Coagulation pathways and diabetic retinopathy: abnormal modulation in a selected group of insulin dependent diabetic patients

Proteomic analysis of diabetic retinopathy identifies potential plasma-protein biomarkers for diagnosis and prognosis

OBJECTIVES

To identify molecular pathways and prognostic- and diagnostic plasma-protein biomarkers for diabetic retinopathy at various stages.

METHODS

This exploratory, cross-sectional proteomics study involved plasma from 68 adults, including 15 healthy controls and 53 diabetes patients for various stages of diabetic retinopathy: non-diabetic retinopathy, non-proliferative diabetic retinopathy, proliferative diabetic retinopathy and diabetic macular edema. Plasma was incubated with peptide library beads and eluted proteins were tryptic digested, analyzed by liquid chromatography-tandem mass-spectrometry followed by bioinformatics.

RESULTS

In the 68 samples, 248 of the 731 identified plasma-proteins were present in all samples. Analysis of variance showed differential expression of 58 proteins across the five disease subgroups. Protein-Protein Interaction network (STRING) showed enrichment of various pathways during the diabetic stages. In addition, stage-specific driver proteins were detected for early and advanced diabetic retinopathy. Hierarchical clustering showed distinct protein profiles according to disease severity and disease type.

CONCLUSIONS

Molecular pathways in the cholesterol metabolism, complement system, and coagulation cascade were enriched in patients at various stages of diabetic retinopathy. The peroxisome proliferator-activated receptor signaling pathway and systemic lupus erythematosus pathways were enriched in early diabetic retinopathy. Stage-specific proteins for early - and advanced diabetic retinopathy as determined herein could be 'key' players in driving disease development and potential 'target' proteins for future therapies. For type 1 and 2 diabetes mellitus, the proteomic profiles were especially distinct during the early disease stage. Validation studies should aim to clarify the role of the detected molecular pathways, potential biomarkers, and potential 'target' proteins for future therapies in diabetic retinopathy.

A systematic proteomic profiling and pathway analysis of protein biomarkers in diabetic retinopathy with subsequent validation of the IL-6 upstream regulator

Purpose

Diabetic retinopathy (DR) is a leading cause of irreversible blindness worldwide. Identifying risk factors associated with DR development and progression is crucial for improving treatment efficacy. Although proteomic changes in DR have been extensively studied, the results remain equivocal. Hence, this study aims to summarize and identify potential diagnostic or prognostic markers for DR. In addition, the upstream regulator responsible for protein deregulation of this disease was also validated.

Methods

We systematically analyzed the current literature on proteomic profile changes in DR, followed by pathway analysis identification. To validate the protein level changes, ELISA was performed from serum samples collected from 27 patients with DR and 25 healthy controls.

Results

Our analysis revealed that 1 candidate marker (afamin [AFM]) distinguished non-proliferative diabetic retinopathy (NPDR) from type 2 diabetic patients with no diabetic retinopathy/controls, 65 candidate markers distinguished proliferative diabetic retinopathy (PDR) from NPDR, 1 candidate marker (thyroid receptor-interacting protein 11 [TRIP11]) distinguished PDR from PDR-DME/DME, and 3 candidate markers for therapeutic evaluation of PDR. Our results pinpoint that inflammatory response, which IL-6 mainly modulated, is responsible for the changes of proteomic profiles identified in DR. This was also validated by ELISA analysis, indicating that IL-6 could be potentially useful for diagnosing DR.

Conclusion

We report a comprehensive patient-based proteomic approach to identify potential biomarkers for DR diagnosis, prognosis, and treatment evaluation.

Supplementary information

The online version contains supplementary material available at 10.1007/s40200-023-01204-6.

Susceptibility-directed anticoagulation after pancreas transplantation: A single-center retrospective study

Pancreas transplant achieves consistent long-term euglycemia in type 1 diabetes. Allograft thrombosis (AT) causes the majority of early graft failure. We compared outcomes of four anticoagulation regimens administered to 95 simultaneous kidney-pancreas or isolated pancreas transplanted between 1/1/2015 and 11/20/2018. Early postoperative anticoagulation regimens included the following: none, subcutaneous heparin/aspirin, with or without dextran, and heparin infusion. The regimens were empirically selected based on each surgeon's assessment of hemostasis of the operative field and personal preference. A sonographic-based global scoring system of AT is presented. The 47-month recipients and graft survival were 95% and 86%, respectively. Recipients with or without AT had similar survival. Five and four grafts were lost due to death and AT, respectively. Outcomes of prophylaxis regimens correlated with intensity of anticoagulation. Compared with no anticoagulation, an increase in hemorrhagic complications occurred exclusively with iv heparin. The higher arterial AT score found in regimens lacking antiplatelet therapy highlights the importance of early antiaggregants therapy. Abnormal fibrinolysis was associated with an increase in AT score. Platelet dysfunction, warm ischemia time, and enteric drainage were predictive of AT and, along with other known risk factors, were incorporated into an algorithm that matches intensity of early postoperative anticoagulation to the thrombotic risk.

Evaluation of serum fibrinogen, plasminogen, α2-anti-plasmin, and plasminogen activator inhibitor levels (PAI) and their correlation with presence of retinopathy in patients with type 1 DM

BACKGROUND. Diabetic retinopathy (DR) is the leading cause of blindness in the world. Retinopathy can still progress despite optimal metabolic control. The aim of the study was to determine whether different degrees of DR (proliferative or nonproliferative) were associated with abnormally modulated hemostatic parameters in patients with T1DM. METHOD. 52 T1DM patients and 40 healthy controls were enrolled in the study. Patients were subdivided into three categories. Group I was defined as those without retinopathy, group II with NPRP, and group III with PRP. We compared these subgroups with each other and the control group (Group IV) according to the serum fibrinogen, plasminogen, alpha2-anti-plasmin ( α2-anti-plasmin), and PAI. RESULTS. We detected that PAI-1, serum fibrinogen, and plasminogen levels were similar between the diabetic and control groups (P = 0.209, P = 0.224, and P = 0.244, resp.), whereas α2-anti-plasmin was higher in Groups I, II, and III compared to the control group (P < 0.01, P < 0.05, and P < 0.001, resp.). There was a positive correlation between serum α2-anti-plasmin and HbA1c levels (r = 0,268, P = 0.031). CONCLUSION. To our knowledge there is scarce data in the literature about α2-anti-plasmin levels in type 1 diabetes. A positive correlation between α2-anti-plasmin with HbA1c suggests that fibrinolytic markers may improve with disease regulation and better glycemic control.

Cerebrovascular complications of diabetic ketoacidosis in children

Neurological deterioration in children with diabetic ketoacidosis (DKA) is commonly caused by cerebral edema. However, subtle cerebral injuries including strokes should also be suspected, since children with hyperglycemia and DKA are prone to thrombosis. In this paper, a case involving a 2 month-old patient that presented cerebral edema and stroke as complications of DKA is reported. In the discussion, the literature on neurological complications of DKA in children is briefly reviewed, emphasizing the prothrombotic tendency of these patients.

Pediatric stroke associated with new onset type 1 diabetes mellitus: case reports and review of the literature

Neurological deterioration in children with diabetic ketoacidosis (DKA) is commonly caused by cerebral edema. However, stroke should also be suspected when focal neurological deficits are apparent, because children with hyperglycemia and DKA are prone to thrombosis. We report three cases of pediatric stroke associated with new onset type 1 diabetes mellitus (T1DM). The first case presented with sinovenous thrombosis, and the other two cases presented in DKA and had a late diagnosis of ischemic stroke following neurological deterioration. Our recent experiences and review of the literature emphasize the importance of early diagnosis, investigation, and treatment for patients that present with new onset T1DM and stroke.

Thrombin-activatable fibrinolysis inhibitor activity and global fibrinolytic capacity in Type 1 diabetes: evidence for normal fibrinolytic state

Hypofibrinolysis is a state that is commonly observed in type 2 diabetic patients, a finding also possibly related to obesity and insulin resistance. There is little information, however, regarding the status of fibrinolytic system in Type 1 diabetes, in particular as reflected by thrombin-activatable fibrinolysis inhibitor (TAFI) activity and global fibrinolytic capacity (GFC). To provide information in this respect, 30 Type 1 diabetic patients (median age=16) and 28 healthy controls (median age=14) were enrolled in this study. The median duration of diabetes was 7 years, and median HbA(1c) was 8.85% (range: 5.5-11.9%) in the diabetic group. None of the patients had macrovascular complications. Microvascular complications were present in a total of eight patients (nephropathy: n=5; retinopathy: n=3). A comparison of the TAFI activity between the patient (median 84.9, range: 71.5-103.3%) and the control groups (median=83.3, range: 63.7-97.4%) yielded no statistically significant difference (P=.950). Similarly, GFC was comparable between the two groups (median=8.22, range: 0.72-22.38 microg/ml, and median=13.32, range: 3.0-23.22 microg/ml, respectively, in the diabetic and control groups, P=.086). TAFI activity did not significantly correlate with age, albumin excretion, fasting plasma glucose, HbA(1c), D-dimer, and fibrinogen by Spearman rank correlation test. There was as a significant inverse correlation between GFC and TAFI activity (r=-.414, P=.006). Contrary to the previous observations in Type 2 diabetes, our data suggest that fibrinolytic activity is not adversely affected by Type 1 diabetes, and it has no relationship with the degree of metabolic control.

Renal Tissue Factor Expression Is Increased in Streptozotocin-Induced Diabetic Mice

BACKGROUND

Tissue factor (TF) is the key initiator of the coagulation cascade. Recent evidence suggests that TF plays a role in renal fibrin formation and renal failure in experimental kidney disease. We hypothesized that hyperglycemia is an important stimulus of TF expression in the kidney.

METHODS

Mice were injected with streptozotocin (STZ) (200 mg/kg) or with control buffer. Three or 10 weeks after injection, fibrin, thrombin and TF staining and TF activity were evaluated in the kidney. The effect of hyperglycemia on TF expression and secretion by tubular epithelial cells was measured in vitro.

RESULTS

Kidneys of STZ-treated mice showed a marked increase in thrombin staining (3.0 +/- 0.5 vs. 1.2 +/- 0.11) (p = 0.002) and an increase in TF clotting activity 10 weeks after STZ injection (33.9 +/- 1.3 vs. 25.4 +/- 1.0 s) (p < 0.0001). Increased glomerular fibrin deposition was present in 3 out of 6 diabetic mice. Tubular cells incubated with D-glucose (25 mmol/l) for 48 h displayed increased cellular TF (p = 0.05). However, soluble TF levels and TF activity in supernatant of cells incubated with D- or L-glucose were not different.

CONCLUSIONS

These data suggest that hyperglycemia is a causal factor in procoagulant activity associated with diabetic nephropathy.

Are phospholipid-binding antibodies implicated in the pathogenesis of diabetic microangiopathy?

Diabetic retinopathy (DR) is a major cause of blindness in the working population of the Western world and there is no doubt that its prevalence is strongly related to the duration of diabetes and the glycemic control. However, although intensive diabetes management, with the goal of achieving near-normal glycemia, has been shown to prevent and/or delay the onset of DR, there is now ample of evidence that the development of this microangiopathy is a multifactorial process in which genetic, metabolic, haemostatic and growth factors play an important role. Moreover, given the suggestions that immunological mechanisms might have a role in the pathogenesis of diabetic microangiopathy via immune complex deposition, it has been hypothesized that antiphospholipid antibodies (A-Ab) directed against endothelial antigens could be responsible for initiating vascular injury. In particular, not only A-Ab production was found to be increased in patients with overt nephropathy or macroangiopathy but also Lupus Anticoagulant positivity, representing an intersection point between immune and haemostatic alterations, has been highlighted as a potential and additional risk factor in the pathogenesis of microangiopathy in type 1 diabetics. Moreover, given the high levels of activated protein C, endothelin-1 and thrombo-modulin that have been observed in normo-albuminuric and uncomplicated patients, it has been concluded that the vascular endothelium shifts pathologically from an antithrombotic to a prothrombotic state even in the early phases of the disease. This condition was found to be more pronounced in subjects with anticardiolipin positivity and/or high circulating immune complexes concentrations, since they possess the ability not only to induce platelet activation and aggregation but also to activate the complement system via the classical pathway. Therefore, a potential synergism between generation of autoantibodies, haemostatic alterations and endothelial stress has been suggested, a stimulating hypothesis that needs further studies to be clarified in its complexity.

Thrombin activatable fibrinolysis inhibitor and hemostatic changes in patients with type I diabetes mellitus with and without microvascular complications

We investigated thrombin activatable fibrinolysis inhibitor (TAFI) and its influence on fibrinolysis by measuring pro-TAFI activity and total TAFI antigen in 38 patients with type I diabetes mellitus (18 with and 20 without microvascular complications), as well as in 20 healthy controls. The pro-TAFI levels in the two groups of patients did not differ from those in the control group. Total TAFI antigen [i.e. pro-TAFI, TAFI and inactive carboxypeptidase U (TAFIi)] tended to decrease in both the patient groups (59.7 +/- 7.2 and 73.4 +/- 8.9% with and without microvascular complications, respectively) compared with controls (91.9 +/- 12.2%) (P = 0.12). We also assessed the overall hemostatic potential (OHP) in plasma, the clot lysis time and the overall fibrinolytic potential. The OHP was significantly higher in patients with complications compared with controls (8.9 +/- 0.9 versus 6.7 +/- 0.4; P < 0.05) and also higher in the diabetics without complications (7.8 +/- 0.6), although the latter difference did not reach statistical significance. Levels of clot lysis time and overall fibrinolytic potential were similar in the two groups of patients and the controls. The increased OHP in plasma from diabetic patients with microvascular complications indicates an imbalance of the hemostatic system towards a prothrombotic state. No signs of impaired fibrinolysis were observed in patients with diabetes. Using the OHP method for estimation of overall hemostasis, it seems that TAFI does not influence either fibrinolysis or the increased thrombotic potential observed in patients with type I diabetes mellitus.

Is medical treatment for diabetic retinopathy still an unreal dream?

Diabetic retinopathy is a highly specific vascular complication of both type 1 and type 2 diabetes, estimated to be the most frequent cause of new cases of blindness in the working population of the Western world. The prevalence of retinopathy is strongly related to the duration of diabetes and glycemic control, even though a multifactorial pathogenesis should be probably considered in genetically susceptible subjects. Intensive diabetes management, with the goal of achieving near-normal glycemia, has been shown to prevent and/or delay the onset of diabetic retinopathy and laser photocoagulation has an established clinical efficacy in preventing visual loss. However, as laser scars always destroy the retinal anatomy permanently, a medical approach to nonproliferative retinopathy should be preferred if its clinical efficacy could be demonstrated. In this paper, recently published reports supporting this hypothesis are reviewed and their conclusions critically discussed.

Retinopathy in juvenile diabetes: a 10-year (1990-2000) review

Diabetic retinopathy (DR) is the most frequent complication of diabetes and a leading cause of impaired vision in the Western world. There is general agreement that early diagnosis and treatment of DR can slow its progression and help to prevent blindness. However, as a result of its asymptomatic nature and its etiopathogenesis, which is still unclear due to its multifactorial complexity, DR-related blindness has a growing social impact in industrialized countries. Therefore, in order to gain a better understanding of this serious disease, the author performed an updated 10-year review of risk factors and management of DR in type 1 diabetes.