Characterization of Inner Medullary Collecting Duct Plug Formation Among Idiopathic Calcium Oxalate Stone Formers

Inflammatory Cells in Nephrectomy Tissue from Patients without and with a History of Urinary Stone Disease

BACKGROUND AND OBJECTIVES

Urinary stone disease has been associated with inflammation, but the specific cell interactions that mediate events remain poorly defined. This study compared calcification and inflammatory cell patterns in kidney tissue from radical nephrectomy specimens of patients without and with a history of urinary stone disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Nontumor parenchyma of biobanked radical nephrectomy specimens from age- and sex-matched stone formers (n=44) and nonstone formers (n=82) were compared. Calcification was detected by Yasue staining and inflammatory cell populations by immunohistochemistry for CD68 (proinflammatory M1 macrophages), CD163 and CD206 (anti-inflammatory M2 macrophages), CD3 (T lymphocytes), and tryptase (mast cells). Calcifications and inflammatory cells were quantified in cortex and medulla using Image-Pro analysis software.

RESULTS

Calcification in the medulla of stone formers was higher than in nonstone formers (P<0.001). M1 macrophages in the cortex and medulla of stone formers were greater than in nonstone formers (P<0.001), and greater in stone former medulla than stone former cortex (P=0.02). There were no differences in age, sex, body mass index, tumor characteristics (size, stage, or thrombus), vascular disease status, or eGFR between the groups. M2 macrophages, T lymphocytes, and mast cells did not differ by stone former status. There was a correlation between M1 macrophages and calcification in the medulla of stone formers (rho=0.48; P=0.001) and between M2 macrophages and calcification in the medulla of nonstone formers (rho=0.35; P=0.001). T lymphocytes were correlated with calcification in the cortex of both nonstone formers (rho=0.27; P=0.01) and stone formers (rho=0.42; P=0.004), whereas mast cells and calcification were correlated only in the cortex of stone formers (rho=0.35; P=0.02).

CONCLUSIONS

Higher medullary calcification stimulated accumulation of proinflammatory rather than anti-inflammatory macrophages in stone formers.

Human jackstone arms show a protein-rich, X-ray lucent core, suggesting that proteins drive their rapid and linear growth

Jackstone calculi, having arms that extend out from the body of the stone, were first described over a century ago, but this morphology of stones has been little studied. We examined 98 jackstones from 50 different patient specimens using micro-computed tomography (micro CT) and infrared (IR) spectroscopy. Micro CT showed that jackstone arms consisted of an X-ray lucent core within each arm. This X-ray lucent core frequently showed sporadic, thin layers of apatite arranged transversely to the axis of the arm. The shells of the jackstones were always composed of calcium oxalate (CaOx), and with the monohydrate form the majority or sole mineral. Study of layering in the shell regions by micro CT showed that growth lines extended from the body of the stone out onto jack arms and that the thickness of the shell covering of jack arms often thinned with distance from the stone body, suggesting that the arms grew at a faster radial rate than did the stone body. Histological cross-sections of decalcified jackstone arms showed the core to be more highly autofluorescent than was the CaOx shell, and immunohistochemistry showed the core to be enriched in Tamm-Horsfall protein. We hypothesize that the protein-rich core of a jack arm might preferentially bind more protein from the urine and resist deposition of CaOx, such that the arm grows in a linear manner and at a faster rate than the bulk of the stone. This hypothesis thus predicts an enrichment of certain urine proteins in the core of the jack arm, a theory that is testable by appropriate analysis.

Stone morphology distinguishes two pathways of idiopathic calcium oxalate stone pathogenesis

Introduction About 1-in-11 Americans will experience a kidney stone, but underlying causes remain obscure. The objective of the present study was to separate idiopathic calcium oxalate stone formers by whether or not they showed positive evidence of forming a stone on Randall's plaque (RP). Materials and Methods In patients undergoing either percutaneous or ureteroscopic procedures for kidney stone removal, all stone material was extracted, and analyzed using micro computed tomographic imaging (micro CT), in order to identify those attached to RP. 24-hour urines were collected weeks after the stone removal procedure and off of medications that would affect urine composition. Endoscopic video was analyzed for papillary pathology (RP, pitting, plugging, dilated ducts, loss of papillary shape) by an observer blinded to the data on stone type. Percent papillary area occupied by RP and ductal plugging was quantified using image analytic software. Results Patients having even 1 stone on RP (N=36) did not differ from Non-RP patients (N=37) in age, sex, BMI, or other clinical characteristics. Compared to the Non-RP group, RP stone formers had more numerous but smaller stones, more abundant papillary RP, and fewer ductal plugs, both by quantitative measurement of surface area (on average, 3 times more plaque area, but only 41% as much plug area as Non-RP) and by semi-quantitative visual grading. Serum and blood values did not differ between RP and Non-RP stone formers by any measure. Conclusions Growth of many small stones on plaque seems the pathogenetic scheme for the RP stone forming phenotype, whereas the Non-RP phenotype stone pathogenesis pathway is less obvious. Higher papillary plugging in Non-RP suggests that plugs play a role in stone formation, and that these patients have a greater degree of papillary damage. Underlying mechanisms that create these distinctive phenotypes are presently unknown.

Anatomic variations and stone formation

PURPOSE OF REVIEW

The pathophysiological mechanisms in kidney stone formation are insufficiently understood. In order to achieve a better understanding of the complexity of stone formation, studies evaluating anatomical variations in the renal papillae have been performed. This review intends to illuminate recent findings. Moreover, new techniques to improve the understanding and interpretation of crystallization mechanisms are reviewed.

RECENT FINDINGS

Due to improvements of digital ureteroscopes, detailed endoscopic mapping of renal papillae is now possible. Connections between papillary morphology and histopathological changes in different subsets of stone formers have been documented. The formation of kidney stones seems to take place in relation to Randall's plaques, Ducts of Bellini or by free formation. Additionally, theories of kidney stone formation because of vascular injury or inflammatory events in the papillae have been suggested.

SUMMARY

Novel techniques including improved digital endoscopic visualization, microcomputed tomography (CT), electron microscopy and energy dispersive compositional analyses of kidney stones seem essential in the search for effective and reliable methods to understand stone forming processes, which ultimately should result in effective measures for more personalized stone prevention strategies in the future.

Development of neutron imaging quantitative data treatment to assess conservation products in cultural heritage

Distribution, penetration depth and amount of new mineralogical phases formed after the interaction between an inorganic treatment and a matrix are key factors for the evaluation of the conservation treatment behaviour. Nowadays, the conventional analytical methodologies, such as vibrational spectroscopies, scanning electron microscopy and X-ray diffraction, provide only qualitative and spot information. Here, we report, for the first time, the proof of concept of a methodology based on neutron imaging able to achieve quantitative data useful to assess the formation of calcium oxalate in a porous carbonatic stone treated with ammonium oxalate. Starting from the neutron attenuation coefficient of Noto stone-treated specimens, the concentrations of newly formed calcium oxalate and the diffusion coefficient have been calculated for both sound and decayed substrates. These outcomes have been also used for a comparative study between different treatment modalities. Graphical abstract Horizontal slice at 300 mm depth and CaOx molar density profile by NEUTRA output.