Cyclosporin reduces renal prostanoid excretion in type 1 diabetic patients

Prostacyclin and thromboxane A₂ are important regulators of kidney blood flow. To examine whether changes in their metabolism could be involved in the nephrotoxicity of cyclosporin, we determined urinary excretion of 6-keto PGF_1a and dinor-6-keto PGF_1a (prostacyclin metabolites) and dinor-TxB₂ (thromboxane metabolite) in five newly diagnosed type 1 diabetic patients during and after stopping cyclosporin therapy. In the resting state, cyclosporin had no effect on prostanoid excretion. In response to exercise, urinary excretion of 6-keto PGF_1a was reduced by 50% (P<0.02), dinor-6-keto PGF_1a by 15% (P<0.05) and dinor-TxB₂ by 45% (P<0.02), while albumin excretion increased 4.5-fold (P<0.05) during cyclosporin therapy. Simultaneously, there was a rise in serum creatinine concentration, and renal biopsy specimens obtained from three patients showed periglomerular and interstitial fibrosis and tubular atrophy. After the discontinuation of cyclosporin therapy, serum creatinine concentrations returned to normal, histological changes improved and there was an associated rise in urinary prostanoid excretion. These data suggest that a reduction in renal prostanoid synthesis by cyclosporin may diminish renal blood flow and function, and lead to histological changes in the kidney.     

Alpha2‐antiplasmin regulates the development of dermal fibrosis in mice by prostaglandin F2α synthesis through adipose triglyceride lipase/calcium‐independent phospholipase A2

Objective

Systemic sclerosis (SSc) is characterized by fibrosis of the skin and visceral organs. Patients with SSc have enhanced plasma levels of the plasmin–α2‐antiplasmin (α2AP) complex, and we recently implicated α2AP in the development of fibrosis through transforming growth factor β (TGFβ) production. This study was undertaken to clarify how α2AP induces TGFβ production and the development of fibrosis.

Methods

To clarify the detailed mechanism by which α2AP induces TGFβ production, we focused on adipose triglyceride lipase (ATGL)/calcium‐independent phospholipase A₂ (iPLA₂) and examined whether ATGL/ iPLA₂ is associated with α2AP‐induced TGFβ production. The mouse model of bleomycin‐induced SSc was used to evaluate the role of α2AP in the development of fibrosis. Dermal thickness and collagen content were determined in mouse skin treated with phosphate buffered saline or bleomycin. Moreover, we cultured SSc‐like fibroblasts from the bleomycin‐treated mouse skin and examined the production of TGFβ and prostaglandin F_2α (PGF_2α).

Results

We found that α2AP binding to ATGL promoted PGF_2α synthesis through iPLA₂ in fibroblasts, and the PGF_2α synthesis that was promoted by α2AP induced TGFβ production in fibroblasts. In addition, the neutralization of α2AP attenuated the production of TGFβ and PGF_2α in SSc‐like fibroblasts from mice. The α2AP deficiency attenuated bleomycin‐induced fibrosis and PGF_2α synthesis, while the administration of PGF_2α to α2AP‐deficient mice facilitated α2AP deficiency–attenuated fibrosis.

Conclusion

These findings suggest that α2AP regulates the development of fibrosis by PGF_2α synthesis through ATGL/iPLA₂. The inhibition of α2AP‐initiated pathways might provide a novel therapeutic approach to fibrotic diseases.

     

Endothelial cells as target for antiphospholipid antibodies. Human Polyclonal and Monoclonal Anti-β2-Glycoprotein I Antibodies React In Vitro with Endothelial Cells Through Adherent β2-Glycoprotein I and Induce Endothelial Activation

Objective. To investigate the ability of human anti-β₂-glycoprotein I (anti-β₂GPI) antibodies to recognize the cofactor adherent on endothelial cells (EC) and to modulate endothelial functions. Methods. Six human affinity-purified polyclonal anti-β₂GPI IgG and 2 IgM monoclonal antibodies (MAb) were obtained from patients with the antiphos-pholipid syndrome. The antibodies were tested for their ability to 1) bind to endothelial monolayers through the adherent β₂GPI and 2) modulate endothelial adhesion molecule expression and interleukin-6 (IL-6) and 6-keto-prostaglandin F_1α (6-keto-PGF_1α) secretion. Results. The affinity-purified IgG and the MAb with anti-β₂GPI activity, but not the respective controls, displayed EC binding, which declined on cells incubated in serum-free medium and was restored in a dose-dependent manner by exogenous human β₂GPI. After EC binding, both polyclonal and monoclonal antibodies up-regulated adhesion molecule expression. Anti-β₂GPI MAb also significantly increased IL-6 and 6-keto-PGF_1α secretion. Conclusion. These findings support the hypothesis that anti-β₂GPI antibodies bind and activate EC through the adherent cofactor β₂GPI, likely leading to a procoagulant state.     

Plasma levels and urinary excretion of prostaglandins in patients with rheumatoid arthritis

Summary No significant differences were found in plasma concentrations and urinary excretion of prostaglandin E₂ (PGE₂), 6-keto-prostaglandin-F₁ (6-keto-F PGF₁) and thromboxane B₂ (T–xB₂), between rheumatoid arthritis patients and controls. However, urinary excretion of PGE_e and 6-keto-PGF₁ tended to be greater and plasma levels of TxB₂ lower in rheumatoid arthritis. Plasma concentrations and urinary excretion showed no marked circadian variation, although night or morning values were slightly lower. Plasma and urine prostaglandins do not correlate with clinical symptomatology in rheumatoid arthritis.     

Effects of 1α-hydroxy-vitamin D3 and 1,25-dihydroxy-vitamin D3 on calcium and phosphorus metabolism in hypoparathyroidism

The effects of 1α-OH D₃ or 1,25-(OH)₂D₃ on calcium and phosphorus metabolism have been evaluated in five hypoparathyroid patients to establish the direct effects of these compounds in adult humans, uncomplicated by compensatory changes in parathyroid hormone secretion. Doses of 1–2.5 μg/day in four patients (5 μg/day in a fifth patient on diphenyl-hydantoin and phenobarbital) caused a marked increase in serum calcium concentration and urinary calcium excretion, without significant changes in renal calcium clearance or urinary hydroxyproline excretion. These results suggest that the correction of hypocalcemia involved primarily a stimulation of intestinal calcium absorption rather than a stimulation of skeletal calcium resorption. Simultaneously, there were increases in urinary phosphorus excretion and variable changes in serum inorganic phosphate concentration.These effects were produced by doses of 1α-OH D₃ and 1,25-(OH)₂D₃ which approach the dose needed to prevent rickets, in contrast to the very large doses of vitamin D or 25-OH D₃ required for comparable effects in hypoparathyroid patients. The increased relative effectiveness of these one-hydroxylated forms of vitamin D reveals a deficiency of vitamin D one-hydroxylation in hypoparathyroidism. The rapidity of action of 1α-OH D₃ and 1,25-(OH)₂D₃ was also striking. Apart from its physiologic implications, the potency of the one-hydroxylated forms of vitamin D offers significant therapeutic advantages in some patients whose hypoparathyroidism is difficult to control with vitamin D itself.     

Nondeletional α-thalassemia: First description of αHphα and αNcoα mutations in a Spanish population

Several different deletions underlie the molecular basis of α-thalassemia. The most common α-thalassemia determinant in Spain is the rightward deletion (−α^3.7). To our knowledge, however, no cases of α-thalassemia due to nondeletional mutations have so far been described in this particular Mediterranean area. Here, we report the existence of nondeletional forms of α-thalassemia in ten Spanish families. The α₂-globin gene was characterized in ten unrelated patients and their relatives only when the presence of deletional α-thalassemia was ruled out. The α₂-globin gene analysis was performed using the polymerase chain reaction (PCR) followed by restriction enzyme analysis or by allele-specific priming. This allowed the identification of a 5-base pair (bp) deletion at the donor site of IVS I (α^Hphα) in 9 cases and the α₂ initiation codon mutation (α^Ncoα) in one case. Although these α₂-globin gene mutations are found in other Mediterranean areas, our results demonstrate their presence in the Spanish population and suggest that the α^Hphα/αα genotype is probably the most common nondeletional form of α-thalassemia in Spain. © 1996 Wiley-Liss, Inc.     

INFLUENCE OF 1α-(OH)D3 ADMINISTRATION ON BONE AND BONE MINERAL METABOLISM IN PATIENTS ON CHRONIC GLUCOCORTICOID TREATMENT; A DOUBLE BLIND CONTROLLED STUDY

We have performed a double-blind placebo controlled study of 1α-hydroxyvita-min D₃ (1α-(OH)D₃) 2 μg daily for 6 months, in 14 patients receiving long-term glucocorticoid treatment. Patients were matched for age, sex, underlying disease and dose of glucocorticoid. Initial values for serum calcium, phosphorus and alkaline phosphatase were in the normal range. Two of the 14 patients showed an increased serum immunoreactive parathyroid hormone (iPTH) concentration. Serum 25-hyd-roxyvitamin D and 1,25-dihydroxyvitamin D (l,25-(OH)₂D) were normal but the average 24,25-dihydroxyvitamin D (24,25-(OH)₂D) was low. The histomorphometrically determined trabecular bone volume of an iliac crest biopsy appeared to be low in 6 patients. The average active bone resorption and osteoid seams were increased, while the average osteoblast seams were within the normal range. Treatment with 1α-(OH)D₃ raised ⁴⁷Ca²⁺ intestinal absorption and 24 h urinary Ca²⁺ excretion significantly at 3 and 6 months and at 6 months serum iPTH concentration and 24 h urinary hydroxyproline excretion had fallen significantly in the treated group. During treatment with 1α-(OH)D₃ the serum 1,25-(OH)₂D and 24,25-(OH)₂D levels increased significantly. In all cases of the 1α-(OH)D₃-group, the second bone biopsy, taken at the end of the treatment period, showed a decrease of active resorption and a more positive course of trabecular bone volume than the biopsy of the placebo-treated counterpart: trabecular bone volume remained constant or even increased in the 1α-(OH)D₃-group. In both groups osteoid seams and osteoblast seams did not change significantly. We conclude that treatment with 1α-(OH)D₃ during 6 months inhibits the increased bone resorption seen in glucocorticoid-induced bone disease, while bone formation is not suppressed by this therapy.     

Proteolytic inactivation of α1-antitrypsin and α1-antichymotrypsin by neutrophils in arthritic joints

Objective. In vitro, activated neutrophils create a microenvironment in which proteinase inhibitors are inactivated through the coordinate action of reactive oxygen species and released elastase. We investigated whether such a mechanism may contribute to the destruction of the joint tissues in arthritis. Methods. We analyzed the state of α₁-antitrypsin (α₁AT) and α₁-antichymotrypsin (α₁ACT), the two major inhibitors of the neutrophilic serine proteinases, in synovial fluid (SF) from patients with inflammatory arthropathies (n = 71) and osteoarthritis (OA) (n = 11), and related the results to neutrophil activation in SF. Results. The ratio of functional to antigenic levels of α₁AT in SF of patients with inflammatory joint diseases was similar to that of α₁AT in normal plasma, whereas that of α₁ACT was significantly decreased. Patients with inflammatory arthropathies had significantly higher levels of inactivated α₁AT (iα₁AT) and inactivated α₁ACT (iα₁ACT) in SF (as determined with monoclonal antibodies specific for the inactivated [i.e., proteolytically inactivated and/or complexed] forms of these inhibitors) than patients with OA (P < 0.005). Inactivated α₁AT and iα₁ACT levels corresponded to 0.3–11% and 3–99%, respectively, of the total amount of these inhibitors in SF. Most of the iα₁AT in SF had a lower M_r than that of native α₁AT. Inactivated α₁ACT in SF had an M_r identical to that of nonfunctional α₁ACT in plasma treated with chymotrypsin. Levels of both iα₁AT and iα₁ACT correlated significantly with lactoferrin and elastase levels. Conclusion. These results suggest that α₁AT and α₁ACT in arthritic joints are inactivated in part by activated neutrophils, suggesting a role for these cells in impairment of the local balance between proteinases and their inhibitors in arthritis.     

Elevated urinary levels of thromboxane and prostacyclin metabolites in sickle cell disease reflects activated platelets in the circulation

There is evidence for increased factor VII turnover and the associated increased thrombin generation and fibrinolytic activities in sickle cell disease (SCD) that may affect in vivo platelet and endothelial cell reactivity. We studied the release of specific eicosanoids that are indicative of in vivo platelet activation and endothelial cell injury. The circulating and urinary levels of 2,3-dinor thromboxane B₂(2,3-dinor-TxB₂), TxB₂, PGI₂ [as 6-keto-PGF_lα], and PGE₂ were measured in 15HbSS patients, eight HbAA nonhaemolytic anaemic individuals and 12 healthy HbAA controls using specific RIAs. The mean urinary 2,3-dinor-TxB₂ in the HbSS patients was significantly higher than in both the healthy HbAA and the anaemic controls. 6-keto-PGF_lα was undetected in the urines of the healthy HbAA controls, but was measured insignificant amounts in the HbSS and the HbAA anaemic patients. The urinary concentrations of PGE₂ and TxB₂ in HbSS patients' samples were also significantly higher than those of both control groups (P < 0.05). PGE₂ and TxB₂ levels were below the detection limit in the plasmas of the HbAA subjects, but were measurable in the HbSS and HbAA anaemic plasmas. The plasma level of 6-keto-PGF_lα in the HbSS patients was also significantly higher than in the control groups. The data indicates a persistent inflammatory process in the HbSS patients, and is consistent with the hypothesis that there is platelet and endothelial cell activation in SCD.     

Stimulation of bile acid 6α-hydroxylation by rifampin

Background: Rifampin was shown to relieve pruritus in cholestatic liver diseases. There has been much speculation about the origin of pruritus, but it has not yet been comprehensively explained. The role of bile acids in producing pruritus is obscure and still under debate. Since rifampin both inhibits the uptake of bile acids into the hepatocyte and strongly induces mixed-function oxidases in the liver, the beneficial effects of this drug might be a consequence of altered bile acid metabolism.Methods: We investigated the influence of rifampin on urinary bile acid excretion with special respect to glucuronide and sulphate conjugates in 14 healthy volunteers before and after administration of rifampin, 600 mg×7 days, using each subject as his or her own control.Results: Bile acid glucuronide excretion increased from 0.55 to 1.19 μmol/24 h. This was in particular due to a significant increase of the urinary excretion of the 6α-hydroxylated hyocholic and hyodeoxycholic acids, the relative amounts of which accounted for about two thirds of the urinary bile acid excretion. Excretion of sulphates, however, decreased from 1.40 to 0.86 μmol/24 h due to a significantly reduced excretion of lithocholic acid sulphate. No changes in the excretion rates of other primary and secondary bile acids and no changes in their conjugation patterns were observed.Conclusions: The results provide evidence that rifampin induces 6α-hydroxylation of bile acids. The products are subsequently glucuronidated at the 6α-hydroxy groups, thus stimulating renal excretion of potentially toxic bile acids.     

Soluble VE‐cadherin in rheumatoid arthritis patients correlates with disease activity: Evidence for tumor necrosis factor α–induced VE‐cadherin cleavage

Objective

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disorder that principally attacks synovial joints. However, accelerated atherosclerosis and increased cardiovascular morbidity and mortality are major clinical consequences of endothelial dysfunction in RA patients. Tumor necrosis factor α (TNFα) is the major mediator of inflammation in RA, related to vascular injury by targeting VE‐cadherin, an endothelium‐specific adhesion molecule of vital importance for endothelium integrity and angiogenesis. We undertook this study to examine the mechanisms regulating VE‐cadherin processing by TNFα and their occurrence in RA.

Methods

Human umbilical vein endothelial cells were used in primary culture and treated with recombinant TNFα to study VE‐cadherin cleavage. Cell lysates and conditioned media were analyzed by Western blotting for VE‐cadherin cytoplasmic domain and extracellular domain (VE‐90) generation, respectively. VE‐90 was analyzed at baseline and at the 1‐year followup in sera from 63 RA patients (from the Very Early Rheumatoid Arthritis cohort) with disease duration of <6 months.

Results

TNFα induced a time‐dependent shedding of VE‐90 in cell media. This effect was prevented by tyrosine kinase inhibitors (genistein and PP2) or by knocking down Src kinase. In contrast, tyrosine phosphatase blockade enhanced VE‐cadherin cleavage, confirming the requirement of tyrosine phosphorylation processes. In addition, using the matrix metalloproteinase (MMP) activator APMA and the MMP inhibitor GM6001, we demonstrated that MMPs are involved in TNFα‐induced VE‐cadherin cleavage. Of major importance, VE‐90 was detected in sera from the 63 RA patients and was positively correlated with the Disease Activity Score at baseline and after 1‐year followup.

Conclusion

These findings provide the first evidence of VE‐cadherin proteolysis upon TNFα stimulation and suggest potential clinical relevance of soluble VE‐cadherin in management of RA.

     

Shell gland responsiveness to prostaglandins F2α and E1 and to arginine vasotocin during the laying cycle of the domestic hen (Gallus domesticus)

Contractile responses of isolated shell gland (SG) strips from laying hens displayed no significant differences 6 hrs before oviposition, at oviposition, and 6 hrs after oviposition when stimulated with arginine vasotocin (AVT), prostaglandin E₁ (PGE₁), or prostaglandin F_2α (PGF_2α). Dose-response curves show that the sensitivity of the SG to these agents, in vitro, is: AVT > PGF₂ > PGE₁. PGF_2α, however, produces the largest contractile response, while PGE₁ appears to be a poor agonist of contractile activity in vitro. These results are discussed in relation to the known hormonal patterns during the ovulatory cycle of the hen and the physiological roles attributed to these oxytocics in the control of oviposition.     

Association of α‐actinin–binding anti–double‐stranded DNA antibodies with lupus nephritis

Objective

Anti–double‐stranded DNA (anti‐dsDNA) antibodies may contribute to the pathogenesis of glomerulonephritis (GN) by cross‐reacting with α‐actinin in murine models and in some patients with systemic lupus erythematosus (SLE). We therefore sought to determine possible disease associations with serologic and clinical features and to characterize this new autoantibody specificity.

Methods

One hundred patients with SLE were recruited into this multicenter study, as well as 100 rheumatic disease controls and 2,100 healthy blood donors. Clinical disease was evaluated by the SLE Disease Activity Index (SLEDAI; excluding the anti‐DNA component). Anti‐dsDNA antibodies were detected by conventional enzyme‐linked immunosorbent assay (ELISA) and by a commercial enzyme immunoassay (EIA). Anti–α‐actinin antibodies were detected by ELISA, and their specificity was confirmed by Western blotting and by indirect immunofluorescence using rat kidney sections and mesangial cells as substrates. Highly positive sera were selected for absorption experiments and were affinity‐purified for cross‐reactivity studies and measurement of antibody avidity.

Results

Sera from 62 of the SLE patients had anti‐dsDNA antibodies; 21 of these sera also had anti–α‐actinin antibodies, as compared with 1 of the 38 sera without anti‐dsDNA antibodies. Of the 22 patients with anti–α‐actinin antibodies, 10 had GN, as compared with 14 of the 78 without anti–α‐actinin antibodies (P < 0.01). In patients with GN, anti–α‐actinin, but not anti‐dsDNA, antibodies correlated with the SLEDAI score (minus the anti‐DNA component) and with treatment. The fraction of serum anti‐dsDNA antibodies that cross‐reacted with α‐actinin exhibited high avidity for dsDNA, as determined using a commercial EIA for high‐avidity anti‐dsDNA antibodies and an in‐house conventional ELISA.

Conclusion

The α‐actinin–binding antibodies are significantly associated with GN in SLE. Whether such autoantibodies may anticipate the development of this complication of SLE remains to be verified.

     

Hypoparathyroidism—a long-term follow-up experience with 1α-vitamin D3 therapy

OBJECTIVE Previous studies have suggested that alpha-D₃ therapy can cause deterioration in renal function. We have, therefore, examined the long-term effect of 1α-hydroxyvitamin D₃ (alpha-D₃) administration upon renal function in hypoparathyroid patients. DESIGN This is a prospective long-term follow-up study of alpha-D₃ administration on hypoparathyroid patients at a mean daily dose of 1 μg (range 0.5–2.5 μg) during a total of 2040 patient-months. PATIENTS Seventeen unselected patients (14 females and 3 males), two with primary and 15 with post-surgical hypoparathyroidism. RESULTS The significant effect of alpha-D₃ on serum and urinary calcium was achieved during the first week of treatment and remained stable at the same range during the close follow-up of 2040 patient-months. No significant change was observed in the serum creatinine during the whole follow-up period. During follow-up, five women developed hypercalcluria and one patient developed hypercalcaemia that disappeared when the dose of the drug was reduced or discontinued. CONCLUSIONS From our study we concluded that alpha-D₃ is a safe and effective drug in the long-term therapy of hypoparathyroid patients.     

α2-macroglobulin-proteinase complexes as correlated with α1-proteinase inhibitor-elastase complexes in synovial fluids of rheumatoid arthritis patients

The levels of α₁-proteinase inhibitor-elastase and α₂-macroglobulin (α₂M)-proteinase complexes were measured in synovial fluids from arthritis patients by use of specific immunosorbent assays. Both types of proteinase inhibitor-proteinase complexes were significantly correlated with each other as well as with the total neutrophil count in synovial fluids of rheumatoid arthritis patients but were discordant in synovial fluids of patients with osteoarthritis. One synovial fluid sample showed active (inhibitory) α₂M as well as active collagenase. We purified α₂M from pooled synovial fluids obtained from patients with rheumatoid arthritis. This α₂M retained approximately 90% of its proteinase binding (inhibiting) capacity, compared with that of normal plasma α₂M. We found no evidence that α₂M was inactivated by means other than proteinases.     

Hb adana or α259(E8)Gly→Aspβ2, A severely unstable α1-globin variant,observed in combination with the -(α)20.5 KB α-thal-1 deletion in two Turkish patients

We have identified a severely unstable hemoglobin variant through sequencing of amplified DNA involving the α₁-globin gene; the mutation is located in codon 59 (CC G CA G) andresults in a Gly—Asp replacement. This amino acid substitution concerns a glycine residue at an internal position in the E helix, which is in close contact with a glycine residue of the B helix; introduction of the larger and charged aspartic acid residue greatly affects the stability of the molecule. This variant was present in association with a common α-thalassemia-1 deletion [-(α)20.5 kb] in two adults and caused a severe type of Hb H disease with anemia, low levels of Hb A₂, increased → chain, and Hb Bart's. In vitro chain synthesis in reticulocytes showed a high specific activity of the variant α chain. Only a minute quantity of Hb H was present but instead about 10% of Hb Bart's was observed. The increased synthesis of γ chains was likely due to specific characteristics of a chromosome with haplotype #3, which was present in both patients. The same family was studied 18 years ago [1]; the improved methodology presently available has led to a corrected diagnosis for these patients. © 1993 Wiley-Liss, Inc.     

Relationships between inflammation,hemodynamic function and RAAS in longstanding type 1 diabetes and diabetic kidney disease

The renin angiotensin aldosterone system (RAAS) is associated with renal disease and inflammation in a diabetes setting, however, little is known about the implicated mechanisms in individuals with long standing diabetes. Accordingly, our aim was to perform an observational study to quantify urinary excretion of inflammatory biomarkers in participants with long standing type 1 diabetes (T1D) (with and without diabetic kidney disease [DKD]) and controls, at baseline and in response to RAAS activation. GFR_INULIN, ERPF_PAH, and 42 urine inflammatory biomarkers were measured in 74 participants with T1D for ≥50 years (21 with DKD and 44 without DKD [DKD resistors]) and 73 healthy controls. Additionally, inflammatory biomarkers were measured before and after an angiotensin II infusion (ANGII, 1 ng?kg^?1?min^?1). Significantly lower urinary excretion of cytokines (IL-18, IL-1RA, IL-8), chemokines (MCP1, RANTES) and growth factors (TGF-α, PDGFAA, PDGFBB, VEGF-A) was observed in participants with T1D at baseline compared to controls. Urinary IL-6 was higher in DKD than in DKD resistors in an exploratory analysis unadjusted for multiple comparisons. In T1D only, lower GFR_INULIN correlated with greater excretion of proinflammatory biomarkers (IL-18, IP-10, & RANTES), growth factors (PDGF-AA & VEGFAA), and chemokines (eotaxin & MCP-1). ANGII increased 31 of 42 inflammatory biomarkers in T1D vs controls (p < 0.05), regardless of DKD resistor status. In conclusion, lower GFR and intra-renal RAAS activation were associated with increased inflammation even after longstanding T1D. The increased urinary IL-6 in patients with DKD requires further investigation to determine whether IL-6 is a candidate protective biomarker for prognostication or targeted therapy in DKD.     

The effect of renal hyperfiltration on urinary inflammatory cytokines/chemokines in patients with uncomplicated type 1 diabetes mellitus

Aims/hypothesis

High intraglomerular pressure causes renal inflammation in experimental models of diabetes. Our objective was to determine whether renal hyperfiltration, a surrogate for intraglomerular hypertension, is associated with increased excretion of urinary cytokines/chemokines in patients with type 1 diabetes mellitus.

Methods

Blood pressure, renal haemodynamic function (inulin and para-aminohippurate clearances for glomerular filtration rate (GFR) and effective renal plasma flow (ERPF), respectively) and urine samples were obtained during clamped euglycaemia in individuals with type 1 diabetes with either hyperfiltration (GFR determined using inulin [GFR_INULIN] ≥135 ml? min^?1 1.73 m^?2, n?=?28) or normofiltration (n?=?21) and healthy control individuals (n?=?18).

Results

Baseline clinical characteristics, dietary sodium and protein intake and blood pressure levels were similar in the diabetic and healthy control groups. In addition, HbA_1c levels were similar in the two diabetic groups. As expected baseline GFR was higher in hyperfilterers than either normofiltering diabetic patients or healthy control patients (165?±?9 vs 113?±?2 and 116?±?4 ml min^?1 1.73 m^?2, respectively, p?<?0.01). ERPF and renal blood flow were also comparatively higher and renal vascular resistance was lower in hyperfiltering patients (p?<?0.01). Hyperfiltering diabetic patients had higher excretion rates for eotaxin, IFNα2, macrophage-derived chemokine, platelet-derived growth factor (PDGF)-AA, PDGF-AB/BB and granulocyte-macrophage colony-stimulating factor (p?≤?0.01). Urinary monocyte chemoattractant protein (MCP)-1 and RANTES (regulated on activation, normal T expressed and secreted) excretion was also higher in hyperfiltering vs normofiltering diabetic individuals (p?<?0.01) and fibroblast growth factor-2, MCP-3 and CD40K excretion was elevated in hyperfiltering diabetic individuals vs healthy controls (p?<?0.01).

Conclusions/interpretation

Renal hyperfiltration is associated with increased urinary excretion of inflammatory cytokines/chemokines in patients with uncomplicated type 1 diabetes.     

Relationship between α1-antitrypsin inactivation and tumor necrosis factor α concentration in the synovial fluid of patients with rheumatoid arthritis

Objective. To examine the relationship between α₁-antitrypsin (α₁AT) specific activity and tumor necrosis factor α (TNFα) concentration in synovial fluid from 48 patients with rheumatoid arthritis. Methods. The specific activity of α₁AT was calculated from the measurement of α₁AT concentration (by rocket immunoelectrophoresis) and elastase inhibitory capacity. TNFα was detected by enzyme-linked immuno-sorbent assay. Results. TNFα concentrations correlated with the extent of α₁AT inactivation. Conclusion. Our findings are consistent with a role of elastase in TNFα release within the inflamed joint.     

Increased cardiovascular responses to prostaglandin F2alpha in spontaneously hypertensive rats: evidence for neural mediation.

Earlier studies have shown that autonomic nerve system integrity is necessary for the spontaneously hypertensive rat (SHR) to demonstrate increased vasodepressor responses to depressor prostaglandins (PG). We compared normotensive rat (NR) and SHR microvascular and blood pressure responses to PGF_2α before and after ganglionic or α-adrenergic blockade to determine whether autonomic nerve integrity is necessary for SHRs to react with increased responses to the pressor prostaglandin F_2α. Before neural blockade, PGF_2α caused mean arterial pressure, pulse pressure, and cremaster muscle arterioles (?75 μm) of young (90–130 g), prehypertensive SHRs to react statistically significantly more than matched NR. PGF_2α had no effect on NR or SHR cremaster venule diameter. After ganglionic or α-adrenergic blockade of NRs and SHRs, PGF_2α increased SHR mean arterial pressure and pulse pressure only to NR levels and increased NR arteriole constriction to the same levels observed in SHRs. This study presents further evidence of altered prostaglandin-autonomic nervous system interaction in SHRs.