Reduction of blood glucose variability in type 1 diabetic patients treated by pancreatic islet transplantation: interest of continuous glucose monitoring

Continuous Glucose Monitoring in Patients Following Simultaneous Pancreas-Kidney Transplantation: Time in Range and Glucose Variability

Simultaneous pancreas-kidney transplantation (SPKT) can improve long-term patient survival and restore endogenous insulin secretion in recipients with type 1 diabetes (T1D). There are currently few data on glucose fluctuations assessed by continuous glucose monitoring (CGM) after SPKT. Aim: to evaluate CGM-derived time in range (TIR) and glucose variability (GV) in patients with T1D and functioning pancreatic grafts after SPKT. Fifty-four CGM recordings from 43 patients, 15 men and 28 women, aged 34 (31; 39) years were analyzed. Time since SKPT was up to 1 year (group 1, n = 13), from 1 to 5 years (group 2, n = 15), and from 5 to 12 years (group 3, n = 26). TIR (3.9-10 mmol/L), Time Above Range (TAR), Time Below Range (TBR), and GV parameters were estimated. There were no differences in mean glucose (5.5 [5.1; 6.2], 5.9 [5.4; 6.2], and 5.9 [5.6; 6.7] mmol/L), TIR (97.6 [92.8-99.1], 97.2 [93.2; 99.1], and 97.5 [93.4; 99]%); TAR (0, 1.8 [1.3; 3.7], and 2.5 [2; 5]%), TBR (5 [3.3; 12.7], 4.1 [2.2; 10.1], and 3.5 [1.3; 6.5]%) and GV parameters between three groups (all p > 0.05). Thus, recipients with functioning pancreatic grafts demonstrate remarkably high TIR and low GV after SPKT.

Pharmacologically Enhanced Regulatory Hematopoietic Stem Cells Revert Experimental Autoimmune Diabetes and Mitigate Other Autoimmune Disorders

Type 1 diabetes (T1D) is characterized by the loss of immune self-tolerance, resulting in an aberrant immune responses against self-tissue. A few therapeutics have been partially successful in reverting or slowing down T1D progression in patients, and the infusion of autologous hematopoietic stem cells (HSCs) is emerging as an option to be explored. In this study, we proposed to pharmacologically enhance by ex vivo modulation with small molecules the immunoregulatory and trafficking properties of HSCs to provide a safer and more efficacious treatment option for patients with T1D and other autoimmune disorders. A high-throughput targeted RNA sequencing screening strategy was used to identify a combination of small molecules (16,16-dimethyl PGE₂ and dexamethasone), which significantly upregulate key genes involved in trafficking (e.g., CXCR4) and immunoregulation (e.g., programmed death ligand 1). The pharmacologically enhanced, ex vivo-modulated HSCs (regulatory HSCs [HSC.Regs]) have strong trafficking properties to sites of inflammation in a mouse model of T1D, reverted autoimmune diabetes in NOD mice, and delayed experimental multiple sclerosis and rheumatoid arthritis in preclinical models. Mechanistically, HSC.Regs reduced lymphocytic infiltration of pancreatic β cells and inhibited the activity of autoreactive T cells. Moreover, when tested in clinically relevant in vitro autoimmune assays, HSC.Regs abrogated the autoimmune response. Ex vivo pharmacological modulation enhances the immunoregulatory and trafficking properties of HSCs, thus generating HSC.Regs, which mitigated autoimmune diabetes and other autoimmune disorders.

Pancreas transplantation perceptions and practice: Results from a national US survey

BACKGROUND

Due to a substantial decline in pancreas transplantation (PT) across the United States over the past 15 years, we sought to understand the perceptions and practices of US PT programs.

METHODS

Surveys were sent to members of the American Society of Transplantation Surgeons and the American Society of Transplantation by email and professional society postings between August 2019 and November 2019.

RESULTS

One hundred twenty three responses were recorded from 56 unique programs. Program characteristics were obtained from the Scientific Registry of Transplant Recipients. Respondents were transplant surgeons (71%), transplant nephrologists (17%), trainees (9%), and allied professionals (3%). Programs were defined according to annual volume as: low (<5 PT/year), intermediate (6-20), or high (>20). High-volume programs reported that these factors were most important for increased PT: expansion of recipient selection, more aggressive donor utilization, and hiring of PT program-specific personnel. At both the program and national level, the vast majority (82% and 79%, respectively) felt the number of PTs currently performed are not in balance with patients' needs.

CONCLUSIONS

Overall, programs reported that the option of PT is not offered adequately to diabetic patients and that strategies to maintain higher PT volume are most evident at intermediate, and especially, high-volume programs.

Reduced glycemic variability and flexible graft function after islet transplantation: A case report

To date, studies of patients with islet transplantation addressing intermittently scanned continuous glucose monitoring profile and the flexibility of the graft islet function under different doses of insulin administration, both of which reflect the real daily life of patients, are quite limited. Here, we report a case of a 46‐year‐old woman who received islet transplantation after kidney transplantation. The patient was followed up over a period of 2 years after initial islet transplantation. Our results show that intermittently scanned continuous glucose monitoring can be useful for monitoring the reduction of glycemic variability, and suggest the appropriate regulation of insulin secretion from graft islets during mixed‐meal test by using different doses of exogenous insulin administration. Additionally, during the 2‐year observational period, glucagon elevation was detected only at hypoglycemia, whereas the level was within the normal range at normoglycemia or hyperglycemia.

Glycemic variability indices can be used to diagnose islet transplantation success in type 1 diabetic patients

AIMS

High glycemic variability (GV) is the major indication for islet transplantation (IT) in patients with type 1 diabetes (T1D). The actual criteria used to assess graft function do not consider GV improvement. Our study aimed to describe GV indices' evolution in T1D patients who benefited from IT during the TRIMECO trial and to evaluate if thresholds might be defined to diagnose IT success.

METHODS

We collected data from 29 patients of the TRIMECO trial, a clinical trial (NCT01148680) comparing the metabolic efficacy of IT with intensive insulin therapy. Based on CGM data, we analyzed mean glucose level and four GV indices (standard deviation, coefficient of variation, MAGE and GVP) before (M0) and 6 months (M6) after IT.

RESULTS

Each GV index decreased significantly between M0 and M6: SD 53.9 mg/dL [44.6-61.5] versus 20.1 mg/dL [13.5-24.3]; CV 35.2% [30.6-37.7] versus 17.3% [12.0-20.5]; MAGE 134.9 mg/dl [111.2-155.8] versus 51.9 mg/dL [32.4-62.4]; GVP 35.3% [24.9-47.2] versus 12.2% [6.2-18.8] (p ≤ 0.0001). Thresholds diagnosing IT success at 6 months post-transplant were an SD at 22.76 mg/dL (sensibility 88.89%, specificity 80.00%), a CV at 17.47% (sensibility 88.89%, specificity 70.00%), a MAGE at 54.81 mg/dL (sensibility 88.89%, specificity 80.00%) and a GVP at 12.27% (sensibility 88.89%, specificity 70.00%).

CONCLUSIONS

This study confirms a positive impact of IT on GV. The proposed thresholds allow an easy evaluation of IT success using only CGM data and may be a clinical tool for the follow-up of transplanted patients.

Hypoglycemia-associated autonomic failure, counterregulatory responses, and therapeutic options in type 1 diabetes

Hypoglycemia remains a major barrier to the achievement of target levels of glycemic control for most individuals with insulin-dependent type 1 diabetes (T1D). Both the loss of β cells and an accompanying defect in the α cell response to hypoglycemia predispose patients with T1D to the development of low blood glucose. Increased glucose variability, exposure to hypoglycemia, and impaired awareness of hypoglycemia all contribute to increased risk of experiencing severe hypoglycemia, which is explained by progressive impairment in epinephrine secretion and autonomic symptom generation in response to hypoglycemia leading to defective glucose counterregulation and hypoglycemia unawareness that characterize hypoglycemia-associated autonomic failure (HAAF). Interruption of HAAF requires interfering with the mechanisms of brain adaptation to low blood glucose that affect central glucose sensing and the autonomic response to hypoglycemia, or avoidance of hypoglycemia that may allow for eventual recovery of counterregulatory and autonomic symptom responses. Strategies for hypoglycemia avoidance that include continuous glucose monitoring may reduce, but do not eliminate, clinically significant hypoglycemia, with ongoing counterregulatory defects and impaired awareness of hypoglycemia. Complete avoidance of hypoglycemia can be achieved following pancreatic islet transplantation and allows for the restoration of counterregulatory and autonomic symptom responses that evidences the potential for reversing HAAF in T1D.

Pancreatic Islet Transplantation in Humans: Recent Progress and Future Directions

Pancreatic islet transplantation has become an established approach to β-cell replacement therapy for the treatment of insulin-deficient diabetes. Recent progress in techniques for islet isolation, islet culture, and peritransplant management of the islet transplant recipient has resulted in substantial improvements in metabolic and safety outcomes for patients. For patients requiring total or subtotal pancreatectomy for benign disease of the pancreas, isolation of islets from the diseased pancreas with intrahepatic transplantation of autologous islets can prevent or ameliorate postsurgical diabetes, and for patients previously experiencing painful recurrent acute or chronic pancreatitis, quality of life is substantially improved. For patients with type 1 diabetes or insulin-deficient forms of pancreatogenic (type 3c) diabetes, isolation of islets from a deceased donor pancreas with intrahepatic transplantation of allogeneic islets can ameliorate problematic hypoglycemia, stabilize glycemic lability, and maintain on-target glycemic control, consequently with improved quality of life, and often without the requirement for insulin therapy. Because the metabolic benefits are dependent on the numbers of islets transplanted that survive engraftment, recipients of autoislets are limited to receive the number of islets isolated from their own pancreas, whereas recipients of alloislets may receive islets isolated from more than one donor pancreas. The development of alternative sources of islet cells for transplantation, whether from autologous, allogeneic, or xenogeneic tissues, is an active area of investigation that promises to expand access and indications for islet transplantation in the future treatment of diabetes.

Long-term Effect of Islet Transplantation on Glycemic Variability

Islet transplantation has been reported to restore normoglycemia and the overall metabolic control in type 1 diabetes mellitus (DM). In the most experienced centers, islet transplantation clinical outcome is similar to that of the whole pancreas transplantation. Long-term islet transplantation function remains a very interesting matter worth discussing. A progressive islet function decrease was reported, probably due to islet exhaustion. In 5 islet-transplanted patients with at least 3-yr follow-up and still insulin independent, their glycemic control was characterized by a blinded retrospective continuous glucose monitoring system (CGMS). Islet transplantation restored glycemic control and glucose variability. Data were compared with patients in the waiting list. All the parameters of glycemic variability tested had improved significantly in patients who had islet transplantation compared with those patients who were on the waiting list. In conclusion, islet transplantation is able to maintain a proper glucose control and normalize glycemic variability in selected patients. A blinded retrospective CGMS is a useful method to characterize glucose homeostasis deeply in vivo in islet-transplanted patients.

Fall in C-Peptide During First 4 Years From Diagnosis of Type 1 Diabetes: Variable Relation to Age, HbA1c, and Insulin Dose

OBJECTIVE

We aimed to describe the natural history of residual insulin secretion in Type 1 Diabetes TrialNet participants over 4 years from diagnosis and relate this to previously reported alternative clinical measures reflecting β-cell secretory function.

RESEARCH DESIGN AND METHODS

Data from 407 subjects from 5 TrialNet intervention studies were analyzed. All subjects had baseline stimulated C-peptide values of ≥0.2 nmol/L from mixed-meal tolerance tests (MMTTs). During semiannual visits, C-peptide values from MMTTs, HbA1c, and insulin doses were obtained.

RESULTS

The percentage of individuals with stimulated C-peptide of ≥0.2 nmol/L or detectable C-peptide of ≥0.017 nmol/L continued to diminish over 4 years; this was markedly influenced by age. At 4 years, only 5% maintained their baseline C-peptide secretion. The expected inverse relationships between C-peptide and HbA1c or insulin doses varied over time and with age. Combined clinical variables, such as insulin-dose adjusted HbA1c (IDAA1C) and the relationship of IDAA1C to C-peptide, also were influenced by age and time from diagnosis. Models using these clinical measures did not fully predict C-peptide responses. IDAA1C ≤9 underestimated the number of individuals with stimulated C-peptide ≥0.2 nmol/L, especially in children.

CONCLUSIONS

Current trials of disease-modifying therapy for type 1 diabetes should continue to use C-peptide as a primary end point of β-cell secretory function. Longer duration of follow-up is likely to provide stronger evidence of the effect of disease-modifying therapy on preservation of β-cell function.

Outcomes of Pancreatic Islet Allotransplantation Using the Edmonton Protocol at the University of Chicago

Objective

The aim of this study was to assess short-term and long-term results of the pancreatic islet transplantation using the Edmonton protocol at the University of Chicago.

Materials and Methods

Nine patients underwent pancreatic islet cell transplantation using the Edmonton Protocol; they were followed up for 10 years after initial islet transplant with up to 3 separate islet infusions. They were given induction treatment using an IL-2R antibody and their maintenance immunosuppression regimen consisted of sirolimus and tacrolimus.

Results

Nine patients received a total of 18 islet infusions. Five patients dropped out in the early phase of the study. Greater than 50% drop-out and noncompliance rate resulted from both poor islet function and recurrent side effects of immunosuppression. The remaining 4 (44%) patients stayed insulin free with intervals for at least over 5 years (cumulative time) after the first transplant. Each of them received 3 infusions, on average 445 000 islet equivalent per transplant. Immunosuppression regimen required multiple adjustments in all patients due to recurrent side effects. In the long-term follow up, kidney function remained stable, and diabetic retinopathy and polyneuropathy did not progress in any of the patients. Patients' panel reactive antibodies remained zero and anti-glutamic acid decarboxylase 65 antibody did not rise after the transplant. Results of metabolic tests including hemoglobin A1c, arginine stimulation, and mixed meal tolerance test were correlated with clinical islet function.

Conclusions

Pancreatic islet transplantation initiated according to Edmonton protocol offered durable long-term insulin-free glycemic control in only highly selected brittle diabetics providing stable control of diabetic neuropathy and retinopathy and without increased sensitization or impaired renal function. Immunosuppression adjustments and close follow-up were critical for patient retention and ultimate success.

Demonstration of an intrinsic relationship between endogenous C-peptide concentration and determinants of glycemic control in type 1 diabetes following islet transplantation

OBJECTIVE

Maintenance of endogenous pancreatic β-cell function could be an important goal in the management of type 1 diabetes. However, the impact of stimulated C-peptide level on overall glycemic control is unknown. The relationship between C-peptide and parameters of glucose control was therefore characterized in a cohort with rapidly changing β-cell function following islet transplantation.

RESEARCH DESIGN AND METHODS

Standardized mixed-meal tolerance test was undertaken in 12 consecutive islet recipients at 1-6-month intervals, with graft function determined by 90-min stimulated C-peptide. Continuous glucose monitoring was undertaken in the week preceding each assessment and the relationship between C-peptide and glucose control evaluated by mixed Poisson regression.

RESULTS

Recipients completed 5 (1-14) [median (range)] clinical assessments over 18 (1-51) months posttransplant encompassing a wide range of stimulated C-peptide levels (7-2,622 pmol/L). Increasing β-cell function across predefined C-peptide groups was associated with reduced insulin dose, HbA1c, mean glucose (low [<200 pmol/L] 10.7 vs. excellent [>1,000 pmol/L] 7.5 mmol/L), and glucose SD (low, 4.4 vs. excellent, 1.4 mmol/L). Highly statistically significant continuous associations between stimulated C-peptide and mean interstitial glucose (lower by 2.5% [95% CI 1.5-3.5%] per 100 pmol/L higher C-peptide), glucose SD, time outside glucose target range, and measures of hyper-/hypoglycemia risk were confirmed.

CONCLUSIONS

Repeated assessment of islet transplant recipients has enabled modeling of the relationship between endogenous β-cell function and measures of glycemic control providing quantitative estimates of likely impact of an acute change in β-cell function in individuals with type 1 diabetes.

Glycemic variability in hospitalized patients: choosing metrics while awaiting the evidence

Hyperglycemia, hypoglycemia, preexisting diabetes, and glycemic variability each may affect hospital outcomes. Observational findings derived from randomized trials or retrospective studies suggest that independent of hypoglycemia and hyperglycemia, a relationship exists between variability and hospital outcomes. A review of studies conducted in diverse hospital populations is reported here, showing a relationship between measures of variability and nonglycemic outcomes, including ICU and hospital mortality and length of stay. "Glycemic variability" has an intuitive meaning, understood as a propensity of a single patient to develop repeated episodes of excursions of BG over a relatively short period of time that exceed the amplitude expected in normal physiology. It is proposed that each of 3 dimensions of variability should be separately studied: (1) magnitude of glycemic excursions during intervals of relative stability of the moving average of BG, (2) frequency with which a critical magnitude of excursion is exceeded, and (3) presence or absence of fine tuning. Multiple hospital studies have found that the standard deviation (SD) of the data set of blood glucose values (BG) of individual patients predicts outcomes. An appropriate refinement would be to report the "Reverse-transformed group mean of the SD of the logarithmically transformed BG data set of each patient," with confidence intervals. In logarithmic space, group means of the SD of BGs of each patient may be compared, using an appropriate parametric test. Upon reverse transformation, the upper and lower bounds of the confidence intervals become asymmetric about the reverse-transformed group mean of the SD. There is a need to understand what patterns of dispersion of BG over time are captured by SD as a predictor of outcomes. Among the causes of high SD, a subgroup may consist of patients having frequent oscillations of BG. Another subgroup may consist of patients experiencing a major change of overall glycemia during the timeframe of data collection. Appropriate metrics should be developed to recognize both variability in the sense of recurrent large oscillations of BG, and separately to recognize any time-dependent change of overall glycemia during hospitalization. Especially in relation to uncontrolled diabetes, there is a need to know whether rapid correction of chronic hyperglycemia adversely affects hospital outcomes. We have some understanding of how to control or prevent change of overall glycemia, and less understanding of how to control variability. Each may be associated with outcomes, and each may be detected by a high SD, but it remains uncertain whether intervention to prevent either pattern of changing glycemia would affect outcomes.

Continuous glucose monitoring after islet transplantation in type 1 diabetes: an excellent graft function (β-score greater than 7) Is required to abrogate hyperglycemia, whereas a minimal function is necessary to suppress severe hypoglycemia (β-score greater than 3)

CONTEXT

For the last 10 yr, continuous glucose monitoring (CGM) has brought up new insights into the accuracy of blood glucose analysis.

OBJECTIVE

Our objective was to determine how islet graft function was able to influence the various components of dysglycemia after islet transplantation (IT).

DESIGN AND SETTING

We conducted a single-arm open-labeled study with a 3-yr follow-up in a referral center (ClinicalTrial.gov identifiers NCT00446264 and NCT01123187).

PATIENTS

Twenty-three consecutive patients with type 1 diabetes (14 islet alone, nine islet after kidney) received IT within 3 months using the Edmonton protocol.

INTERVENTION

INTERVENTION included 72-h CGM before and 3, 6, 9, 12, 24, and 36 months after transplantation.

MAIN OUTCOME MEASURE

Graft function was estimated via β-score, a previously validated index (range 0-8) based on treatment requirements, C-peptide, blood glucose, and glycated hemoglobin.

RESULTS

At the 3-yr visit, graft function persisted in 19 patients (82%), and 10 (43%) remained insulin independent. Glycated hemoglobin decreased in the whole cohort from 8.3% (7.3-9.0%) at baseline to 6.7% (5.9-7.7%) at 3 yr [median (interquartile range), P < 0.01]. Mean glucose, glucose sd, and time spent with glycemia above 10 mmol/liter (hyperglycemia) and below 3 mmol/liter (hypoglycemia) were significantly lower after IT (P < 0.05 vs. baseline). The four CGM outcomes were related to β-score (P < 0.001). However, partial function (β-score >3) was sufficient to abrogate hypoglycemia; suboptimal function (β-score >5) was necessary to significantly improve mean glucose, glucose sd, and hyperglycemia; and optimal function (β score >7) was necessary to normalize them.

CONCLUSION

The four components of dysglycemia were not equally affected by the degree of islet graft function, which could have important implications for future development of β-cell replacement. A β-score above 3 dramatically reduced the occurrence of hypoglycemia.

Assessment of glycemic lability and severity of hypoglycemia in Korean patients with type 1 diabetes

Few studies have focused on the quantification of glycemic lability and hypoglycemic events in Asian patients with type 1 diabetes; therefore, we conducted a study to assess glycemic lability and the severity of hypoglycemia in type 1 diabetic patients in Korea. A total of 124 type 1 diabetic patients were enrolled. Several glycemic lability indexes and hypoglycemic indexes were calculated using four-week self-monitoring of blood glucose (SMBG) data. Due to the dependence of the lability index (LI) on the frequency of glucose measurements, we generated a modified LI by dividing by the number of SMBG measurements per day for a given patient. The numbers of patients in our study with a composite hypoglycemic score ≥ 1,047 or LI ≥ 433 mmol/L(2)/h•week(-1), which was found in a previous study to indicate high risk of severe hypoglycemia or lability, were 0 (0%) and 44 (35%), respectively. Compared to previously reported hypoglycemia indexes, the low blood glucose index was lower in our study. However, the glycemic lability indexes were similar to those in previous studies, with the exception of the LI. The modified LI and the average daily risk range (ADRR) showed higher concordance with other glycemic lability indexes than did the LI or mean amplitude of glycemic excursions (MAGE). The results showed that the hypoglycemic indexes in this study population were lower than the results from Ryan et al. Furthermore, the ADRR or modified LI were better measures for high risk of severe lability than were the LI and MAGE.

Detrended fluctuation analysis is considered to be useful as a new indicator for short-term glucose complexity

BACKGROUND

This study clarified whether detrended fluctuation analysis (DFA) can evaluate how to advance the loss of complexity from impaired glucose tolerance (IGT) through mild diabetes mellitus (DM) to overt DM.

METHODS

Continuous glucose monitoring (CGM) was done during a 48-h interval for 59 subjects from multiple centers. Subjects were divided according to CGM data into those with impaired glucose tolerance (IGT) (n = 20), mild DM (n = 13), and overt DM (n = 26). The short-term (α1) and long-term (α2) range exponentials by DFA were compared among the three groups.

RESULTS

The value of α1 within 1h was significantly lower in the IGT group than in either of the other two groups (IGT vs. mild DM vs. overt DM, 1.53 ± 0.22 vs. 1.71 ± 0.17 vs. 1.77 ± 0.13, P<0.0001), and α1 within 2h differed significantly among the three groups (1.49 ± 0.13 vs. 1.57 ± 0.10 vs. 1.72 ± 0.10, P<0.0001). The α1 within 3h was significantly higher in overt DM than in either of the other two groups but did not change between IGT and mild DM (1.44 ± 0.12 vs. 1.52 ± 0.11 vs. 1.67 ± 0.09, P<0.0001). All short-term exponents decreased gradually but significantly as the window widened in all groups (P<0.0001). The α2 over 1h was significantly higher in overt DM but was unchanged in IGT and mild DM (1.22 ± 0.11 vs. 1.27 ± 0.12 vs. 1.36 ± 0.13, P = 0.0010). The α2 over 3h did not differ among the three groups.

CONCLUSIONS

Progressive loss of complexity in the glycemic profile occurred from the short-term range and spread to the long-term range concomitantly with the progression of the DM state.

Continuous glucose monitoring in subjects after simultaneous pancreas-kidney and kidney-alone transplantation

BACKGROUND

Simultaneous pancreas-kidney (SPK) transplantation is an important replacement therapy for individuals with diabetes and end-stage renal disease. Kidney-alone (KA) transplantation is associated with a high incidence of post-transplant diabetes.

METHODS

This was a cross-sectional study. We studied 48-h glucose concentrations in eight subjects with type 1 diabetes mellitus after SPK transplantation, six subjects post-KA transplantation, and nine healthy controls using the CGMS (Medtronic Minimed, Northridge, CA) continuous glucose monitoring system.

RESULTS

The 48-h mean glucose concentration was 101 +/- 7 mg/dL in the SPK subjects, 105 +/- 12 mg/dL in the KA subjects, and 99 +/- 7 mg/dL in the healthy controls. The glycemic excursions were higher in the KA group compared to the SPK cohort and healthy controls (P < 0.0001). No differences in the incidence of hypoglycemia were detected among the three groups. Significant postprandial hyperglycemia was uncovered in four of the six KA subjects.

CONCLUSIONS

SPK transplantation is very effective at normalizing glycemic excursions. Unsuspected hyperglycemia was identified in the KA group. The CGMS was a useful ambulatory tool to study glucose profiles in the post-transplant period and may help uncover hyperglycemia undetected by routine laboratory testing.

Effect of islet transplantation on metabolic glucose control in rats with diabetes

BACKGROUND

Transplantation of pancreatic islets has been extensively investigated as a strategy for glycemic control in experimental animals and in patients with diabetes. We investigated whether islet transplantation allows us to obtain adequate islet function during glucose stimulation using a continuous glucose monitoring system (CGMS) in the rat.

METHODS

We investigated four groups of eight rats each: healthy rats (controls), rats with diabetes, and rats with diabetes transplanted with microencapsulated islets in the peritoneal cavity or transplanted with free islets under the kidney capsule. Syngeneic islets were isolated from Lewis rats. After diabetes induction and islet implantation, when glycemia was stable, a glucose sensor was implanted, and an intraperitoneal glucose tolerance test (IPGTT) was performed to evaluate islet function. Interstitial glucose levels were analyzed, using a theoretical model, to estimate kinetics of glucose metabolism.

RESULTS

Islet transplantation was effective in inducing normoglycemia in both groups, but results of IPGTTs showed that in animals with islets transplanted in microcapsules values of area under the curve and total glucose elimination constant (k(tot)) were significantly different from those in control animals and that these differences were even more important in animals with islets implanted under the kidney capsule.

CONCLUSIONS

Our present investigation demonstrates that the application of CGMS was effective in evaluation of glucose metabolism by islet transplantation and indicates that efficient diabetes control can be achieved with this technology.

Use of the continuous glucose monitoring system in Goettingen Minipigs, with a special focus on the evaluation of insulin-dependent diabetes

OBJECTIVES

Adult pig islet isolation has greatly improved in the past few years. Islet grafts may now be tested in large animals. Continuous Glucose Monitoring System (CGMS) was applied to diabetic Goettingen Minipigs (GMP) to improve the management of hyperglycemia and hypoglycemia and their welfare before transplantation.

METHODS

GMP (25-35 kg) received a minipig diet once daily. Diabetes was induced by streptozotocin (STZ; 150 mg/kg intravenous [IV]; n = 5) or by surgical pancreatectomy (PGMP; n = 3). Interstitial glucose concentration (IGC) was monitored continuously with an implanted sensor; CGMS was calibrated using conventional blood glucose tests 3-4 times per day; CGMS data were fed into the monitor memory and analyzed using CGMS software.

RESULTS

Glucose sensors were handled accurately. Diabetes occurred 2-3 days after STZ or immediately after pancreatectomy with basal C-peptide secretion of <0.4 ng/mL (measured using intravenous glucose tolerance test) and prompt loss of body weight. Insulin substitution was necessary to keep the GMP in good condition for up to 5-6 months, with stable body weight and normal behavior. Some GMP became hypoglycemic, which was only documented by CGMS, but not by conventional glucose assays. Tight glucose control and substitution of exocrine enzymes (Creon 25,000 E/d) reduced morbidity of the PGMP, which was then comparable with that of STZ-GMP.

CONCLUSIONS

The CGMS, developed for humans, is equally suitable for the 2 GMP diabetes models. Close-meshed glucose monitoring and insulin treatment improved the general condition of the diabetic GMP, ie, the islet graft recipients, and will thus greatly add to posttransplantation success.

Glucocorticoids reduce pro-inflammatory cytokines and tissue factor in vitro and improve function of transplanted human islets in vivo

Factors that upregulate the inflammatory status of islets probably contribute to detrimental processes leading to islet loss and impaired post-transplant function. Glucocorticoids have the potential to counteract inflammation and thus improve islet quality and function. However, glucocorticoids have diabetogenic properties and are known to hamper islet function in vivo. We examined the effect of glucocorticoids on human islets in vitro and in vivo after 48 h of exposure to different concentrations of methylprednisolone. Protein and/or mRNA levels of insulin, interleukin (IL)-8, macrophage chemoattractant protein (MCP)-1, tissue factor (TF), and IL-10 were assessed by enzyme immunosorbent assay and real time quantitative reverse transcription-polymerase chain reaction. Viability was assessed with fluorescein diacetate-propidium iodide staining, adenosine triphosphate (ATP) content and caspase activity. Six-hundred islet equivalents (IEQ) were transplanted to severe combined immunodeficiency disease mice and graft function assessed by glucose measurements and intraperitoneal glucose tolerance tests. Glucocorticoids reduce mRNA and protein levels of TF, MCP-1 and IL-8, and enhance ATP content. Insulin secretion was initially inhibited; however, after 7 days in culture, it was superior to controls. Islets exposed to methylprednisolone cured diabetic mice more effectively than control islets. In conclusion, glucocorticoids have potent anti-inflammatory properties on human islets without permanent effects on insulin metabolism. Brief glucocorticoid exposure improves function of transplanted human islets in vivo.

Impact of islet transplantation on glycemic control as evidenced by a continuous glucose monitoring system

BACKGROUND

This study evaluated the effects of islet allotransplantation (ITx) on metabolic control utilizing a continuous glucose monitoring system (CGMS) and assessed its effectiveness as an indicator and predictor of graft dysfunction (GD).

METHODS

Glycemic control was assessed in 25 patients with type 1 diabetes mellitus (T1DM); 12 ITx recipients and 13 controls. Mean interstitial glucose, standard deviation (SD), glucose variability, and percentage of time in hyperglycemia (%GT >140 mg/dl), hypoglycemia (%GT <54 mg/dl), and normoglycemia (%GT 54-140 mg/dl) were measured in 72-hour time periods from CGMS recordings in the control group at baseline and in the ITx group at 3, 6, 9, 12, 15, and 18 months after ITx completion and were analyzed as predictors and indicators of GD. Hemoglobin A1c (HbA1c), 90-minute glucose after a mixed meal tolerance test, fasting C-peptide/glucose ratio, and insulin requirements were followed.

RESULTS

Compared to the control group, the percentage of time in hypoglycemia was significantly lower in the ITx group at all time points; time in normoglycemia was increased at all times except at 15 months; and time in hyperglycemia was significantly lower at 6, 9, 12, and 18 months. Mean glucose and glucose variability were significantly lower in the ITx group at all times except at 3 and 15 months, whereas HbA1c and 90-minute glucose were significantly lower in the ITx group at all time points. Mean glucose, SD, glucose variability, and %GT >140 mg/dl were significant as indicators but not as predictors of GD.

CONCLUSIONS

The CGMS demonstrated the benefits of ITx in T1DM, with improvements in glycemic control apparent up to 18 months after transplant. CGMS measures were found to be indicators of GD.

Continuous glucose monitoring system for early detection of graft dysfunction in allogenic islet transplant recipients

BACKGROUND

There are no effective indicators of graft dysfunction in islet transplantation. This study evaluated the role of the Continuous Glucose Monitoring System (CGMS) as an early indicator of graft dysfunction in islet transplant recipients.

METHODS

In 5 islet allograft recipients, we retrospectively determined the date of graft dysfunction: 3 fasting blood glucose levels >7.8 mmol/L (140 mg/dL) and/or 3 postprandial blood glucose levels >10 mmol/L (180 mg/dL) in 1 week. We then determined 2 time points in respect to graft dysfunction, 5 to 9 months before (time point A) and 2 to 3 months before (time point B). For these 2 time points, we assessed the following: HbA1c, C-peptide (CP), C-peptide glucose ratio (CPGR), 90-minute glucose from mixed meal tolerance test, and percentage of capillary blood glucose levels >7.8 mmol/L (%CBG >7.8) in a 15-day interval (1 week before and after CGMS placement). From the CGMS recordings, we calculated the glucose variability and the percentage of time spent in hyperglycemia >7.8 mmol/L (%HGT >7.8) and >10 mmol/L (%HGT >10).

RESULTS

No difference was found between time points A and B for the following parameters: HbA1c, CP, CPGR, 90-minute glucose, %CBG >7.8, and %HGT >10. We observed a statistically significant increase from time point A to time point B in glucose variability (1.1 +/- 0.5 mmol/L to 1.6 +/- 0.6 mmol/L; P = .004), and in the %HGT >7.8 (11 +/- 12% to 22 +/- 18%; P = .036).

CONCLUSION

Glucose variability and %HGT >7.8 determined using CGMS are useful as early indicators of graft dysfunction in islet transplant recipients. Further studies with larger sample sizes will help validate these observations.

Evaluation of the superiority of insulin glargine as basal insulin replacement by continuous glucose monitoring system

To evaluate the superiority of insulin glargine as basal insulin replacement by continuous glucose monitoring system (CGMS). Twenty-four patients with type 2 diabetes mellitus (T2DM) whose blood glucose was not well controlled with sulphanylureas were enrolled. At first, they were treated with extended-release glipizide (glucotrol XL) 5mg/d before breakfast for 2 weeks, then randomized to combination treatment with glargine (16 patients) or NPH (8 patients) and treated for 12 weeks. CGMS were carried in the second week after treatment with glucotrol XL, and in the 12th week after combination treatment. The data of CGMS showed: (1) When FPG were well controlled in both groups (glargine group versus NPH group: 6.0+/-1.0 mmol/L versus 5.8+/-1.3 mmol/L), the blood glucose level at 3:00 a.m. (5.1+/-0.9 mmol/L versus 4.2+/-0.8 mmol/L) were higher (P<0.05), TPG< or =3.0 mmol/L at night were lower (2.56+/-1.79 versus 5.88+/-1.96), and the rate of nocturnal hypoglycemia (1/16 versus 4/8) were less (P=0.028) in glargine group than those in NPH group. (2) CGMS showed that the daily blood glucose profile excursion were more smoother in glargine group than those in NPH group. In conclusion, it was confirmed with CGMS that compared with traditionally basal insulin replacement with NPH, the combination treatment with glargine injection at bedtime may be predominant for stabilizing the daily blood glucose profile excursion and decreasing the nocturnal hypoglycemia events incidence. So glargine may be a more ideal basal insulin replacement than NPH.

Glycemic thresholds for activation of counterregulatory hormone and symptom responses in islet transplant recipients

CONTEXT

In patients with type 1 diabetes and reduced awareness of hypoglycemia, the glycemic thresholds for activation of counterregulatory hormone and symptom responses to hypoglycemia are impaired, in part due to recurrent episodes of hypoglycemia. Islet transplantation can ameliorate occurrences of hypoglycemia in these patients.

OBJECTIVE

The objective of the study was to determine whether the avoidance of hypoglycemia achieved through islet transplantation results in improved glycemic thresholds for counterregulatory responses.

SETTING

The study was conducted at a general clinical research center.

PARTICIPANTS

Seven islet transplant recipients, six type 1 diabetic, and eight nondiabetic control subjects participated in the study.

INTERVENTION

We performed a stepped hyperinsulinemic hypoglycemic clamp and, in 12 subjects, a paired hyperinsulinemic euglycemic clamp to calculate the glycemic thresholds for and magnitude of counterregulatory responses.

RESULTS

The glycemic thresholds for all counterregulatory hormone and symptom responses in the islet transplant group were comparable with normal and higher than in the type 1 diabetes group (P < 0.01 for glucagon; P < 0.05 for epinephrine). The magnitude of the glucagon and epinephrine responses in the islet transplant group, although greater than in the type 1 diabetes group (P < 0.05 for both), remained less than normal (P < 0.01 for glucagon; P < 0.05 for epinephrine). The magnitude of GH secretion in the islet transplant group was comparable with normal and greater than in the type 1 diabetes group (P < 0.05).

CONCLUSIONS

The glycemic thresholds for activation of counterregulatory hormone and symptom responses appear normal after islet transplantation; however, the magnitudes of the glucagon and epinephrine responses remain impaired.

Monitoring of the islet graft

The Edmonton trials have brought about a marked improvement in the short-term rate of success of islet transplantation with rates of insulin-independence of 80% at 1-year being reported by several institutions worldwide. Unfortunately, this rate consistently decreases to 10-15% by 5 years post-transplantation. Several mechanisms have been proposed to explain this apparent 'islet exhaustion', but are difficult to pinpoint in a given patient. Understanding the reasons for islet graft exhaustion and its kinetics is a prerequisite for the improvement of islet transplantation outcome. In this regard, efficient monitoring tools for the islet graft have been conspicuously lacking and are required to detect islet damage and diagnose its mechanisms in a timely fashion, so as to initiate salvage therapy such as antirejection treatment. Tools for the monitoring of the islet graft include follow-up of metabolic function but mostly indicate dysfunction when it is too late to take action. Progress is likely to arise in the fields of immune monitoring, molecular monitoring and islet imaging, notably thanks to magnetic resonance (MR) or positron emission tomography (PET) technologies.

Management strategies for brittle diabetes

Type 1 diabetes is an intrinsically unstable condition. However, the term "brittle diabetes" is reserved for those cases in which the instability, whatever its cause, results in disruption of life and often recurrent and/or prolonged hospitalization. It affects 3/1000 insulin-dependent diabetic patients, mainly young women. Its prognosis is poor with lower quality of life scores, more microvascular and pregnancy complications and shortened life expectancy. Three forms have been described: recurrent diabetic ketoacidosis, predominant hypoglycemic forms and mixed instability. Main causes of brittleness include malabsorption, certain drugs (alcohol, antipsychotics), defective insulin absorption or degradation, defect of hyperglycemic hormones especially glucocorticoid and glucagon, and above all delayed gastric emptying as a result of autonomic neuropathy. Psychosocial factors are very important and factitious brittleness may lead to a self-perpetuating condition. The assessment of brittle diabetes requires quantification of the variability of blood glucose levels. To quantify instability, measures which have been developed, include Mean Amplitude of the largest Glycemic Excursions (MAGE), Mean Of Daily Differences (MODD), Lability Index (LI), Low Blood Glucose Index (LBGI), Clarke's score, Hyposcore, and continuous blood glucose monitoring. Once psychogenic problems have been excluded, therapeutic strategies require firstly, the treatment of underlying organic causes of the brittleness whenever possible and secondly optimising standard insulin therapy using analogues, multiple injections and consideration of Continuous Subcutaneous Insulin Infusion. Alternative approaches may still be needed for the most severely affected patients. Isolated islet transplantation (IIT), which restores glucose sensing, should be considered in cases of hypoglycaemic unawareness and/or lability especially if the body mass index is < 25, but with current immunosuppressive protocols patients must have normal renal function and preferably no plans for pregnancy. Implantable pumps have advantages for patients who either weigh more than 80 kgs or have abnormalities of kidney or liver function or are highly sensitised.

Assessment of glycemic control after islet transplantation using the continuous glucose monitor in insulin-independent versus insulin-requiring type 1 diabetes subjects

BACKGROUND

The aim of this study was to assess and compare glycemic control using the continuous glucose monitor (CGMS, Medtronic Minimed, Northridge, CA) in type 1 diabetes mellitus (T1DM) subjects who are insulin-independent versus those who require insulin after islet transplantation alone (ITA).

METHODS

Glycemic control was assessed using 72-h CGMS in eight T1DM subjects who were insulin-independent after ITA (ITA-II), eight T1DM subjects who were C-peptide-positive but insulin-requiring after ITA (ITA-IR), and eight non-transplanted (NT) T1DM subjects.

RESULTS

Standard deviation of glucose values was not significantly different between ITA-II and ITA-IR subjects (ITA-II, 1.2 +/- 0.1 mM; ITA-IR, 2.0 +/- 0.3 mM; P = 0.072). Both ITA groups were more stable than NT subjects (NT, 3.3 +/- 0.3 mM; P = 0.001 vs. ITA). Mean high glucose values were significantly lower in ITA subjects compared with NT subjects (ITA-II, 10.5 +/- 0.6 mM; ITA-IR, 13.0 +/- 1.0 mM; NT, 16.1 +/- 1.1 mM; P = 0.002). Mean average glucose values were not significantly different among all groups (ITA-I, 6.7 +/- 0.2 mM; ITA-IR, 7.8 +/- 0.3 mM; NT, 7.7 +/- 0.6 mM; P = 0.198). Mean low glucose values were significantly higher in both ITA groups compared with NT subjects (ITA-II, 4.5 +/- 0.2 mM; ITA-IR, 4.3 +/- 0.3 mM; NT, 3.0 +/- 0.2 mM; P = 0.003). Duration of hypoglycemic excursions (<3.0 mM) was markedly reduced in both ITA groups (ITA-II, 0%; ITA-IR, 2.4 +/- 0.2%; NT, 11.8 +/- 4.2%). Glycated hemoglobin was not significantly different between ITA groups (ITA-II, 6.4 +/- 0.2%; ITA-IR, 6.5 +/- 0.3%) and was significantly higher in NT subjects (8.3 +/- 0.2%; P < 0.001 vs. ITA).

CONCLUSIONS

CGMS monitoring demonstrates that glycemic lability and hypoglycemia are significantly reduced in C-peptide-positive islet transplant recipients, whether or not supplementary, exogenous insulin is used, compared with non-transplanted T1DM subjects.

Current indications for pancreas or islet transplant

Pancreas or islet transplantation can provide good glycaemic control and insulin independence. Pancreas transplantation has been associated with improvement in diabetic retinopathy, nephropathy, neuropathy and vasculopathy, but has the associated morbidity of major surgery. Both forms of therapy require long-term immunosuppression and its attendant risks and both achieve insulin independence rates of about 80% at 1 year. Pancreas transplantation at the same time as a renal transplant is a worthwhile option to employ, especially if the diabetes has been difficult to control. Diabetes associated with frequent severe hypoglycaemia or extreme lability, despite optimization of diabetes management, may benefit from either pancreas or islet transplant alone with the latter being the lower-risk procedure. More quantitative measures of hypoglycaemia and lability are now available to facilitate the assessment of the severity of these problems with glucose control. Diabetic patients with renal involvement (macroproteinuria, but no major elevation of creatinine) and unstable diabetes may be helped with an islet or pancreas transplant, but this approach should still be considered experimental and such a transplant may hasten the need for renal replacement therapy. In the setting of well-controlled diabetes and intact renal function, it is difficult to justify pancreas or islet transplant alone given the risks of immunosuppression.

Evaluation of metabolic control using a continuous subcutaneous glucose monitoring system in patients with type 1 diabetes mellitus who achieved insulin independence after islet cell transplantation

This study evaluated the Medtronic MiniMed Continuous Glucose Monitoring System (CGMS) in patients with type 1 diabetes mellitus who underwent successful islet cell transplantation (ICT). The results are compared to standardized self-monitoring (SMBG) of hyperglycemia and mean amplitude of glycemic excursions (MAGE). We studied 19 patients (mean age 40.0 +/- 6.7 years) in three groups: six patients post-ICT, seven patients awaiting ICT, and six normal volunteers (controls). Continuous glucose monitoring post-ICT showed remarkable glucose stability compared with patients awaiting ICT. The CGMS group showed modestly higher glucoses (mean 111.5 mg/dl) compared with controls (88 mg/dl). Postprandial glucoses in ICT recipients rarely exceeded 180 mg/dl and were similar to controls. There was no difference in asymptomatic hypoglycemia between control and post-ICT groups. However, a higher incidence of hypoglycemia was observed in patients awaiting ICT. HbA1c and MAGE pre- and post-ICT were 8.3 +/- 0.9% and 6 +/- 0.3% (p < 0.001) and 109 +/- 34 and 41 +/- 11 (p < 0.001), respectively. No complications were associated with CGMS. This study suggests ICT significantly improves metabolic control and rate of hypoglycemia when compared with controls and patients awaiting ICT. Similar improvement in metabolic control was observed with SMBG, HbA1c, and MAGE. Although CGMS was not demonstrated to be a superior tool for routine assessment in ICT, it is very helpful in special clinical situations.

[Diabetes Type I therapy through transplantation]

Diabetes is one of the most common chronic diseases in our society. While insulin treatment for diabetes type I could delay and reduce the incidence of diabetic complications, it is associated with an increased risk of severe hypoglycemia. To restore physiologic insulin metabolism, transplantation of insulin producing cells (pancreatic Beta cells) represent the sole available therapy. It could be done either through pancreas or islet of Langerhans transplantation. In this paper, we review actual knowledge regarding these two types of transplantations.

Selection of diabetic patients for islet transplantation. A single-center experience

OBJECTIVE

Since the Edmonton protocol, islet transplantation (IT) offers the prospect of adequate glycemic control with no major surgical risk. In our single-center experience of IT, we studied the recruitment of eligible diabetic patients.

METHODS

Between 1998 and 2002, we screened 79 diabetic patients that were divided into 2 groups according to their renal status: 41 were not receiving dialysis (ND) while 38 were receiving ongoing dialysis (D).

RESULTS

In the ND group, 20 patients initiated the contact with our team, 8 patients were recruited during hospitalization for very poor glycemic imbalance, and 13 were referred by their diabetologist. 14/41 (34%) patients were ineligible for IT either because of very good glycemic balance, detectable C-peptide (C-p), kidney or liver problems, or plans for future pregnancy. 16/41 (39%) did not wish to proceed, 7 of whom were more interested by a pump. 11/41 (27%) were eligible, among which 8 are currently being assessed, 1 is on the waiting list and 2 have been transplanted. In the D group, 17/38 (45%) had a detectable C-p and received a kidney graft alone. Among the remaining 21 C-p negative diabetic patients, 3 were not eligible for kidney transplantation mainly for psychological reasons, and 4 were enlisted for kidney+pancreas transplantation. The remaining 14 C-p negative patients were kidney-transplanted. Among them, 6 were not eligible for IT, mainly for lack of motivation, slightly positive C-p stimulation tests, obesity, cancer, or increased creatininemia. The remaining 8/14 C-p negative kidney-engrafted patients were enlisted for IT. 3 had secondary failure with the pre-Edmonton immunosuppressive (IS) protocol. Five have been transplanted with the Edmonton-like IS regimen.

CONCLUSION

Twenty-five per cent of the 79 patients for whom islet transplantation was considered underwent pregraft assessment and 12% (10 patients, 8 kidney-transplanted and 2 islet alone) of the 79 have been transplanted. The main eligibility criteria were undetectable Cpeptide, normal kidney function, average weight, glycemic imbalance, hypoglycemia unawareness, and glycemic brittleness.

Risks and side effects of islet transplantation

Islet transplantation can deliver stable glycemic control, relief from recurrent severe hypoglycemia, and insulin independence. Accessing the portal vein via the percutaneous hepatic approach carries the risk of bleeding, and the infusion of islets a risk of portal vein thrombosis. In the long term, common minor problems with immunosuppression are mouth ulcers, diarrhea, and acne. Longer-term risks include malignancy and serious infection, both rare to date in clinical islet transplantation. Sensitization to donor antigens may also occur. The long-term diabetes complications may stabilize, but of this aspect little is known to date. In the short term, there may be some elevation of serum cholesterol and blood pressure, in some patients there has been a decline in renal function, and in a few, acute retinal bleeds. For most, improvement in glucose control with resolution of glycemic lability and hypoglycemia has been a net benefit.

Eligibility of diabetic patients for islet transplantation alone

Since the Edmonton protocol, islet transplantation alone (ITA) offers the prospect of adequate glycemic control in type 1 diabetes without kidney failure. Patient motivation, evolution of diabetic complications, and hypoglycemia unawareness have to be balanced against the risks of portal puncture and long-term immunosuppressive therapy. The aim of this work was to assess the profile of 41 type 1 diabetic patients (21 men and 20 women of age 18 to 63 years) for whom islet transplantation was considered, between January 2000 and December 2002. Thirty-one of these patients lived in the area. The patients were divided into 3 groups according to their recruitment: 20, personal initiative (G1); 8, recruited from hospitalization (G2) for marked glycemic imbalance; and 13, (G3) referred by their diabetologist. Among this series of 41 patients, 14 (8 in G1, 4 in G2, and 2 in G3) did not fit the eligibility criteria, mainly because of a positive C-peptide, kidney failure, desire for pregnancy (G1, G3), liver disorders related to alcohol or iron overload related to HFE heterozygosity (G2), or good glycemic balance (G3). Sixteen did not wish to proceed after the first information step, 6 of these being more interested in a pump. Eleven, mainly recruited in G1 or G3, went through the clinical pretransplantation assessment. Among these, 2 have undergone transplantation, another 1 is enlisted. Therefore, it appears that patient motivation and information to the diabetologists are two important issues in the recruitment of patients eligible for islet transplantation. Equally important is the measurement of C-peptide, plasma creatinine, and microalbuminuria.

Assessment of the severity of hypoglycemia and glycemic lability in type 1 diabetic subjects undergoing islet transplantation

Currently, the major indications for solitary islet transplantation are recurrent severe hypoglycemia and labile glucose control. Quantifying these problems remains subjective. We have developed a scoring system for both hypoglycemia and glycemic lability, established normative data, and used them in patients who have undergone islet transplantation. A composite hypoglycemic score (HYPO score) was devised based on the frequency, severity, and degree of unawareness of the hypoglycemia. In addition, using 4 weeks of glucose records, a lability index (LI) was calculated based on the change in glucose levels over time and compared with a clinical assessment of glycemic lability. A mean amplitude of glycemic excursions (MAGE) was also calculated based on 2 consecutive days of seven readings each day. These scores were determined in 100 randomly selected subjects with type 1 diabetes from our general clinic to serve as a control group and in patients before and after islet transplantation. The mean age of the control diabetic subjects was 38.4 +/- 1.3 years (+/-SE), with a duration of diabetes of 21.5 +/- 1.1 years. The median HYPO score in the control subjects was 143 (25th to 75th interquartile range: 46-423). The LI in the diabetic control subjects was 223 (25th to 75th interquartile range: 130-329 mmol/l(2)/h.week(-1)). The LI correlated much more closely than the MAGE with the clinical assessment of lability. A HYPO score of > or = 1,047 (90th percentile) or an LI > or = 433 mmol/l(2)/h.week(-1) (90th percentile) indicated serious problems with hypoglycemia or glycemic lability, respectively. The islet transplant patients (n = 51) were 42.1 +/- 1.4 years old, with a duration of diabetes of 25.7 +/- 1.4 years. Islet transplant patients had a mean HYPO score of 1,234 +/- 184 pretransplant, which was significantly higher than that of the control subjects (P < 0.001), which became negligible posttransplantation with the elimination of hypoglycemia. The median LI pretransplant was 497 mmol/l(2)/h.week(-1) (25th to 75th interquartile range: 330-692), significantly higher than that of control subjects (P < 0.001), and fell to 40 (25th to 75th interquartile range: 14-83) within a month after the final transplant. In those who had lost graft function, the LI rose again. The HYPO score and LI provide measures of the extent of problems with hypoglycemia and glycemic lability, respectively, complement the clinical assessment of the problems with glucose control before islet transplantation, and will allow comparison of selection of subjects for transplants between centers.

Enregistrement de la glycémie en continu : quelles retombées ?

Continuous glucose monitoring is a recent technique which appears to be highly useful in diabetic patients, particularly in children and adolescents. Its potential interest to study unstable diabetes, to detect asymptomatic and nocturnal hypoglycaemias, to adapt and/or to adjust insulin treatment, etc. has lead to several recent clinical studies, conducted in various conditions. The different techniques, the studies conducted in children and adult diabetic patients, as well as the main current indications for continuous glucose monitoring are described in this article.

Clinical islet transplantation

Type 1 diabetes affects over 1 million persons in the United States, with over 30,000 new cases diagnosed annually. Transplantation of new insulin-producing b cells, in the form of the whole pancreas or isolated islets, has been shown to ameliorate the disease by eliminating the need for exogenous insulin and normalizing glycosylated hemoglobin levels. Islet transplants are a particularly attractive form of therapy because they are a minimally invasive procedure and are more likely to be scaled-up to treat the large numbers of people affected by diabetes. Currently, only a handful of programs have been successful in the endeavor. Nevertheless, the early clinical experience strongly demonstrates that islet transplantation is an effective treatment strategy in select patients with type 1 diabetes. To scale up this therapy and use it earlier in the disease and for more people, the shortage of suitable donor tissue must be solved and the requirement of lifelong immunosuppression must be minimized.