Increment of serum C-peptide measured by glucagon test closely correlates with human relative beta-cell area

Expansion of human alpha-cell area is associated with a higher maximum body mass index before the onset of type 2 diabetes

Highlights: We examined whether maximum body mass index (BMI) before the onset of diabetes (MBBO) affects histological findings of islet cells. We divided patients into two groups according to an MBBO cutoff of 25 kg/m² or BMI cutoff of 21 kg/m². We compared immunohistochemical parameters between the MBBO groups or BMI groups. The relative alpha‐cell area in the high MBBO group was significantly higher than that in the low MBBO group. There was no difference in the other parameters between the MBBO groups or BMI groups.

Lipid droplet accumulation in β cells in patients with type 2 diabetes is associated with insulin resistance, hyperglycemia and β cell dysfunction involving decreased insulin granules

BACKGROUND AND OBJECTIVE

Pancreatic fat is a form of ectopic fat. Lipid droplets (LDs) are also observed in β cells; however, the pathophysiological significance, especially for β cell function, has not been elucidated. Our aim was to assess LD accumulation in β cells in various stages of glucose intolerance and to clarify its relationship with clinical and histological parameters.

METHODS

We examined 42 Japanese patients who underwent pancreatectomy. The BODIPY493/503-positive (BODIPY-positive) area in β cells was measured in pancreatic sections from 32 patients. The insulin granule numbers were counted in an additional 10 patients using electron microscopy.

RESULTS

The BODIPY-positive area in β cells in preexisting type 2 diabetes patients was higher than that in normal glucose tolerance patients (p = 0.031). The BODIPY-positive area in β cells was positively correlated with age (r = 0.45, p = 0.0097), HbA1c (r = 0.38, p = 0.0302), fasting plasma glucose (r = 0.37, p = 0.045), and homeostasis model assessment insulin resistance (r = 0.41, p = 0.049) and negatively correlated with an increase in the C-peptide immunoreactivity level by the glucagon test (r = -0.59, p = 0.018). The ratio of mature insulin granule number to total insulin granule number was reduced in the patients with rich LD accumulation in β cells (p = 0.039).

CONCLUSIONS

Type 2 diabetes patients had high LD accumulation in β cells, which was associated with insulin resistance, hyperglycemia, aging and β cell dysfunction involving decreased mature insulin granules.

Maximum body mass index before onset of type 2 diabetes is independently associated with advanced diabetic complications

INTRODUCTION

The maximum body mass index (BMI) before onset of type 2 diabetes (MBBO) might be used to estimate a patient's insulin secretion capacity. There have been few factors that can predict future diabetic complications at the time of diagnosis of diabetes mellitus. This study aimed to clarify the clinical usefulness of MBBO for predicting the development of advanced diabetic microvascular complications.

RESEARCH DESIGN AND METHODS

This was a cross-sectional observational study. Of 1304 consecutively admitted patients with type 2 diabetes, we enrolled 435 patients for whom we could confirm their MBBO. Univariate and multivariate logistic regression analyses were performed to examine whether MBBO or BMI on admission was associated with advanced diabetic retinopathy or nephropathy. To evaluate the predictive performance of these indexes, we performed cross-validation in various models with MBBO or BMI and evaluated the areas under the curve (AUCs) yielded by these analyses.

RESULTS

Univariate analyses suggested that MBBO was associated with advanced retinopathy and nephropathy, while BMI on admission was associated only with advanced nephropathy. In multivariate analyses, MBBO was significantly associated with advanced complications, while BMI on admission was not. For advanced diabetic retinopathy, the AUCs were 0.70-0.72, and for advanced nephropathy, the AUCs were 0.81-0.83. When comparing the AUCs among models, the models with MBBO sustained high predictive performance for diabetic complications.

CONCLUSIONS

MBBO was independently associated with advanced diabetic complications, while BMI on admission was not. Diabetic microvascular complications in patients with high MBBO could progress more rapidly. At the time of the diagnosis of diabetes mellitus, MBBO would enable us to predict the progress of diabetic complications.

Revisiting Regulators of Human β-cell Mass to Achieve β-cell-centric Approach Toward Type 2 Diabetes

Type 2 diabetes (T2DM) is characterized by insulin resistance and β-cell dysfunction. Because patients with T2DM have inadequate β-cell mass (BCM) and β-cell dysfunction worsens glycemic control and makes treatment difficult, therapeutic strategies to preserve and restore BCM are needed. In rodent models, obesity increases BCM about 3-fold, but the increase in BCM in humans is limited. Besides, obesity-induced changes in BCM may show racial differences between East Asians and Caucasians. Recently, the developmental origins of health and disease hypothesis, which states that the risk of developing noncommunicable diseases including T2DM is influenced by the fetal environment, has been proposed. It is known in rodents that animals with low birthweight have reduced BCM through epigenetic modifications, making them more susceptible to diabetes in the future. Similarly, in humans, we revealed that individuals born with low birthweight have lower BCM in adulthood. Because β-cell replication is more frequently observed in the 5 years after birth, and β cells are found to be more plastic in that period, a history of childhood obesity increases BCM. BCM in patients with T2DM is reduced by 20% to 65% compared with that in individuals without T2DM. However, since BCM starts to decrease from the stage of borderline diabetes, early intervention is essential for β-cell protection. In this review, we summarize the current knowledge on regulatory factors of human BCM in health and diabetes and propose the β-cell–centric concept of diabetes to enhance a more pathophysiology-based treatment approach for T2DM.

Glucose Tolerance after Pancreatectomy: A Prospective Observational Follow-Up Study of Pancreaticoduodenectomy and Distal Pancreatectomy

BACKGROUND

Effects of pancreatectomy on glucose tolerance have not been clarified, and evidence regarding the difference in postoperative glucose tolerance between pancreaticoduodenectomy (PD) and distal pancreatectomy (DP) is lacking.

STUDY DESIGN

This prospective, single-center observational study analyzed 40 patients undergoing PD and 29 patients undergoing DP (Clinical trial registry number UMIN000008122). Glucose tolerance, including insulin secretion (Δ C-peptide immunoreactivity, ΔCPR) and insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR) were assessed before and 1 month after pancreatectomy using the oral glucose tolerance test (OGTT) and glucagon stimulation test. We assessed long-term hemoglobin A1c (HbA1c) levels in patients, with a follow-up time of 3 years.

RESULTS

Percentages of patients diagnosed with abnormal OGTT decreased after PD (from 12 [30%] to 7 [17.5%] of 40 patients, p = 0.096); however, they increased after DP (from 4 [13.8%] to 8 [27.6%] of 29 patients, p = 0.103), although the changes were not statistically significant. ΔCPR decreased after both PD (from 3.2 to 1.0 ng/mL, p < 0.001) and DP (from 3.3 to 1.8 ng/mL, p < 0.001). HOMA-IR decreased after PD (from 1.10 to 0.68, p < 0.001), but did not change after DP (1.10 and 1.07, p = 0.42). Median HbA1c level was higher after DP than after PD for up to 3 years, but the differences were not statistically significant.

CONCLUSIONS

In comparisons of pre- and 1 month post-pancreatectomy data, glucose tolerance showed improvement after PD, whereas it worsened after DP. Insulin secretion decreased after both PD and DP. Insulin resistance improved after PD, but did not change after DP. Further studies are warranted to clarify mechanisms of improved insulin resistance after PD.

Increased NKX6.1 expression and decreased ARX expression in alpha cells accompany reduced beta-cell volume in human subjects

Pancreatic islet cells have plasticity, such as the abilities to dedifferentiate and transdifferentiate. Islet cell conversion to other characteristic cell is largely determined by transcription factors, but significance of expression patterns of these transcription factors in human islet cells remained unclear. Here, we present the NKX6.1-positive ratio of glucagon-positive cells (NKX6.1⁺/GCG⁺ ratio) and the ARX-negative ratio of glucagon-positive cells (ARX⁻/GCG⁺ ratio) in 34 patients who were not administered antidiabetic agents. Both of NKX6.1⁺/GCG⁺ ratio and ARX⁻/GCG⁺ ratio negatively associated with relative beta cell area. And these ratios did not have significant correlation with other parameters including age, body mass index, hemoglobin A1c, fasting plasma glucose level or relative alpha-cell area. Our data demonstrate that these expression ratios of transcription factors in glucagon-positive cells closely correlate with the reduction of beta-cell volume in human pancreas.

Beta-Cell Mass in Obesity and Type 2 Diabetes, and Its Relation to Pancreas Fat: A Mini-Review

Type 2 diabetes (T2DM) is characterized by insulin resistance and beta-cell dysfunction. Although insulin resistance is assumed to be a main pathophysiological feature of the development of T2DM, recent studies have revealed that a deficit of functional beta-cell mass is an essential factor for the pathophysiology of T2DM. Pancreatic fat contents increase with obesity and are suggested to cause beta-cell dysfunction. Since the beta-cell dysfunction induced by obesity or progressive decline with disease duration results in a worsening glycemic control, and treatment failure, preserving beta-cell mass is an important treatment strategy for T2DM. In this mini-review, we summarize the current knowledge on beta-cell mass, beta-cell function, and pancreas fat in obesity and T2DM, and we discuss treatment strategies for T2DM in relation to beta-cell preservation.

Association of glucose tolerance status with pancreatic β- and α-cell mass in community-based autopsy samples of Japanese individuals: The Hisayama Study

AIMS/INTRODUCTION

Changes in histologically quantified β- and α-cell mass during the development of glucose intolerance have not been fully elucidated. The aim of the present study was to explore differences in β- and α-cell mass according to the glucose tolerance status.

MATERIALS AND METHODS

Autopsy samples from a total of 103 individuals (40 with normal glucose tolerance, 31 with prediabetes and 32 with type 2 diabetes mellitus) who underwent a 75-g oral glucose tolerance test within 5 years before death were selected from 643 community-based autopsy samples collected from 2002 to 2016. Fractional β-cell area (BCA) and α-cell area were quantified with Image Pro Plus software. Associations of BCA and α-cell area with glucose tolerance status were assessed using a linear regression analysis, and Spearman's correlation coefficients between glycemic markers and β-cell function were estimated.

RESULTS

The mean values of BCA decreased significantly with worsening glucose tolerance status (mean ± standard error 1.85 ± 0.10% in normal glucose tolerance, 1.59 ± 0.11% in prediabetes and 1.17 ± 0.11% in type 2 diabetes mellitus, P for trend < 0.001), whereas there was no significant association between α-cell area and glucose tolerance status. BCA was inversely correlated with fasting and 2-h plasma glucose levels during oral glucose tolerance test and glycated hemoglobin measurement, and positively correlated with disposition index (all P < 0.01).

CONCLUSIONS

β-Cell mass decreased significantly with worsening glucose tolerance, from the stage of prediabetes, in the Japanese population. Prevention of declining β-cell mass before the onset of glucose intolerance is important to reduce the burden of type 2 diabetes mellitus.

Associations of birthweight and history of childhood obesity with beta cell mass in Japanese adults

AIMS/HYPOTHESIS

Low birthweight is associated with a high risk of diabetes, but there are no reports discussing birthweight and pancreatic tissues in humans. The purpose of this study was to examine the correlation between birthweight and beta and alpha cell mass in humans.

METHODS

Sixty-four Japanese adults with and without diabetes who underwent pancreatectomy and were able to recall their weight history including birthweight were included. Pancreatic tissues were stained for insulin and glucagon, and fractional beta cell area (BCA) and alpha cell area (ACA) were quantified. Islet size and density and beta cell replication were also quantified and their associations with birthweight were evaluated.

RESULTS

In participants without diabetes, there was a weak positive correlation between birthweight and BCA (R = 0.34, p = 0.03). The group with a history of childhood obesity, but not the group with a history of obesity in adulthood only, showed higher BCA compared with those without a history of obesity (1.78 ± 0.74% vs 0.99 ± 0.53%, p = 0.01), and the correlation coefficient between birthweight and BCA increased after excluding those with a history of childhood obesity (R = 0.51, p < 0.01). In those with diabetes, there was no correlation between birthweight and BCA. No correlation was found between birthweight and ACA in either those with or without diabetes.

CONCLUSIONS/INTERPRETATION

Birthweight and beta, but not alpha, cell mass are positively correlated in non-diabetic adults, and a history of childhood obesity may affect beta cell mass. Graphical abstract.

Beneficial effects of combination therapy of canagliflozin and teneligliptin on diabetic polyneuropathy and β-cell volume density in spontaneously type 2 diabetic Goto-Kakizaki rats

AIMS

Parasympathetic nerve (PN) signaling plays a crucial role in the maintenance of pancreatic β-cell volume density (V_β). PN may be pathologically affected in diabetic polyneuropathy (DPN). However, the association between the reduction of PNs in islets and V_β and the therapeutic effects of a DPP4 inhibitor (DPP4i) and an SGLT2 inhibitor (SGLT2i) in nonobese type 2 diabetes mellitus (T2DM) Goto-Kakizaki rats (GK) have not been investigated.

MATERIALS AND METHODS

We divided 5-week old male GK and Wistar rats (W) into a DPP4i-treated group (GKTe), SGLT2i-treated group (GKCa), and combination-treated group (GKCaTe). After 25 weeks, the pancreata was pathologically evaluated.

RESULTS

V_β in GK was significantly decreased (p < 0.01 vs. W), whereas V_β was the most well preserved in GKCaTe (p < 0.05 vs. GKTe), followed by GKTe (p < 0.05 vs. GK). The decreased amount of PNs in the islets and intraepidermal nerve fiber density (IENFD) in GK was significantly improved in the treated groups compared with GK (p < 0.05 vs. GKCa and GKTe and p < 0.01 vs. GKCaTe). PN density and IENFD were significantly correlated with V_β (r = 0.55, p < 0.01 and r = 0.54, p < 0.01, respectively). IENFD was identified as a surrogate marker for the prediction of V_β (cutoff value, 16.39).

CONCLUSIONS

The combination therapy of DPP4i and SGLT2i improved V_β accompanied by PNs density and IENFD. IENFD was proportionally correlated with V_β. Therefore, the prevention of DPN development may be concurrently beneficial for the preservation of V_β in nonobese T2DM.

Association of glucagon-like peptide-1 receptor-targeted imaging probe with in vivo glucagon-like peptide-1 receptor agonist glucose-lowering effects

Aims/Introduction

Glucagon‐like peptide‐1 receptor agonists (GLP‐1RA) are used for treatment of type 2 diabetes mellitus worldwide. However, some patients do not respond well to the therapy, and caution must be taken for certain patients, including those with reduced insulin secretory capacity. Thus, it is clinically important to predict the efficacy of GLP‐1RA therapy. GLP‐1R‐targeted imaging has recently emerged to visualize and quantify β‐cells. We investigated whether GLP‐1R‐targeted imaging can predict the efficacy of GLP‐1RA treatment.

Materials and Methods

We developed ¹¹¹Indium‐labeled exendin‐4 derivative (¹¹¹In‐Ex4) as a GLP‐1R‐targeting probe. Diabetic mice were selected from NONcNZO10/LtJ male mice that were fed for different durations with 11% fat chow. After 3‐week administration of dulaglutide as GLP‐1RA therapy, mice with non‐fasting blood glucose levels <300 mg/dL and >300 mg/dL were defined as responders and non‐responders, respectively. In addition, ex vivo¹¹¹In‐Ex4 pancreatic accumulations (¹¹¹In‐Ex4 pancreatic values) were examined.

Results

The non‐fasting blood glucose levels after treatment were 172.5 ± 42.4 mg/dL in responders (n = 4) and 330.8 ± 20.7 mg/dL in non‐responders (n = 5), respectively. Ex vivo¹¹¹In‐Ex4 pancreatic values showed significant correlations with post‐treatment glycohemoglobin and glucose area under curve during an oral glucose tolerance test (R² = 0.76 and 0.80; P < 0.01 and <0.01, respectively). The receiver operating characteristic area under curve for identifying responders by ex vivo¹¹¹In‐Ex4 pancreatic values was 1.00 (P < 0.01).

Conclusion

Ex vivo¹¹¹In‐Ex4 pancreatic values reflected dulaglutide efficacy, suggesting clinical possibilities for expanding GLP‐1R‐targeted imaging applications.

Clinical Significance of the Maximum Body Mass Index Before Onset of Type 2 Diabetes for Predicting Beta-Cell Function

Objective

This study aimed to clarify the clinical significance of the maximum body mass index (BMI) before the onset of type 2 diabetes (MBBO) for predicting pancreatic beta-cell function.

Methods

This was a cross-sectional observational study. Of 1304 consecutively admitted patients with type 2 diabetes, we enrolled 410 patients satisfying the criteria in this study. The correlations between the C-peptide index (CPI), which is one of the parameters that reflects beta-cell function, and various clinical parameters, including MBBO and duration of diabetes, were analyzed in multiple linear regression analyses.

Results

The analyses revealed that MBBO was correlated with CPI independently after adjustment for age, sex, HbA1c, and duration of diabetes. When we divided the subjects into three subgroups by MBBO (MBBO < 25 kg/m²; 25 kg/m² ≤ MBBO < 30 kg/m²; MBBO ≥ 30 kg/m²), CPI was negatively correlated with duration of diabetes in each subgroup, while the rates of CPI based on the duration of diabetes were not different among the three MBBO subgroups. In contrast, the declining rates of CPI were higher in the BMI ≥ 25 kg/m² group on admission than in the BMI < 25 kg/m² group on admission.

Conclusions

MBBO may be an independent factor correlating with beta-cell function and may predict insulin secretion capacity at diagnosis, but it does not seem to affect the rate of decline in insulin secretion capacity after diagnosis. It is important to preserve beta-cell function by decreasing a patient’s BMI during treatment after diagnosis regardless of MBBO.

Pancreatic fat is related to the longitudinal decrease in the increment of C-peptide in glucagon stimulation test in type 2 diabetes patients

AIMS/INTRODUCTION

The relationship between pancreatic fatty infiltration and diabetes is widely known, whereas the causal relationship is not clear. Furthermore, it is uncertain whether pathogenesis of pancreatic fat is similar to that of liver fat. We aimed to clarify the contribution of this type of fat to glucose metabolism in type 2 diabetes patients by cross-sectional and longitudinal analyses.

MATERIAL AND METHODS

A total of 56 patients with type 2 diabetes who had been hospitalized twice were analyzed. We evaluated the mean computed tomography values of the pancreas (P), liver (L) and spleen (S). Lower computed tomography values indicate a greater fat content. We defined indices of pancreatic or liver fat content as the differences between P or L and S. We assessed the associations among fat content for the two organs (P-S, L-S) and clinical parameters at the first hospitalization, and then analyzed the associations between these fat contents and changes in glycometabolic markers (the second data values minus the first).

RESULTS

In the cross-sectional study, P-S negatively correlated with the increment of C-peptide in the glucagon stimulation test (r = -0.71, P < 0.0001) and body mass index (r = -0.28, P = 0.034). L-S negatively correlated with homeostasis model assessment of insulin resistance (r = -0.73, P < 0.0001), body mass index (r = -0.62, P < 0.0001) and some other obesity-related indicators, but not with the increment of C-peptide in the glucagon stimulation test. In the longitudinal study, P-S positively correlated with the change of the increment of C-peptide in the glucagon stimulation test (r = 0.49, P = 0.021).

CONCLUSIONS

In type 2 diabetes patients, pancreatic fat was less associated with obesity-related indicators than liver fat, but was more strongly associated with the longitudinal decrease in endogenous insulin-secreting capacity.

Effects of sodium-glucose cotransporter 2 inhibitors on hypoglycaemia in brittle diabetic patients with decreased endogenous insulin secretion

AIMS

The effects of sodium-glucose cotransporter 2 inhibitors (SGLT2Is) on fasting blood glucose concentration (FBG) in patients with unstable FBG despite undergoing intensive insulin therapy (IIT) remain unclear. This study aimed to identify the effects of SGLT2Is on unstable FBGs.

MATERIALS AND METHODS

Thirty brittle diabetic patients with unstable FBGs despite undergoing IIT were included in the study. SGLT2Is were added and used in combination. We evaluated the data of the subjects in Evaluation 1 (immediately before using SGLT2Is) and evaluations 2, 3 and 4 (4, 24 and 48 weeks after starting concomitant therapy, respectively). FBGs were measured every day for a period of 28 days immediately before conducting Evaluations 1, 2, 3 and 4. The mean value of the 28 sets of FBG data (FBG mean) and their standard deviation (SD) values were established as each evaluation's FBGs. The changes in the mean values of the 30 subjects as well as their SD before and after concomitant therapy were evaluated.

RESULTS

The concomitant use of SGLT2Is helped reduce not only FBG mean but also SD. FBG max dropped, and the frequency of occurrence of hyperglycaemic FBG (>11.1 mmol/L) decreased. However, FBG min did not drop, and the frequency of occurrence of hypoglycaemic FBG (<3.9 mmol/L) increased. The frequency of occurrence of subjective hypoglycaemia decreased. The decrease in the SD of FBG was related to the decrease in subjective hypoglycaemia.

CONCLUSION

Concomitant use of SGLT2Is in patients with brittle diabetes appears to be useful in terms of improvement of FBG and fewer occurrences of hypoglycaemic events.

Association of fatty pancreas with pancreatic endocrine and exocrine function

Aim

The purpose of this study was to clarify whether fatty pancreas might lead to impaired pancreatic endocrine or exocrine function.

Material and methods

The study involved 109 participants who had undergone the glucagon stimulation test and N-benzoyl-L-tyros-p-amino benzoic acid (BT-PABA) test to assess pancreatic function as well as unenhanced abdominal computed tomography (CT). Pancreatic endocrine impairment was defined as ΔC peptide immunoreactivity less than 2 [mmol/L] in the glucagon stimulation test, and pancreatic exocrine impairment was defined as a urinary PABA excretion rate less than 70% on the BT-PABA test. We defined as the mean CT value of pancreas / CT value of spleen (P/S ratio) as a marker to assess fatty pancreas. We analyzed the association between fatty pancreas and pancreatic impairment using the logistic regression model. The odds ratio (OR) is shown per 0.1 unit.

Results

Pancreatic endocrine function was impaired in 33.0% of the participants, and 56.9% of those were regarded as having pancreatic exocrine impairment. The P/S ratio was significantly correlated with pancreatic endocrine impairment in univariate analysis (OR = 0.61, 95% confidence interval (CI) = 0.43–0.83, P = 0.0013) and multivariate analysis (OR = 0.38, 95% CI = 0.22–0.61, P < .0001) for all participants. Similar significant relationships were observed in both univariate (OR = 0.70, 95% CI = 0.49–0.99, P = 0.04) and multivariate (OR = 0.39, 95% CI = 0.21–0.66, P = 0.0002) analyses for the participants without diabetes (n = 93). The amount of pancreatic fat was not associated with exocrine impairment in univariate analysis (OR = 0.80, 95% CI = 0.59–1.06, P = 0.12).

Conclusion

Fatty pancreas was associated with pancreatic endocrine impairment but did not have a clear relationship with pancreatic exocrine impairment.

Human pancreatic α- to β-cell area ratio increases after type 2 diabetes onset

AIMS/INTRODUCTION

Pancreatic α-cell area and the α- to β-cell area ratio (α/β) might be associated with glucose tolerance. The aim was to clarify how these histological parameters change as glucose tolerance deteriorates.

MATERIALS AND METHODS

We analyzed pancreatic tissues obtained from pancreatectomies of 43 patients. We evaluated the relationships between α-cell area or the α/β and various clinical parameters. Additionally, we analyzed α-cell proliferation and the expression patterns of various pancreatic transcription factors.

RESULTS

The α/β in individuals with longstanding (previously diagnosed) type 2 diabetes (0.36 ± 0.12) was higher than that in those with normal glucose tolerance (0.18 ± 0.10; P < 0.01), impaired glucose tolerance (0.17 ± 0.12; P < 0.05) and newly diagnosed diabetes (0.17 ± 0.12; P < 0.05). In all participants, glycated hemoglobin (HbA1c) correlated with relative α-cell area (P = 0.010). Diabetes duration (P = 0.004), HbA1c (P < 0.001) and plasma glucose levels (P = 0.008) were significantly correlated with the α/β in single regression analyses, and diabetes duration was the only independent and significant determinant in stepwise multiple regression analyses (P = 0.006). The α-cell Ki67-positive ratio in patients with HbA1c ≥6.5% was significantly higher than that in patients with HbA1c <6.5% (P = 0.022). We identified β-cells that expressed aristaless-related homeobox and α-cells that did not express aristaless-related homeobox at all glucose tolerance stages. Aristaless-related homeobox and NK homeobox 6.1 expression patterns varied in insulin and glucagon double-positive cells.

CONCLUSIONS

The pancreatic α/β increases after type 2 diabetes onset and correlates with diabetes duration. This change might occur through α-cell proliferation and phenotypic changes in pancreatic endocrine cells.

Small amounts of tissue preserve pancreatic function: Long-term follow-up study of middle-segment preserving pancreatectomy

Middle-segment preserving pancreatectomy (MPP) is a novel procedure for treating multifocal lesions of the pancreas while preserving pancreatic function. However, long-term pancreatic function after this procedure remains unclear.The aims of this current study are to investigate short- and long-term outcomes, especially long-term pancreatic endocrine function, after MPP.From September 2011 to December 2015, 7 patients underwent MPP in our institution, and 5 cases with long-term outcomes were further analyzed in a retrospective manner. Percentage of tissue preservation was calculated using computed tomography volumetry. Serum insulin and C-peptide levels after oral glucose challenge were evaluated in 5 patients. Beta-cell secreting function including modified homeostasis model assessment of beta-cell function (HOMA2-beta), area under the curve (AUC) for C-peptide, and C-peptide index were evaluated and compared with those after pancreaticoduodenectomy (PD) and total pancreatectomy. Exocrine function was assessed based on questionnaires.Our case series included 3 women and 2 men, with median age of 50 (37-81) years. Four patients underwent pylorus-preserving PD together with distal pancreatectomy (DP), including 1 with spleen preserved. The remaining patient underwent Beger procedure and spleen-preserving DP. Median operation time and estimated intraoperative blood loss were 330 (250-615) min and 800 (400-5500) mL, respectively. Histological examination revealed 3 cases of metastatic lesion to the pancreas, 1 case of chronic pancreatitis, and 1 neuroendocrine tumor. Major postoperative complications included 3 cases of delayed gastric emptying and 2 cases of postoperative pancreatic fistula. Imaging studies showed that segments representing 18.2% to 39.5% of the pancreas with good blood supply had been preserved. With a median 35.0 months of follow-ups on pancreatic functions, only 1 patient developed new-onset diabetes mellitus of the 4 preoperatively euglycemic patients. Beta-cell function parameters in this group of patients were quite comparable to those after Whipple procedure, and seemed better than those after total pancreatectomy. No symptoms of hypoglycemia were identified in any patient, although half of the patients reported symptoms of exocrine insufficiency.In conclusion, MPP is a feasible and effective procedure for middle-segment sparing multicentric lesions in the pancreas, and patients exhibit satisfied endocrine function after surgery.

Effects of Obesity and Diabetes on α- and β-Cell Mass in Surgically Resected Human Pancreas

CONTEXT

The ethnic difference in β-cell regenerative capacity in response to obesity may be attributable to different phenotypes of type 2 diabetes among ethnicities.

OBJECTIVE

This study aimed to clarify the effects of diabetes and obesity on β- (BCM) and α-cell mass (ACM) in the Japanese population.

DESIGN, SETTING, AND PARTICIPANTS

We obtained the pancreases of 99 individuals who underwent pancreatic surgery and whose resected pancreas sample contained adequate normal pancreas for histological analysis. Questionnaires on a family history of diabetes and history of obesity were conducted in 59 patients. Pancreatic sections were stained for insulin or glucagon, and fractional β- and α-cell area were measured. Islet size and density as well as β-cell turnover were also quantified.

RESULTS

In patients with diabetes, BCM was decreased by 46% compared with age- and body mass index-matched nondiabetic patients (1.48% ± 1.08% vs 0.80% ± 0.54%, P < .001), whereas there was no difference in ACM between the groups. There was no effect of obesity or history of obesity on BCM and ACM irrespective of the presence or absence of diabetes. There was a negative correlation between BCM, but not ACM, and glycated hemoglobin before and after pancreatic surgery. In addition, reduced BCM was observed in patients with pancreatic cancer compared with those with other pancreatic tumors.

CONCLUSIONS

These findings suggest that the increase in BCM in the face of insulin resistance is extremely limited in the Japanese, and BCM rather than ACM has a major role in regulating blood glucose level in humans.

The effect of oral and intravenous dextrose on C-peptide secretion in ponies

Managing equine hyperinsulinemia is crucial for preventing laminitis, but our understanding of the mechanisms involved in insulin dysregulation in this species is incomplete. C-peptide is co-secreted with insulin but is resistant to hepatic metabolism and can be used to study insulin dysregulation. This study examined C-peptide secretion in serial blood samples collected after oral and i.v. dextrose (0.75 g/kg) administration to 9 ponies (BCS, 7.1 ± 0.5). The ponies were designated as hyperinsulinemic (HI) or normoinsulinemic (NI) responders before the study, using oral glucose tests and fasted glucose-to-insulin ratios, and responses were compared between the 2 groups. C-peptide concentrations increased ( < 0.01) rapidly from fasted levels after both oral and i.v. dextrose, with similar area under the concentration-time curve (AUC) for both tests and a significant correlation with AUC. The AUC was similar in HI and NI ponies after i.v. dextrose, indicating similar pancreatic capacity for both groups. However, for oral dextrose, the AUC and the AUC were markedly higher ( < 0.05) in the HI ponies, indicating a greater secretion rate of these peptides. Slower insulin clearance might have also contributed to the larger AUC in HI ponies, but this hypothesis requires further investigation with specific measures of hepatic insulin clearance.

Retrospective analysis of safety and efficacy of liraglutide monotherapy and sulfonylurea-combination therapy in Japanese type 2 diabetes: Association of remaining β-cell function and achievement of HbA1c target one year after initiation

AIMS

The GLP-1 receptor agonist liraglutide improves impaired pancreatic β-cell function, thereby exerting glucose-lowering effects. However, the association of remaining β-cell function with long-term therapeutic efficacy of liraglutide remains largely unknown.

METHODS

Patients with type 2 diabetes who started liraglutide as monotherapy or sulfonylurea-combination therapy were retrospectively analyzed to identify possible associations of indices related to β-cell function including increments of C-peptide immunoreactivity in glucagon stimulation test (GST-ΔCPR) with achievement of HbA1c <7.0% at 54weeks after liraglutide initiation.

RESULTS

Among 165 subjects continuing liraglutide for 54weeks, 66 received additional oral anti-diabetic drugs (OADs) during the period. Of those continuing liraglutide without receiving additional OADs, 41 subjects achieved HbA1c <7.0% at 54weeks, while 49 subjects did not. Subjects achieving HbA1c <7.0% showed higher values of GST-ΔCPR. Receiver-operating analysis revealed 2.34ng/mL as the cut-off value for HbA1c <7.0% achievement in these subjects. Subjects with GST-ΔCPR >2.34ng/mL showed continuous and substantial HbA1c reduction throughout the 54weeks. In Kaplan-Meier analysis, subjects with GST-ΔCPR >2.34ng/mL showed longer therapeutic durability of initial liraglutide therapy with no additional OADs or insulin.

CONCLUSIONS

Despite numerous limitations, these results indicate that long-term efficacy of liraglutide is associated with remaining β-cell function at initiation.

Duration of fasting but not diurnal variation affects the response to glucagon in healthy cats

The role of glucagon disturbances in diabetes is increasingly recognized. Glucagon stimulation tests (GSTs) have been described in cats previously, but information is lacking on the response of cats to glucagon under specific conditions. The aim of this study was to assess a novel protocol for GST using human-recombinant glucagon and the effect of diurnal variation and duration of fasting using this protocol in healthy cats. All intravenous doses resulted in occasional vomiting and nausea, and eventually, a 20-μg/kg intramuscular dose was chosen. Five healthy cats were then used in a repeated-measures study. Cats were free-fed regularly at 7:30 AM and 5:30 PM for 30 min. In each cat, GST was performed at 7 PM after a 25-h fast (PM25), at 9 AM after a 25-h fast (AM25), and at 9 AM after a 15-h fast (AM15). Glucose and insulin concentrations were measured at -15, 0, 15, 25, 35, 45, and 60 min after stimulation. Baseline and peak concentrations were compared using the Friedman test. Baseline glucose and insulin did not differ significantly between treatment groups. Peak glucose concentrations occurred at 15 min and were significantly higher (P = 0.0085) at AM15 (mean ± standard deviation = 185.2 ± 43.0 mg/dL) vs AM25 (144.4 ± 10.5 mg/dL) and PM25 (128.0 ± 18.4 mg/dL). Similarly, peak insulin concentrations occurred at 15 min and were significantly higher (P = 0.04) at AM15 (1,911 ± 1,153 pg/mL) vs AM25 (739 ± 52 pg/mL) or PM25 (549 ± 366 pg/mL). In conclusion, prolonged fasting significantly blunted the glycemic response to glucagon compared with shorter fasting, but diurnal variation had no significant effect on glucose or insulin responses.