CD44 immunoreactivity in the developing human kidney: a marker of renal progenitor stem cells?

CD44 is a transmembrane adhesion glycoprotein, functioning as a hyaluronan receptor and participating in the uptake and degradation of hyaluronan. Recently, CD44 has been proposed in the adult kidney as a marker of activated glomerular parietal epithelial cells, the putative niche stem cells that, in case of damage to podocytes, might migrate inside the glomerular tuft and undergo transition to podocytes. Here, immunoreactivity for CD44 was tested in 18 human fetuses and newborns with a gestational age ranging from 11 to 39 weeks. CD44 immunoreactivity was observed in all but one developing kidneys, being localized in several renal cell types including intraglomerular, capsular, cortical and medullary interstitial cells and nerve cells. In some cases, CD44 marked scattered cells in nephrogenic subcapsular zone. Our data indicate that CD44 is involved in human nephrogenesis, probably marking a subset of progenitor/stem cells involved in early phases of kidney development and, putatively, in podocyte and/or interstitial cell differentiation

“Physiological” renal regenerating medicine in VLBW preterm infants: could a dream come true?

An emerging hypothesis from the recent literature explain how specific adverse factors related with growth retardation as well as of low birth weight (LBW) might influence renal development during fetal life and then the insurgence of hypertension and renal disease in adulthood. In this article, after introducing a brief overview of human nephrogenesis, the most important factors influencing nephron number at birth will be reviewed, focusing on the "in utero" experiences that lead to an increased risk of developing hypertension and/or kidney disease in adult. Since nephrogenesis in preterm human newborns does not stop at birth, but it continues for 4-6 weeks postnatally, a better knowledge of the mechanisms able to accelerate nephrogenesis in the perinatal period, could represent a powerful tool in the hands of neonatologists. We suggest to define this approach to a possible therapy of a deficient nephrogenesis at birth "physiological renal regenerating medicine". Our goal in preterm infants, especially VLBW, could be to prolong the nephrogenesis not only for 6 weeks after birth but until 36 weeks of post conceptual age, allowing newborn kidneys to restore their nephron endowment, escaping susceptibility to hypertension and to renal disease later in life

Il peso della non-diagnosi: deficit di adenina fosforibosil transferasi diagnosticato in seguito a nefropatia da cristalli in ricevente di trapianto renale

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Pathology of perinatal and early onset nephrotic syndrome

Nephrotic syndrome rarely occurs in the first year of life. There are some cases which share the pathological changes observed in older children or in adults, but two forms, the congenital nephrotic syndrome of the Finnish type (CNF) and the diffuse mesangial sclerosis (DMS) show peculiar morphologic findings. CNF is characterized in its early phases by the focal dilation of the proximal tubules with formation of small cysts and by mesangial hypercellularity. With progression of the disease, tubular dilation spreads from the deep to the outer cortex and focal-segmental and global glomerulosclerosis become evident. DMS may be renal-limited or be associated with male pseudohermaphroditism and Wilm’s tumor (Denys-Drash syndrome). It shows the increase of the mesangial matrix and mesangial hypercellularity in the early phases of the disease and extensive glomerulosclerosis in the later ones. Podocytes are hypertrophic around the sclerotic areas and form pseudocrescents. Tubular dilations and cysts may be present, but in lesser extent compared with CNF. Interstitial fibrosis occurs with increasing severity from the inner to the outer cortex. Apart from the negative reaction from nephrin in CNF, immunohistochemistry has no diagnostic relevance in both diseases. Electron microscopy shows in both diseases a diffuse effacement of the foot processes and microvillous transformation of the podocytes. Glomerular basement membrane may show changes recalling those found in Alport disease. Due to the rather similar changes in CNF and DMS, a pathological diagnosis may be difficult on small tissue specimens provided by needle biopsies. It follows that accurate clinical and genetic investigations are needed in addition to the pathological study.   Proceedings of the International Course on Perinatal Pathology (part of the 10th International Workshop on Neonatology · October 22nd-25th, 2014) · Cagliari (Italy) · October 25th, 2014 · The role of the clinical pathological dialogue in problem solving Guest Editors: Gavino Faa, Vassilios Fanos, Peter Van Eyke

Pregnancy-related decidualization of subcutaneous endometriosis occurring in a post-caesarean section scar: Case study and review of the literature

Endometriosis of surgical scars is a rare complication of caesarean sections (incidence: 0.03-0.4%) and other surgical procedures. As endometriosis could be responsive to hormonal stimulation, decidualization and other secondary changes may occur during pregnancy or progestin therapy, sometimes causing a clinically-evident increase in the size of the endometriotic nodules, which could be mistaken for malignant tumors. To our knowledge, we report the 8th subcutaneous case of a pregnancy-related decidualization occurring in a post-caesarean section scar endometriosis. A 33-year-old woman showed a painless, firm, subcutaneous nodule (size: 1\u2009cm) located near the scar of a caesarean section performed 3 years before. Ultrasound examination revealed a well-delimited, hypoechogenic nodule showing perilesional inflammatory reaction without vascular signals. The nodule was considered a post-surgical granuloma: its size did not increase during 4 years of follow-up. Finally, the nodule was totally excised during a second caesarean section performed at 39 weeks of gestation. Histological examination showed nodules of decidualized stromal cells surrounding rare, small, atrophic endometrial glands. Nuclear atypia and mitoses were absent. On immunohistochemical examination, the epithelial cells were pan-CK(AE1/AE3)+/ER+/PR+/S100-/Calretinin-/Vimentin-, while the stromal cells were pan-CK(AE1/AE3)-/Vimentin+/ER+/PR+/CD10+/S100-/Calretinin-. We reviewed the literature, discussing the main clinic-pathological diagnostic pitfalls and the possible differential diagnoses

Ciprofloxacin crystal nephropathy

Ciprofloxacin is a widely used fluoroquinolone for the treatment of patients with complicated and uncomplicated infections. With rare exceptions, only immune-mediated interstitial nephritis was described, with direct renal damage reported only in case of overdose. Experimental studies indicated that crystalluria may be associated with the administration of this drug, but the likelihood that ciprofloxacin crystal nephropathy would occur in humans was believed to be very low on the basis of previous data showing that ciprofloxacin crystalluria depended on a urine pH greater than 6.8. However, we report 2 cases of ciprofloxacin crystal-induced nephropathy with a clinical pattern of acute reversible tubular damage and intratubular crystals identical to that previously described in elderly patients treated with ciprofloxacin dosages within therapeutic schedules. Crystals in the tubules were negative for both the von Kossa stain for phosphates and alizarin red stain for calcium