Adiposopathy and bariatric surgery: is 'sick fat' a surgical disease?

OBJECTIVE: To review how bariatric surgery in obese patients may effectively treat adiposopathy (pathogenic adipose tissue or 'sick fat'), and to provide clinicians a rationale as to why bariatric surgery is a potential treatment option for overweight patients with type 2 diabetes, hypertension, and dyslipidaemia. METHODS: A group of clinicians, researchers, and surgeons, all with a background in treating obesity and the adverse metabolic consequences of excessive body fat, reviewed the medical literature regarding the improvement in metabolic disease with bariatric surgery. RESULTS: Bariatric surgery improves metabolic disease through multiple, likely interrelated mechanisms including: (i) initial acute fasting and diminished caloric intake inherent with many gastrointestinal surgical procedures; (ii) favourable alterations in gastrointestinal endocrine and immune responses, especially with bariatric surgeries that reroute nutrient gastrointestinal delivery such as gastric bypass procedures; and (iii) a decrease in adipose tissue mass. Regarding adipose tissue mass, during positive caloric balance, impaired adipogenesis (resulting in limitations in adipocyte number or size) and visceral adiposity are anatomic manifestations of pathogenic adipose tissue (adiposopathy). This may cause adverse adipose tissue endocrine and immune responses that lead to metabolic disease. A decrease in adipocyte size and decrease in visceral adiposity, as often occurs with bariatric surgery, may effectively improve adiposopathy, and thus effectively treat metabolic disease. It is the relationship between bariatric surgery and its effects upon pathogenic adipose tissue that is the focus of this discussion. CONCLUSIONS: In selective obese patients with metabolic disease who are refractory to medical management, adiposopathy is a surgical disease.

Is adiposopathy (sick fat) an endocrine disease?

OBJECTIVE: To review current consensus and controversy regarding whether obesity is a 'disease', examine the pathogenic potential of adipose tissue to promote metabolic disease and explore the merits of 'adiposopathy' and 'sick fat' as scientifically and clinically useful terms in defining when excessive body fat may represent a 'disease'. METHODS: A group of clinicians and researchers, all with a background in endocrinology, assembled to evaluate the medical literature, as it pertains to the pathologic and pathogenic potential of adipose tissue, with an emphasis on metabolic diseases that are often promoted by excessive body weight. RESULTS: The data support pathogenic adipose tissue as a disease. Challenges exist to convince many clinicians, patients, healthcare entities and the public that excessive body fat is often no less a 'disease' than the pathophysiological consequences related to anatomical abnormalities of other body tissues. 'Adiposopathy' has the potential to scientifically define adipose tissue anatomic and physiologic abnormalities, and their adverse consequences to patient health. Adiposopathy acknowledges that when positive caloric balance leads to adipocyte hypertrophy and visceral adiposity, then this may lead to pathogenic adipose tissue metabolic and immune responses that promote metabolic disease. From a patient perspective, explaining how excessive caloric intake might cause fat to become 'sick' also helps provide a rationale for patients to avoid weight gain. Adiposopathy also better justifies recommendations of weight loss as an effective therapeutic modality to improve metabolic disease in overweight and obese patients. CONCLUSION: Adiposopathy (sick fat) is an endocrine disease.

What the mouth has to say about diabetes. Careful examinations can avert serious complications.

Periodontal disease is a major but preventable complication of diabetes mellitus. Patient education, good glycemic control, regular dental care, appropriate diet, and a team approach that involves physicians, dietitians, dentists, and other health professionals offer the best chance for optimum care for these patients. Other oral complications of diabetes include tooth decay, xerostomia, candidiasis, and oral peripheral neuropathy. The mouth may also reflect secondary causes of diabetes, and oral examination may provide clues to diseases that coexist with type 1 diabetes. Truly, the mouth has much to say about diabetes.

Diabetic ketoacidosis and hyperosmolar nonketotic state: gaining control over extreme hyperglycemic complications.

Decompensated hyperglycemia is a frequent, severe complication of diabetes mellitus. Ketoacidosis usually occurs in patients with insulin-dependent (type I) diabetes, and insulin therapy is required to correct their hyperglycemic derangement. Hyperosmolar nonketotic state is more common in patients with non-insulin-dependent (type II) diabetes, who usually present with severe dehydration and hyperosmolar plasma. They respond readily to aggressive volume expansion, and insulin has a lesser role in management. Some patients exhibit a mixture of ketoacidosis and hyperosmolarity, which suggests that the two conditions may represent variants of decompensated hyperglycemia that differ only by the magnitude of dehydration and the severity of acidosis. All diabetic patients with hyperglycemic decompensation should return to their usual hypoglycemic programs as soon as possible and receive close follow-up after hospitalization.

Renal interstitial hydrostatic pressure and PGE2 in pressure natriuresis.

The present study tested the hypothesis that the presence of renal prostaglandin E2 (PGE2) is necessary for full natriuretic response to increased renal interstitial hydrostatic pressure (RIHP) during increased renal perfusion pressure (RPP). In control untreated pentobarbital-anesthetized dogs (n = 7), fractional excretion of sodium (FENa) was 1.17 +/- 0.48, 1.07 +/- 0.24, and 2.69 +/- 0.57% at RPP of 90, 122, and 148 mmHg, respectively. These changes in FENa were associated with effective renal blood flows (ERBF) of 1.43 +/- 0.20, 1.49 +/- 0.23, and 1.99 +/- 0.40 ml.min-1.g kidney wt-1, respectively. Similarly, glomerular filtration rate (GFR) was 0.53 +/- 0.10, 0.71 +/- 0.10, and 0.72 +/- 0.14 ml.min-1.g kidney wt-1, respectively. Treatment with indomethacin, a cyclooxygenase inhibitor, significantly lowered FENa to 0.45 +/- 0.13, 0.77 +/- 0.21, and 1.19 +/- 0.59% at RPP of 91, 121, and 146 mmHg, respectively. Additionally, indomethacin treatment lowered ERBF (0.51 +/- 0.15, 0.52 +/- 0.10, and 0.85 +/- 0.21 ml.min-1.g kidney wt-1) and GFR (0.28 +/- 0.09, 0.34 +/- 0.09, and 0.47 +/- 0.09 ml.min-1.g kidney wt-1) at low, middle, and high RPP, respectively. PGE2 replacement (n = 6) into renal artery at 0.01 microgram.min-1.kg body wt-1 returned FENa, ERBF, and GFR to control levels over the same range of RPP, whereas prostacyclin (PGI2) infusion (n = 7) at the same dose did not. RIHP was 4.2 +/- 1.2, 4.2 + 0.5, and 7.5 +/- 1.7 mmHg with increasing RPP in control untreated group and increased to similar levels with indomethacin treatment and during PGE2 or PGI2 replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Blunted pressure natriuresis in the Brattleboro diabetes insipidus rat.

Antidiuretic hormone is known to stimulate the renal synthesis of prostaglandins. These autacoids, in turn, modulate the pressure natriuresis phenomenon. Accordingly, the present study was done to test the hypothesis that, in the absence of antidiuretic hormone and antidiuretic hormone-dependent prostaglandin synthesis, the pressure natriuresis response is blunted. Experiments were performed on Brattleboro diabetes insipidus rats (n = 7) and Long Evans control rats (n = 14). A change in perfusion pressure in the Long Evans rats from 89.3 +/- 1.0 to 108.7 +/- 1.1 mm Hg (p less than 0.05) was associated with significant increases in the fractional excretion of sodium (1.1 +/- 0.2 to 2.3 +/- 0.3%) and the urinary prostaglandin excretion (32.6 +/- 6.8 to 56.6 +/- 10.0 pg/min). In contrast, a similar change in perfusion pressure in the diabetes insipidus rat from 88.6 +/- 1.4 to 106.2 +/- 1.5 mm Hg (p less than 0.05) resulted in no significant increases in either sodium or prostaglandin excretions. Treatment of a third group of diabetes insipidus rats (n = 9) with 1-desamino-8-D-arginine vasopressin (1 microgram/day) restored the natriuretic response to increases in renal perfusion pressure. Treated diabetes insipidus and Long Evans control rats had comparable natriuretic responses to increases in renal perfusion pressure. Untreated diabetes insipidus rats, on the other hand, had blunted responses. In summary, the pressure natriuresis response in diabetes insipidus rats is blunted compared with Long Evans control rats. We conclude that antidiuretic hormone is necessary for the complete expression of the pressure natriuresis response.

Proximal tubule response in aldosterone escape.

The response of the proximal tubule to chronic aldosterone administration (15 micrograms.kg-1.day-1) was evaluated in eight conscious female mongrel dogs. Temporal profiles between hemodynamic and hormonal changes and the fractional excretions of sodium and lithium were established. Aldosterone infusion resulted in a significant decrease in urinary sodium excretion from 9.2 +/- 1.3 to 5.8 +/- 0.9 meq/h after 1 day, returning to normal by the 5th day. These changes in urinary sodium excretion were associated with significant elevations of the mean arterial pressure (MAP) from 105 +/- 5 to 111 +/- 6 mmHg and plasma atrial natriuretic factor concentrations (ANF) from 30 +/- 2 to 57 +/- 7 pg/ml beginning the 1st day of infusion. Plasma renin activity (PRA), on the other hand, was depressed by aldosterone, falling below the level of detectability. The fractional excretion of lithium increased significantly by day 2 of aldosterone infusion (from 29 +/- 3 to 44 +/- 6%), reflecting the proximal tubular response to the above changes. We conclude that the proximal tubule responds to increases in MAP and ANF and decreases in PRA during aldosterone infusion by decreasing sodium reabsorption. Subsequent nephron segments must also respond to the volume expansion produced by aldosterone, since the sustained proximal tubule natriuretic response is insufficient to explain all of escape.

Localization of human renal cell carcinoma xenografts with a tumor-preferential monoclonal antibody.

We previously described an immunoglobulin G1 monoclonal antibody (UMVA-RCC-A6H) that is highly reactive with human renal cell carcinoma (RCC) and has little cross-reactivity to other cell types both normal and malignant. In efforts detailed herein, radiolabeled A6H selectively localized to RCC xenografts and provided high resolution images of the xenografts. Also, A6H clearly discriminated between RCC xenografts and other human tumor xenografts. Consistent images of RCC xenografts (greater than 60 mg) were obtained without background subtraction. The amount of radiolabeled A6H in the tumor usually ranged from five to twenty times that of the blood. Normal mouse tissues, abscesses, and other human tumor xenografts contained less radiolabel per mg than did blood. A control monoclonal antibody of the same isotype failed to exhibit any localization in xenografts or normal tissues. Approximately 40% of the radiolabeled A6H dose per g was localized in the RCC xenograft 2 days after injection, although at the time of imaging about 60% of the radiolabel remaining in the mouse was associated with the xenograft. These results demonstrate that a RCC restrictive monoclonal antibody does specifically localize to RCC xenografts and supports the hope that this approach may have clinical value for diagnosis, staging, or treatment.