Amyloidosis is a shared name for several rare, complex and serious diseases caused by extra-cellular deposits of different misfolded proteins. Accurate characterization of the amyloid protein is ...essential for patient care. Immunoelectron microscopy (IEM) and laser microdissection followed by tandem mass spectrometry (LMD-MS) are new gold standards for molecular subtyping. Both methods perform superiorly to immunohistochemistry, but their complementarities, strengths and weaknesses across amyloid subtypes and organ biopsy origin remain undefined. Therefore, we performed a retrospective study of 106 Congo Red positive biopsies from different involved organs; heart, kidney, lung, gut mucosa, skin and bone marrow. IEM, performed with gold-labelled antibodies against kappa light chains, lambda light chains, transthyretin and amyloid A, identified specific staining of amyloid fibrils in 91.6%; in six biopsies amyloid fibrils were not identified, and in two, the fibril subtype could not be established. LMD-MS identified amyloid protein signature in 98.1%, but in nine the amyloid protein could not be clearly identified. MS identified protein subtype in 89.6%. Corresponding specificities ranged at organ level from 94-100%. Concordance was 89.6-100% for different amyloid subtypes. Importantly, combined use of both methods increased the diagnostic classification to 100%. Some variety in performances at organ level was observed.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This study used immunohistochemistry and immunofluorescence to investigate the distribution of claudin 10, 16, and 19 in the human, mouse, and rat kidney. The findings showed distinct junctional ...pathways in both human and rodent kidneys, supporting the existence of different permeation profiles in all species investigated.
Functional properties of the paracellular pathway depend critically on the set of claudins (CLDN) expressed at the tight junction. Two syndromes are causally linked to loss-of-function mutations of claudins: hypohidrosis, electrolyte imbalance, lacrimal gland dysfunction, ichthyosis, and xerostomia (HELIX) syndrome caused by genetic variations in the CLDN10 gene and familial hypomagnesemia with hypercalciuria and nephrocalcinosis caused by genetic variations in the CLDN16 or CLDN19 genes. All three genes are expressed in the kidney, particularly in the thick ascending limb (TAL). However, localization of these claudins in humans and rodents remains to be delineated in detail. We studied the segmental and subcellular expression of CLDN10, CLDN16, and CLDN19 in both paraffin-embedded and frozen kidney sections from the adult human, mouse, and rat using immunohistochemistry and immunofluorescence, respectively. Here, CLDN10 was present in a subset of medullary and cortical TAL cells, localizing to basolateral domains and tight junctions in human and rodent kidneys. Weak expression was detected at the tight junction of proximal tubular cells. CLDN16 was primarily expressed in a subset of TAL cells in the cortex and outer stripe of outer medulla, restricted to basolateral domains and tight junctional structures in both human and rodent kidneys. CLDN19 predominantly colocalized with CLDN16 in tight junctions and basolateral domains of the TAL but was also found in basolateral and junctional domains in more distal sites. CLDN10 expression at tight junctions almost never overlapped with that of CLND16 and CLDN19, consistent with distinct junctional pathways with different permeation profiles in both human and rodent kidneys.
NEW & NOTEWORTHY This study used immunohistochemistry and immunofluorescence to investigate the distribution of claudin 10, 16, and 19 in the human, mouse, and rat kidney. The findings showed distinct junctional pathways in both human and rodent kidneys, supporting the existence of different permeation profiles in all species investigated.
It is commonly proposed that bone forming osteoblasts recruited during bone remodeling originate from bone marrow perivascular cells, bone remodeling compartment canopy cells, or bone lining cells. ...However, an assessment of osteoblast recruitment during adult human cancellous bone remodeling is lacking. We addressed this question by quantifying cell densities, cell proliferation, osteoblast differentiation markers, and capillaries in human iliac crest biopsy specimens. We found that recruitment occurs on both reversal and bone-forming surfaces, as shown by the cell density and osterix levels on these respective surfaces, and that bone formation occurs only above a given cell density. Canopies appeared an important source of osteoprogenitors, because (i) canopy cells proved to be more proliferative and less differentiated than bone surface cells, as shown by the inverse levels of Ki-67 and procollagen-3 N-terminal peptide versus osterix, and (ii) canopy cell densities, found to decline with age, and canopy-capillary contacts above eroded surfaces correlated positively with osteoblast density on bone-forming surfaces. Furthermore, we showed that bone remodeling compartment canopies arise from a mesenchymal envelope surrounding the red bone marrow, which is lifted and hypertrophied on initiation of bone resorption. This study, together with earlier reports, led to a model in which canopies and nearby capillaries are critical for reaching the osteoblast density required for bone formation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Digital pathology (DP) is changing pathology departments dramatically worldwide, yet globally, few departments are presently digitalized for the full diagnostic workflow. Denmark is also on the road ...to full digitalization countrywide, and this study aim to cover experiences during the implementation process in a national context. Thus, quantitative questionnaires were distributed to all pathology departments in Denmark (
n
= 13) and distributed to all professions including medical clinical directors, medical doctors (MD) and biomedical laboratory scientists (BLS). For a qualitative perspective, we interviewed four employees representing four professions. Data were collected in 2019–2020. From the questionnaire and interviews, we found strategies differed at the Danish departments with regards to ambitions, technological equipment, workflows, and involvement of type of professions. DP education was requested by personnel. Informants were in general positive toward the digital future but mainly had concerns regarding the political pressure to integrate DP before technological advances are sufficient for maintaining rational budgets, workflows, and for sustaining diagnostic quality. This study is a glance on the Danish implementation process in its early stages from personnel’s point of view. It shows the complexity when large new workflow processes are to be implemented countrywide and with a large diversity of stakeholders like managers, MD, BLS, IT-professionals, and authorities. To ensure best technological and economical solutions and to maintain—or even optimize—diagnostic quality with DP and workflow alignment, we suggest superior inter- and intradepartmental communication. When implementing DP countrywide, a national working group is warranted with the variety of stakeholders represented.
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NUK, SBMB, SBNM, UL, UM, UPUK, VSZLJ
Plasma membrane Ca(2+)-ATPases (PMCAs) participate in epithelial Ca(2+) transport and intracellular Ca(2+) signaling. The Pmca4 isoform is enriched in distal nephron isolates and decreased in mice ...lacking the epithelial transient receptor potential vanilloid 5 Ca(2+) channel. We therefore hypothesized that Pmca4 plays a significant role in transcellular Ca(2+) flux and investigated the localization and regulation of Pmca4 in Ca(2+)-transporting epithelia. Using antibodies directed specifically against Pmca4, we found it expressed only in the smooth muscle layer of mouse and human intestines, whereas pan-specific Pmca antibodies detected Pmca1 in lateral membranes of enterocytes. In the kidney, Pmca4 showed broad localization to the distal nephron. In the mouse, expression was most abundant in segments coexpressing the epithelial ransient receptor potential vanilloid 5 Ca(2+) channel. Significant, albeit lower, expression was also evident in the region encompassing the cortical thick ascending limbs, macula densa, and early distal tubules as well as smooth muscle layers surrounding renal vessels. In the human kidney, a similar pattern of distribution was observed, with the highest PMCA4 expression in Na(+)-Cl(-) cotransporter-positive tubules. Electron microscopy demonstrated Pmca4 localization in distal nephron cells at both the basolateral membrane and intracellular perinuclear compartments but not submembranous vesicles, suggesting rapid trafficking to the plasma membrane is unlikely to occur in vivo. Pmca4 expression was not altered by perturbations in Ca(2+) balance, pointing to a housekeeping function of the pump in Ca(2+)-transporting epithelia. In conclusion, Pmca4 shows a divergent expression pattern in Ca(2+)-transporting epithelia, inferring diverse roles for this isoform not limited to transepithelial Ca(2+) transport.
Low-intensity shockwave therapy (LI-SWT) is suggested as a therapy for promoting tissue regeneration. In pigs, it was recently found that LI-SWT improved renal function after ischaemic injury. Our ...objectives were to study glomerular filtration rate (GFR) and albuminuria in diabetic nephropathy (DN) after treatment with LI-SWT. The present pilot study reports on the clinical safety of LI-SWT in DN.
A total of 14 patients with diabetes mellitus and Stage 3 chronic kidney disease were recruited for this prospective, one-arm Phase 1 study. The patients were treated with six sessions of LI-SWT during a 3-week period. At each session, 3000 shockwaves were applied to each kidney with 0.265 mJ/mm2, extended focal size and 4 Hz. Follow-up visits were performed at 1, 3 and 6 months.
In general, the treatment was well tolerated. Transient macroscopic haematuria was observed in three patients immediately after LI-SWT. The majority of patients experienced lower back tenderness lasting up to 2 days after treatment. There was no need for analgesic treatment. LI-SWT showed no negative effect on GFR and albuminuria. At baseline, median (interquartile range) GFR was 33.5 mL/min/1.73 m2 (27.8-43.8) compared with 36.0 mL/min/1.73 m2 (27.5-52.0) at 6 months follow-up. In parallel, median albuminuria was 256 mg/24 h (79-619) at baseline and tended to decrease to 137 mg/24 h (41-404) 6 months after LI-SWT. There was no statistical difference between baseline and follow-up results.
LI-SWT is a safe treatment for DN. Inclusion of more patients is needed to determine whether LI-SWT can improve renal functional outcomes.
The vacuolar-type H
-ATPase B1 subunit is heavily expressed in the intercalated cells of the collecting system, where it contributes to H
transport, but has also been described in other segments of ...the renal tubule. This study aimed to determine the localization of the B1 subunit of the vacuolar-type H
-ATPase in the early distal nephron, encompassing thick ascending limbs (TAL) and distal convoluted tubules (DCT), in human kidney and determine whether the localization differs between rodents and humans. Antibodies directed against the H
-ATPase B1 subunit were used to determine its localization in paraffin-embedded formalin-fixed mouse, rat, and human kidneys by light microscopy and in sections of Lowicryl-embedded rat kidneys by electron microscopy. Abundant H
-ATPase B1 subunit immunoreactivity was observed in the human kidney. As expected, intercalated cells showed the strongest signal, but significant signal was also observed in apical membrane domains of the distal nephron, including TAL, macula densa, and DCT. In mouse and rat, H
-ATPase B1 subunit expression could also be detected in apical membrane domains of these segments. In rat, electron microscopy revealed that the H
-ATPase B1 subunit was located in the apical membrane. Furthermore, the H
-ATPase B1 subunit colocalized with other H
-ATPase subunits in the TAL and DCT. In conclusion, the B1 subunit is expressed in the early distal nephron. The physiological importance of H
-ATPase expression in these segments remains to be delineated in detail. The phenotype of disease-causing mutations in the B1 subunit may also relate to its presence in the TAL and DCT.
Background
Autosomal recessive polycystic kidney disease is a cystic kidney disease with early onset and clinically characterized by enlarged echogenic kidneys, hypertension, varying degrees of ...kidney dysfunction, and liver fibrosis. It is most frequently caused by sequence variants in the
PKHD1
gene, encoding fibrocystin. In more rare cases, sequence variants in
DZIP1L
are seen, encoding the basal body protein DAZ interacting protein 1-like protein (DZIP1L). So far, only four different
DZIP1L
variants have been reported.
Methods
Four children from three consanguineous families presenting with polycystic kidney disease were selected for targeted or untargeted exome sequencing.
Results
We identified two different, previously not reported homozygous
DZIP1L
sequence variants: c.193 T > C; p.(Cys65Arg), and c.216C > G; p.(Cys72Trp). Functional analyses of the c.216C > G; p.(Cys72Trp) variant indicated mislocalization of mutant DZIP1L.
Conclusions
In line with published data, our results suggest a critical role of the N-terminal domain for proper protein function. Although patients with
PKHD1
-associated autosomal recessive polycystic kidney disease often have liver abnormalities, none of the present four patients showed any clinically relevant liver involvement. Our data demonstrate the power and efficiency of next-generation sequencing-based approaches. While
DZIP1L-
related polycystic kidney disease certainly represents a rare form of the disease, our results emphasize the importance of including
DZIP1L
in multigene panels and in the data analysis of whole-exome sequencing for cystic kidney diseases.
Graphical abstract
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
The Region of Southern Denmark is the first in Denmark to implement digital pathology (DIPA), starting at the end of 2020. The DIPA process involves changes in workflow, and the pathologist will have ...to diagnose based on digital whole slide imaging instead of through the traditional use of the conventional light microscope and glass slides. In addition, in the laboratory, the employees will have to implement one more step to their workflow—scanning of tissue. The aim of our study was to assess the expectations and readiness among employees and management towards the implementation of DIPA, including their thoughts and motivations for starting to use DIPA. We used a mixed-method approach. Based on the findings derived from 18 semi-structured interviews with employees from the region’s departments of pathology, we designed a questionnaire, including questions from the normalization measure development tool. The questionnaires were e-mailed to 181 employees. Of these employees, 131 responded to the survey. Overall, they reported feeling sufficiently tech-savvy to be able to use DIPA, and they had high expectations as well as motivation and readiness for the upcoming changes. However, the employees were skeptical regarding the allocation of resources, and few were aware of reports about the effects of DIPA. Based on the findings, it seems to be important to provide not only a thorough introduction to the new intervention and the changes it will entail, but also to continue to ensure that the staff know how it works and why it is necessary to implement.
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