Capillary basement membrane width in diabetic children

The nuts and bolts of low-level laser (light) therapy

Soon after the discovery of lasers in the 1960s it was realized that laser therapy had the potential to improve wound healing and reduce pain, inflammation and swelling. In recent years the field sometimes known as photobiomodulation has broadened to include light-emitting diodes and other light sources, and the range of wavelengths used now includes many in the red and near infrared. The term "low level laser therapy" or LLLT has become widely recognized and implies the existence of the biphasic dose response or the Arndt-Schulz curve. This review will cover the mechanisms of action of LLLT at a cellular and at a tissular level and will summarize the various light sources and principles of dosimetry that are employed in clinical practice. The range of diseases, injuries, and conditions that can be benefited by LLLT will be summarized with an emphasis on those that have reported randomized controlled clinical trials. Serious life-threatening diseases such as stroke, heart attack, spinal cord injury, and traumatic brain injury may soon be amenable to LLLT therapy.

The nuts and bolts of low-level laser (light) therapy

Soon after the discovery of lasers in the 1960s it was realized that laser therapy had the potential to improve wound healing and reduce pain, inflammation and swelling. In recent years the field sometimes known as photobiomodulation has broadened to include light-emitting diodes and other light sources, and the range of wavelengths used now includes many in the red and near infrared. The term "low level laser therapy" or LLLT has become widely recognized and implies the existence of the biphasic dose response or the Arndt-Schulz curve. This review will cover the mechanisms of action of LLLT at a cellular and at a tissular level and will summarize the various light sources and principles of dosimetry that are employed in clinical practice. The range of diseases, injuries, and conditions that can be benefited by LLLT will be summarized with an emphasis on those that have reported randomized controlled clinical trials. Serious life-threatening diseases such as stroke, heart attack, spinal cord injury, and traumatic brain injury may soon be amenable to LLLT therapy.

Lung function changes related to diabetes mellitus

Diabetic microangiopathy targets the lung as it does other organs. Even though respiratory dysfunction in most patients with diabetes is subclinical and rarely the presenting complaint, there are several reasons why pulmonary assessment is important: (1) Pulmonary function testing noninvasively quantifies physiological reserves in a large microvascular bed that is not clinically devastated by diabetes. (2) Subclinical loss of pulmonary reserves becomes overtly debilitating under conditions of stress, such as with aging, chronic hypoxia due to lung disease or high altitude exposure, or volume overload secondary to cardiac and renal failure. (3) Unlike myocardial or skeletal muscle function, pulmonary indices are largely independent of physical fitness. (4) Interpretation of pulmonary function indices is not complicated by secondary sequelae of diabetic end-organ failure or prior therapy. Lung function could provide useful measures of the progression of systemic microangiopathy. (5) Chronic use of inhaled insulin may affect long-term pulmonary function, while preexisting pulmonary dysfunction may alter the absorption and bioavailability of inhaled insulin. This review will discuss the changes in lung function observed in diabetes, their underlying mechanisms, and their physiological and clinical implications.

The diabetic lung: relevance of alveolar microangiopathy for the use of inhaled insulin

The alveolar-capillary network receives the entire cardiac output and constitutes the largest microvascular organ in the body, making it highly susceptible to systemic microangiopathy. Owing to its large reserves, symptoms and disability develop later in the lung than in smaller microvasculature such as the kidney or retina despite a comparable severity of anatomic involvement. Hence, pulmonary impairment in diabetes mellitus is under-recognized. Nonetheless, respiratory autonomic neuropathy and structural derangement of the thorax and lung parenchyma develop in many asymptomatic diabetic patients; the pathophysiology parallels that in other target organs. Even subclinical loss of alveolar microvascular reserves can be quantified noninvasively from lung diffusing capacity and its components (membrane diffusing capacity and alveolar-capillary blood volume) measured at a given cardiac output at rest or during exercise. The alveolar diffusion-perfusion relation tracks the recruitment of microvascular reserves in a manner independent of physical fitness. This article addresses the importance and pathophysiologic basis of diabetic pulmonary involvement, the assessment of diabetic alveolar microangiopathy, and the relevance of this understanding for the emerging use of inhaled insulin.

Serum prolidase activity as a marker of osteoporosis in type 2 diabetes mellitus

OBJECTIVES

Prolidase is a specific imidodipeptidase involved in collagen degradation. The increase in the enzyme activity is believed to be correlated with the increased intensity of collagen degradation This study aimed to evaluate serum prolidase activity and urinary deoxypyridinoline cross links in type 2 diabetic subjects with and without osteoporosis assessed by bone mineral density.

DESIGN AND METHODS

Seventy-five patients (54 F/21 M) with type 2 DM and 43 age and gender matched healthy subjects (30 F/13 M) were recruited for this study. Serum prolidase activity was assessed with colorimetric determination. Urinary deoxypyridinoline (Dpy) was determined with electrochemiluminesence immunoassay.

RESULTS

Serum prolidase activity was significantly lower in patients with type 2 DM than in the healthy controls (mean +/- SEM; 43.3 +/- 1.4 U/L and 53.3 +/- 2.2 U/L respectively, p: 0.000). Non osteoporotic diabetic patients had lower serum prolidase activity (median: 25th-75th percentiles; 39.5: 30.3-50.5 U/L) than osteoporotic diabetic patients (50.0: 41.8-56.3 U/L, p: 0.030) and healthy controls (52.0: 43.0-58.0 U/L, p: 0.004). Urinary Dpy excretion was not different between osteoporotic and nonosteoporotic diabetic patients. However it was lower in both diabetic groups than the healthy controls. We did not observe a statistically significant difference between the serum prolidase activity of dislipidemic/normolipidemic, hypertensive/normotensive, obese/nonobese, insulin/OAD treated, poorly/well-controlled patients and patients with/without diabetic nephropathy and retinopathy (p > 0.05).

CONCLUSION

This study shows a significant decrease in serum prolidase activity in patients affected with type 2 DM, which may be interpreted as evidence of decreased bone resorption. Our data also suggest that serum prolidase activity may be a better marker of osteoporosis in diabetic state than Dpy.

Effects of photostimulation on wound healing in diabetic mice

BACKGROUND AND OBJECTIVE

Low-level laser irradiation at certain fluences and wavelengths can enhance the release of growth factors from fibroblasts and stimulate cell proliferation in vitro. We evaluated whether low-level laser irradiation can improve wound healing in diabetes mellitus.

STUDY DESIGN/MATERIALS AND METHODS

Genetically diabetic mice (C57BL/Ksj/db/db) were used as the animal model for this wound healing study. The experimental animals were divided among four groups: negative control, positive control (topical basic fibroblast growth factor [bFGF] on wound), laser therapy group; and a combination group of laser therapy and topical bFGF. An argon dye laser (Lexel Auora Model 600) at a wavelength of 630 nm and an output of 20 m W/cm2 was used as the light source. The speed of wound closure and histological evaluation were used to analyze the experimental results.

RESULTS

Laser irradiation enhanced the percentage of wound closure over time as compared to the negative control group (58.4 +/- 2.6 vs. 40.8 +/- 3.4 at day 10 and 95.7 +/- 2 vs. 82.3 +/- 3.6 at day 20, P < .01). Histological evaluation showed that laser irradiation improved wound epithelialization, cellular content, granulation tissue formation, and collagen deposition in laser-treated wounds as compared to the negative control group (6.4 +/- 0.16 vs. 3.8 +/- 0.13 at day 10 and 12 +/- 0.21 vs. 8.2 +/- 0.31, P < .01).

CONCLUSION

This study of laser biostimulation on wound healing in diabetic mice suggests that such therapy may be of great benefit in the treatment of chronic wounds that occur as a complication of diabetes mellitus.

Development of vascular complications in diabetes

Chronic complications of diabetes are dominated by disorders of the vascular system. They are a much larger burden on both diabetic patients and overall medical costs than diabetes itself. Large vessel problems are far more frequent than microvascular disorders. Loss of arterial elasticity alters arterial flow patterns and increases microcirculatory peak flow rates. Hyperglycemia may directly disrupt elastin formation. Diabetic leg artery disease may be generated by nerve damage, reversing this interactive contribution sequence. The major anatomic feature of microangiopathy in long-term diabetes is an unevenly distributed thickening of the intima of smaller arterioles. The thickening is primarily due to accumulation of type IV (basement membrane) collagen. Arterioles change local vessel diameter to adjust blood distribution to meet current needs. The thickening compromises the maximum local blood flow that may be achieved by this means. Compromise of maximal arteriolar dilatation does not disrupt exercising muscle but in the kidney, retina, and possibly in nerve, local circumstances can generate serious damage. Each of these system's responses has unique features that mediate its vulnerability, but all these organs show arteriolar hyalinization. The increased arteriolar accumulation of type IV collagen appears to be a response to the tangential force generated by flow over local endothelial cells. An increase in peak arteriolar wall force is mediated by a diabetes-specific doubling of erythrocyte membrane curvature change resistance. Red cell aggregation rate determines the rate of damage. The same nonspecific burden may also predispose to heart disease and stroke. Intensive metabolic control improves red cell deformability and protects against arteriolar damage. Therapies that address the rheologic problem more directly may add to the effectiveness of good diabetes control in the future.

Gas exchange during exercise in diabetic children

The purpose of this study was to evaluate the cardiorespiratory and metabolic response to exercise in 33 children, aged 9 to 15 years, affected by type I diabetes mellitus, in comparison with 47 age-, sex-, weight-, and height-matched healthy children. All diabetic children were on a mixed split-dose insulin regimen, consisting of both regular and long-acting insulin in the morning and evening. The last insulin injection was administered on average 6 hours before the test. The mean duration of diabetes mellitus was 5.0 +/- 3.1 years. The metabolic control was evaluated on the basis of HbA1 levels (mean, 8.9 +/- 1.8%). Pulmonary function tests and progressive exercise tests on the treadmill were performed. Gas exchange, ventilation, and heart rate (HR) were monitored during the tests. The O2 pulse (VO2/HR) was calculated. There was no difference in the baseline oxygen uptake (VO2) between the diabetic children and the control group. VO2 peak was significantly lower (P less than 0.01) in the diabetic adolescents (41.2 +/- 5.9 mL/min/kg) compared to control subjects (46.3 +/- 9.6 mL/min/kg) and it was achieved at an earlier (P less than 0.01) time of run (7.5 +/- 1.8 vs. 9.1 +/- 2.8 min). Anaerobic threshold and minute ventilation were similar in the two groups. The O2 pulse throughout the test was significantly lower (ANOVA, P less than 0.001) in the diabetic group compared to the controls. No differences were found in resting and post-exercise spirometric values. In conclusion, our study shows that well-controlled diabetic adolescents have a reduced working capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation between decreased collagen production in diabetic animals and in cells exposed to diabetic serum: response to insulin

Collagen production has been shown to be decreased in costal cartilage from nondiabetic animals after incubation with diabetic rat serum. Since collagen was decreased to a similar degree in tissues from diabetic animals, we questioned whether altered collagen production in vivo could be related to altered production induced in vitro. Collagen and noncollagen protein production in articular cartilage from diabetic animals (production in vivo) was compared to protein production in dermal fibroblasts from non-diabetic rats exposed to serum from the same diabetic rats (production in vitro). Diabetes was induced by intravenous administration of 90 mg/kg of streptozotocin into male Sprague-Dawley rats. Cartilage was removed and incubated with [3H]-proline for 2 hours at 37 degrees C (in vivo), while fibroblasts were exposed to experimental serum from individual animals for 24 hours with addition of 5 microCi of [5-3H]-proline for the final 6 hours (in vitro). Collagen and noncollagen protein production were quantitated using purified bacterial collagenase. Collagen production in cartilage decreased to 46% (p less than .01) and noncollagen to 68% (p less than .05) of levels in control animals. Fibroblasts exposed to 2.5% diabetic serum decreased collagen and noncollagen protein production to levels of 30% (p less than .01) and 54% (p less than .05) of production in cells incubated in 2.5% normal rat serum. Correlation between defective collagen production in cartilage from individual rats and the effects of their own serum on collagen production in fibroblasts was significant (r = 0.84, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Diabetic microangiopathy, genetics, environment, and treatment

As the major cause of disability and death in insulin-dependent diabetes, microangiopathy is obviously of major concern to diabetologists. Unlike macroangiopathy, which can readily be prevented by means that are currently on hand, the origin and treatment of microangiopathy remain far more problematical. The complexity of this lesion is indicated by the findings in this laboratory that hyperglycemia induced by the rodenticide, vacor, can cause microangiopathy independent of genetic diabetes, yet significant microangiopathic lesions can be detected in genetic diabetic patients before the appearance of hyperglycemia. Further, there is now intriguing evidence based both on basement membrane measurements from our laboratory and on clinical studies showing that significant microangiopathy only rarely occurs prior to the onset of puberty. The evidence that control or even normalization of blood glucose levels does not influence the course of established microangiopathy is becoming increasingly convincing. Five prospective, randomized studies over the past five years have shown that strict regulation of glucose has no consistent benefit on, and in some studies may, at least transiently, accelerate, the retinopathy of diabetes. Moreover, the first controlled study of successful pancreatic transplantation to achieve normalization of blood glucose levels has again demonstrated that established retinopathy is neither prevented nor even delayed by normal glucose levels. This review, therefore, emphasizes that, though hyperglycemia is required for clinically significant microangiopathy to occur, clearly other factors, genetic, environmental, or both, must play major roles in determining the course of microangiopathy. It is toward these nonglycemic factors in the development of diabetic microangiopathy that future research should increasingly be directed.

Improved diabetes control reduces skeletal muscle capillary basement membrane width in insulin-dependent diabetes mellitus

We studied the relationship between the control of blood glucose and the width of skeletal muscle capillary basement membrane in 54 insulin-dependent diabetic patients. After initial measurement of levels of glycosylated hemoglobin and the width of skeletal muscle capillary basement membrane, the patients were divided into two groups: an intensive treatment group of 30 patients who were treated with continuous subcutaneous insulin infusion and a control group of 24 patients who continued to receive conventional treatment, usually two daily injections of insulin. Both groups have been followed prospectively for periods of time up to 4 years. Within 1 year the intensive treatment group had a significant decrease in glycosylated hemoglobin levels as compared to baseline values reflecting improved control of blood glucose. This level of glycosylated hemoglobin was stable over the remainder of the follow-up period. This group also had a significant reduction in the width of skeletal muscle capillary basement membrane within 1 year and it persisted for the 4 years of observation. The control group of patients had no significant change in their level of glycosylated hemoglobin and the width of the skeletal muscle capillary basement membrane tended to increase with time. It this result in skeletal muscle capillaries applies to those of retinal and renal tissue, meticulous diabetic control for a prolonged period of time may be beneficial in preventing the progression of the microvascular complications of diabetes mellitus.

Subepidermal capillary basement membrane thickness of the skin obtained by punch biopsy in patients with non insulin dependent diabetes mellitus

Thickening and proliferation of the capillary basement membrane is a generalized phenomenon in diabetes mellitus and has been described in many organs including the heart, kidney, pancreas, retina etc. While such changes are specific, it is difficult to obtain specimens from those organs. Tissue samples were obtained from the medial surface of the thigh of 33 diabetics and 4 healthy controls by means of punch biopsy. Measurements carried out by normogram obtained from electron microscopic pictures. HbA1c values were also determined at time of muscle biopsy. 1. The HbA1c values are higher in diabetics than in the control group (p<0.01). 2. The subepidermal capillary basement membrane thickness of the diabetics: 30% of the 5’th decade population, 53.9% of the 6’th decade population and 83.3% of the 7’th decade population was greater than 3,000 A°. Whereas that of the controls was less than 3,000 A°. 3. The subepidermal capillary basement membrane thickness was not significantly increased with the duration of the disease. 4. In cases of greater subepidermal capillary besement membrane thickness, HbA1c showed a significant increase. (p<0.01).

The effect of puberty on the development of early diabetic microvascular disease in insulin-dependent diabetes

We studied the prevalence of early diabetic retinopathy and nephropathy in 21 prepubertal and 55 late-pubertal subjects with insulin-dependent diabetes (IDD). All subjects had IDD of 5-7 years duration at the time of evaluation. The prevalence of early diabetic retinopathy was significantly greater in the late-pubertal subjects than prepubertal subjects (33% vs. 9.5%, P = 0.05), despite similar glycosylated hemoglobin values between the two groups (11.7 +/- 2.7% vs. 10.1 +/- 1.6%) at the time of evaluation. Nephropathy was infrequent in late-pubertal subjects (9%), and absent in the prepubertal subjects. We hypothesize that puberty plays an important role in the development of microvascular complications of IDD, and that increases in growth factors, sex hormones and deterioration in glycemic control at the time of puberty may each enhance the development of diabetic microvascular disease.

Thickening of the capillary basement membrane of the quadriceps muscle in Vacor-induced diabetic patients

The effect of Vacor diabetes mellitus on the quadriceps muscle capillary basement membrane thickness has been examined by the electron microscopic method. With this procedure, it was possible to obtain an objective evaluation of the significance of capillary basement membrane thickening in Vacor diabetes mellitus. The results of such a study on the muscle capillary basement membrane in 10 normal subjects and 9 Vacor-poisoned patients have demonstrated the following: (1) the average basement membrane width of Vacor patients (2801 A +/- SD 614) is over twice that of normal subjects (1300 +/- 185 A), and all 9 cases demonstrated muscle capillary basement membrane thickening; (2) there is a significant association of basement membrane width with age (P less than 0.01), but not with the duration of the disease or fasting blood glucose values in the Vacor group. The results of the present study indicate that diabetes mellitus induced by Vacor poisoning can lead to microangiopathy, and that such basement membrane thickening is an early and consistent finding.

The effect of diabetic control on the width of skeletal-muscle capillary basement membrane in patients with Type I diabetes mellitus

We studied the relation between the control of blood glucose and the width of skeletal-muscle capillary basement membrane in 23 insulin-dependent (Type I) diabetic patients. After initial measurement of levels of glycosylated hemoglobin and width of skeletal-muscle capillary basement membrane, the patients were divided into two groups: an experimental group of 13 patients who were treated with continuous subcutaneous insulin infusion, and a control group of 10 patients who continued to receive conventional treatment--usually two injections of insulin daily. After two years, the experimental group had a significant decrease in glycosylated hemoglobin levels as compared with base-line values (mean +/- S.E.M., 7.6 +/- 0.4 vs 10.2 +/- 0.7 per cent; P less than 0.001), reflecting improved control of blood glucose, and a significant reduction in the width of skeletal-muscle capillary basement membrane (1293 +/- 68 vs. 1717 +/- 182 A; P less than 0.05). The control group of patients had no significant change in their levels of glycosylated hemoglobin or in the width of their skeletal-muscle capillary basement membranes. If changes in the capillaries in skeletal muscle parallel those in the capillaries in retinal or renal tissue, then meticulous control of blood glucose may be beneficial over time in preventing the microvascular complications of diabetes.

Electron microscopic observation of gastric mucosal capillaries in diabetics--relationship between diabetic microangiopathy and complications following gastrectomy

An electron microscopic study was made of the gastric mucosal capillaries (GMC) of diabetic patients. Ultrastructural findings, including diabetic microangiopathy (DMA), and clinical features of these diabetic patients were investigated in relation to anastomotic leakage after gastrectomy. The gastric mucosa of resected stomachs from 12 diabetics and 10 nondiabetics were examined. Ultrastructurally, DMA was demonstrated in the stomachs of diabetics, in which the basement membrane of GMC was thicker. The degree of this DMA in the stomach significantly correlated with the duration of diabetes and the degree of DMA found in the skin, but not with age and fasting plasma glucose (FPG) level. Marked DMA was observed with significant frequency in diabetics with anastomotic leakage after gastrectomy. In our hospital, anastomotic leakage after gastrectomy occurred in 9 out of 53 diabetics. Diabetics with anastomotic leakage had severe FPG, a long duration of diabetes and diabetic retinopathy. It seems reasonable to presume that anastomotic leakage after gastrectomy occurs more frequently in diabetics with ultrastructurally severe DMA, clinically severe FPG and relatively long duration of diabetes.

Comparison of collagen and glycosaminoglycan synthesis in attaching control and diabetic human skin fibroblasts

Cultured fibroblasts derived from normal subjects and juvenile diabetics attach in the absence of serum to plastic culture dishes and secrete macromolecules, including collagenous components, hyaluronic acid, and proteoglycans into the medium and onto the plastic surface where they form a microexudate carpet. Most diabetic fibroblasts examined did not spread as well as normal cells during a 4-hr interval after the initial attachment. There were no significant differences between normal and diabetic cells with respect to proline and lysine incorporation and lysine hydroxylation. The percentage glycosylation of hydroxylysine was marginally higher in the media proteins of diabetic cells, but glycosylation in both normal and diabetic cells was elevated over that typically observed in human skin collagen. Collagenous components were estimated to constitute approximately 15-20% of the microexudate carpet fraction in both normal and diabetic cell strains. Diabetic fibroblasts exhibited a marginally lower ratio of heparan sulfate to chondroitin sulfate in the cell surface to matrix microexudate carpet fraction (trypsinate) than did normal fibroblasts. The hyaluronate and chondroitin sulfate contents of this fraction of diabetic cells were not significantly different from those of normal cells.

Leakage of fluorescein: first sign of juvenile diabetic retinopathy. Role of diabetic control and of duration of diabetes

In order to ascertain the first vascular lesions responsible for juvenile diabetic retinopathy, 408 fluorescein angiographies were performed in 114 diabetic children and adolescents whose diabetes became clinically apparent before the age of 14 years. Compared with regular ophthalmoscopy, fluorescein angiography doubles the frequency of the diagnosis of incipient retinopathy. In addition to the classical diabetic lesions, fluorescein leakages are demonstrated in 50% of diabetic eyes with initial retinopathy. They probably reflect early changes in capillary permeability. They appear often before microaneurysms. Duration of diabetes as well as insufficient and poor metabolic control considerably increase the frequency of retinopathy.

Diabetic angiopathy--its lessons in vascular physiology

Progress in our understanding diabetic angiopathy has been slow, but we are now learning a number of lessons of interest to the cardiologist. Diabetic angiopathy is a collective term for conditions specific to the diabetic state and related to its duration more than to patient age. The angiopathy produces calcification of the media of larger arteries, but its major effects are in the microcirculation. Intense interest in one feature, skeletal muscle capillary basement membrane thickening, has dominated the last decade. Capillary basement membrane thickening, while characteristic of diabetes, is associated with little direct impairment of the microcirculatin. It appears to play no role in the pathogenesis of diabetes itself. The pathology of diabetic retinopathy and diabetic nephropathy suggests that arteriolar changes may be the major mediator of diabetic angiopathy. This concept is supported by the interactions between hypertension and diabetes in the eye and kidney. The course of diabetes of youthful onset differs from that of maturity onset. The relative frequency of diabetic angiopathy is higher, and of atherosclerotic complications is lower. This has made it difficult to demonstrate the potential value of preventive measures. Benefit to one type of problem may become hidden by worsening of the other. If the diabetic benefits from what is learned about how ischemic heart disease risk can be reduced, he will require even more effective management to prevent or control diabetic angiopathy.

Diabetic regulation and its relationship to microangiopathy

This review addresses the question of the effectiveness of rigid regulation of the blood glucose in delaying or preventing the vascular complications of diabetes mellitus. Morphometric, pathologic, biochemical, and clinical evidence on both sides of this question are presented. It is concluded that because of present inadequate methods of completely returning glucose homeostasis to normal in diabetics, the question remains moot.

Joint contracture--common manifestation of childhood diabetes mellitus

Sixty-five of 229 seven to eighteen-year-old campers with diabetes were found to have contractures of finger joints; in two thirds of affected children only the fifth finger was involved. Stiff resistance to passive finger manipulation and thickened adherent skin over the dorsa of the hands were additional features. Short stature was associated with involvement of more than one finger; the shortest youngsters also had contractures of large joints. Joint changes were independent of age, sex, age of onset of diabetes, and control of diabetes, but correlated with duration of the diabetes.