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Minuth WW. Installation of the developing nephron in the fetal human kidney during advanced pregnancy. Mol Cell Pediatr 2023; 10:18. [PMID: 38012334 PMCID: PMC10682366 DOI: 10.1186/s40348-023-00172-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 11/13/2023] [Indexed: 11/29/2023] Open
Abstract
BACKGROUND The kidneys of preterm and low birth weight babies reflect vulnerability, since several noxae can evoke the termination of nephron formation. This again leads to oligonephropathy with severe consequences for health in the later life. While the clinical parameters have been intensely investigated, only little is known about the initial traces left by the noxae. For the fetal human kidney, solely the lack of basophilic S-shaped bodies and the reduction in width of the nephrogenic zone were registered. It is not known in how far also the involved progenitor cells, the earlier nephron stages, the collecting duct (CD) ampullae, and the local interstitium are collaterally harmed. AIM The interstitium at the forming nephron is heterogeneously structured. Thereby, it fulfills quite different mastering and integrative tasks. Since data dealing with the installation of a nephron is not available, the microanatomical features were recorded. RESULTS The microscopic specimens show that the installation of the transient stages of nephron anlage is not synchronized. Instead, it is controlled within a nephrogenic compartment of the nephrogenic zone. It starts near the renal capsule by positioning the nephrogenic niche so that the nephrogenic progenitor cells face the epithelial progenitor cell at the tip of a CD ampulla. Then, the induced nephrogenic progenitor cells assimilate in the pretubular aggregate. While its medial part remains opposite the head of the CD ampulla, at its proximal end, the primitive renal vesicle is formed. Only a part of it separates to stick to the section border between the head and conus of the CD ampulla. This marks the link with the future connecting tubule at the distal pole of the extending renal vesicle. Meanwhile, the proximal pole is mounted next to the connecting tubule of an earlier developed nephron. The resulting two-point mounting serves a common elongation of the conus at the CD ampulla and the medial aspect of the comma-shaped body. In the S-shaped body, it supports to defoliate the arising glomerulus and to link it with the perforating radiate artery at its deep lateral aspect. CONCLUSIONS The investigation depicts that the installation is an interactive process between the stages of nephron anlage and its structural neighbors. A special meaning has the interjacent interstitium. It is vital for the positioning, shaping, and physiological integration. Due to its special location, this is mainly exposed to noxae.
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Affiliation(s)
- Will W Minuth
- Institute of Anatomy, University of Regensburg, D-93053, Regensburg, Germany.
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Minuth WW. The interstitium at the developing nephron in the fetal kidney during advanced pregnancy - a microanatomical inventory. Mol Cell Pediatr 2022; 9:17. [PMID: 36008693 PMCID: PMC9411487 DOI: 10.1186/s40348-022-00149-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 08/15/2022] [Indexed: 11/10/2022] Open
Abstract
Background A series of noxae can evoke the termination of nephron formation in preterm and low birth weight babies. This results in oligonephropathy with severe consequences for health in the later life. Although the clinical parameters have been extensively investigated, little is known about the initial damage. Previous pathological findings indicate the reduction in width of the nephrogenic zone and the lack of S-shaped bodies. Current morphological investigations suggest that due to the mutual patterning beside the forming nephron, also its structural neighbors, particularly the interjacent interstitium, must be affected. However, beside the findings on integrative and mastering functions, systematic microanatomical data explaining the configuration of the interstitium at the developing nephron in the fetal kidney during advanced pregnancy is not available. Therefore, this work explains the typical features. Results The generated data depicts that the progenitor cells, nephrogenic niche, pretubular aggregate, and mesenchymal-to-epithelial transition are restricted to the subcapsular interstitium. During the proceeding development, only the distal pole of the renal vesicles and comma- and S-shaped bodies stays in further contact with it. The respective proximal pole is positioned opposite the peritubular interstitium at the connecting tubule of an underlying but previously formed nephron. The related medial aspect faces the narrow peritubular interstitium of a collecting duct (CD) ampulla first only at its tip, then at its head, conus, and neck, and finally at the differentiating CD tubule. The lateral aspect starts at the subcapsular interstitium, but then it is positioned along the wide perivascular interstitium of the neighboring ascending perforating radiate artery. When the nephron matures, the interstitial configuration changes again. Conclusions The present investigation illustrates that the interstitium at the forming nephron in the fetal kidney consists of existing, transient, stage-specific, and differently far matured compartments. According to the developmental needs, it changes its shape by formation, degradation, fusion, and rebuilding.
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Affiliation(s)
- Will W Minuth
- Institute of Anatomy, University of Regensburg, 93053, Regensburg, Germany.
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Minuth WW. The mutual patterning between the developing nephron and its covering tissues-valid reasons to rethink the search for traces left by impaired nephrogenesis. Mol Cell Pediatr 2021; 8:9. [PMID: 34403001 PMCID: PMC8371049 DOI: 10.1186/s40348-021-00120-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 07/23/2021] [Indexed: 01/08/2023] Open
Abstract
Background The impairment of nephrogenesis can cause the termination of nephron formation in preterm and low birth weight babies. This leads to oligonephropathy with severe health consequences in later life. Although many clinical parameters are known, surprisingly little information is available regarding the initial damage on the developing nephron. Equally astounding, the first morphological data regarding the specifics of nephron formation in the nephrogenic zone of the fetal human kidney during late gestation has only been published within the past few years. In this context, it was observed that each stage of nephron anlage is surrounded by a specific set of tissues. Although highly relevant for the normal progress of nephron formation, the mutual patterning has not been systematically described. Results To contribute, the different stages of nephron anlage in the nephrogenic zone of the fetal human kidney during late gestation were screened by the optical microscope and documented by images. Following this, magnifications (28 × 18 cm) were produced to trace the contours of the developing nephron and its covering tissues. The resulting sketches, almost true to scale, were scanned, edited, and processed by a design program. As a base, first the individual position, size, and shape of the nephrogenic niche, pretubular aggregate, renal vesicles, comma- and S-shaped bodies are presented. Secondly, their structural relations to the renal capsule, collecting duct ampulla, perforating radiate artery, and expanding interstitium are shown. Third of all, the focus is on less considered configurations, such as site-specific approximation, local distancing, punctual adhesion, integration, separation, delamination, formation of congruent and divergent surfaces, and folding and opening of interstitial clefts. Conclusions The present contribution illuminates the mutual patterning between the developing nephron and its covering tissues. It is indispensable to know about the microanatomical relations, in order to identify whether the noxae impairing nephrogenesis targets only the developing nephron or also its covering tissues as interacting and controlling instances.
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Affiliation(s)
- Will W Minuth
- Institute of Anatomy, University of Regensburg, D - 93053, Regensburg, Germany.
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Cong J, Chang SJ, Thomsen JS, Andreasen A, Chen X, Xing J, Zhang J, Gu L, Zhai XY. Ultrastructural identification of developing proximal tubules based on three-dimensional reconstruction. Vet Med Sci 2021; 7:1989-1998. [PMID: 34236772 PMCID: PMC8464306 DOI: 10.1002/vms3.558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND The cellular mechanisms involved in the development of proximal tubules are not only associated with morphogenesis in fetal life, but also with restoration of damaged tubules in adulthood. Knowledge about morphological features of cell differentiation and proliferation along the developing tubule is insufficient, which hinders identification of the cellular origin. OBJECTIVES This study aimed to investigate ultrastructures of the proximal tubule at different stages of nephrogenesis. METHODS Electron microscopy was used and guided by computer-assisted tubular tracing to identify the cellular structures. RESULTS Renal vesicles and S-shaped bodies revealed more proliferative features, such as densely-packed fusiform-shaped cells with numerous protein-producing organelles than membrane specializations typical for mature tubules. At the capillary-loop stage the proximal tubules demonstrated all characteristics of the mature tubules, but not as developed, including shorter but densely packed microvilli, fewer lateral processes with cell-cell contacts, lower basal membrane infoldings, and lower mitochondrial volume density. However, they exhibited an elaborated endocytic system above the nucleus, indicating a membrane transport is being established. Abundant free- and endoplasmic reticulum-adhered ribosomes and Golgi complexes reflected active protein synthesis for cell growth and proliferation. Interestingly, electron dense cells were occasionally intermixed with electron lucent cells characterized by various organelles in less cytosol and a larger nucleus with abundant euchromatin, which is a feature of active proliferation. CONCLUSIONS These ultrastructures indicate that the morphogenesis of the developing proximal tubule corresponds to the gradually established physiological activities. The two different cellular electron densities may suggest distinctive differentiation of the cells along the tubule.
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Affiliation(s)
- Jing Cong
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China.,Department of Histology and Embryology, Shenyang Medical College, Shenyang, China
| | - Shi-Jie Chang
- Department of Biomedical Engineering, College of Fundamental Science, China Medical University, Shenyang, China
| | | | - Arne Andreasen
- Department of Biomedicine-Anatomy, Aarhus University, Aarhus, Denmark
| | - Xue Chen
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Jia Xing
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Jie Zhang
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Ling Gu
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Xiao-Yue Zhai
- Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
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Minuth WW. Microanatomy of the developing nephron in the fetal human kidney during late gestation. Ann Anat 2021; 236:151705. [PMID: 33607225 DOI: 10.1016/j.aanat.2021.151705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 01/13/2021] [Accepted: 01/27/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Clinical experiences reveal that the kidneys of preterm and low birth weight infants are highly vulnerable. Noxae of various molecular composition can damage the outer renal cortex, resulting in an early termination of nephron formation. However, in contrast to what is known about the rodent kidney, with reference to the damage on the early stages of nephron anlage such as the comma-shaped body, renal vesicles, pretubular aggregate or nephrogenic niche, this information in the fetal human kidney is not available. The few documented pathological alterations in the fetal human kidney during late gestation are glomeruli with a dilated Bowman's space and a shrunken tuft, the reduction in width of the nephrogenic zone and the lack of here contained S-shaped bodies. The latter points out that the shaping, folding or expansion of the developing nephron must be disrupted. Since these specific aspects have been little investigated, the aim of the present microanatomical contribution is to highlight it. METHODS Firstly, the individual stages of nephron anlage in the fetal human kidney during late gestation were documented by microscopic images. Then, as a stylistic tool for the pointing to specific sites of the running developmental process, a series of true to scale sketches were produced. RESULTS The generated sketches depict the spatial expansion of the transiently appearing stages of nephron anlage. These are restricted to the nephrogenic zone and are framed by the inner side of the renal capsule, the related collecting duct ampulla and a perforating radiate artery. Practical hints and a consequent nomenclature explain the developmental course and help us to identify the precise location of the proximal - distal poles, medial - lateral profiles, connecting points, adhesion sites or folds at the developing nephron on microscopic specimens. CONCLUSIONS The impairment of nephrogenesis in preterm and low birth weight babies is an unsolved biomedical issue. To contribute, by provided true to scale sketches, numerous practical hints and a consequent nomenclature typical features of nephron formation in the fetal human kidney at late gestation are demonstrated.
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Affiliation(s)
- Will W Minuth
- Institute of Anatomy, University of Regensburg, Regensburg, Germany.
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Minuth WW. Shaping of the nephron - a complex, vulnerable, and poorly explored backdrop for noxae impairing nephrogenesis in the fetal human kidney. Mol Cell Pediatr 2020; 7:2. [PMID: 31965387 PMCID: PMC6974545 DOI: 10.1186/s40348-020-0094-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 01/07/2020] [Indexed: 02/07/2023] Open
Abstract
Background The impairment of nephrogenesis is caused by noxae, all of which are significantly different in molecular composition. These can cause an early termination of nephron development in preterm and low birth weight babies resulting in oligonephropathy. For the fetal human kidney, there was no negative effect reported on the early stages of nephron anlage such as the niche, pretubular aggregate, renal vesicle, or comma-shaped body. In contrast, pathological alterations were identified on subsequently developing S-shaped bodies and glomeruli. While the atypical glomeruli were closely analyzed, the S-shaped bodies and the pre-stages received little attention even though passing the process of nephron shaping. Since micrographs and an explanation about this substantial developmental period were missing, the shaping of the nephron in the fetal human kidney during the phase of late gestation was recorded from a microanatomical point of view. Results The nephron shaping starts with the primitive renal vesicle, which is still part of the pretubular aggregate at this point. Then, during extension of the renal vesicle, a complex separation is observed. The medial part of its distal pole is fixed on the collecting duct ampulla, while the lateral part remains connected with the pretubular aggregate via a progenitor cell strand. A final separation occurs, when the extended renal vesicle develops into the comma-shaped body. Henceforth, internal epithelial folding generates the tubule and glomerulus anlagen. Arising clefts at the medial and lateral aspect indicate an asymmetrical expansion of the S-shaped body. This leads to development of the glomerulus at the proximal pole, whereas in the center and at the distal pole, it results in elongation of the tubule segments. Conclusions The present investigation deals with the shaping of the nephron in the fetal human kidney. In this important developmental phase, the positioning, orientation, and folding of the nephron occur. The demonstration of previously unknown morphological details supports the search for traces left by the impairment of nephrogenesis, enables to refine the assessment in molecular pathology, and provides input for the design of therapeutic concepts prolonging nephrogenesis.
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Affiliation(s)
- Will W Minuth
- Institute of Anatomy, University of Regensburg, D-93053, Regensburg, Germany.
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Minuth W. In Search of Imprints Left by the Impairment of Nephrogenesis. Cells Tissues Organs 2019; 207:69-82. [DOI: 10.1159/000504085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 05/23/2019] [Indexed: 11/19/2022] Open
Abstract
Clinical aspects dealing with the impairment of nephrogenesis in preterm and low birth weight babies were intensely researched. In this context it was shown that quite different noxae can harm nephron formation, and that the morphological damage in the fetal kidney is rather complex. Some pathological findings show that the impairment leads to changes in developing glomeruli that are restricted to the maturation zone of the outer cortex in the fetal human kidney. Other data show also imprints on the stages of nephron anlage including the niche, the pretubular aggregate, the renal vesicle, and comma- and S-shaped bodies located in the overlying nephrogenic zone of the rodent and human kidneys. During our investigations it was noticed that the stages of nephron anlage in the fetal human kidney during the phase of late gestation have not been described in detail. To contribute, these stages were recorded along with corresponding images. The initial nephron formation in the rodent kidney served as a reference. Finally, the known imprints left by the impairment in both specimens were listed and discussed. In sum, the relatively paucity of data on nephron formation in the fetal human kidney during the late phase of gestation is a call to start with intense research so that concepts for a therapeutic prolongation of nephrogenesis can be designed.
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