High intrapatient variability of tacrolimus exposure associated with poorer outcomes in liver transplantation

Tacrolimus (TAC) is a dose‐dependent immunosuppressor with considerable intrapatient variability (IPV) in its pharmacokinetics. The aim of this work is to ascertain the association between TAC IPV at 6 months after liver transplantation (LT) and patient outcome. This single‐center cohort study retrospectively analyzed adult patients who underwent transplantation from 2015 to 2019 who survived the first 6 months with a functioning graft. The primary end point was the patient’s probability of death and the secondary outcome was the loss of renal function between month 6 and the last follow‐up. TAC IPV was estimated by calculating the coefficient of variation (CV) of the dose‐corrected concentration (C₀/D) between the third and sixth months post‐LT. Of the 140 patients who underwent LT included in the study, the low‐variability group (C₀/D CV < 27%) comprised 105 patients and the high‐variability group (C₀/D CV ≥ 27%) 35 patients. One‐, 3‐, and 5‐year patient survival rates were 100%, 82%, and 72% in the high‐variability group versus 100%, 97%, and 93% in the low‐variability group, respectively (p = 0.005). Moreover, significant impaired renal function was observed in the high‐variability group at 1 year (69 ± 16 ml/min/1.73 m² vs. 78 ± 16 ml/min/1.73 m², p = 0.004) and at 2 years post‐LT (69 ± 17 ml/min/1.73 m² vs. 77 ± 15 ml/min/1.73 m², p = 0.03). High C₀/D CV 3–6 months remained independently associated with worse survival (hazard ratio = 3.57, 95% CI = 1.32–9.67, p = 0.012) and loss of renal function (odds ratio = 3.47, 95% CI = 1.30–9.20, p = 0.01). Therefore, high IPV between the third and sixth months appears to be an early and independent predictor of patients with poorer liver transplant outcomes.

Abbreviations

BPAR

Biopsy proven acute rejection

BMI

Body mass index

CKD‐EPI

chronic kidney disease epidemiology collaboration

CV

coefficient of variation

C₀/D

dose‐corrected concentration

CMV

cytomegalovirus

eGFR

estimated glomerular filtration rate

HR

hazard ratio

HCC

hepatocellular carcinoma

ICU

intensive care unit

IPV

intrapatient variability

i.v.

intravenously

LC–MS/MS

liquid chromatography‐ tandem mass spectrometry

LT

liver transplantation

MELD

model for end‐stage liver disease

MMF

mycophenolate mofetil

NASH

Non‐Alcoholic Steatohepatitis

OR

odds ratio

PCR

polymerase chain reaction

SD

Standard Deviation

TAC

tacrolimus

3–6 M

three–six months

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

There is high intrapatient variability of tacrolimus and its correlation with liver transplantation (LT) outcomes.

• WHAT QUESTION DID THIS STUDY ADDRESS?

Could the intrapatient variability of tacrolimus between months 3 and 6 post‐LT be a potential prognostic tool for poor outcomes?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Those patients with dose‐corrected concentration coefficient of variation greater than or equal to 27% between months 3 and 6 post‐LT have worst overall survival and impaired renal function.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

If we promptly identify those patients, a closer therapeutic drug monitoring program should be imperative with the possibility to make therapeutic interventions to improve outcomes.     

Clinical and Metabolomic Effects of Lactiplantibacillus plantarum and Pediococcus acidilactici in Fructose Intolerant Patients

Fructose intolerance (FI) is a widespread non-genetic condition in which the incomplete absorption of fructose leads to gastro-intestinal disorders. The crucial role of microbial dysbiosis on the onset of these intolerance symptoms together with their persistence under free fructose diets are driving the scientific community towards the use of probiotics as a novel therapeutic approach. In this study, we evaluated the prevalence of FI in a cohort composed of Romanian adults with Functional Grastrointestinal Disorders (FGIDs) and the effectiveness of treatment based on the probiotic formulation EQBIOTA^® (Lactiplantibacillus plantarum CECT 7484 and 7485 and Pediococcus acidilactici CECT 7483). We evaluated the impact of a 30-day treatment both on FI subjects and healthy volunteers. The gastrointestinal symptoms and fecal volatile metabolome were evaluated. A statistically significant improvement of symptoms (i.e., bloating, and abdominal pain) was reported in FI patient after treatment. On the other hand, at the baseline, the content of volatile metabolites was heterogeneously distributed between the two study arms, whereas the treatment led differences to decrease. From our analysis, how some metabolomics compounds were correlated with the improvement and worsening of clinical symptoms clearly emerged. Preliminary observations suggested how the improvement of gastrointestinal symptoms could be induced by the increase of anti-inflammatory and protective substrates. A deeper investigation in a larger patient cohort subjected to a prolonged treatment would allow a more comprehensive evaluation of the probiotic treatment effects.     

Effect of Surface Tooling Techniques of Medical Titanium Implants on Bacterial Biofilm Formation In Vitro

The aim of this study was to assess the biofilm formation of Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli on titanium implants with CAD-CAM tooling techniques. Twenty specimens of titanium were studied: Titanium grade 2 tooled with a Planmeca CAD-CAM milling device (TiGrade 2), Ti₆Al₄V grade 5 as it comes from CAD-DMLS device (computer aided design-direct metal laser sintering device) (TiGrade 5), Ti₆Al₄V grade 23 as it comes from a CAD-CAM milling device (TiGrade 23), and CAD-DMLS TiGrade 5 polished with an abrasive disc (TiGrade 5 polished). Bacterial adhesion on the implants was completed with and without saliva treatment to mimic both extraoral and intraoral surgical methods of implant placement. Five specimens/implant types were used in the bacterial adhesion experiments. Autoclaved implant specimens were placed in petri plates and immersed in saliva solution for 30 min at room temperature and then washed 3× with 1× PBS. Bacterial suspensions of each strain were made and added to the specimens after saliva treatment. Biofilm was allowed to form for 24 h at 37 °C and the adhered bacteria was calculated. Tooling techniques had an insignificant effect on the bacterial adhesion by all the bacterial strains studied. However, there was a significant difference in biofilm formation between the saliva-treated and non-saliva-treated implants. Saliva contamination enhanced S. mutans, S. aureus, and E. faecalis adhesion in all material types studied. S. aureus was found to be the most adherent strain in the saliva-treated group, whereas E. coli was the most adherent strain in the non-saliva-treated group. In conclusion, CAD-CAM tooling techniques have little effect on bacterial adhesion. Saliva coating enhances the biofilm formation; therefore, saliva contamination of the implant must be minimized during implant placement. Further extensive studies are needed to evaluate the effects of surface treatments of the titanium implant on soft tissue response and to prevent the factors causing implant infection and failure.     

Evaluation of Reduced Susceptibility to Quaternary Ammonium Compounds and Bisbiguanides in Clinical Isolates and Laboratory-Generated Mutants of Staphylococcus aureus

The MICs and minimum bactericidal concentrations (MBCs) for the biocides benzalkonium chloride and chlorhexidine were determined against 1,602 clinical isolates of Staphylococcus aureus. Both compounds showed unimodal MIC and MBC distributions (2 and 4 or 8 mg/liter, respectively) with no apparent subpopulation with reduced susceptibility. To investigate further, all isolates were screened for qac genes, and 39 of these also had the promoter region of the NorA multidrug-resistant (MDR) efflux pump sequenced. The presence of qacA, qacB, qacC, and qacG genes increased the mode MIC, but not MBC, to benzalkonium chloride, while only qacA and qacB increased the chlorhexidine mode MIC. Isolates with a wild-type norA promoter or mutations in the norA promoter had similar biocide MIC distributions; notably, not all clinical isolates with norA mutations were resistant to fluoroquinolones. In vitro efflux mutants could be readily selected with ethidium bromide and acriflavine. Multiple passages were necessary to select mutants with biocides, but these mutants showed phenotypes comparable to those of mutants selected by dyes. All mutants showed changes in the promoter region of norA, but these were distinct from this region of the clinical isolates. Still, none of the in vitro mutants displayed fitness defects in a killing assay in Galleria mellonella larvae. In conclusion, our data provide an in-depth comparative overview on efflux in S. aureus mutants and clinical isolates, showing also that plasmid-encoded efflux pumps did not affect bactericidal activity of biocides. In addition, current in vitro tests appear not to be suitable for predicting levels of resistance that are clinically relevant.     

Combination of a reduced dose of an intrathecal local anesthetic with a small dose of an opioid: A meta-analysis of randomized trials

We tested whether the combination of a reduced dose of a local anesthetic (LA) with an opioid compared with a standard dose of the same LA alone guaranteed adequate intraoperative anesthesia and postoperative analgesia and decreased LA-related adverse effects. We systematically searched (to November 2012) for randomized comparisons of combinations of a reduced dose of an LA with a concomitant opioid (experimental) with a standard dose of the LA alone (control) in adults undergoing surgery with single-injection intrathecal anesthesia without general anesthesia. We included 28 trials (1393 patients). In experimental groups, the median decrease in LA doses was 40% (range, 12%–70%). There was no difference between experimental and control groups in the need for intraoperative opioids or general anesthesia for failed block or in the duration of postoperative analgesia. With experimental interventions, there was evidence of a reduction in the duration of motor blockade postoperatively (average, −50 minutes), time to discharge from hospital or PACU (−33 minutes), time to ambulation (−28 minutes), and time to urination (−14 minutes). There was also evidence of a decrease in the risk of shivering (risk ratio [RR]: 0.26; 95% confidence interval [CI]: 0.12–0.56), nausea (RR: 0.45; 95% CI: 0.31–0.66), and arterial hypotension (RR: 0.52; 95% CI: 0.35–0.78). The risk of pruritus was increased (RR: 11.7; 95% CI: 6.2–21.9). Adding an opioid to a reduced dose of an intrathecal LA can decrease LA-related adverse effects and improve recovery from the spinal block without compromising intraoperative anesthesia or duration of postoperative analgesia.     

Antithymocyte globulin induction allows a prolonged delay in the initiation of cyclosporine in heart transplant patients with postoperative renal dysfunction

The authors evaluated the efficacy of antithymocyte globulin (ATG) induction and delayed initiation of cyclosporine (CsA) in heart transplant (HTx) patients with postoperative renal dysfunction (RD). The authors compared 15 adult HTx patients with postoperative RD (serum creatinine [SCr] > or =150 microM) to 17 controls without postoperative RD. ATG was given daily (1.5 mg/kg/day for 5 days) in controls and every 2 to 5 days in RD patients (total lymphocyte count <200/mm). All patients received corticosteroids and mycophenolate mofetil. The initiation of CsA was delayed in RD patients until SCr had decreased to less than 150 microM (day 12 +/- 8 vs. 2 +/- 1, P<0.0001). One-year patient survival and acute rejection rates were 87% and 27% in RD patients and 88% and 59% in controls, respectively (P=not significant). SCr improved in RD patients and did not differ from controls after the first month. The authors' results suggest that marked prolongation of the period of ATG induction permits a safe delay in the initiation of CsA in HTx patients with postoperative RD.     

Dynamic of distribution of human bone marrow-derived mesenchymal stem cells after transplantation into adult unconditioned mice

BACKGROUND: The use of mesenchymal stem cells (MSC) for cell therapy relies on their capacity to engraft and survive long-term in the appropriate target tissue(s). Animal models have demonstrated that the syngeneic or xenogeneic transplantation of MSC results in donor engraftment into the bone marrow and other tissues of conditioned recipients. However, there are no reliable data showing the fate of human MSC infused into conditioned or unconditioned adult recipients. METHODS: In the present study, the authors investigated, by using imaging, polymerase chain reaction (PCR), and in situ hybridization, the biodistribution of human bone marrow-derived MSC after intravenous infusion into unconditioned adult nude mice. RESULTS: As assessed by imaging (gamma camera), PCR, and in situ hybridization analysis, the authors' results demonstrate the presence of human MSC in bone marrow, spleen, and mesenchymal tissues of recipient mice. CONCLUSIONS: These results suggest that human MSC transplantation into unconditioned recipients represents an option for providing cellular therapy and avoids the complications associated with drugs or radiation conditioning.