Longitudinal Impacts of Precision Greenness on Alzheimer's Disease

BACKGROUND

The potential for greenness as a novel protective factor for Alzheimer's disease (AD) requires further exploration.

OBJECTIVES

This study assesses prospectively and longitudinally the association between precision greenness - greenness measured at the micro-environmental level, defined as the Census block - and AD incidence.

DESIGN

Older adults living in consistently high greenness Census blocks across 2011 and 2016 were compared to those living in consistently low greenness blocks on AD incidence during 2012-2016.

SETTING

Miami-Dade County, Florida, USA.

PARTICIPANTS

230,738 U.S. Medicare beneficiaries.

MEASUREMENTS

U.S. Centers for Medicare and Medicaid Services Chronic Condition Algorithm for AD based on ICD-9 codes, Normalized Difference Vegetation Index, age, sex, race/ethnicity, neighborhood income, and walkability.

RESULTS

Older adults living in the consistently high greenness tertile, compared to those in the consistently low greenness tertile, had 16% lower odds of AD incidence (OR=0.84, 95% CI: 0.76-0.94, p=0.0014), adjusting for age, sex, race/ethnicity, and neighborhood income. Age, neighborhood income and walkability moderated greenness' relationship to odds of AD incidence, such that younger ages (65-74), lower-income, and non-car dependent neighborhoods may benefit most from high greenness.

CONCLUSIONS

High greenness, compared to low greenness, is associated with lower 5-year AD incidence. Residents who are younger and/or who reside in lower-income, walkable neighborhoods may benefit the most from high greenness. These findings suggest that consistently high greenness at the Census block-level, may be associated with reduced odds of AD incidence at a population level.

POSEIDON study: a pilot, safety and feasibility trial of high-dose omega3 fatty acids and high-dose cholecalciferol supplementation in type 1 diabetes

The anti-inflammatory and immunomodulatory properties of high-dose omega-3 fatty acids and Vitamin D, and the initial encouraging results from case reports on the use of this supplementation in new-onset Type 1 Diabetes (T1D), support further testing of this combination strategy. This intervention appears to be well tolerated, affordable, and sufficiently safe to be further tested in randomized prospective trials to determine whether this combination therapy may be of assistance to halt progression of autoimmunity and/or preserve residual beta-cell function in subjects with new onset and established T1D of up to 10 years duration. In addition, the 1st PreDiRe T1D conference (Preventing Disease and its Recurrence in Type 1 Diabetes - see Editorial in this issue) was organized to discuss initial results and possible alternative/complementary strategies, for collaborative international expansion of these trials, to include strategies for disease prevention. Our POSEIDON clinical trial will test the use of high dose vitamin D3 and highly purified Omega-3 fatty acids in new onset and established T1D. The draft of the study protocol, in addition to the informed consent and assent, is now shared open access to facilitate its international implementation by interested physicians and centers that would like to further test this approach through clinical trials.

Risk Factors for Type 1 Diabetes Recurrence in Immunosuppressed Recipients of Simultaneous Pancreas-Kidney Transplants

Patients with type 1 diabetes (T1D) who are recipients of pancreas transplants are believed to rarely develop T1D recurrence in the allograft if effectively immunosuppressed. We evaluated a cohort of 223 recipients of simultaneous pancreas-kidney allografts for T1D recurrence and its risk factors. With long-term follow-up, recurrence was observed in approximately 7% of patients. Comparing the therapeutic regimens employed in this cohort over time, lack of induction therapy was associated with recurrence, but this occurs even with the current regimen, which includes induction; there was no influence of maintenance regimens. Longitudinal testing for T1D-associated autoantibodies identified autoantibody positivity, number of autoantibodies, and autoantibody conversion after transplantation as critical risk factors. Autoantibodies to the zinc transporter 8 had the strongest and closest temporal association with recurrence, which was not explained by genetically encoded amino acid sequence donor-recipient mismatches for this autoantigen. Genetic risk factors included the presence of the T1D-predisposing HLA-DR3/DR4 genotype in the recipient and donor-recipient sharing of HLA-DR alleles, especially HLA-DR3. Thus, T1D recurrence is not uncommon and is developing in patients treated with current immunosuppression. The risk factors identified in this study can be assessed in the transplant clinic to identify recurrent T1D and may lead to therapeutic advances.

Islet product characteristics and factors related to successful human islet transplantation from the Collaborative Islet Transplant Registry (CITR) 1999-2010

The Collaborative Islet Transplant Registry (CITR) collects data on clinical islet isolations and transplants. This retrospective report analyzed 1017 islet isolation procedures performed for 537 recipients of allogeneic clinical islet transplantation in 1999-2010. This study describes changes in donor and islet isolation variables by era and factors associated with quantity and quality of final islet products. Donor body weight and BMI increased significantly over the period (p<0.001). Islet yield measures have improved with time including islet equivalent (IEQ)/particle ratio and IEQs infused. The average dose of islets infused significantly increased in the era of 2007-2010 when compared to 1999-2002 (445.4±156.8 vs. 421.3±155.4×0(3) IEQ; p<0.05). Islet purity and total number of β cells significantly improved over the study period (p<0.01 and <0.05, respectively). Otherwise, the quality of clinical islets has remained consistently very high through this period, and differs substantially from nonclinical islets. In multivariate analysis of all recipient, donor and islet factors, and medical management factors, the only islet product characteristic that correlated with clinical outcomes was total IEQs infused. This analysis shows improvements in both quantity and some quality criteria of clinical islets produced over 1999-2010, and these parallel improvements in clinical outcomes over the same period.

Antiproinflammatory effects of iodixanol (OptiPrep)-based density gradient purification on human islet preparations

Islet isolation and purification using a continuous density gradient may reduce the volume of tissue necessary for implantation into patients, therefore minimizing the risks associated with intraportal infusion in islet transplantation. On the other hand, the purification procedure might result in a decreased number of islets recovered due to various stresses such as exposure to cytokine/chemokine. While a Ficoll-based density gradient has been widely used in purification for clinical trials, purification with iodixanol (OptiPrep) has been recently reported in islet transplant series with successful clinical outcomes. The aim of the current study was to compare the effects of the purification method using OptiPrep-based and Ficoll-based density gradients. Human islet isolations were performed using a modified automated method. After the digestion phase, pre-purification digests were divided into two groups and purified using a semiautomated cell processor with either a continuous Ficoll- or OptiPrep-based density gradient. The quantity, purity, viability, and cellular composition of islet preparations from each group were assessed. Cytokine/chemokine and tissue factor production from islet preparations after 48-h culture were also measured. Although islet purity, post-purification IEQ, islet recovery rate, FDA/PI, and fractional β-cell viability were comparable, β-cell mass after 48-h culture significantly improved in the OptiPrep group when compared to the Ficoll group. The production of cytokine/chemokine including IL-1β, TNF-α, IFN-γ, IL-6, IL-8, MIP-1β, MCP-1, and RANTES but not tissue factor from the OptiPrep group was significantly lower during 48-h culture after isolation. Each preparation contained the similar number of ductal cells and macrophages. Endotoxin level in both gradient medium was also comparable. The purification method using OptiPrep gradient media significantly reduced cytokine/chemokine production but not tissue factor from human islet preparations and improved β-cell survival during pretransplant culture. Our results suggest that the purification method using OptiPrep gradient media may be of assistance in increasing successful islet transplantation.

Toward improving human islet isolation from younger donors: rescue purification is efficient for trapped islets

Several reports suggest that islets isolated from younger donor pancreata are of better quality for clinical islet transplantation. The relative inefficiency of the continuous gradient purification process (CGP) is one of the major obstacles to the utilization of these younger donor pancreata. This study demonstrates the benefits of utilizing an additional purification step, rescue gradient purification (RGP), to recover trapped islets and examines the possible superiority of these rescued islets. Seventy-three human islet isolations purified by RGP following CGP were divided into two groups based on age, and the isolation results were retrospectively analyzed (group I: age < or = 40, group II: age > 40). The quality of islets from both CGP and RGP were assessed by beta-cell fractional viability (beta FV) and ADP/ATP ratio. Significant increases in the percent islet recovery from RGP and the percent trapped islets in group I compared to group II were observed. Donor age correlated negatively to the percent islets recovered from RGP (R = 0.440) and to the percent of trapped islets (R = 0.511). RGP islets had higher beta FV and better ADP/ATP ratio compared to CGP islets. In conclusion, RGP improved the efficiency in the purification of trapped islets, which often come from younger donor pancreata. The better quality of beta-cells in RGP islets encourages us to perform RGP, considering the higher quality as well as the quantity of remaining islets.

Simple measures to monitor beta-cell mass and assess islet graft dysfunction

The aim of this study was to develop a simple test for the assessment of islet graft dysfunction based on measures involving fasting C-peptide. Calculations were made to account for the dependence of C-peptide secretion on glucose concentration (C-peptide/glucose ratio [CP/G]) and adjusted for renal function by calculating the C-peptide/glucose-creatinine ratio (CP/GCr). Values from 22 recipients were analyzed at different times post-last islet infusion. Receiver operating characteristic curves were used to determine which of these measures best predicts high 90-minute glucose (90 min-Glc; >10 mmol/L) after a Mixed Meal Tolerance Test (MMTT). In this initial analysis, CP/G was found to be superior predicting high 90 min-Glc with a larger area under the ROC curve than C-peptide (p = 0.01) and CP/GCr (p = 0.06). We then correlated C-peptide and CP/G with islet equivalents--IEQ/kg infused, 90 min-Glc after MMTT and clinical outcome (beta-score). C-peptide and CP/G in the first 3 months post-last islet infusion correlated with IEQ/kg infused. CP/G correlated with 90 min-Glc and beta-score. C-peptide and CP/G are good indicators of islet mass transplanted. CP/G is more indicative of graft dysfunction and clinical outcome than C-peptide alone. The ease of calculation and the good correlation with other tests makes this ratio a practical tool when monitoring and managing islet transplant recipients.

Improved human islet isolation using nicotinamide

We investigated the effects of nicotinamide (NA) supplementation of the processing medium during islet isolation. One hundred and two human pancreata were processed for clinical transplantation after preservation either in the University of Wisconsin (UW) or using the two-layer method (TLM). Pancreata were then divided into four groups and retrospectively analyzed. Group I: UW preservation followed by processing without NA, Group II: UW preservation and processing with NA, Group III: TLM preservation without NA, Group IV: TLM preservation with NA. We observed a significant increase in islet yield in Group II (4343+/-348 IEQ/g) [mean+/-SEM], compared to Group I (2789+/-348 IEQ/g) (p=0.005). Similarly, a significant increase in islet yield was observed when NA was used in the processing of organs preserved with TLM (Group IV: 5538+/-413 vs. Group III: 3500+/-629; p=0.02). Furthermore islet yield was higher in Group IV than in Group II (p<0.05). The percentages of preparations that qualified for transplantation were 25, 47, 45, 69% in Groups I, II, III, IV, respectively. Addition of NA to the processing medium significantly improved islet yields in both the UW and TLM preservation protocols, allowing for a higher percentage of islet preparations to qualify for clinical transplantation.

C-peptide and glucose values in the peritransplant period after intraportal islet infusions in type 1 diabetes

BACKGROUND

Successful islet allograft transplantation has been achieved worldwide. This study aimed at evaluating the relationship between peritransplant C-peptide (CP) values and long-term allograft function.

METHODS

We measured CP-to-glucose ratio (CPGR) in intraportal samples pre- and postinfusion, and in peripheral circulation at baseline pretransplant and at 1, 3, 6, 12, 72 hours, 1 week, and 15 and 30 days after first and second infusion in 13 islet allograft recipients. Peritransplant treatment included intravenous (IV) 5% dextrose in saline in all patients. We compared portal CPGR to insulin reduction (%) at 30 days after each infusion, and at 1 year after second infusion.

RESULTS

CPGR peaked between the immediate postinfusion and 3 hours and decreased at 12 hours. At 1 week, CPGR was 0.76 +/- 0.45 and 1.44 +/- 0.37 after first and second infusion, respectively. CPGR at 30 days after second infusion doubled compared to first infusion (P < .001). There was no correlation between peak CPGR and insulin reduction percent at any time point. One patient experienced hypoglycemia (47 mg/dL) 1 hour after second infusion.

CONCLUSIONS

There was no relationship between the CP values in the peritransplant period and long-term graft function or success rate. The early peak in the C-peptide levels is indicative of a significant insulin release after each islet infusion. For this reason, it is important to carefully monitor serum glucose levels in the peritransplant period (hourly for the first 6 hours) and to maintain an IV glucose infusion to avoid hypoglycemia.

Quality of life after islet transplantation

This study analyzed quality of life in patients with type 1 diabetes that received islet transplantation. Twenty-three subjects were followed over 3 years. In addition to an interview, patients self-completed two standardized psychometric questionnaires, HSQ 2.0 and DQOL, before and after transplant, and scores were compared. Analysis was also adjusted for potential "confounders" such as graft dysfunction, insulin therapy and adverse events. DQOL: the Impact score significantly improved at all time points of the follow-up; satisfaction and worry scales also significantly improved at selected time points. Longitudinal analysis demonstrated that reintroduction of insulin had a negative effect on all three scales, but significant improvement in Impact scale persisted even after adjusting for this factor. HSQ 2.0: only the Health Perception scale preliminarily showed significant improvement at most time points. Longitudinal analysis showed loss of significance when insulin therapy was considered. Other scores were improved only at selected time points or not affected. Bodily pain scale showed deterioration at selected times. Interview: glucose control stability, not insulin independence, was reported as the main beneficial factor influencing QOL. In conclusion, islet transplantation has a positive influence on patients' QOL, despite chronic immunosuppression side effects. Re-introduction of insulin modifies QOL outcomes.

Spinal leptomeningeal hemangioblastomatosis in von Hippel-Lindau disease: magnetic resonance and pathological findings

A 55-year-old man with von Hippel-Lindau disease presented with quadriparesis. Multiple enhancing cervical and thoracic spinal masses were seen on magnetic resonance imaging (MRI). A rim of diffuse, nodular enhancement linking all of the discrete masses was apparent on the surface of the cervical and thoracic regions of the cord. Surgical exploration revealed multiple extramedullary-intradural and intramedullary masses, extending to and infiltrating the cord; the leptomeninges contained numerous small tumor seeds at several levels. The excised spinal masses were diagnosed as capillary hemangioblastomas, which infiltrated the pia mater. Diffuse, intense, spinal leptomeningeal enhancement on MRI associated with multiple hemangioblastomas has not been previously reported and may be referred to as spinal "leptomeningeal hemangioblastomatosis."

Effects of enteral and intravenous antimicrobial treatment on survival following intestinal ischemia in rats

One hundred and twenty rats underwent transection of the superior mesenteric artery. The animals were randomly divided into eight groups of 15 animals. Control group 1 and groups 3, 5, and 7 received intravenous normal saline, gentamicin, metronidazole, and gentamicin plus metronidazole, respectively. Control group 2 and groups 4, 6, and 8 received the same compounds enterally. Small and large bowel sections were taken postmortem and a necrosis score was assigned in blinded fashion. Gentamicin did not prolong survival, indicating that gram-negative microbes were not important in this pathology. Longer survival times for animals given either metronidazole or gentamicin plus metronidazole (P less than 0.01) indicate that anaerobes were a causative factor in mortality. During the first 15 hr after ischemia, antibiotics did not change mortality. After 15 hr, enteral administration was superior to intravenous administration in any regimen including metronidazole (P less than 0.01).