Lipofuscin-like granules of the juxtaglomerular apparatus of the kidney. The diagnostic significance of a quasi-normal subcellular structure incidentally encountered in the course of routine ultrastructural evaluation of renal biopsies

Histopathological and ultrastructural study of carotid atherosclerotic plaques: a study of four cases

To clarify the characteristics and origin of the cellular components in atherosclerosis, carotid atherosclerotic plaques (CAPs) of four patients were studied by light microscopy using hematoxylin-eosin, Congo red and alpha-smooth-muscle actin stains, and by transmission electron microscopy of different regions of CAPs. By light microscopy, CAPs were composed of 1) a fibrous cap; 2) an atherosclerotic core presenting focal fibrosis, neovascularization, hemorrhage, necrosis, chondrification and ossification; and 3) a basal band composed of a hyperplasic pseudo-media and affected tunica media. Ultrastructurally, the CAPs contained a diversity of cells including fibroblasts, myofibroblasts, osteochondrocytes, vascular smooth-muscle cells, foam cells and other myoid cells characterized by varied features of the above mentioned cells. The results indicated that CAPs were derived from a proliferation of multipotential mesenchymal stem cells, leading to the presence of degenerated foam cells and lipid-laden cells.

A case report on lipofuscin deposition in a graft biopsy two years after kidney transplantation: an insignificant bystander or a pathogenic benefactor?

Background

Lipofuscin deposition is a characteristic manifestation of aging. There is very limited literature in humans and in animals describing these deposits in native kidneys. Overall, it is thought to be non-pathogenic and successful transplants from a donor with lipofuscin deposits have been reported. We present the case of a patient who underwent a kidney transplant and a for-cause biopsy post-transplantation incidentally revealed lipofuscin deposition.

Case presentation

A 48-year old gentleman with a past medical history of diabetes, hypertension, coronary artery disease, and ischemic and then hemorrhagic cardiovascular accident underwent a successful kidney transplant. His donor was an expanded criteria donor with no major past medical history. Post-transplant course was complicated by delayed graft function requiring one dialysis treatment for hyperkalemia. After that he had an uneventful course and achieved a baseline creatinine of 1.2 mg/dL, with no proteinuria. On a routine 19-month follow-up he was noted to have proteinuria and an antibody against the major-histocompatibility-complex class I-related chain A. A graft biopsy revealed acute antibody-mediated rejection and impressive lipofuscin deposition. He was subsequently treated with an antibody-mediated rejection protocol that included high dose steroids, Rituximab, plasmapheresis, and intravenous immunoglobulin, but responded poorly to this regimen. A 6-month follow up biopsy continued to show lipofuscin deposition, with similar microvascular injury scores and 12-months later his creatinine remained stable but his proteinuria worsened. Patient was struggling with recurrent infectious episodes requiring hospitalizations and thus no further diagnostic or therapeutic treatments were pursued.

Conclusions

Lipofuscin deposition has been reported in solid organ transplants but the significance and cause are not well understood. Several physiologic and some pathologic causes to these deposits have been reported including age, diabetes, medications and a genetic syndrome. We propose that immunologic causes such as rejection in the presence of other risk factors could potentiate the oxidative stress leading to excessive lipofuscin deposition in kidney transplants. In the case of our patient, we conclude that these deposits were likely recipient-derived, and postulate that the cumulative burden of inflammation from rejection, and underlying medical conditions led to increased lipofuscin deposition. We speculate them to be an innocent bystander.

Transplantation of a Blue Kidney: A Case Report

A blue kidney, although very rare, can be encountered upon a live kidney donor. Literature has shown hemosiderin deposits, lipofuscin pigment, and melanosis as possible reasons. We report on a 37-year-old woman who wished to donate a kidney to her husband. The donor's preoperative biochemistry and imaging tests showed normal renal function. During the laparoscopic left kidney nephrectomy, the kidney was observed to be blue in color. Perioperatively, Doppler ultrasonography was used to rule out vascular reasons, and a wedge biopsy was performed. The other kidney was also explored, and it turned out to be blue as well. Histopathological analysis showed melanosis in the tubules without malignity or pathologic changes in the glomeruli, the interstitium, or the vessels. Even though some causes of blue kidney may result in impairment of the renal function, after the necessary tests show no signs of malignity and functional impairment, a blue-colored kidney may be suitable for transplantation.

Usefulness of rectal biopsy for the diagnosis of Kufs disease: a controlled study and review of the literature

BACKGROUND AND PURPOSE

Rectal biopsy is usually performed for in vivo diagnosis of Kufs disease (KD). We evaluated the usefulness of rectal biopsy in the diagnosis of such condition by comparing ultrastructural data of patients with suspicion of KD with those of control subjects. Furthermore, we reviewed literature data concerning the value of such a diagnostic procedure in the diagnosis of KD.

METHODS

Sixty-five subjects were enrolled and underwent rectal biopsy. Of these, 13 had a clinical picture in keeping with KD, whereas 52, affected by Irritable Bowel Syndrome, constituted the control group.

RESULTS

Ultrastructural analysis evidenced fingerprint (FP) inclusions in 12 subjects, 4/13 with suspicion of KD and 8/52 controls. In patients, FPs were mainly located in vascular smooth muscle cells (VSMC) while in controls they were mostly found in pericytes and VSMC. No FPs were found in one patient with genetically confirmed KD. In literature, we identified 14 KD patients who underwent rectal biopsy. In most reports, ultrastructural features were not systematically analyzed or described.

CONCLUSIONS

Fingerprints are the most common ultrastructural finding in rectal biopsy in patients with suspicion of KD. However, their presence in pericytes and VSMC is not specific for KD because they may be found in controls subjects. Our literature review revealed that data on the value of rectal biopsy in the diagnosis of KD are scarce. In light of these findings, the relevance of rectal biopsy in such condition should be re-evaluated.