nanomaterials Review Inflammatory Bowel Disease: The Emergence of New Trends in Lifestyle and Nanomedicine as the Modern Tool for Pharmacotherapy Eden Mariam Jacob, Ankita Borah, Sindhu C Pillai and D. Sakthi Kumar * Bio-Nano Electronics Research Centre, Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, Saitama 350-8585, Japan; [email protected] (E.M.J.); [email protected] (A.B.); [email protected] (S.C.P.) * Correspondence: [email protected]; Tel.: +81-0-492-39-1636 (ext. 1375 or ext. 1640) (O) or +81-909-9647-605; Fax: +81-0-366-77-1140 (O) Received: 3 October 2020; Accepted: 7 December 2020; Published: 9 December 2020 Abstract: The human intestine, which harbors trillions of symbiotic microorganisms, may enter into dysbiosis when exposed to a genetic defect or environmental stress. The naissance of chronic inflammation due to the battle of the immune system with the trespassing gut bacteria leads to the rise of inflammatory bowel disease (IBD). Though the genes behind the scenes and their link to the disease are still unclear, the onset of IBD occurs in young adults and has expanded from the Western world into the newly industrialized countries. Conventional drug deliveries depend on a daily heavy dosage of immune suppressants or anti-inflammatory drugs targeted for the treatment of two types of IBD, ulcerative colitis (UC) and Crohn’s disease (CD), which are often associated with systemic side effects and adverse toxicities. Advances in oral delivery through nanotechnology seek remedies to overcome the drawbacks of these conventional drug delivery systems through improved drug encapsulation and targeted delivery. In this review, we discuss the association of genetic factors, the immune system, the gut microbiome, and environmental factors like diet in the pathogenesis of IBD. We also review the various physiological concerns required for oral delivery to the gastrointestinal tract (GIT) and new strategies in nanotechnology-derived, colon-targeting drug delivery systems. Keywords: inflammatory bowel disease (IBD); Crohn’s disease (CD); ulcerative colitis (UC); gut microbiome; immunity; nutrition; probiotics; nano-drug delivery 1. Introduction Inflammatory bowel disease (IBD) represents an umbrella term for the chronic remission and relapse of immunologically-mediated idiopathic diseases. IBD is generally diagnosed under two major classifications as Crohn’s disease (CD) and ulcerative colitis (UC) with significantly contrasting etiologies [1]. Multiple studies over the decades have still remarkably left the pathogenesis of the diseases an unresolved mystery. CD tends to occur in any part of the gastrointestinal tract (GIT) and is associated with complications [2], whereas UC, on the other hand, is strictly restricted to the inflammation of the colon [3]. The onset of the diseases is marked at young adulthood [4] in genetically susceptible individuals responding to commensal microbes or environmental cues [5] like poor hygiene [6,7], unbalanced dietary intake [8], a lack of physical exercise [9], smoking, and stress [10] (Figure1). The downhill trajectory on the quality of life demands a heavier burden of therapy and hospitalization due to the delayed diagnosis of the disease. An improved understanding of the disease mechanisms from a molecular to a higher organ level can attenuate the misconceptions in its diagnosis and treatment. The identification of IBD as a polygenic disease genetics, along with the Nanomaterials 2020, 10, 2460; doi:10.3390/nano10122460 www.mdpi.com/journal/nanomaterials Nanomaterials 2020, 10, 2460 2 of 32 Nanomaterials 2020, 10, x FOR PEER REVIEW 2 of 31 identificationidentification of commensal microfloramicroflora participation in gastrointestinal environments, has led to an extravagant immuneimmune response response in in the the gut gut [11 ].[11]. IBD IBD patients patients have have an increased an increased risk linked risk linked to colon to cancer, colon whichcancer, is which the third is the most-common third most-common one globally one [12 glob] dueally to the[12] developmentdue to the development of chronic inflammation of chronic thatinflammation is characterized that is bycharacterized massive immune by massive filtration immune and immune-mediated filtration and immune-mediated tissue destruction tissue [13]. Sporadicdestruction colorectal [13]. 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Nanotechnologyinconsistent efficacy has been of the upraised drug calls in the for pharmaceutical advancements field in fortargeted climbing drug barriers delivery in systems the crafted [19]. delivery Nanotechnology of hydrophobic has been drugs upraised with a reducedin the pharmaceutical dosage and a highfield eforffi ciency,climbing thereby barriers minimizing in the crafted the systemicdelivery toxicitiesof hydrophobic that were drugs once with a burden a reduced [20]. dosage The nanoparticle and a high deliveryefficiency, system thereby has minimizing not only uplifted the systemic conventional toxicities delivery that were systems once but a burden also aided [20]. in The the developmentnanoparticle delivery system has not only uplifted conventional delivery systems but also aided in the Nanomaterials 2020, 10, 2460 3 of 32 of new therapeutic drugs [21]. The usage of nanomedicine in oral delivery significantly enhances the biodistribution of therapeutics to the colon and also focuses on the cellular uptake of the drug within the diseased cells without harming the healthy tissues [21]. This review focuses on the pathophysiology of IBD through its genetics, microbial, and nutritional factors; the physiological consideration for oral delivery; new strategies in the nano-drug delivery systems for colon targeting through oral routes; and the future direction of this research. 2. Epidemiology of IBD IBD has evolved into a global disease with great variations affecting not only the highly developed countries in North America and Europe but also the newly industrialized countries in Asia [22,23]. In Europe, the incidence of UC is 24.3–505 per 100,000 person-years, and that of CD is 12.7–322 per 100,000 person-years. Meanwhile, in North America, the prevalence of UC is 19.2–249 per 100,000 person-years and that of CD is 20.2–319 per 100,000 person-years. In Canada alone, the incidence of IBD is 18.7–28.3 per 100,000 person-years [24]. The cases