Evaluation of Liver and Renal Toxicity in Peptide Receptor Radionuclide Therapy for Somatostatin Receptor Expressing Tumors: A 2-Year Follow-Up

BackgroundPeptide receptor radionuclide therapy (PRRT) with radiolabeled somatostatin receptor (SSR) analogs is now an established systemic treatment for neuroendocrine tumors (NET). However, more short- and long-term data about renal and hepatotoxicity is needed. Here we present our experience in this clinical scenario.MethodsEighty-six patients with progressive SSR-expressing malignancies underwent PRRT with Lu-177 Dotatate and were followed up for up to 2 years. Laboratory tests were done 1 week before each cycle and every 2 months at follow-up. Hepatic and renal toxicity was determined based on NCI CTCAE V5.0.Results55/86 (64%) patients completed all 4 cycles of PRRT; 18/86 (20.9%) are currently being treated; 13/86 (15.1%) had to discontinue PRRT: 4/13 (31%) due to hematologic toxicity, 9/13 (69%) due to non-PRRT-related comorbidities. Out of the patients who finished treatment, only transient grade 2 toxicities were observed during PRRT: hypoalbuminemia in 5.5% (3/55), and renal toxicity (serum creatinine and estimated glomerular filtration rate) in 1.8% (1/55). No grade 3 or 4 liver and renal toxicity occurred. Patients presenting with impaired liver or renal function prior to PRRT, either improved or had stable findings. No deterioration was observed.ConclusionPeptide receptor radionuclide therapy does not have a negative impact on liver and renal function, even in patients with pre-existing impaired parameters. No grade 3 or 4 hepatic or renal toxicity was identified. Only transient grade 2 hypoalbuminemia in 5.5% and nephrotoxicity in 1.8% of patients were seen during PRRT.     

Coordination of hypothalamic and pituitary T3 production regulates TSH expression

Type II deiodinase (D2) activates thyroid hormone by converting thyroxine (T4) to 3,5,3′-triiodothyronine (T3). This allows plasma T4 to signal a negative feedback loop that inhibits production of thyrotropin-releasing hormone (TRH) in the mediobasal hypothalamus (MBH) and thyroid-stimulating hormone (TSH) in the pituitary. To determine the relative contributions of these D2 pathways in the feedback loop, we developed 2 mouse strains with pituitary- and astrocyte-specific D2 knockdown (pit-D2 KO and astro-D2 KO mice, respectively). The pit-D2 KO mice had normal serum T3 and were systemically euthyroid, but exhibited an approximately 3-fold elevation in serum TSH levels and a 40% reduction in biological activity. This was the result of elevated serum T4 that increased D2-mediated T3 production in the MBH, thus decreasing Trh mRNA. That tanycytes, not astrocytes, are the cells within the MBH that mediate T4-to-T3 conversion was defined by studies using the astro-D2 KO mice. Despite near-complete loss of brain D2, tanycyte D2 was preserved in astro-D2 KO mice at levels that were sufficient to maintain both the T4-dependent negative feedback loop and thyroid economy. Taken together, these data demonstrated that the hypothalamic-thyroid axis is wired to maintain normal plasma T3 levels, which is achieved through coordination of T4-to-T3 conversion between thyrotrophs and tanycytes.     

Laparoscopic Common Bile Duct Exploration

Since the introduction of laparoscopic cholecystectomy, the management of common bile duct (CBD) stones has undergone significant change. Preoperative endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy is now routinely done in cases where the diagnosis of choledocholithiasis is suspected preoperatively, with clearance of the bile ducts before laparoscopic cholecystectomy. Intraoperative discovery of CBD stones by cholangiography represents a challenge to the surgeon, who must make a decision about when to perform laparoscopic CBD exploration, convert to open surgery, or send the patient for ERCP during the postoperative period. Because ERCP has a definite failure rate, laparoscopic CBD exploration can be a treatment option. Among 2500 laparoscopic cholecystectomies done by our group from January 1991 to June 1997, 50 patients (2%) underwent laparoscopic CBD exploration, 13 by the transcystic technique and 37 by choledocotomy, with a conversion rate of 8% and a hospital stay of 4.3 days. One patient died from complicated pancreatitis following ERCP and unsuccessful extraction of a CBD stone. We obtained our goal of a CBD free of stones in 92% of the cases. We conclude that laparoscopic CBD exploration is an effective method for treating choledocolithiasis that allows management of this pathology in one stage, although it requires advanced laparoscopic skills and adequate equipment.     

Ministernotomy versus median sternotomy for aortic valve replacement: a prospective, randomized study

Background. Minimally invasive aortic valve replacement reduces surgical trauma and, supposedly, postoperative pain, blood loss, and length of stay. A prospective, randomized study was designed to prove these theoretical advantages.

Methods. Forty patients undergoing isolated, elective aortic valve replacement were randomized into two equal groups. Patients in group M underwent aortic valve replacement through a ministernotomy (reversed or reversed ). In group S, a median sternotomy was used. The anesthetic and surgical protocol was identical for both groups. Pain was evaluated on a daily basis. Pulmonary function tests were performed preoperatively and before hospital discharge in all patients.

Results. There were two deaths in each group. Cross-clamp time was longer in group M: 70 ± 19 minutes versus 51 ± 13 minutes in group S (p = 0.005). There were no statistically significant differences between groups M and S in pump time (95 ± 20 minutes versus 83 ± 19 minutes), extubation time (9.9 hours in both groups), chest drainage (479 ± 274 mL/ 24 hours versus 355 ± 159 mL/ 24 hours), transfusion requirements (27% in both groups), pain evaluation (1.34 ± 1.3 versus 2.15 ± 1.5), length of stay (6.2 ± 2.3 days versus 6.3 ± 2.5 days), and cosmetic appraisal. Forced vital capacity decreased 26% from preoperative reference values in group M and 33% in group S (p = not significant). Forced expiratory volume in 1 second decreased 22% and 35%, respectively (p = not significant).

Conclusions. This study has failed to prove the theoretical advantages of minimally invasive aortic valve replacement. With this technique, cross-clamp time is longer than with a median sternotomy.     

The rs12594956 polymorphism in the NRF-2 gene is associated with top-level Spanish athlete's performance status

ObjectivesTo determine the association between the nuclear respiratory factor 2 (NRF-2) polymorphisms and elite athletic performance.DesignWe compared the genotype and allele frequencies of the NRF-2 A/C (rs12594956), NRF-2 A/G (rs7181866), and NRF-2 C/T (rs8031031) polymorphisms between world-class endurance athletes (n = 89), elite power-oriented athletes (n = 38), and non-athletic controls (n = 110) of the same Caucasian (Spanish) origin.MethodsGenomic DNA was extracted from peripheral EDTA-treated, anti-coagulated blood using a standard protocol. Genotyping was performed using polymerase chain reaction (PCR).ResultsThe frequency of the AA genotype of the NRF-2 A/C (rs12594956) polymorphism was significantly higher in endurance athletes compared with power athletes (P < 0.01) and controls (P < 0.01) (48% vs. 13% and 21%, respectively). The likelihood of having the AA (rs12594956) genotype was higher in elite endurance athletes compared with controls [odds ratio (OR): 3.536, 95% confidence interval (CI): 1.903–6.571] and elite power athletes (OR: 6.170, 95%CI: 2.206–17.253).ConclusionsOur results suggest that the NRF-2 A/C polymorphism might belong to a growing group of polymorphisms associated with endurance performance at the elite level. However, it is important to replicate these findings in other groups of elite athletes using larger sample sizes.     

ERα signaling regulates MMP3 expression to induce FasL cleavage and osteoclast apoptosis

The benefits of estrogens on bone health are well established; how estrogens signal to regulate bone formation and resorption is less well understood. We show here that 17β‐estradiol (E2)‐induced apoptosis of bone‐resorbing osteoclasts is mediated by cleavage and solubilization of osteoblast‐expressed Fas ligand (FasL). U2OS‐ERα osteoblast‐like cells expressing an EGFP‐tagged FasL at the C‐terminus showed decreased fluorescence after E2 treatment, indicative of a cleavage event. Treatment of U2OS‐ERα cultures with a specific MMP3 inhibitor in the presence of E2 blocked FasL cleavage and showed an increase in the number of EGFP‐FasL⁺ cells. siRNA experiments successfully knocked down MMP3 expression and restored full‐length FasL to basal levels. E2 treatment of both human and murine primary osteoblasts showed upregulation of MMP3 mRNA expression, and calvarial organ cultures showed increased expression of MMP3 protein and colocalization with the osteoblast‐specific RUNX2 after E2 treatment. In addition, osteoblast cell cultures derived from ERαKO mice showed decreased expression of MMP3 but not MMP7 and ADAM10, two known FasL proteases, demonstrating that ERα signaling regulates MMP3. Also, conditioned media of E2‐treated calvarial osteoblasts showed an approximate sixfold increase in the concentration of soluble FasL, indicating extensive cleavage, and soluble FasL concentrations were reduced in the presence of a specific MMP3 inhibitor. Finally, to show the role of soluble FasL in osteoclast apoptosis, human osteoclasts were cocultured with MC3T3 osteoblasts. Both a specific MMP3 inhibitor and an MMP inhibitor cocktail preserved osteoclast differentiation and survival in the presence of E2 and demonstrate the necessity of MMP3 for E2‐induced osteoclast apoptosis. These experiments further define the molecular mechanism of estrogen's bone‐protective effects by inducing osteoclast apoptosis through upregulation of MMP3 and FasL cleavage. © 2013 American Society for Bone and Mineral Research