Validation and Feasibility of the Postnatal Growth and Retinopathy of Prematurity Retinal Screening Criteria at a Level IV Tertiary Care Neonatal Intensive Care Unit.

OBJECTIVE: Retinopathy of prematurity (ROP) is detected in preterm infants by standardized screening programs, but in general, they have poor sensitivity. The Postnatal Growth and Retinopathy of Prematurity (G-ROP) algorithm uses weight gain to predict ROP superior reported sensitivity. Our objectives are to (1) independently validate the sensitivity of G-ROP criteria for the detection of ROP in infants born at >28 weeks' gestation in a tertiary care unit in the United States and (2) to calculate the cost savings associated with a potential reduction in examinations. STUDY DESIGN: This is a retrospective analysis of retinal screening examination data, with post-hoc application of G-ROP criteria to determine whether G-ROP criteria had acceptable sensitivity and specificity in diagnosing Type 1 and Type 2 ROP. All infants born at >28 weeks who were screened by current American Academy of Pediatric Ophthalmologists/American Academy of Pediatrics guidelines at Oklahoma Children's Hospital at the University of Oklahoma Health Sciences Center, between 2014 and 2019, were included. Subset analysis of infants screened by second tier criteria was also performed. Potential cost savings were estimated by analyzing frequency of billing codes. And by calculating the number of infants who could have potentially been spared examination. RESULTS: The G-ROP criteria had 100% sensitivity in detecting type 1 and 87.6% sensitivity in detecting type 2 ROP, which would have reduced infants screened by 50%. All infants in the second tier who would require treatment were detected. A cost saving of 49% was projected. CONCLUSION: The G-ROP criteria are easy to apply in real-world setting, thus establishing feasibility. The algorithm identified all cases of type 1 ROP; however, some cases of type 2 ROP were not detected. The annual savings in hospital examination cost by using these criteria would be 50%. Therefore, G-ROP criteria can safely be used to screen for ROP and may reduce the number of unnecessary examinations. KEY POINTS: · The G-ROP screening criteria are safe and predict 100% of treatment warranted ROP.. · Adoption of G-ROP criteria is feasible for level IV NICUs.. · Adoption of G-ROP screening guidelines will result in significant cost savings..

Association of Cardiovascular Disease with Retinopathy of Prematurity.

PURPOSE: To determine the associations of presence and types of cardiovascular diseases (CVDs) with development of retinopathy of prematurity (ROP) in premature infants undergoing ROP examinations. STUDY DESIGN: We performed secondary analyses of data from the multi-center Postnatal Growth and ROP Validation Study (GROP-2). CVD was categorized based on pulmonary blood flow (PBF), systemic blood flow (SBF), pulmonary hypertension (PPHN), or dysrhythmia. Adjusted odds ratios (aOR) and 95% confidence intervals (95% CI) were calculated from multivariable logistic regression models that included any ROP or severe ROP as outcome variable and any CVD or type of CVD as independent variable, with adjustment of covariates including birth weight (BW), gestational age (GA), and days on supplemental oxygen in the first month of postnatal life. RESULT: Among 3980 infants, 528 (13.3%) had CVD (304 had increased PBF, 101 had decreased PBF, and 49 had PPHN), 1643 (40.4%) developed ROP, and 503 (12.6%) developed severe ROP. In multivariable analyses, presence of CVD was not significantly associated with increased risk of any ROP (aOR = 1.15, 95% CI: 0.90-1.46, p = .26) or severe ROP (aOR = 0.98, 95% CI: 0.72-1.34, p = .92). However, there were trends associating CVD resulting in increased PBF with a higher risk of ROP (aOR = 1.32, 95% CI: 0.97-1.80, p = .08) and PPHN with a higher risk of severe ROP (aOR = 2.04, 95% CI: 0.96-4.35, p = .07). When adjusting only for BW and GA, these associations were significant (aOR = 1.47, 95% CI: 1.09-1.99, and aOR = 2.35, 95% CI: 1.19-4.65, respectively). CONCLUSION: CVD with increased PBF likely increases the risk of ROP. PPHN likely increases the risk of severe ROP.

Early Pathological and Magnetic Resonance Detection of Cerebral Injury Using a Rat Model of Neonatal Hypoxic Ischemic Encephalopathy.

Perinatal hypoxic-ischemic encephalopathy (HIE) is an acute disease that may afflict newborns, resulting in variable long- and short-term neurodevelopmental outcomes. Early diagnosis is critical to identifying infants who may benefit from intervention; however, early diagnosis relies heavily on clinical criteria. No molecular or radiological tests have shown promise in detecting early cerebral injury. Studies have shown that magnetic resonance imaging (MRI) can show changes in both blood flow/ischemia and metabolic disruption. However, they have all been used to evaluate the secondary phase of the disease (>12 h) after the onset of the injury. Early diagnosis is critical to rapidly starting therapeutic hypothermia in eligible infants, which is currently recommended to be initiated within 6 h of birth. The rat model of hypoxic-ischemic injury was developed in 1981 and has been validated and used extensively to study changes in brain perfusion, cerebral injury markers, and morphology. However, it has primarily been used as a "late model", evaluating injury several days after the initial ischemic insult. The model has been known to have poor sensitivity in evaluating reliable and reproducible early cerebral changes. The objective of this study was to develop a reliable model to study early gross morphological and radiological markers of HIE using pathological staining and cerebral magnetic resonance imaging/magnetic resonance spectroscopy.

An inhibitor of endothelial ETS transcription factors promotes physiologic and therapeutic vessel regression.

During the progression of ocular diseases such as retinopathy of prematurity and diabetic retinopathy, overgrowth of retinal blood vessels results in the formation of pathological neovascular tufts that impair vision. Current therapeutic options for treating these diseases include antiangiogenic strategies that can lead to the undesirable inhibition of normal vascular development. Therefore, strategies that eliminate pathological neovascular tufts while sparing normal blood vessels are needed. In this study we exploited the hyaloid vascular network in murine eyes, which naturally undergoes regression after birth, to gain mechanistic insights that could be therapeutically adapted for driving neovessel regression in ocular diseases. We found that endothelial cells of regressing hyaloid vessels underwent down-regulation of two structurally related E-26 transformation-specific (ETS) transcription factors, ETS-related gene (ERG) and Friend leukemia integration 1 (FLI1), prior to apoptosis. Moreover, the small molecule YK-4-279, which inhibits the transcriptional and biological activity of ETS factors, enhanced hyaloid regression in vivo and drove Human Umbilical Vein Endothelial Cells (HUVEC) tube regression and apoptosis in vitro. Importantly, exposure of HUVECs to sheer stress inhibited YK-4-279-induced apoptosis, indicating that low-flow vessels may be uniquely susceptible to YK-4-279-mediated regression. We tested this hypothesis by administering YK-4-279 to mice in an oxygen-induced retinopathy model that generates disorganized and poorly perfused neovascular tufts that mimic human ocular diseases. YK-4-279 treatment significantly reduced neovascular tufts while sparing healthy retinal vessels, thereby demonstrating the therapeutic potential of this inhibitor.

Temporal Profile of Retinopathy of Prematurity in Extremely Premature Compared to Premature Infants.

PURPOSE: To compare the time course of retinopathy of prematurity (ROP) in premature (≥ 28 to 34 weeks' gestational age) and extremely premature (< 28 weeks' gestational age) infants. METHODS: This study was a retrospective single-center chart review that included 582 eyes (122 premature, 464 extremely premature) of 299 infants (65 premature, 234 extremely premature) diagnosed as having ROP who were born between January 1, 2010, and December 31, 2015. Data collected were analyzed with shared frailty models, chi-square, and Fisher's exact tests. RESULTS: Extremely premature infants were diagnosed as having ROP earlier than premature infants at 33.6 weeks (95% CI [confidence interval]: 33.4 to 33.9) versus 36.0 weeks (95% CI: 34.7 to 36.4, P < .0001). The time from diagnosis to spontaneous regression was more than 4 weeks longer for extremely premature infants than premature infants with stage 1 ROP (82.0 vs 50.0 days, P < .0001), and more than 6 weeks longer for extremely premature infants than premature infants with stage 2 ROP (99 vs 55 days, P < .0001). Extremely premature infants had more bilateral ROP (96.6% vs 87.1%, P < .01) and were three times more likely to require treatment than premature infants (29.7% vs 9.9%, P < .0001). On average, infants who required treatment weighed 137 grams less at birth (P < .0001) and gained 37.7 grams less per week than infants who underwent spontaneous regression (P < .0001). CONCLUSIONS: Extremely premature infants developed ROP earlier, had more bilateral ROP, took longer to achieve spontaneous regression, and required treatment more often than premature infants. Infants who required treatment had a lower birth weight and rate of weight gain than infants who underwent spontaneous regression. [J Pediatr Ophthalmol Strabismus. 2019;56(2):116-123.].

rhIGF-1/rhIGFBP-3 in Preterm Infants: A Phase 2 Randomized Controlled Trial.

OBJECTIVE: To investigate recombinant human insulin-like growth factor 1 complexed with its binding protein (rhIGF-1/rhIGFBP-3) for the prevention of retinopathy of prematurity (ROP) and other complications of prematurity among extremely preterm infants. STUDY DESIGN: This phase 2 trial was conducted from September 2014 to March 2016. Infants born at a gestational age of 230/7 weeks to 276/7 weeks were randomly allocated to rhIGF-1/rhIGFBP-3 (250 µg/kg/ 24 hours, continuous intravenous infusion from <24 hours of birth to postmenstrual age 296/7 weeks) or standard neonatal care, with follow-up to a postmenstrual age of 404/7 weeks. Target exposure was ≥70% IGF-1 measurements within 28-109 µg/L and ≥70% intended therapy duration. The primary endpoint was maximum severity of ROP. Secondary endpoints included time to discharge from neonatal care, bronchopulmonary dysplasia, intraventricular hemorrhage, and growth measures. RESULTS: Overall, 61 infants were allocated to rhIGF-1/rhIGFBP-3, 60 to standard care (full analysis set); 24 of 61 treated infants achieved target exposure (evaluable set). rhIGF-1/rhIGFBP-3 did not decrease ROP severity or ROP occurrence. There was, however, a 53% decrease in severe bronchopulmonary dysplasia in the full analysis set (21.3% treated vs 44.9% standard care), and an 89% decrease in the evaluable set (4.8% vs 44.9%; P = .04 and P = .02, respectively) for severity distribution between groups. There was also a nonsignificant trend toward decrease in grades 3-4 intraventricular hemorrhage in the full analysis set (13.1% vs 23.3%) and in the evaluable set (8.3% vs 23.3%). Fatal serious adverse events were reported in 19.7% of treated infants (12/61) and 11.7% of control infants (7/60). No effect was observed on time to discharge from neonatal care/growth measures. CONCLUSIONS: rhIGF-1/rhIGFBP-3 did not affect development of ROP, but decreased the occurrence of severe bronchopulmonary dysplasia, with a nonsignificant decrease in grades 3-4 intraventricular hemorrhage. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01096784.

Retinal degeneration mutation in Sftpa1tm1Kor/J and Sftpd -/- targeted mice.

Surfactant proteins are important collectin immune molecules with a wide distribution throughout the body, including the ocular system. Mice with gene deletions for the surfactant protein genes Sftpa1 and Sftpd were observed to have visual impairment and thinning of the outer nuclear layers of the retina. We hypothesized that gene deletion of Sftpa1 and Sftpd (Sftpa1tm1Kor/J and Sftpd-/-) results in early retinal degeneration in these mice. Sftpa1tm1Kor/J and Sftpd-/- retinas were evaluated by histopathology and optical coherence tomography (OCT). Retinas from Sftpa1tm1Kor/J and Sftpd -/- mice showed early retinal degeneration with loss of the outer nuclear layer. After screening of mice for known retinal degeneration mutations, the mice were found to carry a previously unrecognized Pde6brd1 genotype which resulted from earlier breeding of the strain with Black Swiss mice during their generation. The mutation was outbred and the genotype of Sftpa1tm1Kor/J and Sftpd-/- was confirmed. Outbreeding of the Pde6brd1 mutation resulted in restoration of normal retinal architecture confirmed by in vivo and in vitro examination. We can therefore conclude that loss of Sftpa1 and Sftpd do not result in retinal degeneration. We have now generated retinal Sftpa1 and Sftpd targeted mice that exhibit normal retinal histology.

Structure, genetics and function of the pulmonary associated surfactant proteins A and D: The extra-pulmonary role of these C type lectins.

The collectins family encompasses several collagenous Ca2+-dependent defense lectins that are described as pathogen recognition molecules. They play an important role in both adaptive and innate immunity. Surfactant proteins A and D are two of these proteins which were initially discovered in association with surfactant in the pulmonary system. The structure, immune and inflammatory functions, and genetic variations have been well described in relation to their roles, function and pathophysiology in the pulmonary system. Subsequently, these proteins have been discovered in a wide range of other organs and organ systems. The role of these proteins outside the pulmonary system is currently an active area of research. This review intends to provide a current overview of the genetics, structure and extra-pulmonary functions of the surfactant collectin proteins.

Pulmonary surfactant protein a is expressed in mouse retina by Müller cells and impacts neovascularization in oxygen-induced retinopathy.

PURPOSE: Surfactant protein A (SP-A) up-regulates cytokine expression in lung disease of prematurity. Here we present data that for the first time characterizes SP-A expression and localization in the mouse retina and its impact on neovascularization (NV) in the mouse. METHODS: Retinal SP-A was localized in wild-type (WT) mice with the cell markers glutamine synthetase (Müller cells), neurofilament-M (ganglion cells), glial acid fibrillary acid protein (astrocytes), and cluster of differentiation 31 (endothelial cells). Toll-like receptor 2 and 4 (TLR-2 and TLR-4) ligands were used to up-regulate SP-A expression in WT and myeloid differentiation primary response 88 (MyD88) protein (necessary for NFκB signaling) null mouse retinas and Müller cells, which were quantified using ELISA. Retinal SP-A was then measured in the oxygen-induced retinopathy (OIR) mouse model. The effect of SP-A on retinal NV was then studied in SP-A null (SP-A(-/-)) mice. RESULTS: SP-A is present at birth in the WT mouse retina and colocalizes with glutamine synthetase. TLR-2 and TLR-4 ligands increase SP-A both in the retina and in Müller cells. SP-A is increased at postnatal day 17 (P17) in WT mouse pups with OIR compared to that in controls (P = 0.02), and SP-A(-/-) mice have reduced NV compared to WT mice (P = 0.001) in the OIR model. CONCLUSIONS: Retinal and Müller cell SP-A is up-regulated via the NFκB pathway and up-regulated during the hypoxia phase of OIR. Absence of SP-A attenuates NV in the OIR model. Thus SP-A may be a marker of retinal inflammation during NV.

Spatial and temporal localization of caveolin-1 protein in the developing retina.

Caveolin-1 (Cav-1), the signature protein of caveolae is expressed in several cell types in the adult retina and is linked to ocular pathologies including uveitis, diabetic retinopathy, and primary open angle glaucoma. Genetic ablation of Cav-1 causes retinal functional deficits due to disruptions in environmental homeostasis. To better understand Cav-1 function in the retina, we examined its expression/localization during postnatal retinal development. From P0-P5, Cav-1 was detected only in the developing superficial retinal vessels, in hyaloid and choroidal vasculature, and in the retinal pigment epithelium (RPE). At P7, staining began to be observed centrally in radial cells in the neuroretina, and this staining increased dramatically by P9/10 in identifiable Müller glia. Prominent vascular staining continued throughout development. These results support the idea that Cav-1 is an indicator of Müller glial differentiation and suggests that it plays an important role in Müller cell function.

Exon B of human surfactant protein A2 mRNA, alone or within its surrounding sequences, interacts with 14-3-3; role of cis-elements and secondary structure.

Human surfactant protein A, an innate immunity molecule, is encoded by two genes: SFTPA1 (SP-A1) and SFTPA2 (SP-A2). The 5' untranslated (5'UTR) splice variant of SP-A2 (ABD), but not of SP-A1 (AD), contains exon B (eB), which is an enhancer for transcription and translation. We investigated whether eB contains cis-regulatory elements that bind trans-acting factors in a sequence-specific manner as well as the role of the eB mRNA secondary structure. Binding of cytoplasmic NCI-H441 proteins to wild-type eB, eB mutant, AD, and ABD 5'UTR mRNAs were studied by RNA electromobility shift assays (REMSAs). The bound proteins were identified by mass spectroscopy and specific antibodies (Abs). We found that 1) proteins bind eB mRNA in a sequence-specific manner, with two cis-elements identified within eB to be important; 2) eB secondary structure is necessary for binding; 3) mass spectroscopy and specific Abs in REMSAs identified 14-3-3 proteins to bind (directly or indirectly) eB and the natural SP-A2 (ABD) splice variant but not the SP-A1 (AD) splice variant; 4) other ribosomal and cytoskeletal proteins, and translation factors, are also present in the eB mRNA-protein complex; 5) knockdown of 14-3-3 ß/α isoform resulted in a downregulation of SP-A2 expression. In conclusion, proteins including the 14-3-3 family bind two cis-elements within eB of hSP-A2 mRNA in a sequence- and secondary structure-specific manner. Differential regulation of SP-A1 and SP-A2 is mediated by the 14-3-3 protein family as well as by a number of other proteins that bind UTRs with or without eB mRNA.

17beta-Estradiol supplementation reduces tubulointerstitial fibrosis by increasing MMP activity in the diabetic kidney.

We previously reported that supplementation with 17beta-estradiol (E2) attenuates albuminuria, glomerulosclerosis, and tubulointerstitial fibrosis in diabetic nephropathy. The present study examined the mechanisms by which E2 regulates extracellular matrix (ECM) metabolism, a process that contributes to the development of glomerulosclerosis and tubulointerstitial fibrosis. The study was performed in female nondiabetic (ND), streptozotocin-induced diabetic (D), and diabetic with E2 supplementation (D+E2) Sprague-Dawley rats for 12 wk. Diabetes was associated with an increase in the renal expression of collagen alpha type IV [ND, 0.22 +/- 0.02; D, 0.99 +/- 0.09 relative optical density (ROD); P < 0.05] and fibronectin protein (ND, 0.36 +/- 0.08; D, 1.47 +/- 0.08 ROD; P < 0.05), as measured by Western blot analysis. E2 supplementation partially attenuated this increase in collagen alpha type IV (D+E2, 0.47 +/- 0.10 ROD) and fibronectin (D+E2, 0.71 +/- 0.16 ROD) protein expression associated with D. Diabetes was also associated with a decrease in the expression of matrix metalloproteinase (MMP) isoform MMP-2 (ND, 0.79 +/- 0.01; D, 0.62 +/- 0.06 ROD; P < 0.05) and MMP-9 protein (ND, 0.49 +/- 0.02; D, 0.33 +/- 0.03 ROD; P < 0.05). E2 supplementation restored MMP-2 and MMP-9 protein to levels similar or even greater than in the ND kidneys (MMP-2, 0.75 +/- 0.06; MMP-9, 0.73 +/- 0.01 ROD). The activities of MMP-2 (ND, 7.88 +/- 0.44; D, 5.60 +/- 0.54 ROD; P < 0.05) and MMP-9 (ND, 29.9 +/- 1.8; D, 12.9 +/- 2.3 ROD; P < 0.05), as measured by zymography, were also decreased with D. E2 supplementation restored MMP-2 and MMP-9 activity to levels similar to that in ND kidneys (MMP-2, 7.66 +/- 0.35; MMP-9, 21.4 +/- 2.9 ROD). We conclude that E2 supplementation is renoprotective by attenuating glomerulosclerosis and tubulointerstitial fibrosis by reducing ECM synthesis and increasing ECM degradation.

Mechanisms of antioxidant and pro-oxidant effects of alpha-lipoic acid in the diabetic and nondiabetic kidney.

BACKGROUND: alpha-Lipoic acid is a potent antioxidant that improves renal function in diabetes by lowering glycemia, however, the mechanisms by which alpha-lipoic acid exerts its antioxidant effects are not completely understood. METHODS: Metabolic parameters, renal function, and morphology, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and subunit expression were analyzed in nondiabetic and streptozotocin-induced diabetic rats fed normal rat chow (control) with or without alpha-lipoic acid (30 mg/kg body weight) for 12 weeks. RESULTS: Blood glucose was increased with diabetes (nondiabetic + control 89 +/- 3 mg/dL and diabetic + control 336 +/- 28 mg/dL) and was similar with alpha-lipoic acid treatment (diabetic +alpha-lipoic acid 351 +/- 14 mg/dL). In contrast, alpha-lipoic acid attenuated albuminuria (nondiabetic + control 8.9 +/- 1.3 mg/day; diabetic + control 28.1 +/- 4.6 mg/day; and diabetic +alpha-lipoic acid 17.8 +/- 1.2 mg/day) associated with diabetes. Similarly, alpha-lipoic acid attenuated glomerulosclerosis (nondiabetic + control 0.22 +/- 0.01; diabetic + control 0.55 +/- 0.04; diabetic +alpha-lipoic acid 0.36 +/- 0.03), tubulointerstitial fibrosis (nondiabetic + control 0.42 +/- 0.18; diabetic + control 1.52 +/- 0.05; diabetic +alpha-lipoic acid 1.10 +/- 0.05), superoxide anion (O(.-) (2)) generation (nondiabetic +control 15.8 +/- 1.7; diabetic +control 87.1 +/- 3.5; diabetic +alpha-lipoic acid 25.5 +/- 3.3 RLU/mg protein), and urine 8-isoprostane (8-iso) excretion (nondiabetic + control 7.4 +/- 1.4; diabetic + control 26.0 +/- 4.5; diabetic +alpha-lipoic acid 19.6 +/- 5.6 ng/day) associated with diabetes. alpha-Lipoic acid also reduced kidney expression of NADPH oxidase subunits p22phox and p47phox. Surprisingly, alpha-lipoic acid appears to cause pro-oxidant effects in nondiabetic animals, resulting in increased albuminuria (nondiabetic +alpha-lipoic acid 14.2 +/- 1.2 mg/day), increase in plasma creatinine levels (nondiabetic + control 59 +/- 6; diabetic + control 68 +/- 6; nondiabetic +alpha-lipoic acid 86 +/- 9; diabetic +alpha-lipoic acid 69 +/- 7 mumol/L), exacerbated glomerulosclerosis and tubulointerstitial fibrosis, increased O(.-) (2) generation, up-regulated p22phox and p47phox expression and increased 8-iso excretion. CONCLUSION: We conclude that alpha-lipoic acid improves albuminuria and pathology in diabetes by reducing oxidative stress, while in healthy animals, alpha-lipoic acid may act as a pro-oxidant, contributing to renal dysfunction.

Diabetic nephropathy is associated with decreased circulating estradiol levels and imbalance in the expression of renal estrogen receptors.

BACKGROUND: The incidence of cardiovascular and renal disease is lower in premenopausal women than in aged-matched men. However, in the setting of diabetes mellitus (DM), this "female advantage" no longer exists: the incidence and progression of DM and its associated end-organ complications are equal in men and women, regardless of age. We have recently reported that estrogen supplementation attenuates the progression of diabetic nephropathy, suggesting that lack of estrogen may nullify female sex as a protective factor against DM. OBJECTIVE: This study examined circulating levels of estradiol in DM and expression of estrogen receptor subtypes (ERa and ERP) in the nondiabetic (ND) and diabetic (D) kidney. METHODS: : The study was performed in ND and streptozotocin-induced D Sprague-Dawley rats after 2 weeks (male and female) and 12 weeks (female) of DM. The animals (N = 8/group) were kept either intact, ovariectomized (OVX), or OVX with 17beta-estradiol (E(2)) supplementation (OVX + E(2), 5 mug/kg/d). Plasma estradiol levels were measured by enzyme-linked immunosorbent assay, and expression of renal ERalpha and ERbeta was measured by immunohistochemistry and Western blot analysis. RESULTS: DM was associated with reduced circulating estradiol levels (ND: mean [SEM] 37.1 [7.2]; D: 24.5 [9.3] pg/mL; P < 0.05). The diabetic kidney exhibited increased expression of ERalpha protein (ND: 0.82 [0.06]; D: 1.15 [0.09] arbitrary units; P < 0.05), but no differences in ERP were observed. This resulted in an overall increase in the ratio of ERalpha/ERbeta protein expression in the diabetic kidney. No differences in the expression of ERa were observed in either females or males with similar glycemic levels after 2 weeks of DM. CONCLUSIONS: Reduced circulating levels of estradiol and imbalance in the expression of estrogen receptor subtypes in the diabetic kidney may explain why female sex is no longer a protective factor in the setting of DM. Thus, estradiol supplementation may be an effective regimen in attenuating the onset and progression of diabetic renal complications.

17beta-Estradiol replacement improves renal function and pathology associated with diabetic nephropathy.

The protective factor of female gender appears to be lost in diabetes; the incidence of diabetes and its complications, including diabetic nephropathy, are equal in women and men. This study examined the effects of estrogen deficiency by ovariectomy (OVX) and replacement with 17beta-estradiol (OVX+E2) on renal function and pathology in the nondiabetic (ND) and streptozotocin (STZ)-induced diabetic (D) rat kidneys for 12 wk. Diabetes was associated with an increase in urine albumin excretion (UAE; ND, 0.39 +/- 0.03; D, 5.9 +/- 0.8 mg/day; P < 0.001), decrease in creatinine clearance (CrCl; ND, 0.69 +/- 0.03; D, 0.43 +/- 0.09 mg x min(-1) x 100 g body wt(-1); P < 0.05), increase in the index of glomerulosclerosis [GSI; ND, 0.01 +/- 0.01; D, 0.15 +/- 0.04 arbitrary units (AU); P < 0.01], tubulointerstitial fibrosis (TIFI; ND, 0.04 +/- 0.04; D, 0.68 +/- 0.2 AU; P < 0.01), and transforming growth factor-beta (TGF-beta) protein expression (ND, 0.61 +/- 0.02; D, 1.25 +/- 0.07 AU; P < 0.01). In the D group, the severity of these changes was augmented with OVX (UAE, 8.1 +/- 0.6 mg/day; CrCl, 0.40 +/- 0.04 mg x min(-1) x 100 g body wt(-1); GSI, 0.29 +/- 0.04 AU; TIFI, 0.90 +/- 0.06 AU; TGF-beta, 1.26 +/- 0.10 AU), whereas E2 replacement attenuated these changes (UAE, 6.3 +/- 0.8 mg/day; CrCl, 0.66 +/- 0.03 mg x min(-1) x 100 g body wt(-1); GSI, 0.06 +/- 0.02 AU; TIFI, 0.36 +/- 0.08 AU; TGF-beta, 0.57 +/- 0.08 AU). We conclude that E2 deficiency increases the severity of renal disease in a diabetic animal model and that E2 replacement is renoprotective by attenuating the decline in renal function and pathology associated with diabetes.