Short-time intermittent preexposure of living human donors to hyperoxia improves renal function in early posttransplant period: a double-blind randomized clinical trial

Effect of post-perfusion hyperoxemia on early graft function in renal transplant recipients: a retrospective observational cohort study

BACKGROUND

The effects of hyperoxemia on the transplanted grafts arouse interest nowadays, particularly intraoperative hyperoxemia, on transplant kidney function and survival in the 1-year post-operative period.

AIMS

We aimed to investigate the effect of post-perfusion (5 min after perfusion) hyperoxemia on early graft function and survival in renal transplant recipients.

METHODS

Two hundred forty-seven living donor kidney transplant recipients were included in the study. Patients were divided into the three groups according to their partial arterial oxygen pressure in post-perfusion blood gas samples: group 1: normoxia (n = 52, PaO2 pressure: < 120 mmHg, 103 ± 13); group 2: moderate hyperoxemia (n = 121, PaO2: 120-200 mmHg, 169 ± 21); group 3: severe hyperoxemia (n = 74, PaO2: > 200 mmHg, 233 ± 25). Graft functions (serum creatinine levels, estimated-glomerular filtration rate values, spot urine protein/creatinine ratio), survival rates, and groups' clinical outcomes were compared in the first year after transplantation.

RESULTS

Graft survival rates were similar in the groups and the rate of BK virus viremia was the lowest in the group 3 (groups 1, 2, and 3: 15.4% (n = 8), 6.6% (n = 8), 1.4% (n = 1), respectively, P: 0.009). Serum creatinine and proteinuria levels were lower, and estimated-glomerular filtration rate values were higher in group 3. A negative correlation between partial arterial oxygen pressure and serum creatinine levels and a positive correlation with estimated-glomerular filtration rate value were noted. These results were confirmed by univariate and multivariate analyses.

CONCLUSIONS

We demonstrated that the kidney transplant recipients with post-perfusion hyperoxemia have better early graft functions and lower BK virus viremia rates.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04420897.

Cellular Preoxygenation Partially Attenuates the Antitumoral Effect of Cisplatin despite Highly Protective Effects on Renal Epithelial Cells

Our previous in vitro studies demonstrated that oxygen pretreatment significantly protects human embryonic renal tubular cell against acute cisplatin- (CP-) induced cytotoxicity. The present study was designed to investigate whether this protective effect is associated with decreasing therapeutic effects of cisplatin on malignant cells. For this purpose, cultured human embryonic kidney epithelial-like (AD293), cervical carcinoma epithelial-like (Hela), and ovarian adenocarcinoma epithelial-like (OVCAR-3) cells were subjected to either 2-hour pretreatment with oxygen (≥90%) or normal air and then to a previously determined 50% lethal dose of cisplatin for 24 hours. Cellular viability was evaluated via MTT and Neutral Red assays. Also, activated caspase-3 and Bax/Bcl-2 ratio, as the biochemical markers of cell apoptosis, were determined using immunoblotting. The hyperoxic preexposure protocol significantly protects renal AD293 cells against cisplatin-induced toxicity. Oxygen pretreatment also partially attenuated the cisplatin-induced cytotoxic effects on Hela and OVCAR-3 cells. However, it did not completely protect these cells against the therapeutic cytotoxic effects of cisplatin. In summary, the protective methods for reducing cisplatin nephrotoxic side effects like oxygen pretreatment might be associated with concurrent reduction of the therapeutic cytotoxic effects of cisplatin on malignant cells like cervical carcinoma (Hela) and ovarian adenocarcinoma (OVCAR-3) cells.

Effects of pretreatment with single-dose or intermittent oxygen on Cisplatin-induced nephrotoxicity in rats

Background:

Renal injury is the main side effect of cisplatin (CP), an anticancer drug. It has been shown that pretreatment with single-dose oxygen (0.5 to six hours) could reduce CP-induced renal toxicity in rats.

Objectives:

The present study aimed to compare the effects of pretreatment with single-dose and intermittent O₂ on CP-induced nephrotoxicity.

Materials and Methods:

Adult male rats were allocated to seven groups (eight rats in each group). The rats were kept in normal air or hyperoxic environment (O₂, 80%) for either a single six-hour period or intermittent six hours per day for seven days and then were subjected to intraperitoneal injection of saline or CP (5 mg/kg) at 48 hours, 72 hours, or seven days after exposure to O₂. Three days after CP (or Saline) injection, renal function tests, renal tissue injury scores, and cleaved Caspase-3 and Bax/Bcl-2 genes expression (as markers of renal cell apoptosis) were assessed.

Results:

Treatment with the 6-hour single-dose O₂ reduced renal injury significantly when CP was administrated 48 hours after O₂ pretreatment. Pretreatment with intermittent seven days of six hours per day had no protective effects and even relatively worsened renal injury when CP was injected 48 hours or 72 hours after the last session of O₂ pretreatment. The beneficial effects of pretreatment with O₂ on renal structure and function were seen if CP was administrates seven days after pretreatment with intermittent O₂.

Conclusions:

The pattern of pretreatment with O₂ could change this potential and highly protective strategy against CP-induced nephropathy to an ineffective or even mildly deteriorating one. Therefore, O₂ administration before CP injection to patients with cancer, for therapeutic purposes or as a preconditioning approach, should be performed and investigated with caution until exact effects of different protocols has been determined in human.