Granular cell tumor of distal bile duct treated with Whipple’s procedure

Granular cell tumors (GCTs) are rare benign neoplasms that are most often located in the soft tissues of the extremities and chest wall. Malignant GCTs have also been reported. GCTs of the biliary tract are extremely rare, uncommon non-epithelial benign neoplasms that cause focal thickening of bile duct wall without mucosal invasion. They consist of polygonal cells with granular appearance and stain positive in S-100 protein, indicating a neural (Schwann cell) origin. We report our experience of a 57-year-old Caucasian woman who presented with obstructing jaundice due to a distal bile duct stricture highly suspicious of cholangiocarcinoma. A Whipple’s procedure was successfully performed, and the final pathology revealed a benign GCT of the distal bile duct. Whipple’s is an extremely radical procedure for such benign lesions and additional investigations, such as cytology sample, may result in a less aggressive approach as those tumors grow slowly and do not metastasize.

Characterization of substantia nigra neurogenesis in homeostasis and dopaminergic degeneration: beneficial effects of the microneurotrophin BNN-20

Background

Loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) underlines much of the pathology of Parkinson’s disease (PD), but the existence of an endogenous neurogenic system that could be targeted as a therapeutic strategy has been controversial. BNN-20 is a synthetic, BDNF-mimicking, microneurotrophin that we previously showed to exhibit a pleiotropic neuroprotective effect on the dopaminergic neurons of the SNpc in the “weaver” mouse model of PD. Here, we assessed its potential effects on neurogenesis.

Methods

We quantified total numbers of dopaminergic neurons in the SNpc of wild-type and “weaver” mice, with or without administration of BNN-20, and we employed BrdU labelling and intracerebroventricular injections of DiI to evaluate the existence of dopaminergic neurogenesis in the SNpc and to assess the origin of newborn dopaminergic neurons. The in vivo experiments were complemented by in vitro proliferation/differentiation assays of adult neural stem cells (NSCs) isolated from the substantia nigra and the subependymal zone (SEZ) stem cell niche to further characterize the effects of BNN-20.

Results

Our analysis revealed the existence of a low-rate turnover of dopaminergic neurons in the normal SNpc and showed, using three independent lines of experiments (stereologic cell counts, BrdU and DiI tracing), that the administration of BNN-20 leads to increased neurogenesis in the SNpc and to partial reversal of dopaminergic cell loss. The newly born dopaminergic neurons, that are partially originated from the SEZ, follow the typical nigral maturation pathway, expressing the transcription factor FoxA2. Importantly, the pro-cytogenic effects of BNN-20 were very strong in the SNpc, but were absent in other brain areas such as the cortex or the stem cell niche of the hippocampus. Moreover, although the in vitro assays showed that BNN-20 enhances the differentiation of NSCs towards glia and neurons, its in vivo administration stimulated only neurogenesis.

Conclusions

Our results demonstrate the existence of a neurogenic system in the SNpc that can be manipulated in order to regenerate the depleted dopaminergic cell population in the “weaver” PD mouse model. Microneurotrophin BNN-20 emerges as an excellent candidate for future PD cell replacement therapies, due to its area-specific, pro-neurogenic effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02398-3.

MO960RENAL TRANSPLANTATION FROM A LIVING DONOR WITH RENAL ARTERY FIBROMUSCULAR DYSPLASIA

Background and Aims

Renal transplantation is considered the most effective and less costly modality of renal replacement therapy in patients with end stage renal disease. The disparity between kidney allografts and recipients has led to a global effort to increase the pool of kidney donors. Accordingly, fibromuscular dysplasia (FMD) is no longer considered an absolute contraindication for kidney donation. The incidence of FMD is about 2.3%-5.8% in potential kidney donors. There are few cases in the literature where renal artery stenosis in allografts with known pre-transplantation FMD became worse after transplantation, indicating the importance of a proper follow up in the recipients.

This is a case of a living kidney donor with no history of hypertension, proteinuria or elevated serum creatinine, whose intra-arterial digital subtraction angiography revealed FMD lesions in the left renal artery.

Method

Case report

Results

A 54-year-old Caucasian female with medical history of hypothyroidism took the decision to offer her kidney to her 37-year-old son who was diagnosed with end-stage renal disease five years ago secondary to diabetes mellitus type I. She had no history for diabetes, hypertension and renal disease. Her vital signs on admission were heart rate of 78 beats/min and blood pressure of 130/70 mmHg. Urinalysis, biochemical profile and serological evaluations were all within normal ranges. Blood urea was 36 mg/dL and serum creatinine was 0.6 mg/dL (eGFR 97ml/min/1.73m2). The abdominal ultrasound and renogram with Tc-99m DTPA showed no remarkable findings. On intra-arterial digital subtraction angiography an abnormal succession of dilatations and multifocal stenoses of the left renal artery, characteristic of medial FMD, was found. The right renal artery was normal.

Apart from a dysfunctional permanent left femoral catheter, the patient had no other vascular access for hemodialysis because of Superior Vena Cava syndrome, so he needed urgent transplantation.

Taking all of these into consideration, the patient was offered renal transplantation as the best option. A left open donor nephrectomy was performed; the renal artery was divided distal to the stenotic dysplastic area. The allograft was placed at the right iliac fossa of the recipient with arterial and venous anastomosis to the extrarenal iliac vessels. Post-operatively, the recipient had a delayed graft function lasted 13 days. On renal artery Doppler in the allograft we found increased resistance index (RI) that gradually normalized without any intervention. An immunosuppressive regiment of tacrolimus, mycophenolate and prednisone was administered according to our center protocol. At discharge serum creatinine was 1.7 mg/dL (eGFR: 50ml/min/1.73m2).

At the year follow-up, the donor was normotensive and had near normal renal function (Cr:1.3mg/dL, eGFR: 70ml/min/1.73m2). The recipient has a well-controlled blood pressure receiving two antihypertensive drugs and maintains a satisfactory renal function.

Conclusion

Few cases with FMD in renal allografts from living and deceased donors have been described. In a review of 4 studies the authors concluded that the outcome of transplantation with allografts from living donors with medial FMD was satisfactory and these allografts could be used to increase the donor pool. Furthermore, it is strongly recommended to have a thorough pre-transplantation check of the donor as well as a close monitoring of both the donor and recipient after transplantation. This case shows that allografts harvested from carefully selected donors with renal arterial FMD can be successfully used, particularly in urgent conditions. Detailed pre-tranplantation imaging of donor’s renal arteries, selection of the appropriate screening method, as well as close monitoring of both donor and recipient for early interventions after transplantation is of paramount importance.

BNN-20, a synthetic microneurotrophin, strongly protects dopaminergic neurons in the "weaver" mouse, a genetic model of dopamine-denervation, acting through the TrkB neurotrophin receptor

Neurotrophic factors are among the most promising treatments aiming at slowing or stopping and even reversing Parkinson's disease (PD). However, in most cases, they cannot readily cross the human blood-brain-barrier (BBB). Herein, we propose as a therapeutic for PD the small molecule 17-beta-spiro-[5-androsten-17,2'-oxiran]-3beta-ol (BNN-20), a synthetic analogue of DHEA, which crosses the BBB and is deprived of endocrine side-effects. Using the "weaver" mouse, a genetic model of PD, which exhibits progressive dopaminergic neurodegeneration in the Substantia Nigra (SN), we have shown that long-term administration (P1-P21) of BNN-20 almost fully protected the dopaminergic neurons and their terminals, via i) a strong anti-apoptotic effect, probably mediated through the Tropomyosin receptor kinase B (TrkB) neurotrophin receptor's PI3K-Akt-NF-κB signaling pathway, ii) by exerting an efficient antioxidant effect, iii) by inducing significant anti-inflammatory activity and iv) by restoring Brain-Derived Neurotrophic Factor (BDNF) levels. By intercrossing "weaver" with NGL mice (dual GFP/luciferase-NF-κΒ reporter mice, NF-κΒ.GFP.Luc), we obtained Weaver/NGL mice that express the NF-κB reporter in all somatic cells. Acute BNN-20 administration to Weaver/NGL mice induced a strong NF-κB-dependent transcriptional response in the brain as detected by bioluminescence imaging, which was abolished by co-administration of the TrkB inhibitor ANA-12. This indicates that BNN-20 exerts its beneficial action (at least in part) through the TrkB-PI3K-Akt-NF-κB signaling pathway. These results could be of clinical relevance, as they suggest BNN-20 as an important neuroprotective agent acting through the TrkB neurotrophin receptor pathway, mimicking the action of the endogenous neurotrophin BDNF. Thus BNN-20 could be proposed for treatment of PD.