Morphometric index of the developing murine kidney

Abstract

Mammalian kidney morphogenesis begins when the ureteric bud (UB) induces surrounding metanephric mesenchyme to differentiate into nephrons, the functional units of the mature organ. Although several genes required for this process have been identified, the mechanisms that control final nephron number and the localization of distinct tubular segments to cortical and medullary zones of the kidney remain poorly understood. This finding is due, in part, to the lack of quantitative studies describing the acquisition of mature renal structure. We have analyzed the following parameters of the developing murine kidney throughout embryogenesis: nephron and UB tip number, distance between UB branch points and total kidney, and cortical and medullary volume. Results of this morphometric analysis reveal previously unrecognized changes in the pattern of UB growth and rate of nephrogenesis. In addition, this morphometric index provides a much-needed reference for accurately describing renal patterning defects exhibited by genetically altered mice. Developmental Dynamics 231:601-608, 2004.

A spatially-averaged mathematical model of kidney branching morphogenesis

“…2B). This behaviour is consistent with observations from (Cebrian et al, 2004) and (Short et al, 2014). We have applied a trigger that increases mv r is activated at the time of birth (E19.5 in the mouse).…”

“…Branching does slow across developmental time (Cebrian et al, 2004), indicating that the ϲ relationship between these populations changes with time. The final nephrons form in the immediate postnatal period, arguably in both mouse (Rumballe et al, 2011) and humans (Faa et al, 2010).…”

GDNF/Ret signaling and the development of the kidney

“…After the ureteric bud grows out from the Wolffian duct into the metanephric mesenchyme, it starts to branch while continuing to elongate, and undergoes approximately 11 generations of branching (in the mouse) to reach its final form. (56) Most branching occurs at the tips of the UB, while lateral branching occurs less frequently, (57) in contrast to the lung epithelium where lateral branching is more frequent. (58,59) The process of terminal branching begins with the ballooning of the UB tip to form an ampulla.…”

“…3c,d); (74) furthermore, much of the growth of the UB at later stages of kidney development apparently occurs by interstitial growth of the trunks. (8,56) However, proliferation of UB tip cells is clearly an important mechanism of UB growth and possibly of branching. What is the role of GDNF/Ret signaling in UB tip cell proliferation?…”

Transcriptional profiling of Wnt4 mutant mouse kidneys identifies genes expressed during nephron formation

“…renal vesicle, S-shaped body). An exception, the loop-of-Henle (LOH), does not progress beyond the anlage stage until after E16.5 (Cebrián et al, 2004;Kim et al, 2002). By comparing wildtype to Wnt4 mutant, we sought to identify genes expressed in the nephron structures that were present in the wildtype, but absent in Wnt4 mutant kidneys.…”