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Benagiano V, Rizzi A, Sannace C, Alessio G, Ribatti D, Dammacco R. Aqueous humor as eye lymph: A crossroad between venous and lymphatic system. Exp Eye Res 2024; 243:109904. [PMID: 38642600 DOI: 10.1016/j.exer.2024.109904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/18/2024] [Accepted: 04/17/2024] [Indexed: 04/22/2024]
Abstract
Aqueous humor (AQH) is a transparent fluid with characteristics similar to those of the interstitial fluid, which fills the eyeball posterior and anterior chambers and circulates in them from the sites of production to those of drainage. The AQH volume and pressure homeostasis is essential for the trophism of the ocular avascular tissues and their normal structure and function. Different AQH outflow pathways exist, including a main pathway, quite well defined anatomically and referred to as the conventional pathway, and some accessory pathways, more recently described and still not fully morphofunctionally understood, generically referred to as unconventional pathways. The conventional pathway is based on the existence of a series of conduits starting with the trabecular meshwork and Schlemm's Canal and continuing with a system of intrascleral and episcleral venules, which are tributaries to veins of the anterior segment of the eyeball. The unconventional pathways are mainly represented by the uveoscleral pathway, in which AQH flows through clefts, interstitial conduits located in the ciliary body and sclera, and then merges into the aforementioned intrascleral and episcleral venules. A further unconventional pathway, the lymphatic pathway, has been supported by the demonstration of lymphatic microvessels in the limbal sclera and, possibly, in the uvea (ciliary body, choroid) as well as by the ocular glymphatic channels, present in the neural retina and optic nerve. It follows that AQH may be drained from the eyeball through blood vessels (TM-SC pathway, US pathway) or lymphatic vessels (lymphatic pathway), and the different pathways may integrate or compensate for each other, optimizing the AQH drainage. The present review aims to define the state-of-the-art concerning the structural organization and the functional anatomy of all the AQH outflow pathways. Particular attention is paid to examining the regulatory mechanisms active in each of them. The new data on the anatomy and physiology of AQH outflow pathways is the key to understanding the pathophysiology of AQH outflow disorders and could open the way for novel approaches to their treatment.
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Affiliation(s)
- Vincenzo Benagiano
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy.
| | - Anna Rizzi
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
| | - Carmela Sannace
- Azienda Sanitaria Locale Bari, Ophthalmology Day Service Triggiano-Gioia del Colle, Bari, Italy
| | - Giovanni Alessio
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
| | - Domenico Ribatti
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
| | - Rosanna Dammacco
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
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Hu Z, Zhao X, Wu Z, Qu B, Yuan M, Xing Y, Song Y, Wang Z. Lymphatic vessel: origin, heterogeneity, biological functions, and therapeutic targets. Signal Transduct Target Ther 2024; 9:9. [PMID: 38172098 PMCID: PMC10764842 DOI: 10.1038/s41392-023-01723-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 11/03/2023] [Accepted: 11/23/2023] [Indexed: 01/05/2024] Open
Abstract
Lymphatic vessels, comprising the secondary circulatory system in human body, play a multifaceted role in maintaining homeostasis among various tissues and organs. They are tasked with a serious of responsibilities, including the regulation of lymph absorption and transport, the orchestration of immune surveillance and responses. Lymphatic vessel development undergoes a series of sophisticated regulatory signaling pathways governing heterogeneous-origin cell populations stepwise to assemble into the highly specialized lymphatic vessel networks. Lymphangiogenesis, as defined by new lymphatic vessels sprouting from preexisting lymphatic vessels/embryonic veins, is the main developmental mechanism underlying the formation and expansion of lymphatic vessel networks in an embryo. However, abnormal lymphangiogenesis could be observed in many pathological conditions and has a close relationship with the development and progression of various diseases. Mechanistic studies have revealed a set of lymphangiogenic factors and cascades that may serve as the potential targets for regulating abnormal lymphangiogenesis, to further modulate the progression of diseases. Actually, an increasing number of clinical trials have demonstrated the promising interventions and showed the feasibility of currently available treatments for future clinical translation. Targeting lymphangiogenic promoters or inhibitors not only directly regulates abnormal lymphangiogenesis, but improves the efficacy of diverse treatments. In conclusion, we present a comprehensive overview of lymphatic vessel development and physiological functions, and describe the critical involvement of abnormal lymphangiogenesis in multiple diseases. Moreover, we summarize the targeting therapeutic values of abnormal lymphangiogenesis, providing novel perspectives for treatment strategy of multiple human diseases.
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Affiliation(s)
- Zhaoliang Hu
- Department of Surgical Oncology and General Surgery, The First Hospital of China Medical University; Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors (China Medical University), Ministry of Education, 155 North Nanjing Street, Heping District, Shenyang, 110001, China
| | - Xushi Zhao
- Department of Surgical Oncology and General Surgery, The First Hospital of China Medical University; Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors (China Medical University), Ministry of Education, 155 North Nanjing Street, Heping District, Shenyang, 110001, China
| | - Zhonghua Wu
- Department of Surgical Oncology and General Surgery, The First Hospital of China Medical University; Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors (China Medical University), Ministry of Education, 155 North Nanjing Street, Heping District, Shenyang, 110001, China
| | - Bicheng Qu
- Department of Surgical Oncology and General Surgery, The First Hospital of China Medical University; Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors (China Medical University), Ministry of Education, 155 North Nanjing Street, Heping District, Shenyang, 110001, China
| | - Minxian Yuan
- Department of Surgical Oncology and General Surgery, The First Hospital of China Medical University; Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors (China Medical University), Ministry of Education, 155 North Nanjing Street, Heping District, Shenyang, 110001, China
| | - Yanan Xing
- Department of Surgical Oncology and General Surgery, The First Hospital of China Medical University; Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors (China Medical University), Ministry of Education, 155 North Nanjing Street, Heping District, Shenyang, 110001, China.
| | - Yongxi Song
- Department of Surgical Oncology and General Surgery, The First Hospital of China Medical University; Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors (China Medical University), Ministry of Education, 155 North Nanjing Street, Heping District, Shenyang, 110001, China.
| | - Zhenning Wang
- Department of Surgical Oncology and General Surgery, The First Hospital of China Medical University; Key Laboratory of Precision Diagnosis and Treatment of Gastrointestinal Tumors (China Medical University), Ministry of Education, 155 North Nanjing Street, Heping District, Shenyang, 110001, China.
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Subileau M, Vittet D. Ontogenesis of the Mouse Ocular Surface Lymphatic Vascular Network. Invest Ophthalmol Vis Sci 2023; 64:7. [PMID: 38054922 DOI: 10.1167/iovs.64.15.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023] Open
Abstract
Purpose Ocular lymphatic vessels play major physiological role in eye homeostasis and their dysfunction can contribute to the progression of several eye diseases. In this study, we characterized their spatiotemporal development and the cellular mechanisms occurring during their ontogenesis in the mouse eye. Methods Whole mount immunofluorescent staining and imaging by standard or lightsheet fluorescence microscopy were performed on late embryonic and early postnatal eye mouse samples. Results We observed that the ocular surface lymphatic vascular network develops at the early postnatal stages (between P0 and P5) from two nascent trunks arising at the nasal side on both sides of the nictitating membrane. These nascent vessels further branch and encircle the whole eye surface by sprouting lymphangiogenesis. In addition, we got evidence for the existence of a transient lymphvasculogenesis process generating lymphatic vessel fragments that will mostly formed the corneolimbal lymphatic vasculature which further connect to the conjunctival lymphatic network. Our results also support that CD206-positive macrophages can transdifferentiate and then integrate into the lymphatic neovessels. Conclusions Several complementary cellular processes participate in the development of the lymphatic ocular surface vasculature. This knowledge paves the way for the design of new therapeutic strategies to interfere with ocular lymphatic vessel formation when needed.
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Affiliation(s)
- Mariela Subileau
- University Grenoble Alpes, CEA, Inserm, IRIG, UA13 BGE, Grenoble, France
| | - Daniel Vittet
- University Grenoble Alpes, CEA, Inserm, IRIG, UA13 BGE, Grenoble, France
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Blei F. Update August 2023. Lymphat Res Biol 2023; 21:410-429. [PMID: 37616587 DOI: 10.1089/lrb.2023.29146.fb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2023] Open
Affiliation(s)
- Francine Blei
- Hassenfeld Children's Hospital at NYU Langone, The Laurence D. And Lori Weider Fink Children's Ambulatory Care Center, New York, New York, USA
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