Real-life hypoglycaemia partially blunts the inflammatory response to experimental hypoglycaemia in people with type 1 diabetes.

AIM: To determine whether recent repeated exposure to real-life hypoglycaemia affects the pro-inflammatory response during a hypoglycemia episode. MATERIALS AND METHODS: This was a post hoc analysis of a hyperinsulinaemic normoglycaemic-hypoglycaemic clamp study, involving 40 participants with type 1 diabetes. Glucose levels 1 week before the clamp were monitored using a Freestyle Libre 1. Blood was drawn during normoglycaemia and hypoglycaemia, and 24 hours after resolution of hypoglycaemia for measurements of inflammatory responses and counterregulatory hormone levels. We determined the relationship between the frequency and duration of spontaneous hypoglycaemia, and time below range (TBR) and the inflammatory response to experimental hypoglycaemia. RESULTS: On average, participants experienced 0.79 (0.43, 1.14) hypoglycaemia episodes per day, with a duration of 78 (47, 110) minutes and TBR of 5.5% (2.8%, 8.5%). TBR and hypoglycaemia frequency were inversely associated with the increase in circulating granulocyte and lymphocyte counts during experimental hypoglycaemia (P < .05 for all). A protein network consisting of DNER, IF-R, uPA, Flt3L, FGF-5 and TWEAK was negatively associated with hypoglycaemia frequency (P < .05), but not with the adrenaline response. Neither other counterregulatory hormones, nor hypoglycaemia awareness status, was associated with any of the inflammatory parameters markers. CONCLUSIONS: Repeated exposure to spontaneous hypoglycaemia is associated with blunted effects of subsequent experimental hypoglycaemia on circulating immune cells and the number of inflammatory proteins.

Association between recent exposure to continuous glucose monitoring-recorded hypoglycaemia and counterregulatory and symptom responses to subsequent controlled hypoglycaemia in people with type 1 diabetes.

AIM: Experimental hypoglycaemia blunts the counterregulatory hormone and symptom responses to a subsequent episode of hypoglycaemia. In this study, we aimed to assess the associations between antecedent exposure and continuous glucose monitoring (CGM)-recorded hypoglycaemia during a 1-week period and the counterregulatory responses to subsequent experimental hypoglycaemia in people with type 1 diabetes. MATERIALS AND METHODS: Forty-two people with type 1 diabetes (20 females, mean ± SD glycated haemoglobin 7.8% ± 1.0%, diabetes duration median (interquartile range) 22.0 (10.5-34.9) years, 29 CGM users, and 19 with impaired awareness of hypoglycaemia) wore an open intermittently scanned CGM for 1 week to detect hypoglycaemic exposure before a standardized hyperinsulinaemic-hypoglycaemic [2.8 ± 0.1 mmol/L (50.2 ± 2.3 mg/dl)] glucose clamp. Symptom responses and counterregulatory hormones were measured during the clamp. The study is part of the HypoRESOLVE project. RESULTS: CGM-recorded hypoglycaemia in the week before the clamp was negatively associated with adrenaline response [ß -0.09, 95% CI (-0.16, -0.02) nmol/L, p = .014], after adjusting for CGM use, awareness of hypoglycaemia, glycated haemoglobin and total daily insulin dose. This was driven by level 2 hypoglycaemia [<3.0 mmol/L (54 mg/dl)] [ß -0.21, 95% CI (-0.41, -0.01) nmol/L, p = .034]. CGM-recorded hypoglycaemia was negatively associated with total, autonomic, and neuroglycopenic symptom responses, but these associations were lost after adjusting for potential confounders. CONCLUSIONS: Recent exposure to CGM-detected hypoglycaemia was independently associated with an attenuated adrenaline response to experimental hypoglycaemia in people with type 1 diabetes.

The impact of prior exposure to hypoglycaemia on the inflammatory response to a subsequent hypoglycaemic episode.

BACKGROUND: Hypoglycaemia has been shown to induce a systemic pro-inflammatory response, which may be driven, in part, by the adrenaline response. Prior exposure to hypoglycaemia attenuates counterregulatory hormone responses to subsequent hypoglycaemia, but whether this effect can be extrapolated to the pro-inflammatory response is unclear. Therefore, we investigated the effect of antecedent hypoglycaemia on inflammatory responses to subsequent hypoglycaemia in humans. METHODS: Healthy participants (n = 32) were recruited and randomised to two 2-h episodes of either hypoglycaemia or normoglycaemia on day 1, followed by a hyperinsulinaemic hypoglycaemic (2.8 ± 0.1 mmol/L) glucose clamp on day 2. During normoglycaemia and hypoglycaemia, and after 24 h, 72 h and 1 week, blood was drawn to determine circulating immune cell composition, phenotype and function, and 93 circulating inflammatory proteins including hs-CRP. RESULTS: In the group undergoing antecedent hypoglycaemia, the adrenaline response to next-day hypoglycaemia was lower compared to the control group (1.45 ± 1.24 vs 2.68 ± 1.41 nmol/l). In both groups, day 2 hypoglycaemia increased absolute numbers of circulating immune cells, of which lymphocytes and monocytes remained elevated for the whole week. Also, the proportion of pro-inflammatory CD16+-monocytes increased during hypoglycaemia. After ex vivo stimulation, monocytes released more TNF-α and IL-1ß, and less IL-10 in response to hypoglycaemia, whereas levels of 19 circulating inflammatory proteins, including hs-CRP, increased for up to 1 week after the hypoglycaemic event. Most of the inflammatory responses were similar in the two groups, except the persistent pro-inflammatory protein changes were partly blunted in the group exposed to antecedent hypoglycaemia. We did not find a correlation between the adrenaline response and the inflammatory responses during hypoglycaemia. CONCLUSION: Hypoglycaemia induces an acute and persistent pro-inflammatory response at multiple levels that occurs largely, but not completely, independent of prior exposure to hypoglycaemia. Clinical Trial information Clinicaltrials.gov no. NCT03976271 (registered 5 June 2019).

Counterregulatory hormone and symptom responses to hypoglycaemia in people with type 1 diabetes, insulin-treated type 2 diabetes or without diabetes: the Hypo-RESOLVE hypoglycaemic clamp study.

AIM: The sympathetic nervous and hormonal counterregulatory responses to hypoglycaemia differ between people with type 1 and type 2 diabetes and may change along the course of diabetes, but have not been directly compared. We aimed to compare counterregulatory hormone and symptom responses to hypoglycaemia between people with type 1 diabetes, insulin-treated type 2 diabetes and controls without diabetes, using a standardised hyperinsulinaemic-hypoglycaemic clamp. MATERIALS: We included 47 people with type 1 diabetes, 15 with insulin-treated type 2 diabetes, and 32 controls without diabetes. Controls were matched according to age and sex to the people with type 1 diabetes or with type 2 diabetes. All participants underwent a hyperinsulinaemic-euglycaemic-(5.2 ± 0.4 mmol/L)-hypoglycaemic-(2.8 ± 0.13 mmol/L)-clamp. RESULTS: The glucagon response was lower in people with type 1 diabetes (9.4 ± 0.8 pmol/L, 8.0 [7.0-10.0]) compared to type 2 diabetes (23.7 ± 3.7 pmol/L, 18.0 [12.0-28.0], p < 0.001) and controls (30.6 ± 4.7, 25.5 [17.8-35.8] pmol/L, p < 0.001). The adrenaline response was lower in type 1 diabetes (1.7 ± 0.2, 1.6 [1.3-5.2] nmol/L) compared to type 2 diabetes (3.4 ± 0.7, 2.6 [1.3-5.2] nmol/L, p = 0.001) and controls (2.7 ± 0.4, 2.8 [1.4-3.9] nmol/L, p = 0.012). Growth hormone was lower in people with type 2 diabetes than in type 1 diabetes, at baseline (3.4 ± 1.6 vs 7.7 ± 1.3 mU/L, p = 0.042) and during hypoglycaemia (24.7 ± 7.1 vs 62.4 ± 5.8 mU/L, p = 0.001). People with 1 diabetes had lower overall symptom responses than people with type 2 diabetes (45.3 ± 2.7 vs 58.7 ± 6.4, p = 0.018), driven by a lower neuroglycopenic score (27.4 ± 1.8 vs 36.7 ± 4.2, p = 0.012). CONCLUSION: Acute counterregulatory hormone and symptom responses to experimental hypoglycaemia are lower in people with type 1 diabetes than in those with long-standing insulin-treated type 2 diabetes and controls.

Hypoglycaemia induces a sustained pro-inflammatory response in people with type 1 diabetes and healthy controls.

AIM: To determine the duration and the extension of the pro-inflammatory response to hypoglycaemia both in people with type 1 diabetes and healthy controls. MATERIALS AND METHODS: Adults with type 1 diabetes (n = 47) and matched controls (n = 16) underwent a hyperinsulinaemic-euglycaemic hypoglycaemic (2.8 ± 0.1 mmoL/L [49.9 ± 2.3 mg/dL]) glucose clamp. During euglycaemia, hypoglycaemia, and 1, 3 and 7 days later, blood was drawn to determine immune cell phenotype, monocyte function and circulating inflammatory markers. RESULTS: Hypoglycaemia increased lymphocyte and monocyte counts, which remained elevated for 1 week. The proportion of CD16+ monocytes increased and the proportion of CD14+ monocytes decreased. During hypoglycaemia, monocytes released more tumour necrosis factor-α and interleukin-1ß, and less interleukin-10, after ex vivo stimulation. Hypoglycaemia increased the levels of 19 circulating inflammatory proteins, including high sensitive C-reactive protein, most of which remained elevated for 1 week. The epinephrine peak in response to hypoglycaemia was positively correlated with immune cell number and phenotype, but not with the proteomic response. CONCLUSIONS: Overall, despite differences in prior exposure to hypoglycaemia, the pattern of the inflammatory responses to hypoglycaemia did not differ between people with type 1 diabetes and healthy controls. In conclusion, hypoglycaemia induces a range of pro-inflammatory responses that are sustained for at least 1 week in people with type 1 diabetes and healthy controls.

Consistent Effects of Hypoglycemia on Cognitive Function in People With or Without Diabetes.

OBJECTIVE: Hypoglycemia poses an immediate threat for cognitive function. Due to its association with acute cognitive impairment, the International Hypoglycemia Study Group (IHSG) defines a blood glucose level <3.0 mmol/L as "level 2 hypoglycemia." In the current study we investigated whether having diabetes, type of diabetes, or hypoglycemia awareness moderates this association. RESEARCH DESIGN AND METHODS: Adults with type 1 diabetes with normal (n = 26) or impaired (n = 21) hypoglycemic awareness or with insulin-treated type 2 diabetes (n = 15) and age-matched control subjects without diabetes (n = 32) underwent a hyperinsulinemic-euglycemic-hypoglycemic glucose clamp (2.80 ± 0.13 mmol/L [50.2 ± 2.3 mg/dL]). At baseline and during hypoglycemia, calculation ability, attention, working memory and cognitive flexibility were measured with the Paced Auditory Serial Addition Test (PASAT) and the Test of Attentional Performance (TAP). RESULTS: For the whole group, hypoglycemia decreased the mean ± SD proportion of correct answers on the PASAT by 8.4 ± 12.8%, increased reaction time on the TAP Alertness task by 32.1 ± 66.6 ms, and increased the sum of errors and omissions on the TAP Working Memory task by 2.0 ± 5.5 (all P < 0.001). Hypoglycemia-induced cognitive declines were largely irrespective of the presence or type of diabetes, level of symptomatic awareness, diabetes duration, or HbA1c. CONCLUSIONS: IHSG level 2 hypoglycemia impairs cognitive function in people with and without diabetes, irrespective of type of diabetes or hypoglycemia awareness status. These findings support the cutoff value of hypoglycemia <3.0 mmol/L (<54 mg/dL) as being clinically relevant for most people with diabetes.

Glycaemic thresholds for counterregulatory hormone and symptom responses to hypoglycaemia in people with and without type 1 diabetes: a systematic review.

AIM/HYPOTHESIS: The physiological counterregulatory response to hypoglycaemia is reported to be organised hierarchically, with hormone responses usually preceding symptomatic awareness and autonomic responses preceding neuroglycopenic responses. To compare thresholds for activation of these responses more accurately between people with or without type 1 diabetes, we performed a systematic review on stepped hyperinsulinaemic-hypoglycaemic glucose clamps. METHODS: A literature search in PubMed and EMBASE was conducted. We included articles published between 1980 and 2018 involving hyperinsulinaemic stepped hypoglycaemic glucose clamps among people with or without type 1 diabetes. Key exclusion criteria were as follows: data were previously published; other patient population; a clamp not the primary intervention; and an inadequate clamp description. Glycaemic thresholds for counterregulatory hormone and/or symptom responses to hypoglycaemia were estimated and compared using generalised logrank test for interval-censored data, where the intervals were either extracted directly or calculated from the data provided by the study. A glycaemic threshold was defined as the glucose level at which the response exceeded the 95% CI of the mean baseline measurement or euglycaemic control clamp. Because of the use of interval-censored data, we described thresholds using median and IQR. RESULTS: A total of 63 articles were included, whereof 37 papers included participants with type 1 diabetes (n=559; 67.4% male sex, aged 32.7±10.2 years, BMI 23.8±1.4 kg/m2) and 51 papers included participants without diabetes (n=733; 72.4% male sex, aged 31.1±9.2 years, BMI 23.6±1.1 kg/m2). Compared with non-diabetic control individuals, in people with type 1 diabetes, the median (IQR) glycaemic thresholds for adrenaline (3.8 [3.2-4.2] vs 3.4 [2.8-3.9 mmol/l]), noradrenaline (3.2 [3.2-3.7] vs 3.0 [2.8-3.1] mmol/l), cortisol (3.5 [3.2-4.2]) vs 2.8 [2.8-3.4] mmol/l) and growth hormone (3.8 [3.3-3.8] vs. 3.2 [3.0-3.3] mmol/l) all occurred at lower glucose levels in people with diabetes than in those without diabetes (all p≤0.01). Similarly, although both autonomic (median [IQR] 3.4 [3.4-3.4] vs 3.0 [2.8-3.4] mmol/l) and neuroglycopenic (median [IQR] 3.4 [2.8-N/A] vs 3.0 [3.0-3.1] mmol/l) symptom responses were elicited at lower glucose levels in people with type 1 diabetes, the thresholds for autonomic and neuroglycopenic symptoms did not differ for each individual subgroup. CONCLUSIONS/INTERPRETATION: People with type 1 diabetes have glycaemic thresholds for counterregulatory hormone and symptom responses at lower glucose levels than people without diabetes. Autonomic and neuroglycopenic symptoms responses are generated at about similar levels of hypoglycaemia. There was a considerable variation in the methodology of the articles and the high insulin doses in most of the clamps may affect the counterregulatory responses. FUNDING: This article has received funding from the Innovative Medicines Initiative 2 Joint Undertaking (JU) under grant agreement no. 777460. REGISTRATION: This systematic review is registered in PROSPERO (CRD42019120083).

Sustained Proinflammatory Effects of Hypoglycemia in People With Type 2 Diabetes and in People Without Diabetes.

Iatrogenic hypoglycemia activates the immune system and is associated with an increased risk for atherosclerotic disease. We determined acute and long-term effects of insulin-induced hypoglycemia on inflammatory markers in humans with or without type 2 diabetes. A total of 15 adults with type 2 diabetes and 16 matched control subjects (17 men and 14 women, age 59.6 ± 7.1 years, BMI 28.5 ± 4.3 kg/m2) underwent a hyperinsulinemic-euglycemic (5.31 ± 0.32 mmol/L) hypoglycemic (2.80 ± 0.12 mmol/L) glucose clamp. Blood was drawn during euglycemia and hypoglycemia and 1, 3, and 7 days later to determine circulating immune cell composition, function, and inflammatory proteins. In response to hypoglycemia, absolute numbers of circulating lymphocytes and monocytes significantly increased and remained elevated for 1 week. The proportion of CD16+ monocytes increased, and the proportion of CD14+ monocytes decreased, which was sustained for 1 week in people without diabetes. During hypoglycemia, ex vivo stimulated monocytes released more tumor necrosis factor-α and interleukin 1ß, and less interleukin 10, particularly in people with diabetes. hs-CRP and 25 circulating inflammatory proteins increased, remaining significantly elevated 1 week after hypoglycemia. While levels at euglycemia differed, responses to hypoglycemia were broadly similar in people with or without type 2 diabetes. We conclude that hypoglycemia induces a proinflammatory response at the cellular and protein level that is sustained for 1 week in people with type 2 diabetes and control subjects.

Synthetic long-acting insulin analogs for the management of type 1 diabetes: an update.

INTRODUCTION: Type 1 diabetes is characterized by insulin deficiency and requires near-physiological insulin replacement. In most patients, this is accomplished by basal bolus therapy consisting of a long-acting basal insulin administered once or twice daily and short-acting insulin with main meals. Several long-acting insulin analogs have been developed to optimize basal insulin therapy. AREAS COVERED: This paper reviews the design of - and data from - randomized controlled trials (RCTs) to assess glucose lowering efficacy and safety of long-acting insulin analogs for the treatment of type 1 diabetes. EXPERT OPINION: Due to the non-inferiority treat-to-target design of insulin, RCTs treatment differences primarily appear as differences in hypoglycemia risk. Data suggest that the first generation long-acting insulin analogs insulin glargine U100 and insulin detemir have a similar glucose lowering efficacy compared to NPH insulin but a lower risk of hypoglycemia, particularly during nighttime. The newer analogs insulin glargine U300 and insulin degludec provide non-inferior efficacy, although insulin glargine U300 is less potent unit-to-unit. Insulin degludec reduces hypoglycemia risk compared to insulin glargine U100. Future studies should explore the potential for further improvement of treatment results in type 1 diabetes by a structured approach to personalization of basal insulin therapy.

Hyperinsulinaemic-hypoglycaemic glucose clamps in human research: a systematic review of the literature.

AIMS/HYPOTHESIS: The hyperinsulinaemic-hypoglycaemic glucose clamp technique has been developed and applied to assess effects of and responses to hypoglycaemia under standardised conditions. However, the degree to which the methodology of clamp studies is standardised is unclear. This systematic review examines how hyperinsulinaemic-hypoglycaemic clamps have been performed and elucidates potential important differences. METHODS: A literature search in PubMed and EMBASE was conducted. Articles in English published between 1980 and 2018, involving adults with or without diabetes, were included. RESULTS: A total of 383 articles were included. There was considerable variation in essential methodology of the hypoglycaemic clamp procedures, including the insulin dose used (49-fold difference between the lowest and the highest rate), the number of hypoglycaemic steps (range 1-6), the hypoglycaemic nadirs (range 2.0-4.3 mmol/l) and the duration (ranging from 5 to 660 min). Twenty-seven per cent of the articles reported whole blood glucose levels, most venous levels. In 70.8% of the studies, a dorsal hand vein was used for blood sampling, with some form of hand warming to arterialise venous blood in 78.8% of these. Key information was missing in 61.9% of the articles. CONCLUSIONS/INTERPRETATION: Although the hyperinsulinaemic-hypoglycaemic clamp procedure is considered the gold standard to study experimental hypoglycaemia, a uniform standard with key elements on how to perform these experiments is lacking. Methodological differences should be considered when comparing results between hypoglycaemic clamp studies. PROSPERO REGISTRATION: This systematic review is registered in PROSPERO (CRD42019120083).