				Neuroendocrine Pathway
	9.4 Factors Affecting Viability of Probiotics
	9.5 Delivery Systems for Probiotics
		9.5.1 Conventional Delivery Systems
		9.5.2 Controlled Delivery Systems
			9.5.2.1 Encapsulation
			9.5.2.2 Microencapsulation
			9.5.2.3 Freeze-Drying
	9.6 Clinical Trials of Probiotics for AD
	9.7 Constraints of Probiotic Delivery
	9.8 Future Trends and Conclusion
	References
10: Safety Concerns, Regulatory Guidelines, Current Market Trends, and Future Directions toward the Use of Probiotics in Gut-B...
	10.1 Introduction
		10.1.1 Strategies Used to Validate the Relationship Between Gut Microbiota and Diseases
		10.1.2 Role of Gut Microbiota in Metabolic Disorders
		10.1.3 Probiotic Supplementation
		10.1.4 Interaction Between Gut Microbiota and Skin Microflora
		10.1.5 Relationship Between Gut Microbiota and Brain Disorders
		10.1.6 Role of Probiotics During COVID-19
	10.2 Safety Concerns
		10.2.1 Role of the Food and Drug Administration (FDA) in the Marketing of Probiotics
		10.2.2 Guidelines to Use Probiotics as Drugs
		10.2.3 Complexity and Requirements for Probiotic Formulation
		10.2.4 Cross-Contamination During Probiotic Administration
	10.3 Global Regulations for Probiotic Products
		10.3.1 Regulatory Guidelines
		10.3.2 Specific Guidelines from the Food Safety and Standards Authority of India (FSSAI) for Probiotic Products to be Sold in ...
		10.3.3 Mechanistic Approach of Probiotics
	10.4 Market Trends
		10.4.1 Major Impacting Factors in the World Probiotic Market
		10.4.2 Current Market Trend of Probiotics
		10.4.3 Major Breakthroughs in the Global Probiotic Market
		10.4.4 Segmentation of World Probiotic Market
		10.4.5 Probiotic Research and Technological Advancements in Host-Bacteria Interactions
	10.5 Futuristic Approach
	References
11: Probiotics as Edible Vaccines
	11.1 Introduction
	11.2 Bacteria-Based Vaccine Probiotics
		11.2.1 Bacteria as Vaccines
			11.2.1.1 Lactic Acid Bacteria
			11.2.1.2 Bifidobacteria
			11.2.1.3 Bacillus subtilis
	11.3 Yeast-Based Probiotic Vaccines
	11.4 Way Forward in Formulation Development
	11.5 Conclusion
	References