Role of Patient Factors and Practice Patterns in Determining Access to Liver Waitlist.

Geographic variability in access to care is a persistent challenge in transplantation. Little is known about how patients with end-stage liver disease are chosen for referral, evaluation and listing. Utilizing death certificate data from the Centers for Disease Control and Prevention from 2002 to 2009, estimated liver demand (ELD) was measured by aggregating annual deaths from liver disease and liver transplants performed in each donor service area (DSA). In DSAs with higher ELD, more patients per capita were listed for transplantation (p < 0.001). In addition, listing rates per ELD varied fivefold across DSAs, with more patients per ELD being transplanted in DSAs with higher listing rates (p < 0.001). After adjusting for liver donor risk index and MELD at transplant, there was no association between listing rate and posttransplant survival (HR 1.002, p = 0.77). In addition, DSAs with lower listing rates were more likely to export organs (p < 0.001) of lower liver donor risk index (p < 0.001). Listing sicker patients was associated with increased access to the waitlist and transplantation and more efficient organ utilization, but had minimal effect on posttransplant outcomes after adjusting for the resulting organ shortage.

Use of CTLA4Ig for induction of mixed chimerism and renal allograft tolerance in nonhuman primates.

We have previously reported successful induction of renal allograft tolerance via a mixed chimerism approach in nonhuman primates. In those studies, we found that costimulatory blockade with anti-CD154 mAb was an effective adjunctive therapy for induction of renal allograft tolerance. However, since anti-CD154 mAb is not clinically available, we have evaluated CTLA4Ig as an alternative agent for effecting costimulation blockade in this treatment protocol. Two CTLA4Igs, abatacept and belatacept, were substituted for anti-CD154 mAb in the conditioning regimen (low dose total body irradiation, thymic irradiation, anti-thymocyte globulin and a 1-month posttransplant course of cyclosporine [CyA]). Three recipients treated with the abatacept regimen failed to develop comparable lymphoid chimerism to that achieved with anti-CD154 mAb treatment and these recipients rejected their kidney allografts early. With the belatacept regimen, four of five recipients developed chimerism and three of these achieved long-term renal allograft survival (>861, >796 and >378 days) without maintenance immunosuppression. Neither chimerism nor long-term allograft survival were achieved in two recipients treated with the belatacept regimen but with a lower, subtherapeutic dose of CyA. This study indicates that CD28/B7 blockade with belatacept can provide a clinically applicable alternative to anti-CD154 mAb for promoting chimerism and renal allograft tolerance.

Pretransplant IgG reactivity to apoptotic cells correlates with late kidney allograft loss.

Preexisting serum antibodies have long been associated with graft loss in transplant recipients. While most studies have focused on HLA-specific antibodies, the contribution of non-HLA-reactive antibodies has been largely overlooked. We have recently characterized mAbs secreted by B cell clones derived from kidney allograft recipients with rejection that bind to apoptotic cells. Here, we assessed the presence of such antibodies in pretransplant serum from 300 kidney transplant recipients and examined their contribution to the graft outcomes. Kaplan-Meier survival analysis revealed that patients with high pretransplant IgG reactivity to apoptotic cells had a significantly increased rate of late graft loss. The effect was only apparent after approximately 1 year posttransplant. Moreover, the association between pretransplant IgG reactivity to apoptotic cells and graft loss was still significant after excluding patients with high reactivity to HLA. This reactivity was almost exclusively mediated by IgG1 and IgG3 with complement fixing and activating properties. Overall, our findings support the view that IgG reactive to apoptotic cells contribute to presensitization. Taking these antibodies into consideration alongside anti-HLA antibodies during candidate evaluation would likely improve the transplant risk assessment.

Alefacept promotes immunosuppression-free renal allograft survival in nonhuman primates via depletion of recipient memory T cells.

Renal allograft tolerance has been achieved in MHC-mismatched primates via nonmyeloablative conditioning beginning 6 days prior to planned kidney and donor bone marrow transplantation (DBMT). To extend the applicability of this approach to deceased donor transplantation, we recently developed a novel-conditioning regimen, the "delayed protocol" in which donor bone marrow (DBM) is transplanted several months after kidney transplantation. However, activation/expansion of donor-reactive CD8(+) memory T cells (TMEM) occurring during the interval between kidney and DBM transplantation impaired tolerance induction using this strategy. In the current study, we tested whether, Alefacept, a fusion protein which targets LFA-3/CD2 interactions and selectively depletes CD2(high) CD8(+) effector memory T cells (TEM) could similarly induce long-term immunosuppression-free renal allograft survival but avoid the deleterious effects of anti-CD8 mAb treatment. We found that Alefacept significantly delayed the expansion of CD2(high) cells including CD8(+) TEM while sparing naïve CD8(+) T and NK cells and achieved mixed chimerism and long-term immunosuppression-free renal allograft survival. In conclusion, elimination of CD2(high) T cells represents a promising approach to prevent electively the expansion/activation of donor-reactive TEM and promotes tolerance induction via the delayed protocol mixed chimerism approach.

HCC patients suffer less from geographic differences in organ availability.

It has been suggested that the number of exception model for end-stage liver disease (MELD) points for hepatocellular carcinoma (HCC) overestimates mortality risk. Average MELD at transplant, a measure of organ availability, correlates with mortality on an intent-to-treat basis and varies by donation service area (DSA). We analyzed Scientific Registry of Transplant Recipients data from 2005 to 2010, comparing transplant and death parameters for patients transplanted with HCC exception points to patients without HCC diagnosis (non-HCC), to determine whether the two groups were impacted differentially by DSA organ availability. HCC candidates are transplanted at higher rates than non-HCC candidates and are less likely to die on the waitlist. Overall risk of death trends downward by 1% per MELD point (p = 0.65) for HCC, but increases by 7% for non-HCC patients (p < 0.0001). The difference in the change of mortality with MELD is statistically significant between HCC and non-HCC candidates p < 0.0001. Posttransplant risk of death trends downward by 2% per MELD point (p = 0.28) for HCC patients, but increases by 3% per MELD point in non-HCC patients (p = 0.027), with the difference being statistically significant with p < 0.005. In summary, increasing wait time impacts HCC candidates less than non-HCC candidates and under increased competition for donor organs, HCC candidates' advantage increases.

Effects of growth hormone withdrawal in obese premenopausal women.

OBJECTIVE: We previously reported improved body composition and cardiovascular risk markers plus a small decrease in glucose tolerance with GH administration vs placebo for 6 months to abdominally obese premenopausal women. The objective of this study was to determine whether the effects of GH treatment on cardiovascular risk markers, body composition and glucose tolerance in obese women persist 6 months after GH withdrawal. DESIGN AND PATIENTS: Fifty abdominally obese premenopausal women completed a trial of rhGH vs placebo for 6 months; thirty-nine women completed a subsequent 6-month withdrawal observation period. MEASUREMENTS: IGF-I, body composition by CT, (1) H-MRS and DXA, serum cardiovascular risk markers, oral glucose tolerance test (OGTT). RESULTS: IGF-I standard deviation scores (SDS) within the GH group were -1.7 ± 0.1 (pretreatment),-0.1 ± 0.3 (after 6 months of GH) and -1.7 ± 0.1 (6 months post-GH withdrawal). Six months after GH withdrawal, total abdominal and subcutaneous adipose tissue, total fat, trunk fat, trunk/extremity fat, hsCRP, apoB, LDL, and tPA were higher than at the 6-month (GH discontinuation) timepoint (P ≤ 0.05). All body composition and cardiovascular risk markers that had improved with GH returned to baseline levels by 6 months after GH discontinuation, as did fasting and 2-h OGTT glucose levels. CONCLUSION: The effects of GH administration to abdominally obese premenopausal women have a short time-course. The beneficial effects on body composition and cardiovascular risk markers, and the side effect of altered glucose tolerance returned to pretreatment levels after GH withdrawal. There was no suppression of endogenous IGF-I levels, which returned to baseline after GH withdrawal.

Low-dose IL-2 for In vivo expansion of CD4+ and CD8+ regulatory T cells in nonhuman primates.

IL-2 is a known potent T cell growth factor that amplifies lymphocyte responses in vivo. This capacity has led to the use of high-dose IL-2 to enhance T cell immunity in patients with AIDS or cancer. However, more recent studies have indicated that IL-2 is also critical for the development and peripheral expansion of regulatory T cells (Tregs). In the current study, low-dose IL-2 (1 million IU/m(2) BSA/day) was administered to expand Tregs in vivo in naïve nonhuman primates. Our study demonstrated that low-dose IL-2 therapy significantly expanded peripheral blood CD4(+) and CD8(+) Tregs in vivo with limited expansion of non-Treg cells. These expanded Tregs are mainly CD45RA(-) Foxp3(high) activated Tregs and demonstrated potent immunosuppressive function in vitro. The results of this preclinical study can serve as a basis to develop Treg immunotherapy, which has significant therapeutic potential in organ/cellular transplantation.

Changes in the expression of the Alzheimer's disease-associated presenilin gene in drosophila heart leads to cardiac dysfunction.

Mutations in the presenilin genes cause the majority of early-onset familial Alzheimer's disease. Recently, presenilin mutations have been identified in patients with dilated cardiomyopathy (DCM), a common cause of heart failure and the most prevalent diagnosis in cardiac transplantation patients. However, the molecular mechanisms, by which presenilin mutations lead to either AD or DCM, are not yet understood. We have employed transgenic Drosophila models and optical coherence tomography imaging technology to analyze cardiac function in live adult Drosophila. Silencing of Drosophila ortholog of presenilins (dPsn) led to significantly reduced heart rate and remarkably age-dependent increase in end-diastolic vertical dimensions. In contrast, overexpression of dPsn increased heart rate. Either overexpression or silencing of dPsn resulted in irregular heartbeat rhythms accompanied by cardiomyofibril defects and mitochondrial impairment. The calcium channel receptor activities in cardiac cells were quantitatively determined via real-time RT-PCR. Silencing of dPsn elevated dIP3R expression, and reduced dSERCA expression; overexprerssion of dPsn led to reduced dRyR expression. Moreover, overexpression of dPsn in wing disc resulted in loss of wing phenotype and reduced expression of wingless. Our data provide novel evidence that changes in presenilin level leads to cardiac dysfunction, owing to aberrant calcium channel receptor activities and disrupted Wnt signaling transduction, indicating a pathogenic role for presenilin mutations in DCM pathogenesis.

Revised statistical motor unit number estimation in the Celecoxib/ALS trial.

Techniques to estimate motor unit number (MUNE) measure the number of functioning motor units in a muscle. As amyotrophic lateral sclerosis (ALS) is characterized by progressive motor unit loss, this disease offers an ideal setting for the use of MUNE. Statistical MUNE was employed in a recent multicenter trial of creatine in ALS, and was shown to be reliable, reproducible, and to decline with disease progression. However, motor unit amplitude stayed constant over 7 months, a finding believed to reflect an artifact of the method. The statistical method was revised to reflect more accurately the presence of larger motor units and employed in a 12-month study of Celecoxib in ALS. MUNE declined by 49% in 12 months; however, motor unit amplitude again stayed constant over the same period. Statistical MUNE estimates motor unit number based on the variability of response to a repeated stimulus of constant strength, with an underlying assumption that this variability is due solely to the number of motor units responding in an intermittent manner. Based on studies showing that single motor units in ALS display excessive amplitude variability when stimulated repeatedly, we show that response variability in ALS patients is in large part due to single unit changes. Thus, we conclude that the statistical method is not an appropriate measure of motor unit number in any disease associated with motor unit instability.

Effects of testosterone replacement in androgen-deficient women with hypopituitarism: a randomized, double-blind, placebo-controlled study.

CONTEXT: Hypopituitarism in women is characterized by profound androgen deficiency due to a loss of adrenal and/or ovarian function. The effects of testosterone replacement in this population have not been reported. OBJECTIVE: The objective of the study was to determine whether physiologic testosterone replacement improves bone density, body composition, and/or neurobehavioral function in women with severe androgen deficiency secondary to hypopituitarism. DESIGN: This was a 12-month randomized, placebo-controlled study. SETTING: The study was conducted at a general clinical research center. STUDY PARTICIPANTS: Fifty-one women of reproductive age with androgen deficiency due to hypopituitarism participated. INTERVENTION: Physiologic testosterone administration using a patch that delivers 300 microg daily or placebo was administered. MAIN OUTCOME MEASURES: Bone density, fat-free mass, and fat mass were measured by dual x-ray absorptiometry. Thigh muscle and abdominal cross-sectional area were measured by computed tomography scan. Mood, sexual function, quality of life, and cognitive function were assessed using self-administered questionnaires. RESULTS: Mean free testosterone increased into the normal range during testosterone administration. Mean hip (P = 0.023) and radius (P = 0.007), but not posteroanterior spine, bone mineral density increased in the group receiving testosterone, compared with placebo, as did mean fat-free mass (P = 0.040) and thigh muscle area (P = 0.038), but there was no change in fat mass. Mood (P = 0.029) and sexual function (P = 0.044) improved, as did some aspects of quality of life, but not cognitive function. Testosterone at physiologic replacement levels was well tolerated, with few side effects. CONCLUSIONS: This is the first randomized, double-blind, placebo-controlled study to show a positive effect of testosterone on bone density, body composition, and neurobehavioral function in women with severe androgen deficiency due to hypopituitarism.

Creatine in Huntington disease is safe, tolerable, bioavailable in brain and reduces serum 8OH2'dG.

In a randomized, double-blind, placebo-controlled study in 64 subjects with Huntington disease (HD), 8 g/day of creatine administered for 16 weeks was well tolerated and safe. Serum and brain creatine concentrations increased in the creatine-treated group and returned to baseline after washout. Serum 8-hydroxy-2'-deoxyguanosine (8OH2'dG) levels, an indicator of oxidative injury to DNA, were markedly elevated in HD and reduced by creatine treatment.

A clinical trial of creatine in ALS.

BACKGROUND: Mitochondrial dysfunction occurs early in the course of ALS, and the mitochondria may be an important site for therapeutic intervention. Creatine stabilizes the mitochondrial transition pore, and is important in mitochondrial ATP production. In a transgenic mouse model of ALS, administration of creatine prolongs survival and preserves motor function and motor neurons. METHODS: The authors conducted a randomized double-blind, placebo controlled trial on 104 patients with ALS from 14 sites to evaluate the efficacy of creatine supplementation in ALS. The primary outcome measure was maximum voluntary isometric contraction of eight upper extremity muscles, with secondary outcomes including grip strength, ALS Functional Rating Scale-Revised, and motor unit number estimates. Patients were treated for 6 months, and evaluated monthly. RESULTS: Creatine was tolerated well, but no benefit of creatine could be demonstrated in any outcome measure. CI analysis showed that the study, although powered to detect a 50% or greater change in rate of decline of muscle strength, actually made an effect size of greater than 23% unlikely. It was also demonstrated that motor unit number estimation was performed with acceptable reproducibility and tolerability, and may be a useful outcome measure in future clinical trials. CONCLUSION: Any beneficial effect of creatine at 5 g per day in ALS must be small. Other agents should be considered in future studies of therapeutic agents to address mitochondrial dysfunction in ALS. In addition, motor unit number estimation may be a useful outcome measure for future clinical trials in ALS.

Functional outcome measures as clinical trial endpoints in ALS.

The topiramate study was a 12-month randomized placebo-controlled trial in patients with ALS. Follow-up evaluation of the placebo group (n = 97) constituted a well-described cohort of patients with ALS, in whom multiple outcome measures were assessed at 3-month intervals. During the 12-month study period, the decline of forced vital capacity (FVC%) and ALS functional rating scale (ALSFRS) was linear, whereas the decline of maximum voluntary isometric contraction-arm (MVIC-arm) and MVIC-grip Z scores was curvilinear. Rates of FVC% and ALFRS decline, but not of MVIC-arm or MVIC-grip, were independent predictors of survival.

The use of statistical MUNE in a multicenter clinical trial.

Techniques to estimate motor unit number (MUNE) measure the number of functioning motor units in a muscle. In diseases characterized by progressive motor unit loss, such as amyotrophic lateral sclerosis (ALS), MUNE may be useful to monitor disease progression or beneficial response to treatment. As part of a multicenter, placebo-controlled, randomized, double-blind clinical trial testing the efficacy of creatine in patients with ALS, statistical MUNE was measured in 104 patients tested monthly for 6 months. The objective was to determine whether MUNE was a reliable and sensitive outcome measure in the context of a multicenter trial. Formal training and reliability testing was required for all MUNE evaluators. Testing of normal controls showed a high degree of test-retest reliability. All patient data were combined as the experimental treatment showed no efficacy. There was a 23% decline in MUNE over 6 months. The technique as employed in this trial overemphasized the presence of small motor units; this problem was partially addressed by poststudy data monitoring and censuring. Thus, MUNE can be used reliably as an outcome measure in multicenter clinical trials; specific remedies are suggested for the difficulties encountered in this study.

A randomized, placebo-controlled trial of topiramate in amyotrophic lateral sclerosis.

OBJECTIVE: To determine if long-term topiramate therapy is safe and slows disease progression in patients with ALS. METHODS: A double-blind, placebo-controlled, multicenter randomized clinical trial was conducted. Participants with ALS (n = 296) were randomized (2:1) to receive topiramate (maximum tolerated dose up to 800 mg/day) or placebo for 12 months. The primary outcome measure was the rate of change in upper extremity motor function as measured by the maximum voluntary isometric contraction (MVIC) strength of eight arm muscle groups. Secondary endpoints included safety and the rate of decline of forced vital capacity (FVC), grip strength, ALS functional rating scale (ALSFRS), and survival. RESULTS: Patients treated with topiramate showed a faster decrease in arm strength (33.3%) during 12 months (0.0997 vs 0.0748 unit decline/month, p = 0.012). Topiramate did not significantly alter the decline in FVC and ALSFRS or affect survival. Topiramate was associated with an increased frequency of anorexia, depression, diarrhea, ecchymosis, nausea, kidney calculus, paresthesia, taste perversion, thinking abnormalities, weight loss, and abnormal blood clotting (pulmonary embolism and deep venous thrombosis). CONCLUSIONS: At the dose studied, topiramate did not have a beneficial effect for patients with ALS. High-dose topiramate treatment was associated with a faster rate of decline in muscle strength as measured by MVIC and with an increased risk for several adverse events in patients with ALS. Given the lack of efficacy and large number of adverse effects, further studies of topiramate at a dose of 800 mg or maximum tolerated dose up to 800 mg/day are not warranted.

Effect of neurophilin ligands on motor units in mice with SOD1 ALS mutations.

BACKGROUND: Mice with trangenes that express mutations in the gene for cytosolic copper/zinc superoxide dismutase (SOD1) develop motor neuron degeneration resembling human ALS. Neurophilin ligands are small molecules that promote neurite outgrowth. OBJECTIVE: To test the hypothesis that treatment with two neurophilin ligands increases survival in these ALS mice by slowing the loss of motor neurons and increasing the sizes of motor units. METHODS: Transgenic mice hemizygous for the G93A mutation were untreated or treated from 30 days of age with one of two doses of two neurophilin ligands (V-13,670; V-10,367, Vertex Pharmaceuticals, Boston, MA). Onset of behavioral abnormalities and survival were recorded. Motor unit number estimation (MUNE) was performed every 21 days starting at age 60 days. RESULTS: In control animals, disease onset occurred at 77.0 days of age and death occurred at 137 days of age. Neither neurophilin ligand affected the disease course. In control animals, MUNE declined with time beginning before behavioral abnormalities were noted, and motor unit size increased concomitantly. There was no effect of drug on motor unit loss as assessed by MUNE; however, motor unit size increased more rapidly and to a greater degree in animals treated with V-13,670. CONCLUSION: As in human ALS, the transgenic ALS mice show physiologic changes in the motor unit prior to the development of clinical signs: MUNE declines as motor unit size increases. Although neither neurophilin ligand significantly affected survival, one produced an increase in motor unit size. The fact that survival was not altered by the increase in motor unit size may reflect the rapid disease course in this animal model.

Posttransplant diabetes mellitus in liver transplant recipients: risk factors, temporal relationship with hepatitis C virus allograft hepatitis, and impact on mortality.

BACKGROUND: Recent studies suggest an association between diabetes mellitus and hepatitis C virus (HCV) infection. Our aim was to determine (1) the prevalence and determinants of new onset posttransplant diabetes mellitus (PTDM) in HCV (+) liver transplant (OLT) recipients, (2) the temporal relationship between recurrent allograft hepatitis and the onset of PTDM, and (3) the effects of antiviral therapy on glycemic control. METHODS: Between January of 1991 and December of 1998, of 185 OLTs performed in 176 adult patients, 47 HCV (+) cases and 111 HCV (-) controls were analyzed. We reviewed and analyzed the demographics, etiology of liver failure, pretransplant alcohol abuse, prevalence of diabetes mellitus, and clinical characteristics of both groups. In HCV (+) patients, the development of recurrent allograft hepatitis and its therapy were also studied in detail. RESULTS: The prevalence of pretransplant diabetes was similar in the two groups, whereas the prevalence of PTDM was significantly higher in HCV (+) than in HCV (-) patients (64% vs. 28%, P=0.0001). By multivariate analysis, HCV infection (hazard ratio 2.5, P=0.001) and methylprednisolone boluses (hazard ratio 1.09 per bolus, P=0.02) were found to be independent risk factors for the development of PTDM. Development of PTDM was found to be an independent risk factor for mortality (hazard ratio 3.67, P<0.0001). The cumulative mortality in HCV (+) PTDM (+) versus HCV (+) PTDM (-) patients was 56% vs. 14% (P=0.001). In HCV (+) patients with PTDM, we could identify two groups based on the temporal relationship between the allograft hepatitis and the onset of PTDM: 13 patients developed PTDM either before or in the absence of hepatitis (group A), and 12 concurrently with the diagnosis of hepatitis (group B). In gr. B, 11 of 12 patients received antiviral therapy. Normalization of liver function tests with improvement in viremia was achieved in 4 of 11 patients, who also demonstrated a marked improvement in their glycemic control. CONCLUSION: We found a high prevalence of PTDM in HCV (+) recipients. PTDM after OLT was associated with significantly increased mortality. HCV infection and methylprednisolone boluses were found to be independent risk factors for the development of PTDM. In approximately half of the HCV (+) patients with PTDM, the onset of PTDM was related to the recurrence of allograft hepatitis. Improvement in glycemic control was achieved in the patients who responded to antiviral therapy.

A simple algorithm for designing group sequential clinical trials.

This article describes a simple algorithm for calculating probabilities associated with group sequential trials. This allows the choice of boundaries that may not be among those implemented in available software.