Plasma-derived Exosomes Reverse Epithelial-to-Mesenchymal Transition after Photodynamic Therapy of Patients with Head and Neck Cancer

Photodynamic therapy (PDT) is a palliative treatment option for head and neck squamous cell carcinoma (HNSCC) patients which induces local inflammation and alters tumor cell morphology. We show that exosomes in plasma of HNSCC patients undergoing PDT reprogram tumor cells towards an epithelial phenotype. Nine HNSCC patients were treated with PDT and plasma was collected prior to and at three timepoints after therapy. Exosome levels of E-Cadherin, N-Cadherin and TGF-β1 were tested by flow cytometry. Exosomes were co-incubated with cancer cells, and changes in expression of EMT markers were evaluated as were proliferation, migration, chemotaxis and invasiveness of tumor cells. Exosomes harvested pre- and 24h after PDT were enriched in N-Cadherin and TGF-β1. They induced the mesenchymal phenotype and up-regulated Vimentin and transcripts for Snail, Twist, α-SMA, Slug and ZEB1 in epithelial tumor cells. These exosomes also enhanced tumor proliferation, migration and invasion. In contrast, exosomes obtained on day 7 or 4-6 weeks after PDT carried E-cadherin, restored epithelial morphology and EpCAM expression in tumor cells, down-regulated expression of mesenchymal genes and inhibited proliferation, migration and invasion. The PDT-mediated conversion from the mesenchymal to epithelial tumor phenotype was mediated by exosomes, which also served as non-invasive biomarkers of this transition.

Contrast-enhanced MR angiography in patients after kidney transplantation

The aim of this study was to investigate the value of a contrast-enhanced 3D MR angiography in detecting postoperative vascular complications after kidney transplantation in comparison with digital subtraction angiography (DSA). Forty-one patients who underwent a kidney transplantation were examined with MR angiography and DSA. Contrast-enhanced MR angiography was performed as a dynamic measurement with one precontrast and three postcontrast measurements. Maximum intensity projection reconstructions were performed for all postcontrast data sets after DSA. The results were evaluated by two independent observers who were unaware of the DSA results. Twenty-three hemodynamically significant arterial stenoses were identified with DSA in the iliac arteries ( n=7), the renal allograft arteries ( n=12), and in their first branches ( n=4). For a patient-based analysis the sensitivity and specificity, respectively, for observer 1 were 100 and 97%, and for observer 2, 100 and 93%. Respective data were 100 and 100% after a consensus evaluation by two observers. Complications involving the renal veins were detected in 2 cases and perfusion defects of the kidney parenchyma were detected in 4 cases. Contrast-enhanced MR angiography is a reliable method in identifying postoperative arterial stenoses after kidney transplantation. In addition, dynamic MR angiography can be helpful in detecting venous complications and perfusion defects in kidney allografts.

Hyperimmunoglobulin prophylaxis, monitoring and preemptive ganciclovir treatment eliminate the risk of CMV infection to improve patient and renal allograft survival

This study was designed to investigate whether the introduction of ganciclovir to clinical use for anti-CMV treatment changes the risk of CMV infection in renal transplant patients. A total of 1545 cases who had received cadaveric renal transplants were divided into two groups: group 1 (n = 721) was made up of patients who received their transplants within 6 years before the introduction (1991) of ganciclovir and group 2 (n = 824), of individuals transplanted thereafter. Patient and graft survival of CMV D+/R- patients was uni- and multivariately compared with non-CMV D+/R- patients. In CMV D+/R- patients in group 1, survival was significantly lower, and their relative risk for graft loss was 1.32-fold (P = 0.0483) that of non-CMV D+/R- patients. In group 2 patient and graft survival was identical regardless of whether the patients were at risk for CMV infection or not. The risk of CMV infection can be eliminated by hyperimmunoglobulin prophylaxis, CMV monitoring and preemptive ganciclovir treatment in renal transplant patients.

[Living donors in kidney transplantation. Renaissance by non-related donors?]

Renal Transplantation is hampered worldwide by the continuing lack of cadaveric organs. The discrepancy between the number of patients on the waiting list and the number of organs available is further compounded by the still unresolved problem of chronic transplant failure. Against this background, the arguments for increasing acceptance of the use of kidneys from living donors, both related and unrelated, are discussed. Initial reports on appreciably improved transplant survival rates of organs from unrelated living donors (85% survival after 3 years [19]) have since been confirmed by more recent studies. Our own results, in part obtained during a prospective study involving 103 patients (53 related, 50 unrelated) done between October 1994 and April 1999, with strict psychological care/evaluation prior to and after transplantation, revealed a four-year transplant survival rate of 98% in both groups. So far, the higher rejection rate of 34% in unrelated, vs. 13.2% in related, donors has not led to any earlier chronic dysfunction of the transplant. The expanded use of living kidney donors is not only ethically justifiable, but also improves the outcome.

Large de novo renal cell carcinoma in a 10-year-old transplanted kidney: successful organ-preserving therapy

BACKGROUND

A recent review of the Cincinnati Transplant Tumor Registry recorded 24 de novo renal cell carcinomas developing in renal allografts. However, late development of these tumors after transplantation is very rare. Only four reports exist regarding conservative surgery on kidney transplant tumors.

METHODS

This is a report on a case of a large 6-cm de novo renal cell carcinoma in a 10-year-old transplanted kidney. Optimal therapy by transplant nephrectomy or tumor enucleation was discussed.

RESULTS

Partial resections or enucleations of renal cell carcinoma are still less than ideal in carcinomas larger than 3 cm considering the higher risk of local recurrence. But the recipient in this case had done so well and had had such a high quality of life after transplantation that partial nephrectomy as therapy of choice was selected. Now the patient is 2 years tumor free.

CONCLUSION

The case report demonstrates that in certain select cases of large tumors, organ-preserving surgery could be an alternative approach in combining complete tumor removal with preservation of graft function.

[Contrast enhanced MR angiography in the preoperative evaluation of living kidney donors]

PURPOSE

To compare Gadolinium-enhanced MR angiography with conventional DSA in the preoperative evaluation of living kidney donors.

MATERIAL AND METHODS

27 potential living kidney donors were examined with contrast-enhanced MR angiography after conventional angiography. The MR angiograms were evaluated for the number of renal arteries, the presence of early arterial branching and vascular pathologies by two independent readers. The results were compared with those of selective conventional angiography and intraoperative findings.

RESULTS

Conventional angiography detected 14 accessory renal arteries. Reader A detected 13 of 14 accessory arteries with no false positive result (sensitivity 93%, specificity 100%). Reader B detected 11 of 14 accessory vessels with one false positive finding (sensitivity 79%, specificity 98%). Early arterial branching was detected by both readers in 9 of 12 vessels with no false positive result (sensitivity 75%, specificity 100%). None of the patients had additional vascular pathology.

DISCUSSION

Gadolinium-enhanced MR angiography is a non-invasive alternative to conventional angiography in the preoperative evaluation of living kidney donors. In order to achieve high accuracy in detecting accessory renal arteries and early arterial branching extensive experience with the method and the specific preoperative needs is required. Selective conventional angiography is still superior in detecting very small accessory vessels and early arterial branching.

Aggressive treatment of the first acute rejection episode using first-line anti-lymphocytic preparation reduces further acute rejection episodes after human kidney transplantation

The detrimental effect of acute rejection episodes on long-term outcome of renal allografts in cyclosporin-treated patients is well established, although has not been seen by all investigators. To analyse the possibility that aggressive treatment of the first episode may ameliorate this detrimental effect, we performed an open label, randomised prospective trial in cyclosporin-based, immunosuppressed recipients of postmortem renal allografts in order to compare two different treatment protocols during primary acute rejection episodes: (1) group 1 of 25 patients received 3 x 250 mg methylprednisolone (MP) i.v.; (2) group 2 of 25 patients received 7 x anti-thymocyte globulin (ATG)-Fresenius i.v. (4 mg/kg body weight). During a period of 4 years, the following clinical observations were made: (1) The incidence of an acute re-rejection episode was significantly reduced in the ATG-treated study group (16%) compared to the MP-treated study group (72%); (2) The severity of the first acute rejection episode (intensity of renal dysfunction measured in terms of 10-day creatinine area under curve) showed no significant difference between the groups (37 mg x 10-d/dl to 58 mg x 10-d/dl); and (3) The half-lives of allografts in both groups have not shown any significant differences so far. In conclusion, aggressive treatment of the first rejection episode of renal allografts with the use of ATG reduced the incidence of re-rejection episodes which, however, are not reflected so far by improvement of the 4-year survival rate of these allografts. Since it could be observed that re-rejection is an even worse predictor for chronic transplant failure, a better long-term outcome of renal allografts in ATG-treated patients may be expected during a longer observation period. The incidence of a third episode was also reduced in the ATG-treated group (0%) compared to the MP-treated group (12%).

Assessment of oxygen radicals during kidney transplantation--effect of radical scavenger

In the present study, levels of free oxygen radicals, generated in the very early period of reperfusion during human kidney transplantation, were assessed by determination of malondialdehyde (MDA) levels using a high-pressure liquid chromatography (HPLC) method. Renal blood samples were obtained during reperfusion by intraoperative cannulation of the renal vein. Simultaneously, systemic MDA levels were determined. Furthermore, local and systemic levels of interleukin 6 (IL-6), tumor necrosis factor (TNF) receptors, p55 and p75, and vitamin E were measured. In a second group of patients, 500 mg of ascorbic acid were given prior to reperfusion. Renal MDA levels in the control group were always higher compared to systemic levels. IL-6 showed a marked increase shortly after reperfusion in the renal blood. In the scavenger group there was a diminution of these effects. TNF receptor levels and vitamin E remained largely unchanged. The results of this pilot study demonstrated clinically the moderate production of reactive oxygen species and the liberation of IL-6 shortly after reperfusion of human transplanted kidneys. Furthermore, the modulating effect of a radical scavenger on these effects was shown.

[Laser coagulation treatment of urothelial tumors of the upper urogenital tract with the Nd:-YAG laser]

Six patients with upper urinary tract tumors were treated in our department with the Nd:-YAG laser between 1989 and 1993. The average follow-up was 23.8 months. The mean age of the patients was 65.7 years. The patients were selected for organ-conserving treatment because of bilateral synchronous tumors (2 cases), a solitary renal unit (2 cases), renal insufficiency with high surgical risk (1 case) and high surgical risk alone (1 case). Two patients were treated with open tumor excision and laser, two patients with ureteroscopic and percutaneous procedures one patient with percutaneous treatment and one patient with ureteroscopy. Two patients underwent nephroureterectomy; one of them died of metastatic bladder cancer 9 months later. Local relapses were observed in one patient who had been treated endoscopically. In a follow-up period of 6-36 months there were three patients who had no relapses. Three patients received intracavitary therapy. Kidney conserving procedures with the Nd:-YAG laser in patients with upper urinary tract tumors should be reserved for highly selected cases.

Cytochrome c and cytochrome c oxidase interactions: the effects of ionic strength and hydrostatic pressure studied with site-specific modifications of cytochrome c

Seven cytochromes c, in which individual lysines have been modified to the propylthiobimane derivatives, have been prepared. These derivatives were also converted to the porphyrin cytochromes c by treatment with HF. The properties of both types of modified proteins were studied in their reactions with cytochrome c oxidase. The results show that lysines 25, 27, 60, 72, and 87 do not contribute a full charge to the binding interaction with the oxidase. These five residues, with the exception of the lysine-60 derivative, on the front surface of the protein and contain the solvent-accessible edge of the heme prosthetic group. By contrast, lysines 8 and 13 at the top of the front surface do contribute a full charge to the binding interaction with the oxidase. The removal of the positive charge on any one lysine weakens the binding to cytochrome c oxidase by at least 1 kcal (1 cal = 4.1868 J). The presence of bimane at lysines 13 and 87 clearly forces the separation of the cytochrome c and oxidase, but this does not occur with the other complexes. The bimane-modified lysine-13 protein, and to a lesser extent that modified at lysine 8, show the interesting effect of enhanced complex formation with cytochrome c oxidase when subjected to pressure, possibly because of entrapment of water at the newly created interface of the complex. Our observations indicate that the two proteins of the cytochrome c - cytochrome oxidase complex have preferred, but not obligatory, spatial orientations and that interaction occurs without either protein losing significant portions of its hydration shell.